Photonic structures from self assembly of brush block copolymers and polymer blends
10732321 ยท 2020-08-04
Assignee
Inventors
- Garret M. Miyake (Pasadena, CA, US)
- Raymond Weitekamp (Glendale, CA)
- Robert H. Grubbs (South Pasadena, CA)
- Victoria Piunova (Altadena, CA)
Cpc classification
C08L87/005
CHEMISTRY; METALLURGY
C08F293/00
CHEMISTRY; METALLURGY
G02F1/0054
PHYSICS
C08G81/00
CHEMISTRY; METALLURGY
C08F299/00
CHEMISTRY; METALLURGY
International classification
C08L87/00
CHEMISTRY; METALLURGY
G02B1/00
PHYSICS
Abstract
The invention provides a class of block copolymers having a plurality of chemically different blocks, at least a portion of which incorporating polymer side chain groups having a helical secondary structure. The invention also provides structures generated by self-assembly of polymer blends including at least one block copolymer component, such as a brush block polymer or wedge-type block polymer. The invention provides, for example, periodic nanostructures and microstructures generated by self-assembly of block copolymers and polymer blends comprising a mixture of at least one block copolymer component, such as a brush block copolymer, and at least a second component.
Claims
1. A structure comprising a supramolecular assembly of a polymer blend of at least one block copolymer and at least a second component; wherein said polymer blend comprises: a first block copolymer comprising: a first polymer block comprising first repeating units; wherein each of said first repeating units of said first polymer block comprises a first polymer backbone group directly or indirectly covalently linked to a first polymer side chain group; and a second polymer block comprising second repeating units; wherein each of said second repeating units of said second polymer block comprises a second polymer backbone group directly or indirectly covalently linked to a second polymer side chain group or second wedge group that is different than said first polymer side chain group; the second component having a composition that is different from said first block copolymer; wherein said first block copolymer has the formula (FX6A) or (FX6B1): ##STR00023## K is a repeating group of said second polymer side chain group, G.sup.2 is said second wedge group; each of R.sup.10 and R.sup.11 is independently a polymer side chain terminating group; L.sup.1 is a first linking group; L.sup.2 is a second linking group; each of n and m is independently an integer selected from the range of 20 to 2000; each of p and q is independently an integer selected from the range of 30 to 2000; R.sup.1 is independently a hydrogen, C.sub.1-C.sub.30 alkyl, C.sub.3-C.sub.30 cycloalkyl, C.sub.5-C.sub.30 aryl, C.sub.5-C.sub.30 heteroaryl, C.sub.1-C.sub.30 acyl, C.sub.1-C.sub.30 hydroxyl, C.sub.1-C.sub.30 alkoxy, C.sub.2-C.sub.30 alkenyl, C.sub.2-C.sub.30 alkynyl, C.sub.5-C.sub.30 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.30 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, silsesquioxane, C.sub.2-C.sub.30 halocarbon chain, C.sub.2-C.sub.30 perfluorocarbon, C.sub.2-C.sub.30 polyethylene glycol, a metal, or a metal complex, wherein each of R.sup.30-R.sup.42 is independently H, C.sub.5-C.sub.10 aryl or C.sub.1-C.sub.10 alkyl; and wherein each of Q.sup.1 and Q.sup.2 is independently hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, acrylate, or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen, C.sub.1-C.sub.10 alkyl or C.sub.5-C.sub.10 aryl.
2. The structure of claim 1, wherein said second component comprises a homopolymer, a copolymer, an oligomer, a solvent, a metal, a small molecule or particle.
3. The structure of claim 1, wherein said structure is formed via molecular self-assembly of said first block polymers and said second component of said polymer blend to generate said supramolecular assembly.
4. The structure of claim 1, wherein said structure is formed via thermal annealing, solvent annealing, spin coating, shear alignment, painting, tape casting, co-extrusion, drop casting, spray coating or by the application of an external pressure to said polymer blend.
5. The structure of claim 1 comprising a periodic structure or a photonic band gap material.
6. The structure of claim 1, wherein said structure absorbs, scatters or reflects electromagnetic radiation having wavelengths greater than or equal to 400 nm.
