Polycarbonate block copolymers

Abstract

The disclosure pertains to amphiphilic block copolymers comprising an aliphatic polycarbonate chain coupled to a hydrophilic polymer. Such amphiphilic polymers may have the formula A-L-B, where A- is a polycarbonate or polyethercarbonate chain having from about 3 to about 500 repeating units, L is a linker moiety and -B is a hydrophilic oligomer having from about 4 to about 200 repeating units. Provided copolymers are useful as surfactants capable of emulsifying aqueous solutions and supercritical carbon dioxide. Provided copolymers also have utility as additives for use in enhanced oil recovery methods.

Claims

1. A method of enhancing product recovery from oil wells by introducing a solution comprising a block copolymer, A-L-B, to an oil containing geological formation, wherein: A is a polycarbonate or polyether carbonate chain having from about 3 to about 500 repeating units; L is a bond or polyfunctional moiety; and B is a hydrophilic oligomer having from about 4 to about 500 repeating units.

2. The method of claim 1 comprising the step of pumping the solution comprising a block copolymer into an oil well.

3. The method of claim 1, wherein the solution comprising a block copolymer is introduced in combination with supercritical CO.sub.2.

4. The method of claim 3, wherein the supercritical CO.sub.2 is combined with water or brine to form an emulsion capable of flushing trapped oil from the geological formation.

5. The method of claim 1, wherein the block copolymer, A-L-B is represented by structural formula: ##STR00115## where X is selected from the group consisting of: halogen, —OH, azide, nitrile, and —OR.sup.z; each R.sup.a, R.sup.b, R.sup.c, and R.sup.d is independently selected from the group consisting of: hydrogen, halogen, —CH.sub.2OR.sup.z, optionally substituted C.sub.1-10 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, and where any two or more of R.sup.a, R.sup.b, R.sup.c, and R.sup.d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms; L is a bond or a polyfunctional moiety; B is a hydrophilic oligomer having from about 4 to about 100 repeating units; n is an integer between 4 and 100; R.sup.z is selected from the group consisting of R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2; and R.sup.10 is an optionally substituted moiety selected from the group consisting of: C.sub.1-20 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

6. The method of claim 5, wherein X is selected from the group consisting of: halogen, azide, nitrile, and —OR.sup.z.

7. The method of claim 5, wherein the block copolymer has the formula: ##STR00116## wherein, R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, and —CH.sub.2Cl.

8. The method of claim 7, wherein the block copolymer has the formula: ##STR00117## wherein X′ is selected from the group consisting of —OH and —OR.sup.z.

9. The method of claim 7, wherein R.sup.100 is a methyl group.

10. The method of claim 7, wherein R.sup.100 is a random mixture of methyl groups and one or more moieties selected from group consisting of ethyl, trifluoromethyl, chloromethyl, —CH.sub.2OR.sup.z and a C.sub.6-30 alkyl group.

11. The method of claim 5, wherein X is —OH.

12. The method of claim 5, wherein -B is selected from the group consisting of: polyethers, polyolefin bearing hydrophilic functional groups, polypeptides, polysaccharides and polyamines.

13. The method of claim 12, wherein -B is a polyether.

14. The method of claim 5, wherein the block copolymer has the formula: ##STR00118## wherein, m is an integer between 5 and 200; R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, and —CH.sub.2Cl; —Z— is an optionally substituted C.sub.1-6 aliphatic group; and —Y is selected from the group consisting of —H and R.sup.z.

15. The method of claim 14, wherein the copolymer is selected from the group consisting of: ##STR00119##

16. The method of claim 14, wherein —Z— is —CH.sub.2CH.sub.2—.

17. The method of claim 14, wherein —Z— is —CH(CH.sub.3)CH.sub.2—.

18. The method of claim 14, wherein the copolymer has the formula: ##STR00120## wherein X′, is —OH or —OR.sup.z, and Y′ is selected from the group consisting of optionally substituted C.sub.1-8 aliphatic, a silyl protecting group, —H, and —C(O)R.sup.10.

19. The method of claim 14, wherein the block copolymer comprises poly(propylene carbonate) and poly(ethylene glycol).

20. The method of claim 18, wherein the block copolymer is selected from the group consisting of: ##STR00121## ##STR00122##

21. The method of claim 1, wherein the solution comprises a block copolymer having a formula: ##STR00123## wherein X′ is selected from the group consisting of —OH and —OR.sup.z; R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, and —CH.sub.2Cl; each n is independently an integer between 4 and 100; —Z— is an optionally substituted C.sub.1-6 aliphatic group; m is an integer between 5 and 200; R.sup.z is selected from the group consisting of R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2; and R.sup.10 is at each occurrence an optionally substituted moiety independently selected from the group consisting of: C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

22. The method of claim 21, wherein at least one X′ is —OR.sup.z.

23. The method of claim 21, wherein the copolymer is selected from the group consisting of: ##STR00124## ##STR00125##

24. The method of claim 1, wherein the solution comprises a block copolymer having the formula B-A-B, wherein -A- is a polycarbonate chain having from about 3 to about 500 repeating units and each B is independently a hydrophilic oligomer having from about 4 to about 200 repeating units, wherein B is selected from the group consisting of: polyethers, polyolefin bearing hydrophilic functional groups, polypeptides, polysaccharides, and polyamines.

25. The method of claim 24, wherein -B is a polyether.

26. The method of claim 24, wherein -A- is poly(propylene carbonate).

27. The method of claim 24, wherein -A- is poly(ethylene carbonate).

28. The method of claim 25, wherein the triblock copolymer has a formula: ##STR00126## wherein —Z— is an optionally substituted C.sub.1-6 aliphatic group, —Y is selected from the group consisting of —H and R.sup.z; each R.sup.a, R.sup.b, R.sup.c, and R.sup.d is independently selected from the group consisting of: hydrogen, halogen, —CH.sub.2OR.sup.z, optionally substituted C.sub.1-10 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, and wherein any two or more of R.sup.a, R.sup.b, R.sup.c, and R.sup.d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms, each L is independently a bond or a polyfunctional moiety, n is an integer between 4 and 100, m is an integer between about 4 and about 500, m′ is, on average approximately equal to m, R.sup.z is selected from the group consisting of R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2, and R.sup.10 is an optionally substituted moiety selected from the group consisting of: C.sub.1-20 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

29. The method of claim 28, wherein the triblock copolymer has a formula: ##STR00127##

30. The method of claim 29, wherein the copolymer has a formula: ##STR00128## wherein R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, —CH.sub.2Cl, a C.sub.3-30 alkyl group, and mixtures of two or more of these.

31. The method of claim 29, wherein Y is —H.

32. The method of claim 30, wherein R.sup.100 is absent.

33. The method of claim 30, wherein R.sup.100 is methyl.

34. The method of claim 30, wherein R.sup.100 comprises a random mixture of methyl and one or more C3-30 alkyl groups.

35. The method of claim 28, wherein the value of n is selected from the group consisting of: between about 3 and about 50; between about 3 and about 25; between about 10 and about 20; and between about 3 and about 10.

36. The method of claim 28, wherein the value of m is selected from the group consisting of: between about 5 and about 200; between about 5 and about 50; between about 5 and about 25; between about 10 and about 20; and between about 5 and about 10.

37. The method of claim 24, wherein -A- contains greater than about 95% carbonate linkages.

38. The method of claim 24, wherein the triblock copolymer has the formula: ##STR00129## wherein n is an integer between 4 and 100, m is an integer between about 4 and about 500, m′ is, on average approximately equal to m; R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sup.2OR.sup.z, and —CH.sub.2Cl; each R.sup.z is independently R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, or —C(O)N(R.sup.10).sub.2; and each R.sup.10 is independently optionally substituted C.sub.1-20 aliphatic, optionally substituted C.sub.1-12 heteroaliphatic, optionally substituted 6- to 14-membered aryl, or optionally substituted 5- to 14-membered heteroaryl.

39. The method of claim 38, wherein R.sup.100 is absent.

40. The method of claim 38, wherein R.sup.100 is methyl.

41. The method of claim 24, wherein the triblock copolymer has the formula: ##STR00130## wherein n is an integer between 4 and 100, m is an integer between about 4 and about 500, m′ is, on average approximately equal to m; and R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sup.2OR.sup.z, and —CH.sub.2Cl; each R.sup.z is independently R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, or —C(O)N(R.sup.10).sub.2; and each R.sup.10 is independently optionally substituted C.sub.1-20 aliphatic, optionally substituted C.sub.1-12 heteroaliphatic, optionally substituted 6- to 14-membered aryl, or optionally substituted 5- to 14-membered heteroaryl.

42. The method of claim 41, wherein R.sup.100 is absent.

43. The method of claim 41, wherein R.sup.100 is methyl.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 depicts supercritical CO.sub.2 solubility of a composition of the present invention comprising a diblock copolymer of poly(propylene carbonate) (PPC) and poly(ethylene glycol) (PEG).

(2) FIG. 2 depicts supercritical CO.sub.2 solubility of a composition of the present invention comprising a diblock copolymer of PPC and PEG.

(3) FIG. 3 depicts supercritical CO.sub.2 solubility of a composition of the present invention comprising a diblock copolymer of PPC and PEG.

(4) FIG. 4 depicts supercritical CO.sub.2 solubility of a composition of the present invention comprising a triblock copolymer of PPC and PEG.

(5) FIG. 5 shows the stability over time of CO.sub.2/water foams stabilized by PPC/PEG diblock co-polymers (28-34A) and PPC/PEG/PPC triblock copolymers (28-53B-53C and -53D) of the present invention where the bottom half of the y-axis represents the depth of foam in the aqueous phase, and the upper half of the y-axis represents the height of foam in the supercritical CO.sub.2 phase.

(6) FIG. 6 shows the stability over time of CO.sub.2/water foams stabilized by PPC/PPG/PPC triblock copolymers of the present invention where each block in the copolymer comprises between 3 and 12 repeat units.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

(7) The present disclosure encompasses the recognition that block copolymers comprising a polycarbonate chain have utility in a number of applications involving interaction with CO.sub.2. In some embodiments, the present disclosure provides copolymers and compositions thereof comprising a polycarbonate or a polyether-polycarbonate chain, methods of making, and methods of using the same.