7. The structure of claim 1, wherein said structure is characterized by a periodically varying refractive index.
8. The structure of claim 1, wherein a size (S) of the structure increases substantially linearly with molecular weight (MW) of said first block copolymer pursuant to the expression (E4) wherein 0.85<x<1:
SMW.sup.x(E4).
9. The structure of claim 1, wherein said second component is a second block copolymer comprising at least one polymer block different from said first polymer block and said second polymer block of said first block copolymer.
10. The structure of claim 9, wherein the ratio of the molecular weight of the first block copolymer to the molecular weight of the second block copolymer is selected over the range of 0.2 to 5.
11. The structure of claim 1, wherein each K is independently an unsubstituted or substituted isocyanate group, methacrylate group, acrylate group, acrylamide group, methacrylamide group, quinoxaline group, guanidine group, silane group, acetylene group, amino acid group, chloral group, lactide group, styrene group, acrylate group, tert-butyl, siloxane group, dimethylsiloxane group, n-butyl acrylate group, ethylene glycol group, ethylene oxide group, ethylene group, propylene group, tetrafluoroethylene group, or vinyl chloride group.
12. The structure of claim 1, wherein each of R.sup.10 and R.sup.11 is independently hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane acrylate, or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen or C.sub.1-C.sub.5 alkyl.
13. The structure of claim 1, wherein said first block copolymer has the formula (FX7): ##STR00024## wherein R.sup.12 is independently a hydrogen, C.sub.1-C.sub.30 alkyl, C.sub.3-C.sub.30 cycloalkyl, C.sub.5-C.sub.30 aryl, C.sub.5-C.sub.30 heteroaryl, C.sub.1-C.sub.30 acyl, C.sub.1-C.sub.30 hydroxyl, C.sub.1-C.sub.30 alkoxy, C.sub.2-C.sub.30 alkenyl, C.sub.2-C.sub.30 alkynyl, C.sub.5-C.sub.30 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.30 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, silsesquioxane, C.sub.2-C.sub.30 halocarbon chain, C.sub.2-C.sub.30 perfluorocarbon, C.sub.2-C.sub.30 polyethylene glycol, a metal, or a metal complex, wherein each of R.sup.30-R.sup.42 is independently H, C.sub.5-C.sub.10 aryl or C.sub.1-C.sub.10 alkyl; and wherein R.sup.1 and R.sup.12 are different groups.
14. The structure of claim 13, wherein R.sup.1 is a C.sub.1-C.sub.30 alkyl and R.sup.12 is a C.sub.5-C.sub.30 aryl.
15. The structure of claim 13, having the formula (FX8a) or (FX8b): ##STR00025## wherein each of r, s, t and v are independently an integer selected from the range of 1 to 10.
16. The structure of claim 1 wherein said second polymer block comprises said second wedge groups.
17. The structure of claim 16, wherein each of said second wedge groups is characterized by at least two branch points each terminating in an independent terminating branch moiety comprising at least 4 atoms.
18. The structure of claim 16, wherein each of the second wedge groups is characterized by at least three branching points each terminating in an independent terminating branch moiety comprising at least 10 atoms.
19. The structure of claim 16, wherein each of said second wedge groups independently comprises a C.sub.2-C.sub.30 alkyl, C.sub.3-C.sub.30 cycloalkyl, C.sub.5-C.sub.30 aryl, C.sub.5-C.sub.30 heteroaryl, C.sub.2-C.sub.30 ester, C.sub.2-C.sub.30 ether, C.sub.2-C.sub.30 thioether, C.sub.2-C.sub.30 amine, C.sub.2-C.sub.30 imide, C.sub.2-C.sub.30 halocarbon chain, C.sub.2-C.sub.30 perfluorocarbon or C.sub.2-C.sub.30 polyethylene glycol.
20. The structure of claim 16, wherein each of said second wedge groups independently comprises a group derived from a substituted or unsubstituted adamantane, silsesquioxane, norbornane, terpenoid, polyethylene glycol, or borneol.
21. The structure of claim 1, wherein each of L.sup.1 and L.sup.2, is independently a single bond, (CH.sub.2).sub.q, (CH.sub.2).sub.qO(CH.sub.2).sub.r, (CH.sub.2).sub.qS(CH.sub.2).sub.r, (CH.sub.2).sub.qO.sub.2(CH.sub.2).sub.r, (CH.sub.2).sub.qSO(CH.sub.2).sub.r, (CH.sub.2).sub.qSO.sub.2(CH.sub.2).sub.r, (CH.sub.2).sub.qSO.sub.3(CH.sub.2).sub.r, (CH.sub.2).sub.qOSO.sub.2(CH.sub.2).sub.r, (CH.sub.2).sub.qNR.sup.19(CH.sub.2).sub.r, (CH.sub.2).sub.qCO(CH.sub.2).sub.r, (CH.sub.2).sub.qCOO(CH.sub.2).sub.r, (CH.sub.2).sub.qOCO(CH.sub.2).sub.r, (CH.sub.2).sub.qOCOO(CH.sub.2).sub.r, (CH.sub.2).sub.qCONR.sup.20(CH.sub.2).sub.r, (CH.sub.2).sub.qNR.sup.21CO(CH.sub.2).sub.r, (CH.sub.2).sub.qOCONR.sup.22(CH.sub.2).sub.r, (CH.sub.2).sub.qNR.sup.23COO(CH.sub.2).sub.r, or (CH.sub.2).sub.qNR.sup.24CONR.sup.25(CH.sub.2).sub.r; wherein each of R.sup.19-R.sup.25 is independently hydrogen or C.sub.1-C.sub.5 alkyl; and wherein each of q and r is independently an integer selected from the range of 0 to 10.
22. The structure of claim 1, wherein each of R.sup.10 and R.sup.11 is independently a hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, acrylate or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen or C.sub.1-C.sub.5 alkyl.
23. A method of modulating incident electromagnetic radiation; said method comprising: providing a structure comprising a supramolecular assembly of a polymer blend of at least one block copolymer and at least a second component; wherein said polymer blend comprises: (i) a first block copolymer comprising: a first polymer block comprising first repeating units; wherein each of said first repeating units of said first polymer block comprises a first polymer backbone group covalently linked to a first polymer side chain group; and a second polymer block comprising second repeating units; wherein each of said second repeating units of said second polymer block comprises a second polymer backbone group covalently linked to a second polymer side chain group or second wedge group that is different than said first polymer side chain group; and (ii) the second component having a composition that is different from said first block copolymer; wherein said first block copolymer has the formula (FX6A) or (FX6B1): ##STR00026## K is a repeating group of said second polymer side chain group, G.sup.2 is said second wedge group; each of R.sup.10 and R.sup.11 is independently a polymer side chain terminating group: L.sup.1 is a first linking group; L.sup.2 is a second linking group; each of n and m is independently an integer selected from the range of 20 to 2000; each of p and q is independently an integer selected from the range of 30 to 2000; R.sup.1 is independently a hydrogen, C.sub.1-C.sub.30 alkyl, C.sub.3-C.sub.30 cycloalkyl, C.sub.5-C.sub.30 aryl, C.sub.5-C.sub.30 heteroaryl, C.sub.1-C.sub.30 acyl, C.sub.1-C.sub.30 hydroxyl, C.sub.1-C.sub.30 alkoxy, C.sub.2-C.sub.30 alkenyl, C.sub.2-C.sub.30 alkynyl, C.sub.5-C.sub.30 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.30 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, silsesquioxane, C.sub.2-C.sub.30 halocarbon chain, C.sub.2-C.sub.30 perfluorocarbon, C.sub.2-C.sub.30 polyethylene glycol, a metal, or a metal complex, wherein each of R.sup.30-R.sup.42 is independently H, C.sub.5-C.sub.10 aryl or C.sub.1-C.sub.10 alkyl; and wherein each of Q.sup.1 and Q.sup.2 is independently hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, acrylate, or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen, C.sub.1-C.sub.10 alkyl or C.sub.5-C.sub.10 aryl; and directing said incident electromagnetic radiation on to said structure.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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STATEMENTS REGARDING CHEMICAL COMPOUNDS AND NOMENCLATURE
(16) In an embodiment, a composition or compound of the invention is isolated or purified. In an embodiment, an isolated or purified compound is at least partially isolated or purified as would be understood in the art. In an embodiment, the composition or compound of the invention has a chemical purity of at least 95%, optionally for some applications at least 99%, optionally for some applications at least 99.9%, optionally for some applications at least 99.99%, and optionally for some applications at least 99.999% pure.