(8) In certain embodiments, provided block copolymers of formula A-L-B, where A- is a polycarbonate or a polyether-polycarbonate chain having from about 3 to about 500 repeating units, L is a linker moiety or a covalent bond and -B is a hydrophilic oligomer having from about 4 to about 500 repeating units.

(9) In some embodiments, A- is a polycarbonate chain. In some embodiments, A- is a polycarbonate chain containing greater than about 95%, greater than about 98%, or greater than about 99% carbonate linkages. In some embodiments, A- is an aliphatic polycarbonate chain. In certain embodiments, the aliphatic polycarbonate is a copolymer of an optionally substituted epoxide and carbon dioxide. In certain embodiments, the polycarbonate is selected from the group consisting of poly(ethylene carbonate), poly(propylene carbonate), poly(butylene carbonate), poly(glycidylether carbonate), poly(chloromethylethylene carbonate), poly(cyclopentene carbonate), poly(cyclohexene carbonate), poly(3-vinyl cyclohexene carbonate) and random-, block- or tapered-copolymers of any two or more of the above.

(10) In certain embodiments, a polycarbonate chain A- is poly(propylene carbonate). In certain embodiments, a polycarbonate chain A- is poly(ethylene carbonate). In certain embodiments, a polycarbonate chain A- is poly(chloromethylethylene carbonate). In certain embodiments, a polycarbonate chain A- is poly(butylene carbonate). In certain embodiments, a polycarbonate chain A- is a poly(glycidyl ether carbonate). In certain embodiments, a polycarbonate chain A- is a poly(glycidyl ester carbonate). In certain embodiments, a polycarbonate chain A- is a random copolymer comprising poly(propylene carbonate) and poly(ethylene carbonate). In some embodiments, a polycarbonate chain A- is a random copolymer comprising poly(propylene carbonate) and poly(n-butylene carbonate). In certain embodiments, a polycarbonate chain A- is a random copolymer comprising poly(propylene carbonate) and a polycarbonate derived from the epoxide of a C.sub.6-30 alpha olefin.

(11) In certain embodiments, a polycarbonate chain A- includes about 3 to about 500 repeating units. In certain embodiments, a polycarbonate chain includes about 5 to about 50 repeating units. In certain embodiments, a polycarbonate chain includes about 3 to about 20 repeating units. In certain embodiments, a polycarbonate chain includes about 10 to about 15 repeating units. In certain embodiments, a polycarbonate chain includes about 20 to about 50 repeating units.

(12) In some embodiments, a polymer chain A- is a random or tapered polyether polycarbonate copolymer. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 50%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A-ranges from about 0.1% to about 44%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 43%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 42%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 41%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 40%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 35%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 30%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 25%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 20%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 15%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 10%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 5%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 2%.

(13) In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 50%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 44%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 43%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 42%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 41%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 40%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 35%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 30%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 25%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 20%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 15%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 10%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 9%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 8%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 7%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 6%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 5%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 4%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 3%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 2%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- is less than 1%.

(14) In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 0.1% to about 25%. In certain embodiments the proportion of ether linkages in a polyether polycarbonate chain A- is less than about 10%. In certain embodiments the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 1% to about 5%. In certain embodiments, the proportion of ether linkages in a polyether polycarbonate chain A- ranges from about 20% to about 50%.

(15) In certain embodiments, L is a covalent bond (i.e. A- is bonded directly to -B). In other embodiments, L is a polyfunctional moiety having appropriate functionality to form a covalent chemical bond with both the polycarbonate chain and the hydrophilic oligomer. In certain instances, L is a moiety formed by the reaction of one functional group on A- and one functional group on -B with a polyfunctional molecule capable of reaction with the functional groups on A- and -B thereby linking them. Examples of suitable polyfunctional moieties for L include, but are not limited to: agents that can form one or more linkages such as ester, amide, ether, amine, thioether, carbonate, or other similar linkages. Examples of polyfunctional molecules suitable for incorporation as L include, but are not limited to: phosgene, diacids, anhydrides, acrylates, diisocyanates, epoxides, diols, diamines, hydroxy mercaptans, mercapto acids, hydroxy acids, amino acids, and any precursors or reactive equivalents thereof.

(16) In certain embodiments, a linker L is a moiety formed directly by the reaction of complementary functional groups on termini of A- and -B. Examples of such moieties include, but are not limited to: L being an ester, (formed from an alcohol group on the terminus of A- and a carboxy group on the terminus of -B, or vice versa); L being an amide; (formed from an amine group on the terminus of A- and a carboxy group on the terminus of -B, or vice versa); L being an olefin (formed, for example, by olefin metathesis); L being a heterocycle, (for example a triazole formed by cycloaddition of an azide and an alkyne), and L being a cyclohexene ring formed by Diels Alder cycloaddition of a diene and a dienophile.

(17) In certain embodiments, a hydrophilic oligomer -B is a polyether chain. In some embodiments, -B is a polyolefin chain bearing hydrophilic functional groups. In certain embodiments, a hydrophilic oligomer -B is a polyamine chain. In certain embodiments, -B is selected from the group consisting of polyoxymethylene, poly(ethylene oxide), poly(propylene oxide), polyvinyl alcohol, poly(vinyl acetate), partially hydrolyzed poly(vinyl acetate), poly(acrylic acid), polyacrylamide, polyethyleneimine, poly(2-hydroxyethyl methacrylate), poly(N-vinylpyrrolidone), polypeptides, polysaccharides, polyepoxysuccinic acid, poly(methyl vinyl ether), poly(allylamine), poly(2-ethyl-2-oxazoline), and block, tapered or random copolymers of any two or more of the above. In some embodiments, -B is polyoxymethylene. In some embodiments, -B is poly(ethylene oxide). In some embodiments, -B is poly(propylene oxide).

(18) In certain embodiments, a hydrophilic oligomer -B includes from about 4 to about 400 repeating units. In certain embodiments, a hydrophilic oligomer chain includes less than about 100 repeating units. In certain embodiments, a hydrophilic oligomer chain includes about 10 to about 50 repeating units. In certain embodiments, a hydrophilic oligomer chain includes about 10 to about 20 repeating units.

(19) In certain embodiments, polymers of the present invention have a total average molecular weight between about 300 g/mol and about 25,000 g/mol. In certain embodiments, polymers have a total average molecular weight between about 500 g/mol and about 5,000 g/mol. In some embodiments, polymers have a total average molecular weight between about 800 g/mol and about 2,500 g/mol.

(20) Polycarbonates

(21) In certain embodiments, a polymer A-L-B has the formula I:

(22) ##STR00002## where X is selected from the group consisting of: halogen; —OH; azide, nitrile, and —OR.sup.z; each R.sup.a, R.sup.b, R.sup.c, and R.sup.d is independently selected from the group consisting of: hydrogen, halogen, —CH.sub.2OR.sup.z, optionally substituted C.sub.1-30 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, where any two or more of R.sup.a, R.sup.b, R.sup.c, and R.sup.d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms; L is a bond or a polyfunctional moiety; B is a hydrophilic oligomer having from 4 to 100 repeating units; n is an integer between 3 and 100; R.sup.z is selected from the group consisting of R.sup.10, —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, and —C(O)N(R.sup.10).sub.2; and R.sup.10 is an optionally substituted moiety selected from the group consisting of: C.sub.1-20 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

(23) In certain embodiments, polymers of formula I comprise a polycarbonate chain containing greater than about 90% carbonate linkages. In certain embodiments, the polycarbonate chain contains greater than about 95%, greater than about 98%, or greater than about 99% carbonate linkages. In certain embodiments, the polycarbonate chain contains essentially no detectable ether linkages.

(24) In certain embodiments, the polymer A-L-B has the formula I-a:

(25) ##STR00003##
where X, L, B, and n are as defined above, and R.sup.100 is optionally present, and if present is selected from the group consisting of CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, —CH.sub.2Cl, a C.sub.3-30 alkyl group, and mixtures of two or more of these where R.sup.z is as defined above.

(26) In certain embodiments, a polymer A-L-B has the formula I-b:

(27) ##STR00004##
where X, L, B, R.sup.100, and n are as defined above.

(28) In certain embodiments, a polymer A-L-B has formula I-c:

(29) ##STR00005##
where
L, B, R.sup.100, and n are as defined above, and X′ is selected from the group consisting of —OH and —OR.sup.z.

(30) In certain embodiments, where a polymer has one of the formulae I-b or I-c, where R.sup.100 is present, the head to tail ratio of adjacent

(31) ##STR00006##
groups is greater than about 80%. In certain embodiments, the head to tail ratio is greater than about 90%. In certain embodiments, the head to tail ratio is greater than about 91%. In certain embodiments, the head to tail ratio is greater than about 92%. In certain embodiments, the head to tail ratio is greater than about 93%. In certain embodiments, the head to tail ratio is greater than about 94%. In certain embodiments, the head to tail ratio is greater than about 95%.

(32) In certain embodiments, in polymers of formulae I-a through I-c R.sup.100 is absent (e.g. the polycarbonate chain comprises poly(ethylene carbonate). In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a methyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a C.sub.3-30 alkyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a C.sub.3-10 alkyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a C.sub.3-6 alkyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is an ethyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a chloromethyl group. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a random mixture of methyl and ethyl groups. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a random mixture of methyl and chloromethyl groups. In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a random mixture of methyl and one or more C.sub.3-30 alkyl groups.

(33) In certain embodiments, in polymers of formulae I-a through I-c, R.sup.100 is a —CH.sub.2OR.sup.z group. In certain embodiments, the CH.sub.2OR.sup.z group comprises an ether group (e.g. the polycarbonate chain is a poly(glycidyl ether carbonate)). In other embodiments the CH.sub.2OR.sup.z group comprises an ester group (e.g. the polycarbonate chain is a poly(glycidyl ester carbonate)). In certain embodiments, R.sup.100 is a random mixture of C.sub.3-30 alkyl and —CH.sub.2OR.sup.z groups.

(34) In certain embodiments, for polymers of formula I-b, X is —OR.sup.10. In other embodiments, for polymers of formula I-b, X is —OC(O)R.sup.10. In certain embodiments, for polymers of formula I-b, X is Cl, or Br. In certain embodiments, for polymers of formula I-b, X is azide or a nitrile. In certain embodiments, for polymers of formula I-b, X is acetate. In certain embodiments, for polymers of formula I-b, X is trifluoroacetate. In certain embodiments, for polymers of formula I-b, X is optionally substituted benzoate. In certain embodiments, for polymers of formulae I-b, X is optionally substituted phenoxide. In certain embodiments, for polymers of formulae I-b, X is a nitro phenoxide.