(17) As used herein, the term polymer refers to a molecule composed of repeating structural units connected by covalent chemical bonds often characterized by a substantial number of repeating units (e.g., equal to or greater than 10 repeating units and often equal to or greater than 50 repeating units and often equal to or greater than 100 repeating units) and a high molecular weight (e.g. greater than or equal to 50,000 Da). Polymers are commonly the polymerization product of one or more monomer precursors. The term polymer includes homopolymers, or polymers consisting essentially of a single repeating monomer subunit. The term polymer also includes copolymers which are formed when two or more different types of monomers are linked in the same polymer. Copolymers may comprise two or more monomer subunits, and include random, block, alternating, segmented, grafted, tapered and other copolymers. Useful polymers include organic polymers or inorganic polymers that may be in amorphous, semi-amorphous, crystalline or partially crystalline states. Cross linked polymers having linked monomer chains are useful for some applications.
(18) An oligomer refers to a molecule composed of repeating structural units connected by covalent chemical bonds often characterized by a number of repeating units less than that of a polymer (e.g., equal to or less than 10 repeating units) and a lower molecular weights (e.g. less than or equal to 50,000 Da) than polymers. Oligomers may be the polymerization product of one or more monomer precursors.
(19) Block copolymers are a type of copolymer comprising blocks or spatially segregated domains, wherein different domains comprise different polymerized monomers, for example, including at least two chemically distinguishable blocks. Block copolymers may further comprise one or more other structural domains, such as hydrophobic groups, hydrophilic groups, etc. In a block copolymer, adjacent blocks are constitutionally different, i.e. adjacent blocks comprise constitutional units derived from different species of monomer or from the same species of monomer but with a different composition or sequence distribution of constitutional units. Different blocks (or domains) of a block copolymer may reside on different ends or the interior of a polymer (e.g. [A][B]), or may be provided in a selected sequence ([A][B][A][B]). Diblock copolymer refers to block copolymer having two different chemical blocks.
(20) Polymer backbone group refers to groups that are covalently linked to make up a backbone of a polymer, such as a block copolymer. Polymer backbone groups may be linked to side chain groups, such as wedge groups and polymer side chain groups. Some polymer backbone groups useful in the present compositions are derived from polymerization of a monomer selected from the group consisting of a substituted or unsubstituted norbornene, olefin, cyclic olefin, norbornene anhydride, cyclooctene, cyclopentadiene, styrene and acrylate. Some polymer backbone groups useful in the present compositions are obtained from a ring opening metathesis polymerization (ROMP) reaction. Polymer backbones may terminate in a range of backbone terminating groups including hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane, acrylate, or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen, C.sub.1-C.sub.10 alkyl or C.sub.5-C.sub.10 aryl.
(21) Wedge group refers to a group covalently linked to a polymer backbone group that comprises a branched moiety, optionally imparting steric properties to the polymer. In an embodiment, for example, a wedge group is characterized by at least two branch points, optionally at least three, each terminating in an independent terminating branch moiety comprising at least 4 atoms, and optionally at least 10 atoms, and optionally at least 20 atoms and optionally at least 50 atoms. A wedge group may be directly or indirectly linked to the polymer back bone group. In some embodiments, wedge groups provide steric bulk and/or interactions that result in an extended polymer backbone and/or a rigid polymer backbone.
(22) Wedge-type block copolymer refers a block copolymer that comprises at least one polymer block comprising wedge groups directly or indirectly linked to the polymer backbone. Wedge-type block copolymers include brush block copolymers having at least one polymer block comprising wedge groups directly or indirectly linked to a polymer back bone and at least one polymer block comprising polymer side chain groups directly or indirectly linked to a polymer back bone.