(35) In certain embodiments, for polymers of formulae I-c, X′ is —OH. In certain embodiments, for polymers of formulae I-c, X′ is —OR.sup.y, where R.sup.y is an —OH protecting group. In certain embodiments, for polymers of formulae I-c, X′ is —OC(O)R.sup.10. In certain embodiments, for polymers of formulae I-c, X′ is —OS(O).sub.2R.sup.10. In certain embodiments, for polymers of formulae I-c, X′ is —OSi(R.sup.10).sub.3. In certain embodiments, for polymers of formulae I-c, X′ is —OC(O)N(R.sup.10).sub.2. In certain embodiments, for polymers of formulae I-c, X′ is acetate. In certain embodiments, for polymers of formulae I-c, X′ is trifluoroacetate. In certain embodiments, for polymers of formulae I-c, X′ is optionally substituted benzyl or benzoate.

(36) The present invention encompasses polymer compositions comprising polymer chains of formulae I through I-c above wherein the value of n is, on average, between about 5 and about 200. In certain embodiments, the value of n is, on average between about 5 and about 100. In certain embodiments, the value of n is, on average between about 5 and about 50. In certain embodiments, the value of n is, on average between about 5 and about 25. In certain embodiments, the value of n is, on average between about 5 and about 10. In certain embodiments, the value of n is, on average between about 10 and about 20.

(37) In certain embodiments, a polymer A-L-B has the formula II:

(38) ##STR00007##
where A and L are as defined above,
m is an integer between about 4 and about 500,
—Z— is an optionally substituted C.sub.1-6 aliphatic group, and
—Y is selected from the group consisting of —H and R.sup.z.

(39) In certain embodiments, a polymer A-L-B has the formula II-a:

(40) ##STR00008##
where X, R.sup.a, R.sup.b, R.sup.c, R.sup.d, n, L, Z, m, and Y are as defined above.

(41) In certain embodiments, a polymer A-L-B has the formula II-b:

(42) ##STR00009##
where X, R.sup.100, n, L, Z, m, and Y are as defined above.

(43) In certain embodiments, a polymer A-L-B has the formula II-c:

(44) ##STR00010##
where R.sup.100, n, L, Z, and m are as defined above and wherein X is other than —OH.

(45) In certain embodiments, a polymer A-L-B has the formula II-d:

(46) ##STR00011## where X′, R.sup.100, n, L, Z, and m are as defined above, and Y′ is optionally substituted C.sub.1-8 aliphatic, a silyl protecting group, or —C(O)R.sup.11, wherein R.sup.11 is optionally substituted C.sub.1-14 aliphatic or 6- to 14-membered aryl.

(47) In certain embodiments, for polymers of formulae II through II-d, Z is —CH.sub.2— (e.g. the hydrophilic oligomer -B is polyoxymethylene). In certain embodiments, for polymers of formulae II through II-d, Z is —CH.sub.2CH.sub.2— (e.g. the hydrophilic oligomer -B is polyethylene glycol). In certain embodiments, for polymers of formulae II through II-d, Z is —CH(CH.sub.3)CH.sub.2— (e.g. the hydrophilic oligomer -B is polypropylene glycol).

(48) In certain embodiments, in polymers of formulae II, II-a, or II-b, —Y is an optionally substituted C.sub.1-20 aliphatic group. In certain embodiments, Y is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl. In certain embodiments, in polymers of formulae II, II-a or II-b, —Y is an acyl group. In certain embodiments, Y is selected from the group consisting of formate, acetate, trifluoroacetate, propionate, butyrate, acrylate, and optionally substituted benzoate. In certain embodiments, in polymers of formulae II, II-a or II-b, —Y is —Si(R.sup.10).sub.3. In certain embodiments, in polymers of formulae II, II-a or II-b, —Y is a silyl protecting group. In certain embodiments, Y is selected from the group consisting of trimethylsilyl, triethylsilyl, triisopropyl silyl, t-butyldimethylsilyl, and t-butyldiphenylsilyl. In certain embodiments, in polymers of formulae II, II-a or II-b, —Y is —H.

(49) In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is absent (e.g. the polycarbonate chain comprises poly(ethylene carbonate). In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a C.sub.3-30 alkyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a C.sub.3-10 alkyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a C.sub.3-6 alkyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a methyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is an ethyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a random mixture of methyl and ethyl groups. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a chloromethyl group. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a random mixture of methyl and chloromethyl groups. In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a random mixture of methyl and one or more C.sub.3-30 alkyl groups. In certain embodiments, R.sup.100 is partially absent, wherein one or more n-bracketed repeating units comprise no R.sup.100 group, while the remaining n-bracketing repeating units comprise a R.sup.100 group.

(50) In certain embodiments, in polymers of formulae II-b through II-d, R.sup.100 is a —CH.sub.2OR.sup.z group. In certain embodiments, the CH.sub.2OR.sup.z group comprises an ether group (e.g. the polycarbonate chain is a poly(glycidyl ether carbonate)). In other embodiments the CH.sub.2OR.sup.z group comprises an ester group (e.g. the polycarbonate chain is a poly(glycidyl ester carbonate)). In certain embodiments, R.sup.100 is a random mixture of methyl and —CH.sub.2OR.sup.z groups.

(51) In certain embodiments, the present invention encompasses polymer compositions comprising polymer chains of formulae II through II-d above wherein the value of n is, on average, between about 5 and about 200. In certain embodiments, the value of n is, on average between about 5 and about 100. In certain embodiments, the value of n is, on average between about 5 and about 50. In certain embodiments, the value of n is, on average between about 5 and about 25. In certain embodiments, the value of n is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 5 and about 10.

(52) In certain embodiments, the present invention encompasses polymer compositions comprising polymer chains of formulae II through II-d above wherein the value of m is, on average, between about 4 and about 500. In certain embodiments, the value of m is, on average between about 5 and about 200. In certain embodiments, the value of m is, on average between about 5 and about 50. In certain embodiments, the value of m is, on average between about 5 and about 25. In certain embodiments, the value of m is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 5 and about 10.

(53) In certain embodiments, where the polymer has one of the formulae II-c or II-d, and R.sup.100 is present, the head to tail ratio of adjacent

(54) ##STR00012##
groups is greater than about 80%. In certain embodiments, the head to tail ratio is greater than about 90%. In certain embodiments, the head to tail ratio is greater than about 91%. In certain embodiments, the head to tail ratio is greater than about 92%. In certain embodiments, the head to tail ratio is greater than about 93%. In certain embodiments, the head to tail ratio is greater than about 94%. In certain embodiments, the head to tail ratio is greater than about 95%.

(55) In certain embodiments, copolymers of formula A-L-B described above are characterized in that they have narrow polydispersity indices. In some embodiments, the PDIs of block copolymers of the present invention are less than about 2. In certain embodiments, the PDI is less than 1.5. In some embodiments, the PDI is less than 1.4, less than 1.2 or less than about 1.1.

(56) In certain embodiments, a polymer A-L-B is a block copolymer of polypropylene carbonate) (PPC) or a derivative thereof and poly(ethylene glycol) (PEG) or a derivative thereof. In certain embodiments, such PPC-PEG block copolymers have a formula selected from the group consisting of:

(57) ##STR00013## ##STR00014## ##STR00015## ##STR00016##

(58) In certain embodiments, a polymer A-L-B is a block copolymer of poly(propylene carbonate) (PPC) or a derivative thereof and poly(propylene glycol) (PPG) or a derivative thereof. In certain embodiments, such PPC-PPG block copolymers have a formula selected from the group consisting of:

(59) ##STR00017## ##STR00018## ##STR00019##

(60) In certain embodiments, a polymer A-L-B is a block copolymer of poly(propylene carbonate) (PPC) or a derivative thereof and polyoxymethylene (POM) or a derivative thereof. In certain embodiments, such PPC-POM block copolymers have a formula selected from the group consisting of:

(61) ##STR00020## ##STR00021## ##STR00022##

(62) In certain embodiments, a polymer A-L-B is a block copolymer of poly(ethylene carbonate) (PEC) or a derivative thereof and poly(ethylene glycol) (PEG) or a derivative thereof. In certain embodiments, such PEC-PEG block copolymers have a formula selected from the group consisting of:

(63) ##STR00023##

(64) In certain embodiments, a polymer A-L-B is a block copolymer of poly(ethylene carbonate) (PEC) or a derivative thereof and polypropylene glycol (PPG) or a derivative thereof. In certain embodiments, such PEC-PPG block copolymers have a formula selected from the group consisting of:

(65) ##STR00024## ##STR00025## ##STR00026##

(66) In certain embodiments, a polymer A-L-B is a block copolymer of poly(ethylene carbonate) (PEC) or a derivative thereof and polyoxymethylene (POM) or a derivative thereof. In certain embodiments, such PEC-POM block copolymers have a formula selected from the group consisting of:

(67) ##STR00027## ##STR00028##

(68) In certain embodiments, a polymer A-L-B is a block copolymer of an aliphatic polycarbonate (APC) and a polyether, wherein the APC comprises a random copolymer such as those derived from copolymerization of two or more different epoxides and carbon dioxide. In certain embodiments, such block copolymers comprise PEG (poly(ethylene glycol)), polypropylene glycol), or polyoxymethylene.

(69) In certain embodiments, APC-PEG block copolymers have a formula selected from the group consisting of:

(70) ##STR00029## ##STR00030## ##STR00031##
wherein
R.sup.1 is a mixture of two or more moieties selected from the group consisting of —H, methyl, ethyl, C.sub.3-30 alkyl, CH.sub.2Cl, CF.sub.3, and CH.sub.2OR.sup.z.

(71) In certain embodiments, R.sup.1 is a mixture of methyl and ethyl groups. In some embodiments, R.sup.1 is a mixture of —H and methyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.3-6 alkyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.6-24 alkyl groups.

(72) In certain embodiments, a polymer A-L-B is a block copolymer of an aliphatic polycarbonate (APC) and poly(propylene glycol) (PPG) or a derivative thereof, wherein the APC comprises a random copolymer such as those derived from copolymerization of two or more different epoxides and carbon dioxide. In certain embodiments, such APC-PPG block copolymers have a formula selected from the group consisting of:

(73) ##STR00032## ##STR00033##
wherein R.sup.1 is a mixture of two or more moieties selected from the group consisting of —H, methyl, ethyl, C.sub.3-30 alkyl, CH.sub.2Cl, CF.sub.3, and CH.sub.2OR.sup.z. In certain embodiments, R.sup.1 is a mixture of methyl and ethyl groups. In other embodiments, R.sup.1 is a mixture of —H and methyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.3-6 alkyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.6-24 alkyl groups.

(74) In certain embodiments, polymers of the present invention encompass triblock copolymers having a hydrophilic central block flanked by two polycarbonate chains. In certain embodiments, such triblock copolymers have the formula A-B-A, where each A is a polycarbonate or polyethercarbonate chain having from about 3 to about 500 repeating units and -B- is a hydrophilic oligomer having from about 4 to about 200 repeating units.

(75) In certain embodiments, A-B-A triblock copolymers have the formula X:

(76) ##STR00034## where R.sup.a, R.sup.b, R.sup.c, R.sup.d, n, Z, and m are as defined above, and where n′ is, on average approximately equal to n.

(77) In certain embodiments, A-B-A triblock copolymers have the formula X-a:

(78) ##STR00035##
where R.sup.z, R.sup.a, R.sup.b, R.sup.c, R.sup.d, n, m, and n′ are as defined above.

(79) In certain embodiments, A-B-A triblock copolymers have the formula X-b:

(80) ##STR00036##
where R.sup.100, n, n′, and m are as defined above.

(81) In certain embodiments, A-B-A triblock copolymers have the formula X-c:

(82) ##STR00037## where R.sup.100, n, n′, and m are as defined above.

(83) In certain embodiments, A-B-A triblock copolymers have the formula X-d:

(84) ##STR00038##
where R.sup.100, n, n′, and m are as defined above.

(85) In certain embodiments, A-B-A triblock copolymers have the formula X-e:

(86) ##STR00039##
where R.sup.z, R.sup.100, n, n′, and m are as defined above.

(87) In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is R.sup.10. In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is an optionally substituted aliphatic group. In certain embodiments, R.sup.z is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl. In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is an acyl group. In certain embodiments, R.sup.z is selected from the group consisting of formate, acetate, trifluoroacetate, propionate, and optionally substituted benzoate. In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is —Si(R.sup.10).sub.3. In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is a silyl group. In certain embodiments, R.sup.z is selected from the group consisting of trimethylsilyl, triethylsilyl, triisopropyl silyl, t-butyldimethylsilyl, and t-butyldiphenylsilyl. In certain embodiments, in polymers of formulae X-a or X-e, R.sup.z is a sulfonate group.

(88) In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is absent (e.g. the polycarbonate chain comprises poly(ethylene carbonate). In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a methyl group. In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is an ethyl group. In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a random mixture of methyl and ethyl groups. In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a chloromethyl group. In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a random mixture of methyl and chloromethyl groups. In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a random mixture of methyl and one or more C.sub.3-30 alkyl groups.

(89) In certain embodiments, in polymers of formulae X-b through X-e, R.sup.100 is a —CH.sub.2OR.sup.z group. In certain embodiments, the CH.sub.2OR.sup.z group comprises an ether group (e.g. the polycarbonate chain is a poly(glycidyl ether carbonate)). In some embodiments, the CH.sub.2OR.sup.z group comprises an ester group (e.g. the polycarbonate chain is a poly(glycidyl ester carbonate)). In certain embodiments, R.sup.100 is a random mixture of —H and —CH.sub.2OR.sup.z groups. In certain embodiments, R.sup.100 is a random mixture of C.sub.1-4 alkyl groups and —CH.sub.2OR.sup.z groups. In certain embodiments, R.sup.100 is a random mixture of methyl and —CH.sub.2OR.sup.z groups.

(90) In certain embodiments, provided polymer compositions comprise polymer chains of formulae X through X-e, wherein the value of n is, on average, between about 3 and about 200. In certain embodiments, the value of n is, on average between about 3 and about 100. In certain embodiments, the value of n is, on average between about 3 and about 50. In certain embodiments, the value of n is, on average between about 3 and about 25. In certain embodiments, the value of n is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 3 and about 10.

(91) In certain embodiments, provided polymer compositions comprise polymer chains of formulae X through X-e above wherein the value of m is, on average, between about 4 and about 500. In certain embodiments, the value of m is, on average between about 5 and about 200. In certain embodiments, the value of m is, on average between about 5 and about 50. In certain embodiments, the value of m is, on average between about 5 and about 25. In certain embodiments, the value of m is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 5 and about 10.

(92) In certain embodiments, where a provided polymer has one of the formulae X-b through X-e, the head to tail ratio of adjacent

(93) ##STR00040##
groups is greater than about 80%. In certain embodiments, the head to tail ratio is greater than about 90%. In certain embodiments, the head to tail ratio is greater than about 92%. In certain embodiments, the head to tail ratio is greater than about 95%.

(94) In certain embodiments, provided A-B-A copolymers have narrow polydisperisity indices. In some embodiments, the PDI of block copolymers of the present invention is less than about 2. In certain embodiments, the PDI is less than 1.5. In some embodiments, the PDI is less than 1.4, less than 1.2 or less than about 1.1.

(95) In certain embodiments, triblock copolymers of the present invention comprise copolymers of poly(ethylene glycol) (PEG) or a derivative thereof and polypropylene carbonate) (PPC) or derivatives thereof. In certain embodiments, these copolymers have a formula selected from the group consisting of:

(96) ##STR00041##

(97) In certain embodiments, provided triblock copolymers comprise copolymers of poly(ethylene glycol) (PEG) or a derivative thereof and poly(ethylene carbonate) (PEC) or derivatives thereof. In certain embodiments, these PEG-PEC triblock copolymers have a formula selected from the group consisting of:

(98) ##STR00042##

(99) In certain embodiments, provided triblock copolymers comprise copolymers of an aliphatic polycarbonate (APC) and poly(ethylene glycol) (PEG) or a derivative thereof, wherein an APC comprises a random copolymer such as those derived from copolymerization of two or more different epoxides and carbon dioxide. In certain embodiments, such APC-PEG triblock copolymers have a formula selected from the group consisting of:

(100) ##STR00043## wherein R.sup.1 is a mixture of two or more moieties selected from the group consisting of —H, methyl, ethyl, C.sub.3-30 alkyl, CH.sub.2Cl CF.sub.3, and CH.sub.2OR.sup.z. In certain embodiments, R.sup.1 is a mixture of methyl and ethyl groups. In other embodiments, R.sup.1 is a mixture of —H and methyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.3-6 alkyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.6-24 alkyl groups.

(101) In certain embodiments, provided triblock copolymers comprise copolymers of poly(propylene glycol) (PPG) or a derivative thereof and poly(propylene carbonate) (PPC) or derivatives thereof. In certain embodiments, such copolymers have a formula selected from the group consisting of:

(102) ##STR00044##

(103) In certain embodiments, provided triblock copolymers comprise copolymers of polypropylene glycol) (PPG) or a derivative thereof and poly(ethylene carbonate) (PEC) or derivatives thereof. In certain embodiments, these PPG-PEC triblock copolymers have a formula selected from the group consisting of:

(104) ##STR00045##

(105) In certain embodiments, provided triblock copolymers comprise copolymers of an aliphatic polycarbonate (APC) and polypropylene glycol) (PPG) or a derivative thereof, wherein the APC comprises a random copolymer such as those derived from copolymerization of two or more different epoxides and carbon dioxide. In certain embodiments, such APC-PPG triblock copolymers have a formula selected from the group consisting of:

(106) ##STR00046##
wherein, R.sup.1 is a mixture of two or more moieties selected from the group consisting of —H, methyl, ethyl, C.sub.3-30 alkyl, CH.sub.2Cl, CF.sub.3, and CH.sub.2OR.sup.z. In certain embodiments, R.sup.1 is a mixture of methyl and ethyl groups. In other embodiments, R.sup.1 is a mixture of —H and methyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.3-6 alkyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.6-24 alkyl groups.

(107) In certain embodiments, provided triblock copolymers comprise copolymers of polyoxymethylene (POM) or a derivative thereof and poly(propylene carbonate) (PPC) or derivatives thereof. In certain embodiments, such copolymers have a formula selected from the group consisting of:

(108) ##STR00047##

(109) In certain embodiments, provided triblock copolymers comprise copolymers of polyoxymethylene (POM) or a derivative thereof and poly(ethylene carbonate) (PEC) or derivatives thereof. In certain embodiments, these POM-PEC triblock copolymers have a formula selected from the group consisting of:

(110) ##STR00048##

(111) In certain embodiments, provided triblock copolymers comprise copolymers of an aliphatic polycarbonate (APC) and polyoxymethylene (POM) or a derivative thereof, wherein an APC comprises a random copolymer such as those derived from copolymerization of two or more different epoxides and carbon dioxide. In certain embodiments, such APC-POM triblock copolymers have a formula selected from the group consisting of:

(112) ##STR00049##
wherein, R.sup.1 is a mixture of two or more moieties selected from the group consisting of —H, methyl, ethyl, C.sub.3-30 alkyl, CH.sub.2Cl, CF.sub.3, and CH.sub.2OR.sup.z. In certain embodiments, R.sup.1 is a mixture of methyl and ethyl groups. In other embodiments, R.sup.1 is a mixture of —H and methyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.3-6 alkyl groups. In certain embodiments, R.sup.1 is a mixture of methyl groups and C.sub.6-24 alkyl groups.

(113) In certain embodiments, provided polymers are triblock copolymers having an aliphatic polycarbonate central block flanked by two hydrophilic oligomers. In certain embodiments, such triblock copolymers have the formula B-A-B, where -A- is a polycarbonate or polyethercarbonate chain having from about 3 to about 500 repeating units and each B is independently a hydrophilic oligomer having from about 4 to about 200 repeating units.

(114) In certain embodiments, such B-A-B triblock copolymers have the formula XI:

(115) ##STR00050## where R.sup.a, R.sup.b, R.sup.c, R.sup.d, n, L, Z, Y, and m are as defined above, and where m′ is, on average approximately equal to m.