(23) Polymer side chain group refers to a group covalently linked to a polymer backbone group that comprises a polymer side chain, optionally imparting steric properties to the polymer. In an embodiment, for example, a polymer side chain group is characterized by a plurality of repeating units having the same, or similar, chemical composition. A polymer side chain group may be directly or indirectly linked to the polymer back bone groups. In some embodiments, polymer side chain groups provide steric bulk and/or interactions that result in an extended polymer backbone and/or a rigid polymer backbone. Some polymer side chain groups useful in the present compositions include unsubstituted or substituted unsubstituted or substituted polyisocyanate group, polymethacrylate group, polyacrylate group, polymethacrylamide group, polyacrylamide group, polyquinoxaline group, polyguanidine group, polysilane group, polyacetylene group, polyamino acid group, polypeptide group, polychloral group, polylactide group, polystyrene group, polyacrylate group, poly tert-butyl acrylate group, polymethyl methacrylate group, polysiloxane group, polydimethylsiloxane group, poly n-butyl acrylate group, polyethylene glycol group, polyethylene oxide group, polyethylene group, polypropylene group, polytetrafluoroethylene group, and polyvinyl chloride group. Some polymer side chain groups useful in the present compositions comprise repeating units obtained via anionic polymerization, cationic polymerization, free radical polymerization, group transfer polymerization, or ring-opening polymerization. A polymer side chain may terminate in a wide range of polymer side chain terminating groups including hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.5-C.sub.10 aryl, C.sub.5-C.sub.10 heteroaryl, C.sub.1-C.sub.10 acyl, C.sub.1-C.sub.10 hydroxyl, C.sub.1-C.sub.10 alkoxy, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.5-C.sub.10 alkylaryl, CO.sub.2R.sup.30, CONR.sup.31R.sup.32, COR.sup.33, SOR.sup.34, OSR.sup.35, SO.sub.2R.sup.36, OR.sup.37, SR.sup.38, NR.sup.39R.sup.40, NR.sup.41COR.sup.42, C.sub.1-C.sub.10 alkyl halide, phosphonate, phosphonic acid, silane, siloxane acrylate, or catechol; wherein each of R.sup.30-R.sup.42 is independently hydrogen or C.sub.1-C.sub.5 alkyl.
(24) Polymer blend refers to a mixture comprising at least one polymer, such as a block copolymer, and at least one additional component, and optionally more than one additional component. In some embodiments, for example, a polymer blend of the invention comprises a first block copolymer and one or more additional component comprising a homopolymer, a copolymer, a block copolymer, a brush block copolymer, an oligomer, a solvent, a metal, a metal oxide, a ceramic, a liquid, a small molecule (e.g., molecular weight less than 500 Da, optionally less than 100 Da), a particle or any combination of these. Polymer blends useful for some applications comprise a first block copolymer, such as a brush block copolymer or a wedge-type block copolymer, and one or more additional components comprising block copolymers, brush block copolymers, wedge-type block copolymers, linear block copolymers, random copolymers, homopolymers, or any combinations of these. Polymer blends of the invention include mixture of two, three, four, five and more components.
(25) As used herein, the term group may refer to a functional group of a chemical compound. Groups of the present compounds refer to an atom or a collection of atoms that are a part of the compound. Groups of the present invention may be attached to other atoms of the compound via one or more covalent bonds. Groups may also be characterized with respect to their valence state. The present invention includes groups characterized as monovalent, divalent, trivalent, etc. valence states.
(26) As used herein, the term substituted refers to a compound wherein a hydrogen is replaced by another functional group.
(27) As is customary and well known in the art, hydrogen atoms in formulas (FX1a)-(FX10h) and (W1)-(W10) are not always explicitly shown, for example, hydrogen atoms bonded to the carbon atoms of aromatic, heteroaromatic, and alicyclic rings are not always explicitly shown in formulas (FX1a)-(FX10h) and (W1)-(W10). The structures provided herein, for example in the context of the description of formulas (FX1a)-(FX10h) and (W1)-(W10) and schematics and structures in the drawings, are intended to convey to one of reasonable skill in the art the chemical composition of compounds of the methods and compositions of the invention, and as will be understood by one of skill in the art, the structures provided do not indicate the specific positions and/or orientations of atoms and the corresponding bond angles between atoms of these compounds.