(116) In certain embodiments, B-A-B triblock copolymers have the formula XI-a:

(117) ##STR00051## where Y, Z, R.sup.a, R.sup.b, R.sup.c, R.sup.d, n, m, and m′ are as defined above.

(118) In certain embodiments, B-A-B triblock copolymers have the formula XI-b:

(119) ##STR00052##
where Y, Z, R.sup.100, n, m′, and m are as defined above.

(120) In certain embodiments, B-A-B triblock copolymers have the formula XI-c:

(121) ##STR00053##
where R.sup.100, n, m′, and m are as defined above.

(122) In certain embodiments, B-A-B triblock copolymers have the formula XI-d:

(123) ##STR00054##
where R.sup.100, n, m′, and m are as defined above.

(124) In certain embodiments, in polymers of formulae XI through XI-b, Y is —H. In certain embodiments, in polymers of formulae XI through XI-b, Y is an optionally substituted aliphatic group. In certain embodiments, Y is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl, allyl and benzyl. In certain embodiments, in polymers of formulae XI through XI-b, Y is an acyl group. In certain embodiments, Y is selected from the group consisting of formate, acetate, trifluoroacetate, propionate, and optionally substituted benzoate. In certain embodiments, in polymers of formulae XI through XI-b, Y is —Si(R.sup.10).sub.3. In certain embodiments, in polymers of formulae XI through XI-b, Y is a silyl group. In certain embodiments, Y is selected from the group consisting of trimethylsilyl, triethylsilyl, triisopropyl silyl, t-butyldimethylsilyl, and t-butyldiphenylsilyl. In certain embodiments, in polymers of formulae XI through XI-b, Y is a sulfonate group.

(125) In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is absent (e.g. the polycarbonate chain comprises poly(ethylene carbonate). In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a methyl group. In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is an ethyl group. In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a random mixture of methyl and ethyl groups. In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a chloromethyl group. In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a random mixture of methyl and chloromethyl groups. In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a random mixture of methyl and one or more C.sub.3-30 alkyl groups.

(126) In certain embodiments, in polymers of formulae XI-b through XI-d, R.sup.100 is a —CH.sub.2OR.sup.z group. In certain embodiments, a CH.sub.2OR.sup.Z group comprises an ether group (e.g.

(127) the polycarbonate chain is a poly(glycidyl ether carbonate)). In some embodiments, a CH.sub.2OR.sup.z group comprises an ester group (e.g. the polycarbonate chain is a poly(glycidyl ester carbonate)). In certain embodiments, R.sup.100 is a random mixture of —H and —CH.sub.2OR.sup.z groups. In certain embodiments, R.sup.100 is a random mixture of C.sub.1-4 alkyl groups and —CH.sub.2OR.sup.z groups. In certain embodiments, R.sup.100 is a random mixture of methyl and —CH.sub.2OR.sup.z groups.

(128) In certain embodiments, provided polymer compositions comprise polymer chains of formulae XI through XI-d above wherein the value of n is, on average, between about 3 and about 200. In certain embodiments, the value of n is, on average between about 3 and about 100. In certain embodiments, the value of n is, on average between about 3 and about 50. In certain embodiments, the value of n is, on average between about 3 and about 25. In certain embodiments, the value of n is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 3 and about 10.

(129) In certain embodiments, provided polymer compositions comprise polymer chains of formulae XI through XI-d above wherein the value of m is, on average, between about 4 and about 500. In certain embodiments, the value of m is, on average between about 5 and about 200. In certain embodiments, the value of m is, on average between about 5 and about 50. In certain embodiments, the value of m is, on average between about 5 and about 25. In certain embodiments, the value of m is, on average between about 10 and about 20. In certain embodiments, the value of n is, on average between about 5 and about 10.

(130) In certain embodiments, where the polymer has one of the formulae XI-b through XI-d, R.sup.100 is present, and the head to tail ratio of adjacent

(131) ##STR00055##
groups is greater than about 80%. In certain embodiments, the head to tail ratio is greater than about 90%. In certain embodiments, the head to tail ratio is greater than about 92%. In certain embodiments, the head to tail ratio is greater than about 95%.

(132) In certain embodiments, copolymers B-A-B have narrow polydisperisity indices. In some embodiments, the PDI of provided block copolymers is less than about 2. In certain embodiments, the PDI is less than 1.5. In some embodiments, the PDI is less than 1.4, less than 1.2 or less than about 1.1.

(133) In certain embodiments, for each of the formulae described herein, R.sup.10 is optionally substituted C.sub.1-20 aliphatic. In some embodiments, R.sup.10 is C.sub.1-12 heteroaliphatic. In some embodiments, R.sup.10 is 6- to 14-membered aryl. In some embodiments, R.sup.10 is 5- to 14-membered heteroaryl. In some embodiments, R.sup.10 is C.sub.1-12 heteroaliphatic. In some embodiments, R.sup.10 is methyl.

(134) Polyether-Polycarbonates

(135) In certain embodiments, provided copolymers are amphiphilic block copolymers wherein the carbonate-containing portion of the polymer comprises a polycarbonate containing both carbonate and ether linkages. In certain embodiments, a polymer A-L-B comprises a random poly(ether-co-carbonate) and has the formula VI:

(136) ##STR00056##
where
X, B, R.sup.a, R.sup.b, R.sup.c, R.sup.d, L, and n are as defined above.

(137) It will be appreciated that in chemical formulae described herein, a dashed line “” means that the repeating unit on either side of the line occurs randomly throughout the polymer block contained within the parentheses between which the dashed line appears.

(138) In certain embodiments, a polymer A-L-B has the formula VI-a:

(139) ##STR00057##
where
X, L, B, R.sup.100, and n are as defined above.

(140) In certain embodiments, a polymer A-L-B has the formula VII:

(141) ##STR00058##
where X, L, R.sup.100, n and m are as defined above.

(142) In certain embodiments, a polymer A-L-B has the formula VII-a:

(143) ##STR00059##
where X, R.sup.100, n and m are as defined above.

(144) In certain embodiments, a polymer A-L-B has the formula VII-b:

(145) ##STR00060##
where X, n and m are as defined above.

(146) In certain embodiments, a polymer A-L-B has the formula VII-c:

(147) ##STR00061##
where X, n and m are as defined above.

(148) In certain embodiments, a polymer A-L-B has the formula VII-d:

(149) ##STR00062##

(150) In certain embodiments, a polymer A-L-B has the formula VII-e:

(151) ##STR00063##

(152) In certain embodiments, a polymer A-L-B has the formula VII-f:

(153) ##STR00064##
where n and m are as defined above.

(154) In certain embodiments, a polymer A-L-B has the formula VII-g:

(155) ##STR00065##

(156) In certain embodiments, a polymer A-L-B has the formula VII-h:

(157) ##STR00066##

(158) In certain embodiments, a polymer A-L-B has the formula VII-i:

(159) ##STR00067##
where n and m are as defined above.

(160) In certain embodiments, a polymer A-L-B has the formula VII-j:

(161) ##STR00068##

(162) In certain embodiments, a polymer A-L-B has the formula VII-k:

(163) ##STR00069##

(164) In certain embodiments, a polymer A-L-B has the formula VIII:

(165) ##STR00070##
where X, L, R.sup.100, n and m are as defined above.

(166) In certain embodiments, a polymer A-L-B has the formula VIII-a:

(167) ##STR00071##
where X, R.sup.100, n and m are as defined above.

(168) In certain embodiments, a polymer A-L-B has the formula VIII-b:

(169) ##STR00072##
where X, n and m are as defined above.

(170) In certain embodiments, a polymer A-L-B has the formula VIII-c:

(171) ##STR00073##
where n and m are as defined above.

(172) In certain embodiments, a polymer A-L-B has the formula VIII-d:

(173) ##STR00074##

(174) In certain embodiments, a polymer A-L-B has the formula VIII-e:

(175) ##STR00075##

(176) In certain embodiments, a polymer A-L-B has the formula VIII-f:

(177) ##STR00076##
where n and m are as defined above.

(178) In certain embodiments, a polymer A-L-B has the formula VIII-g:

(179) ##STR00077##

(180) In certain embodiments, a polymer A-L-B has the formula VIII-h:

(181) ##STR00078##

(182) In certain embodiments, a polymer A-L-B has the formula IX:

(183) ##STR00079##
where X, n and m are as defined above.

(184) In certain embodiments, a polymer A-L-B has the formula IX-a:

(185) ##STR00080##
where n and m are as defined above.

(186) In certain embodiments, a polymer A-L-B has the formula IX-b:

(187) ##STR00081##

(188) In certain embodiments, a polymer A-L-B has the formula IX-c:

(189) ##STR00082##

(190) In certain embodiments, a polymer A-L-B has the formula IX-d:

(191) ##STR00083##
where n and m are as defined above.

(192) In certain embodiments, a polymer A-L-B has the formula IX-e:

(193) ##STR00084##

(194) In certain embodiments, a polymer A-L-B has the formula IX-f:

(195) ##STR00085##

(196) In certain embodiments, provided triblock copolymers have the formula A-B-A wherein A is a polycarbonate chain containing both carbonate and ether linkages has the formula (IX-g):

(197) ##STR00086##
where R.sup.z, R.sup.100, Z, n, n′ and m are as defined above.

(198) As mentioned above, in some embodiments, provided copolymers have a high percentage of carbonate linkages and a low percentage of ether linkages. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 50%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 46%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 40%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 30%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 20%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 10%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 5%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 1%. In certain embodiments, for copolymers of formulae VI through IX-g, the proportion of ether linkages in the polyethercarbonate is less than about 0.1%.

(199) In some embodiments, provided polymer compositions have an average molecular weight between 200 and 10,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 200 and 5,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 500 and 2,500 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 800 and 2,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 500 and 1,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 1,000 and 2,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 1,000 and 5,000 g/mol. In some embodiments, provided polymer compositions have an average molecular weight between 200 and 1,000 g/mol.

(200) In certain embodiments, a block copolymer is provided in a quantity of less than 5 weight % relative to the CO.sub.2 phase. In certain embodiments, the block copolymer is provided in a quantity of less than 1 weight %. In certain embodiments, the block copolymer is provided in a quantity of less than 0.5 weight %. In certain embodiments, the block copolymer is provided in a quantity of less than 0.1 weight %. In certain embodiments, the block copolymer is provided in a quantity of less than 0.05 weight %. In certain embodiments, the block copolymer is provided in a quantity of about 0.01 weight %.

(201) In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.01 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.05 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.1 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.2 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.5 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 1.0 weight % at a pressure of 4,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.01 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.05 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.1 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.2 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.5 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 1.0 weight % at a pressure of 3,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.01 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.05 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.1 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.2 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.5 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 1.0 weight % at a pressure of 2,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.01 weight % at a pressure of 1,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.05 weight % at a pressure of 1,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.1 weight % at a pressure of 1,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.2 weight % at a pressure of 1,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 0.5 weight % at a pressure of 1,000 psi or higher. In some embodiments, a provided copolymer composition has a solubility in supercritical CO.sub.2 of at least 1.0 weight % at a pressure of 1,000 psi or higher.

(202) In some embodiments, provided copolymers form polymerosomes. Having read the present disclosure, one of ordinary skill in the art would be able to carry out routine experimentation to form polymerosomes from provided amphiphilic copolymers. Using methods well known to the skilled artisan, parameters such as polymer concentration, solvent, temperature, and various physical means (e.g., shearing, dialysis, etc.) can be applied to achieve vesicle formation. Depending upon the desired use of the vesicle (e.g., drug delivery, viscosifying agent, etc.), the skilled artisan will select the appropriate copolymer to achieve the desired polymersome properties.

(203) One of ordinary skill will also be familiar with a variety of characterization techniques that can be used to determine the degree of vesicle formation. For example, T.sub.m, scanning electron microscopy, transmission electron microscopy, dynamic stress rheometer, and dynamic light scattering, to name but a few, are all routine techniques in characterizing polymersome vesicles. Further guidance can be found in U.S. Pat. Appl. Publication 2005/0215438.

(204) Certain polymers of the present invention can be produced by copolymerization of carbon dioxide and epoxides using catalysts adapted from those disclosed in U.S. Pat. Nos. 6,870,004; and 7,304,172, in pending PCT application Nos. PCT/US09/56220, PCT/US09/54773, and in published PCT applications WO2008136591A1 and WO2008150033A1, the entirety of each of which is incorporated herein by reference.

(205) In certain methods of the present invention, the methods include synthesizing a polymer by reacting an epoxide and carbon dioxide in the presence of a suitable catalyst and a polyether chain transfer agent having one free OH group as shown in Scheme 1:

(206) ##STR00087##

(207) The method of Scheme 1 is suitable for the synthesis of compounds described above wherein the polyether moiety is capped with a Y group that is not —H, and the polycarbonate chain is terminated with an OH group. Experimental conditions and methods suitable for this process are described more fully in the Examples section below, and in co-pending International Patent Application No. PCT/US2009/056220, filed Sep. 8, 2009, the entire contents of which are hereby incorporated by reference.

(208) The products of Scheme 1 can be further modified by reactions well known to those skilled in the art of organic synthesis such as alkylation, acylation, sulfonation, or silylation to yield compounds wherein the polycarbonate chain is capped with a non-OH end group. This is shown in Scheme 2:

(209) ##STR00088##

(210) It will be appreciated that there are many possible variations encompassed by the synthetic approaches detailed in Schemes 1-5, including the choice of suitable protecting (capping) chemistries for the polymer termini. Suitable hydroxyl and carboxyl protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3.sup.rd edition, John Wiley & Sons, 1999, the entirety of which is incorporated herein by reference.

(211) For example, where it is desired that the polyether portion of such polymers have a free OH group, the polyether chain transfer agent of Scheme 1 can be chosen to contain on one terminus a labile group that can be removed after construction of the block co-polymer. Exemplary approaches include the use of mono-benyl or mono-allyl polyether starting material followed by hydrogenolysis of the benzyl or allyl ether after construction of the copolymer. Another viable approach is the use of a monosilylated polyether chain transfer agent followed by fluoride mediated cleavage of the silyl ether after construction of the copolymer. It will be appreciated that numerous other hydroxyl protecting groups that can be cleaved under relatively mild conditions are known in the art and can be used to similar effect in accordance with the present disclosure.

(212) In certain embodiments, it is desirable to have a free —OH group on the hydrophilic polyether portion of the block co-polymer and a non-OH end-group on the polycarbonate. Polymers of this type can be produced using the methods just described by capping the —OH group of the polycarbonate as described above and shown in Scheme 2, followed by removal of a suitably chosen protecting group on the polyether block of the copolymer as just described.

(213) For block copolymers comprising polycarbonates derived from monosubstituted epoxides, it will be appreciated that there are different regiochemical arrangements possible for the orientation of the polycarbonate chain relative to the polyether. For example, the two compounds shown below are both block co-polymers of PEG and polypropylene carbonate):

(214) ##STR00089##

(215) Compound (A) is typical of the product formed using the method shown in Scheme 1, where the epoxide is propylene oxide. The directionality of the epoxide enchainment during the polymerization will be predominately (>60%) from the less hindered ring carbon, therefore the last enchained epoxide which comprises the chain terminus at the end of synthesis will be oriented predominately as shown in the first structure. If one uses a complementary approach described below in Scheme 5, wherein a preformed monofunctional polycarbonate chain is ligated to a polyether chain, the regiochemistry will be predominantly as shown in structure (B) since a mono-hydroxy terminated polypropylene carbonate) chain resulting from initiation by a moiety X, will have predominately secondary OH groups at the reactive terminus. Reaction of these OH groups to ligate or initiate a polyether chain will result predominantly (e.g. >60%) in the regiochemistry shown in compound (B). It will be appreciated that this phenomenon is observed also with the use of other epoxide substrates such as butylene oxide, epichlorohydrin, and glycidol derivatives, but not with unsubstituted, or symmetrically substituted epoxides such as ethylene oxide or 2-butene oxide.

(216) In certain embodiments of the present invention, the methods include synthesizing a triblock copolymer by reacting an epoxide and carbon dioxide in the presence of a suitable catalyst and a polyether chain transfer agent having two free OH group as shown in Scheme 3. Compounds of formulae X through X-d described above can be made according to this method.

(217) ##STR00090##

(218) As shown in scheme 4, the products of Scheme 3, can be end-capped as described above for diblock co-polymers.

(219) ##STR00091##

(220) It will be appreciated that these methods can also be applied using other —OH or CO.sub.2H terminated oligomers as chain transfer agents in place of the polyethers depicted above. For example, polyesters, polyacrylates, or propoxylated or ethoxylated derivatives thereof can be used as well.

(221) In some embodiments, the present disclosure encompasses methods of making amphiphilic polymers as described hereinabove comprising the step of synthesizing a polycarbonate chain having one end terminated with an —OH group, followed by ligation to a polyether. Such ligation may be accomplished by forming an ether bond to a preformed polyether molecule or, more preferably, by conducting a second polymerization in the presence of a suitable polyether precursor such as an epoxide or formaldehyde to synthesize the polyether block directly onto the co-polymer. This approach is outlined in Scheme 5.

(222) ##STR00092##

(223) It will be appreciated that this approach leads to compounds having an —OH terminal group on the polyether block and a non-OH group derived from the polycarbonate chain initiator at the polycarbonate terminus of the polymer.

(224) Similarly, triblock co-polymers derived from ether synthesis upon a di-hydroxy terminated polycarbonate are also possible, this process will yield compounds of formula XI-b described hereinabove.

(225) For block co-polymers made by polymerizing a polyether precursor onto a preformed polycarbonate, it should be noted that the resulting compounds may contain a linker between the polycarbonate and the polyether corresponding to a ring-opened molecule of the epoxide from which the polycarbonate was formed. This is shown in structure (C) below for a polycarbonate-co-polyethylene glycol where the linker is denoted “L” and in other similar examples hereinabove.

(226) ##STR00093##

(227) Of course, in cases where the epoxide subunit of the polycarbonate corresponds to the repeat unit of a polyether block (i.e. poly(ethylene carbonate)-block-poly(ethylene glycol)), such a linker moiety will not be distinguishable and the linker 1′ can be regarded as comprising a single covalent bond.

(228) In some embodiments, the present invention encompasses methods for the formation of emulsions between supercritical carbon dioxide and a polar liquid. In certain embodiments, the polar liquid comprises water or an aqueous solution. In certain embodiments, the method includes the step of agitating a biphasic mixture of supercritical CO.sub.2 and the polar liquid in the presence of any one or more of the block copolymers described hereinabove. In another embodiment, the method of forming the emulsion comprises forcing a mixture of the two phases and the surfactant through a porous substance.

(229) In certain embodiments, the present invention provides a method of forming an emulsion of supercritical CO.sub.2 and an aqueous phase, the method comprising a step of agitating supercritical CO.sub.2 and the aqueous phase in the presence of a block copolymer having a formula:

(230) ##STR00094##
wherein X is selected from the group consisting of: halogen; —OH; azide, nitrile, and —OR.sup.z; each R.sup.a, R.sup.b, R.sup.c, and R.sup.d is independently selected from the group consisting of: hydrogen, halogen, —CH.sub.2OR.sup.z, optionally substituted C.sub.1-10 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, and where any two or more of R.sup.a, R.sup.b, R.sup.c, and R.sup.d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms; L is a bond or a polyfunctional moiety, B is a hydrophilic oligomer having from about 4 to about 100 repeating units, n is an integer between 4 and 100, R.sup.z is selected from the group consisting of —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2, optionally substituted C.sub.1-12 aliphatic; optionally substituted C.sub.1-12 heteroaliphatic; optionally substituted 6- to 14-membered aryl; and optionally substituted 5- to 14-membered heteroaryl, and

(231) R.sup.10 is an optionally substituted moiety selected from the group consisting of: C.sub.1-20 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

(232) In certain embodiments, the present invention provides a method of forming an emulsion of supercritical CO.sub.2 and an aqueous phase, the method comprising a step of agitating supercritical CO.sub.2 and the aqueous phase in the presence of a block copolymer having a formula:

(233) ##STR00095##
wherein X′ is selected from the group consisting of —OH, and —OR.sup.z, R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, and —CH.sub.2Cl, each n is independently an integer between 4 and 100, —Z— is an optionally substituted C.sub.1-6 aliphatic group, m is an integer between 5 and 200, R.sup.z is selected from the group consisting of —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2, optionally substituted C.sub.1-12 aliphatic; optionally substituted C.sub.1-12 heteroaliphatic; optionally substituted 6- to 14-membered aryl; and optionally substituted 5- to 14-membered heteroaryl, and R.sup.10 is at each occurrence an optionally substituted moiety independently selected from the group consisting of: C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

(234) In certain embodiments, provided block co-polymers useful for forming an emulsion are of the formula:

(235) ##STR00096##
wherein R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, —CH.sub.2Cl, a C.sub.6-30 alkyl group, and mixtures of any two or more of these.