(28) As used herein, the terms alkylene and alkylene group are used synonymously and refer to a divalent group derived from an alkyl group as defined herein. The invention includes compounds having one or more alkylene groups. Alkylene groups in some compounds function as linking and/or spacer groups. Compounds of the invention may have substituted and/or unsubstituted C.sub.1-C.sub.20 alkylene, C.sub.1-C.sub.10 alkylene and C.sub.1-C.sub.5 alkylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(29) As used herein, the terms cycloalkylene and cycloalkylene group are used synonymously and refer to a divalent group derived from a cycloalkyl group as defined herein. The invention includes compounds having one or more cycloalkylene groups. Cycloalkyl groups in some compounds function as linking and/or spacer groups. Compounds of the invention may have substituted and/or unsubstituted C.sub.3-C.sub.20 cycloalkylene, C.sub.3-C.sub.10 cycloalkylene and C.sub.3-C.sub.5 cycloalkylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(30) As used herein, the terms arylene and arylene group are used synonymously and refer to a divalent group derived from an aryl group as defined herein. The invention includes compounds having one or more arylene groups. In some embodiments, an arylene is a divalent group derived from an aryl group by removal of hydrogen atoms from two intra-ring carbon atoms of an aromatic ring of the aryl group. Arylene groups in some compounds function as linking and/or spacer groups. Arylene groups in some compounds function as chromophore, fluorophore, aromatic antenna, dye and/or imaging groups. Compounds of the invention include substituted and/or unsubstituted C.sub.3-C.sub.30 arylene, C.sub.3-C.sub.20 arylene, C.sub.3-C.sub.10 arylene and C.sub.1-C.sub.5 arylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(31) As used herein, the terms heteroarylene and heteroarylene group are used synonymously and refer to a divalent group derived from a heteroaryl group as defined herein. The invention includes compounds having one or more heteroarylene groups. In some embodiments, a heteroarylene is a divalent group derived from a heteroaryl group by removal of hydrogen atoms from two intra-ring carbon atoms or intra-ring nitrogen atoms of a heteroaromatic or aromatic ring of the heteroaryl group. Heteroarylene groups in some compounds function as linking and/or spacer groups. Heteroarylene groups in some compounds function as chromophore, aromatic antenna, fluorophore, dye and/or imaging groups. Compounds of the invention include substituted and/or unsubstituted C.sub.3-C.sub.30 heteroarylene, C.sub.3-C.sub.20 heteroarylene, C.sub.1-C.sub.10 heteroarylene and C.sub.3-C.sub.5 heteroarylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(32) As used herein, the terms alkenylene and alkenylene group are used synonymously and refer to a divalent group derived from an alkenyl group as defined herein. The invention includes compounds having one or more alkenylene groups. Alkenylene groups in some compounds function as linking and/or spacer groups. Compounds of the invention include substituted and/or unsubstituted C.sub.2-C.sub.20 alkenylene, C.sub.2-C.sub.10 alkenylene and C.sub.2-C.sub.5 alkenylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(33) As used herein, the terms cylcoalkenylene and cylcoalkenylene group are used synonymously and refer to a divalent group derived from a cylcoalkenyl group as defined herein. The invention includes compounds having one or more cylcoalkenylene groups. Cycloalkenylene groups in some compounds function as linking and/or spacer groups. Compounds of the invention include substituted and/or unsubstituted C.sub.3-C.sub.20 cylcoalkenylene, C.sub.3-C.sub.10 cylcoalkenylene and C.sub.3-C.sub.5 cylcoalkenylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(34) As used herein, the terms alkynylene and alkynylene group are used synonymously and refer to a divalent group derived from an alkynyl group as defined herein. The invention includes compounds having one or more alkynylene groups. Alkynylene groups in some compounds function as linking and/or spacer groups. Compounds of the invention include substituted and/or unsubstituted C.sub.2-C.sub.20 alkynylene, C.sub.2-C.sub.10 alkynylene and C.sub.2-C.sub.5 alkynylene groups, for example, as one or more linking groups (e.g. L.sup.1-L.sup.4 and/or W.sup.1-W.sup.5).
(35) As used herein, the term halo refers to a halogen group such as a fluoro (F), chloro (Cl), bromo (Br), iodo (I) or astato (At).