(236) In certain embodiments, the block copolymers and methods described hereinabove have utility in modifying the viscosity of supercritical CO.sub.2 water mixtures. Such viscosity modifying properties can have utility in the use of supercritical CO.sub.2 as a fluid for secondary or tertiary recovery of product from oil wells. Methods of using and means of modeling compounds for such applications are described in published PCT application WO 2000035998 A2 which is incorporated herein by reference and in references cited therein.

(237) In some embodiments, the present invention provides a method of modifying the viscosity of a fluid comprising a mixture of supercritical CO.sub.2 and water, the method comprising a step of agitating the mixture in the presence of a block copolymer having a formula:

(238) ##STR00097##
wherein X is selected from the group consisting of: halogen; —OH; azide, nitrile, and —OR.sup.z; each R.sup.a, R.sup.b, R.sup.c, and R.sup.d is independently selected from the group consisting of: hydrogen, halogen, —CH.sub.2OR.sup.z, optionally substituted C.sub.1-10 aliphatic, optionally substituted 6- to 14-membered aromatic, optionally substituted 3- to 14-membered heterocyclic, and optionally substituted 5- to 14-membered heteroaryl, and where any two or more of R.sup.a, R.sup.b, R.sup.c, and R.sup.d may be taken together to form an optionally substituted 3- to 12-membered ring, optionally containing one or more heteroatoms; L is a bond or a polyfunctional moiety, B is a hydrophilic oligomer having from about 4 to about 100 repeating units, n is an integer between 4 and 100, R.sup.z is selected from the group consisting of —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2, optionally substituted C.sub.1-12 aliphatic; optionally substituted C.sub.1-12 heteroaliphatic; optionally substituted 6- to 14-membered aryl; and optionally substituted 5- to 14-membered heteroaryl, and

(239) R.sup.10 is an optionally substituted moiety selected from the group consisting of: C.sub.1-20 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

(240) In certain embodiments, the present invention provides a method of modifying the viscosity of a fluid comprising a mixture of supercritical CO.sub.2 and water, the method comprising a step of agitating the mixture in the presence of a block copolymer having a formula:

(241) ##STR00098##
wherein X′ is selected from the group consisting of —OH, and —OR.sup.z R.sup.100 is optionally present, and if present is selected from the group consisting of —CH.sub.3, —CF.sub.3, —CH.sub.2CH.sub.3, —CH.sub.2OR.sup.z, and —CH.sub.2Cl; each n is independently an integer between 4 and 100, —Z— is an optionally substituted C.sub.1-6 aliphatic group, m is an integer between 5 and 200, R.sup.z is selected from the group consisting of —C(O)R.sup.10, —SO.sub.2R.sup.10, —Si(R.sup.10).sub.3, —C(O)N(R.sup.10).sub.2, optionally substituted C.sub.1-12 aliphatic; optionally substituted C.sub.1-12 heteroaliphatic; optionally substituted 6- to 14-membered aryl; and optionally substituted 5- to 14-membered heteroaryl, and R.sup.10 is at each occurrence an optionally substituted moiety independently selected from the group consisting of: C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic; 6- to 14-membered aryl; and 5- to 14-membered heteroaryl.

(242) In certain embodiments of the methods described above, a block copolymer is provided as a solution in supercritical CO.sub.2.

(243) In certain embodiments, the present invention includes methods of enhancing product recovery from oil wells by introducing any of the above-described polymers to an oil-containing geological formation. In some embodiments, such methods comprise the step of pumping a provided copolymer into an oil well. In certain embodiments, the polymers are introduced in combination with supercritical CO.sub.2. In certain methods, the supercritical CO.sub.2 is combined with water or brine to form an emulsion capable of flushing trapped oil from geological formations.

EXAMPLES

Example 1: Synthesis of Poly(propylene carbonate)-block-poly(ethylene glycol) methyl Ether 1

(244) ##STR00099##
(a compound of formula II-d wherein X′ is OH, R.sup.100 is —CH.sub.3, L is a bond, and Z is —CH.sub.2CH.sub.2— and Y′ is CH.sub.3 with n being approximately 11 and m being approximately 11)

(245) ##STR00100##

(246) Procedure A:

(247) A 3 oz. Fischer-Porter bottle was fitted with a pressure head and magnetic stirrer. The reaction vessel was dried in vacuo using a heat gun and cooled to rt. catalyst C-I (24 mg, 3.6×10.sup.−5 mol) and bis(triphenylphosphine)iminium chloride (21 mg, 3.6×10.sup.−5 mol) were charged to the reaction vessel. The vessel was evacuated for 15 min, then backfilled with nitrogen. This procedure was repeated twice more. While under the positive flow of nitrogen, propylene oxide (20 mL, 0.29 mol) and poly(ethylene glycol) methyl ether (M.sub.n=550 g/mol, 2.2 mL, 7.1×10.sup.−3 mol) were charged to the reaction vessel. The reaction was placed into a 30° C. water bath, stirred, and pressurized with carbon dioxide (100 psi).

(248) After 21.5 h the reaction was vented and quenched with a methanolic solution (3 mL) of tosic acid (14 mg, 7.2×10.sup.−5 mol). The reaction was stirred for 10 min at rt and the unreacted propylene oxide was removed by evaporation. The resulting polymer was diluted with acetone (10 mL) and filtered through filter paper to remove solids. The filtrate was shaken with Dowex MSC (H) (5.0 g) for 2 h and filtered through a fine mesh. The filtrate was concentrated, in vacuo, to produce 1.0 g (4% yield) of a tan, slightly viscous polymer (M.sub.w=1,688 g/mol, M.sub.w/M.sub.n=1.06; T.sub.d(onset)=210° C., containing 24% propylene carbonate).

(249) Procedure B:

(250) A 300 mL stainless steel reactor was dried, in vacuo, using a hot plate (120° C.) and cooled to rt. catalyst C-I (60 mg, 8.9×10.sup.−5 mol) and bis(triphenylphosphine)iminium chloride (51 mg, 8.9×10.sup.−5 mol) were charged to the reaction vessel. The vessel was evacuated for 15 min, then backfilled with nitrogen. This procedure was repeated twice more.

(251) While under the positive flow of nitrogen, propylene oxide (50 mL, 0.71 mol) and poly(ethylene glycol) monomethylether (M.sub.n=550 g/mol, 4.5 mL, 8.9×10.sup.−3 mol) were charged to the reaction vessel. The reaction was pressurized to 300 psi of carbon dioxide and heated to 30° C. using a heating mantle.

(252) After 16 h the reaction was vented and quenched with a methanolic solution (3 mL) of tosic acid (approx. 34 mg, 1.8×10.sup.−4 mol). The reaction was stirred for 10 min at rt and the unreacted propylene oxide was removed by evaporation. The resulting polymer samples were diluted with acetone (100 mL) and filtered through filter paper to remove solids. The filtrate was shaken with Dowex MSC (H) (9.0 g) for 2 h and filtered through a fine mesh. The filtrate was concentrated, in vacuo, to produce a total of 11.5 g (16% yield) of a tan viscous polymer (M.sub.w=3,057 g/mol, M.sub.w/M.sub.n=1.06; T.sub.g=−34° C.; T.sub.d(onset)=252° C., 7% propylene carbonate).

Example 2: Synthesis of Poly(Propylene Carbonate)-Block-Poly(Propylene Glycol)Monobutyl Ether (2)

(253) ##STR00101##
(a compound of formula II-d wherein X′ is OH, R.sup.100 is —CH.sub.3, L is a bond, and Z is —CH(CH.sub.3)CH.sub.2— and Y′ is n-butyl with n being approximately 5 and m being approximately 19)

(254) ##STR00102##

(255) Procedure A for 1 was followed except poly(propylene glycol) monobutyl ether (M.sub.n=340 g/mol, 2.4 mL, 7.1×10.sup.−3 mol) was used as a chain transfer agent. This produced 1.6 g (7% yield) of a yellow viscous polymer (M.sub.w=2,258 g/mol, M.sub.w/M.sub.n=1.08; T.sub.g=−47° C.; T.sub.d(onset)=229° C., containing 15% propylene carbonate).

Example 3: Synthesis of poly(propylene carbonate)-block-poly(ethylene glycol)-block-poly(propylene Carbonate) (3)

(256) ##STR00103##

(257) (compounds of formula X-b where R.sup.100 is methyl).

(258) ##STR00104##

(259) A 300 mL stainless steel reactor was dried, in vacuo, using a hot plate (120° C.) and cooled to rt. Catalyst C-I (182 mg, 2.7×10.sup.−4 mol) and Bis(triphenylphosphine)iminium chloride (154 mg, 2.7×10.sup.−4 mol) were charged to the reaction vessel. The vessel was evacuated for 15 min, then backfilled with nitrogen. This procedure was repeated twice more. While under the positive flow of nitrogen, propylene oxide (150 mL, 2.2 mol) and poly(ethylene glycol) (M.sub.n=400 g/mol, 9.5 mL, 2.7×10.sup.−2 mol) were charged to the reaction vessel. The reaction was pressurized to 300 psi of carbon dioxide and heated to 30° C. using a heating mantle.

(260) At 2, 4, 6, and 8 h, 10 mL samples were removed from the reaction and quenched with a methanolic solution (3 mL) of tosic acid (7 mg, 3.9×10.sup.−5 mol). After 26 h the reaction was vented and quenched with a methanolic solution (3 mL) of tosic acid (54 mg, 3.0×10.sup.−4 mol). The reaction was stirred for 10 min at rt and the unreacted propylene oxide was removed by evaporation. The resulting polymer samples were diluted with acetone (10 mL) and filtered through filter paper to remove solids. The filtrates were shaken with Dowex MSC (H) (5.0 g) for 2 h and filtered through a fine mesh. Each filtrate was concentrated, in vacuo, to produce a total of 66.0 g (30% yield) of a tan, slightly viscous polymer. 2 h sample (M.sub.w=1,134 g/mol, M.sub.w/M.sub.n=1.14); 4 h sample (M.sub.w=1,543 g/mol, M.sub.w/M.sub.n=1.07; T.sub.g=−66° C.; T.sub.d(onset)=257° C.); 6 h sample (M.sub.w=2,004 g/mol, M.sub.w/M.sub.n=1.06); 8 h sample (M.sub.w=2,422 g/mol, M.sub.w/M.sub.n=1.04; T.sub.g=−49° C.; T.sub.d(onset)=248° C., 6% propylene carbonate); 26 h sample (M.sub.w=5,423 g/mol, M.sub.w/M.sub.n=1.02).

Example 4: Synthesis of polypropylene carbonate)-acetate-block-poly(ethylene Glycol) (4)

(261) ##STR00105##

(262) (a compound of formula II-c wherein X′ is —OAc, R.sup.100 is —CH.sub.3, L is a bond, and Z is —CH.sub.2CH.sub.2— and Y′ is —H)

(263) ##STR00106##

(264) A 3 oz. Fischer-Porter bottle is fitted with a pressure head and magnetic stirrer. The reaction vessel is dried in vacuo using a heat gun and cooled to rt. Catalyst C-I (24 mg, 3.6×10.sup.−5 mol) and bis(triphenylphosphine)iminium chloride (21 mg, 3.6×10.sup.−5 mol) are charged to the reaction vessel. The vessel is evacuated for 15 min, then backfilled with nitrogen. While under a positive flow of nitrogen, propylene oxide (20 mL, 0.29 mol) and poly(ethylene glycol) mono t-butyldimethylsilyl ether (7.1×10.sup.−3 mol prepared as described in Journal of Organic Chemistry (1991), 56(13), 4326-4329) are charged to the reaction vessel. The reaction is placed into a 30° C. water bath, stirred, and pressurized with carbon dioxide (100 psi).

(265) After 24 h the reaction is vented and quenched with a methanolic solution (3 mL) of tosic acid (14 mg, 7.2×10.sup.−5 mol). The mixture is stirred for 10 min at rt and the unreacted propylene oxide is removed by evaporation. The resulting polymer is diluted with acetone (10 mL) and filtered through filter paper to remove solids. The filtrate is shaken with Dowex MSC (H) (5.0 g) for 2 h and filtered through a fine mesh. The filtrate is concentrated, in vacuo, to produce polymer 4a. This polymer is dissolved in dichloromethane (10 mL) containing triethyl amine (1 mL) and treated with acetic anhydride (0.5 mL). The mixture is heated to reflux for 16 h, then cooled to rt, diluted with dichloromethane (40 mL) and washed with water and then brine. The dichloromethane solution is dried on anhydrous K.sub.2CO.sub.3 and concentrated to give compound 4b. Polymer 4b is dissolved in THF (20 mL) in a PTFE container and tetrabutylammonium fluoride (0.2 g) is added. The mixture is stirred for 1 h, then poured into water and extracted with dichloromethane (5×20 mL). The combined dichloromethane extracts are dried on K.sub.2CO.sub.3, filtered and concentrated to afford polymer 4.

Example 5: Synthesis of Poly(Propylene Carbonate)-Pivalate-Block-Poly(Propylene Glycol) (5)

(266) ##STR00107##

(267) (a compound of formula II-d wherein X′ is pivaloyl, R.sup.100 is —CH.sub.3, L is a bond, Z is —CH(CH.sub.3)CH.sub.2— and Y′ is —H)

(268) ##STR00108##

(269) Compound 5 is synthesized under conditions similar to those described in Example 4, except mono-TMS-protected polypropylene glycol is used as the starting material, and pivaloyl chloride is substituted for acetic anhydride.

Example 7: Synthesis of polypropylene carbonate)-acetate-block-poly(ethylene glycol) (7)

(270) ##STR00109##

(271) (a compound of formula II-c wherein X is —OAc, R.sup.100 is —CH.sub.3, L is —CH.sub.2CH(CH.sub.3)O—, and Z is —CH.sub.2CH.sub.2—)

(272) ##STR00110##

(273) In a glovebox, catalyst C-II (5.4 mg) and PPN-acetate (4.8 mg) are charged to an oven-dried 20 mL glass liner. The liner is inserted into a stainless steel high pressure reactor. The system is purged with N.sub.2 five times and purged with CO.sub.2 twice. While under the positive flow of CO.sub.2, propylene oxide (5 mL) and acetic acid (200 μL) are charged to the reaction vessel. The reaction is heated to 50° C., then pressurized with carbon dioxide (300 psi) and stirred. After 6 h the reaction is vented and quenched with acidic methanol (0.2 mL). The reaction is cooled to room temperature, and the resulting polymer is diluted with acetone (5 mL) and transferred to a foil pan. The unreacted propylene oxide and acetone are removed by evaporation to produce polymer 7a as an oil.

(274) In a dry 100 ml flask, 1 g of polymer 7a is dissolved in 15 mL of dichloromethane. To this mixture is added 2 g of ethylene oxide followed by 150 mg of catalyst C-III dissolved in 5 mL of dichloromethane. This mixture is stirred at rt for 48 h, then quenched by addition of a large excess of methanol. The volatile components are then removed under vacuum, the residue is dissolved in THF (100 mL) and filtered through a 0.22 μm filter. Evaporation of the filtrate provides polymer 7 as a viscous oil.

Example 8: Synthesis of Isopropyl Ether Capped Poly(Propylene Carbonate)-Block-Poly(Propylene Glycol) (8)

(275) ##STR00111##

(276) (a compound of formula II-c wherein X is —O-i-Pr, R.sup.100 is —CH.sub.3, L is a bond, and Z is —CH.sub.2CH(CH.sub.3)—)

(277) ##STR00112##

(278) In a glovebox, catalyst C-II (50 mg) and PPN-chloride (48 mg) are charged to an oven-dried 200 mL high pressure reactor. The reactor is purged with N.sub.2 five times and purged with CO.sub.2 twice. While under the positive flow of CO.sub.2, propylene oxide (70 mL) and isopropyl alcohol (0.5 mL) are charged to the reaction vessel. The reaction is heated to 35° C., then pressurized with carbon dioxide (300 psi) and stirred. After 6 h the reaction is vented and quenched with acidic methanol (5 mL). The reaction is cooled to room temperature, and the resulting polymer is diluted with acetone (50 mL) and transferred to a pan. The unreacted propylene oxide and acetone are removed by evaporation to provide polymer 8a as a viscous oil.

(279) A 100 mL reactor is charged with polymer 8a (10 g) and zinc hexacyanocobaltate catalyst (0.02 g). The mixture is stirred and heated to 105° C., and is stripped under vacuum to remove traces of water from polymer 8a. Ethylene oxide (2-3 g) is added in one portion. The reactor pressure is then monitored carefully. Additional ethylene oxide is not added until an accelerated pressure drop occurs in the reactor indicating that the catalyst has become activated. When catalyst activation is verified, the remaining ethylene oxide (20 g) is added gradually to keep the reactor pressure at about 10 psig. After ethylene oxide addition is complete, the mixture is held at 105° C. until a constant pressure is observed. Residual unreacted monomer is then stripped under vacuum from the product, and the residue is cooled and recovered to provide polymer 8 as a viscous oil.

Example 9: Synthesis of block-poly(ethylene glycol)-block polypropylene carbonate)-block-poly(ethylene Glycol) (9)

(280) ##STR00113##

(281) (a compound of formula XI-b wherein Y is H, Z is —CH.sub.2CH.sub.2, and —R.sup.100 is —CH.sub.3)

(282) ##STR00114##

(283) In a glovebox, catalyst C-I (5.4 mg) and PPN-chloride (4.8 mg) are charged to an oven-dried 20 mL glass liner. The liner is inserted into a stainless steel high pressure reactor. The system is purged with N.sub.2 five times and purged with CO.sub.2 twice. While under the positive flow of CO.sub.2, propylene oxide (5 mL) and propylene glycol (200 μL) are charged to the reaction vessel. The reaction is heated to 35° C., then pressurized with carbon dioxide (300 psi) and stirred. After 6 h the reaction is vented and quenched with acidic methanol (0.2 mL). The reaction is cooled to room temperature, and the resulting polymer is diluted with acetone (5 mL) and transferred to a foil pan. The unreacted propylene oxide and acetone are removed by evaporation to produce polymer 9a as a viscous oil.

(284) In a dry flask, 1 g of polymer 9a and 5 mg of zinc hexacyanocobaltate catalyst are combined. To this mixture is added 2 g of ethylene oxide. This mixture is stirred at rt for 48 h, then heated to 105° C. for 1 h. Residual unreacted monomer is then stripped under vacuum from the product, and the residue is cooled and recovered to provide polymer 9 as a viscous oil.

(285) Supercritical Carbon Dioxide Solubility Tests:

(286) Samples were evaluated for supercritical CO.sub.2 (sc-CO.sub.2) solubility at a range of pressures and concentrations using the apparatus and conditions described in the Journal of Supercritical Fluids 34 (2005), pp. 11-16, and Journal of Physical Chemistry 100 (1996) which are incorporated herein by reference.

(287) The solubility of the polymers of Examples 1-3 and related compounds in supercritical CO.sub.2 and various concentrations, temperatures, and pressures are shown in FIGS. 1-4.

(288) Emulsion Tests:

(289) Samples were evaluated for the ability to stabilize foams between supercritical CO.sub.2 (sc-CO.sub.2) and water. Foam test conditions used a windowed cell containing equal volumes of liquid sc-CO.sub.2 and brine or water. The mixtures were agitated in the presence of 0.1 wt % surfactant (based on mass of CO.sub.2) and the stability of the foam was observed visually by periodically measuring the height of foam present in the CO.sub.2 phase and the depth of foam present in the aqueous phase. Plots of these data for the polymer compositions of examples 1-3 and related materials are shown in FIGS. 4 and 5.

(290) Further detail on suitable experimental conditions for these measurements are found in Fluid Phase Equilibria (2003), 211(2), pp 211-217 and in Chemistry of Materials (2002), 14(10), pp 4273-4280 which are both incorporated herein by reference.

OTHER EMBODIMENTS

(291) The foregoing has been a description of certain non-limiting embodiments of the invention. Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.