(36) The term heterocyclic refers to ring structures containing at least one other kind of atom, in addition to carbon, in the ring. Examples of such heteroatoms include nitrogen, oxygen and sulfur. Heterocyclic rings include heterocyclic alicyclic rings and heterocyclic aromatic rings. Examples of heterocyclic rings include, but are not limited to, pyrrolidinyl, piperidyl, imidazolidinyl, tetrahydrofuryl, tetrahydrothienyl, furyl, thienyl, pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrazinyl, indolyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, pyridinyl, benzoxadiazolyl, benzothiadiazolyl, triazolyl and tetrazolyl groups. Atoms of heterocyclic rings can be bonded to a wide range of other atoms and functional groups, for example, provided as substituents.
(37) The term carbocyclic refers to ring structures containing only carbon atoms in the ring. Carbon atoms of carbocyclic rings can be bonded to a wide range of other atoms and functional groups, for example, provided as substituents.
(38) The term alicyclic ring refers to a ring, or plurality of fused rings, that is not an aromatic ring. Alicyclic rings include both carbocyclic and heterocyclic rings.
(39) The term aromatic ring refers to a ring, or a plurality of fused rings, that includes at least one aromatic ring group. The term aromatic ring includes aromatic rings comprising carbon, hydrogen and heteroatoms. Aromatic ring includes carbocyclic and heterocyclic aromatic rings. Aromatic rings are components of aryl groups.
(40) The term fused ring or fused ring structure refers to a plurality of alicyclic and/or aromatic rings provided in a fused ring configuration, such as fused rings that share at least two intra ring carbon atoms and/or heteroatoms.
(41) As used herein, the term alkoxyalkyl refers to a substituent of the formula alkyl-O-alkyl.
(42) As used herein, the term polyhydroxyalkyl refers to a substituent having from 2 to 12 carbon atoms and from 2 to 5 hydroxyl groups, such as the 2,3-dihydroxypropyl, 2,3,4-trihydroxybutyl or 2,3,4,5-tetrahydroxypentyl residue.
(43) As used herein, the term polyalkoxyalkyl refers to a substituent of the formula alkyl-(alkoxy).sub.n-alkoxy wherein n is an integer from 1 to 10, preferably 1 to 4, and more preferably for some embodiments 1 to 3.
(44) Amino acids include glycine, alanine, valine, leucine, isoleucine, methionine, proline, phenylalanine, tryptophan, asparagine, glutamine, glycine, serine, threonine, serine, rhreonine, asparagine, glutamine, tyrosine, cysteine, lysine, arginine, histidine, aspartic acid and glutamic acid. As used herein, reference to a side chain residue of a natural -amino acid specifically includes the side chains of the above-referenced amino acids. Peptides are comprised of two or more amino-acid connected via peptide bonds.
(45) Alkyl groups include straight-chain, branched and cyclic alkyl groups. Alkyl groups include those having from 1 to 30 carbon atoms. Alkyl groups include small alkyl groups having 1 to 3 carbon atoms. Alkyl groups include medium length alkyl groups having from 4-10 carbon atoms. Alkyl groups include long alkyl groups having more than 10 carbon atoms, particularly those having 10-30 carbon atoms. The term cycloalkyl specifically refers to an alky group having a ring structure such as ring structure comprising 3-30 carbon atoms, optionally 3-20 carbon atoms and optionally 2-10 carbon atoms, including an alkyl group having one or more rings. Cycloalkyl groups include those having a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-member carbon ring(s) and particularly those having a 3-, 4-, 5-, 6-, or 7-member ring(s). The carbon rings in cycloalkyl groups can also carry alkyl groups. Cycloalkyl groups can include bicyclic and tricycloalkyl groups. Alkyl groups are optionally substituted. Substituted alkyl groups include among others those which are substituted with aryl groups, which in turn can be optionally substituted. Specific alkyl groups include methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, s-butyl, t-butyl, cyclobutyl, n-pentyl, branched-pentyl, cyclopentyl, n-hexyl, branched hexyl, and cyclohexyl groups, all of which are optionally substituted. Substituted alkyl groups include fully halogenated or semihalogenated alkyl groups, such as alkyl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted alkyl groups include fully fluorinated or semifluorinated alkyl groups, such as alkyl groups having one or more hydrogens replaced with one or more fluorine atoms. An alkoxy group is an alkyl group that has been modified by linkage to oxygen and can be represented by the formula RO and can also be referred to as an alkyl ether group. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy and heptoxy. Alkoxy groups include substituted alkoxy groups wherein the alky portion of the groups is substituted as provided herein in connection with the description of alkyl groups. As used herein MeO refers to CH.sub.3O. Compositions of some embodiments of the invention comprise alkyl groups as terminating groups, such as polymer backbone terminating groups and/or polymer side chain terminating groups.
(46) Alkenyl groups include straight-chain, branched and cyclic alkenyl groups. Alkenyl groups include those having 1, 2 or more double bonds and those in which two or more of the double bonds are conjugated double bonds. Alkenyl groups include those having from 2 to 20 carbon atoms. Alkenyl groups include small alkenyl groups having 2 to 3 carbon atoms. Alkenyl groups include medium length alkenyl groups having from 4-10 carbon atoms. Alkenyl groups include long alkenyl groups having more than 10 carbon atoms, particularly those having 10-20 carbon atoms. Cycloalkenyl groups include those in which a double bond is in the ring or in an alkenyl group attached to a ring. The term cycloalkenyl specifically refers to an alkenyl group having a ring structure, including an alkenyl group having a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-member carbon ring(s) and particularly those having a 3-, 4-, 5-, 6- or 7-member ring(s). The carbon rings in cycloalkenyl groups can also carry alkyl groups. Cycloalkenyl groups can include bicyclic and tricyclic alkenyl groups. Alkenyl groups are optionally substituted. Substituted alkenyl groups include among others those which are substituted with alkyl or aryl groups, which groups in turn can be optionally substituted. Specific alkenyl groups include ethenyl, prop-1-enyl, prop-2-enyl, cycloprop-1-enyl, but-1-enyl, but-2-enyl, cyclobut-1-enyl, cyclobut-2-enyl, pent-1-enyl, pent-2-enyl, branched pentenyl, cyclopent-1-enyl, hex-1-enyl, branched hexenyl, cyclohexenyl, all of which are optionally substituted. Substituted alkenyl groups include fully halogenated or semihalogenated alkenyl groups, such as alkenyl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted alkenyl groups include fully fluorinated or semifluorinated alkenyl groups, such as alkenyl groups having one or more hydrogen atoms replaced with one or more fluorine atoms. Compositions of some embodiments of the invention comprise alkenyl groups as terminating groups, such as polymer backbone terminating groups and/or polymer side chain terminating groups.
(47) Aryl groups include groups having one or more 5-, 6- or 7-member aromatic rings, including heterocyclic aromatic rings. The term heteroaryl specifically refers to aryl groups having at least one 5-, 6- or 7-member heterocyclic aromatic rings. Aryl groups can contain one or more fused aromatic rings, including one or more fused heteroaromatic rings, and/or a combination of one or more aromatic rings and one or more nonaromatic rings that may be fused or linked via covalent bonds. Heterocyclic aromatic rings can include one or more N, O, or S atoms in the ring. Heterocyclic aromatic rings can include those with one, two or three N atoms, those with one or two O atoms, and those with one or two S atoms, or combinations of one or two or three N, O or S atoms. Aryl groups are optionally substituted. Substituted aryl groups include among others those which are substituted with alkyl or alkenyl groups, which groups in turn can be optionally substituted. Specific aryl groups include phenyl, biphenyl groups, pyrrolidinyl, imidazolidinyl, tetrahydrofuryl, tetrahydrothienyl, furyl, thienyl, pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrazinyl, indolyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl, pyridinyl, benzoxadiazolyl, benzothiadiazolyl, and naphthyl groups, all of which are optionally substituted. Substituted aryl groups include fully halogenated or semihalogenated aryl groups, such as aryl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted aryl groups include fully fluorinated or semifluorinated aryl groups, such as aryl groups having one or more hydrogens replaced with one or more fluorine atoms. Aryl groups include, but are not limited to, aromatic group-containing or heterocylic aromatic group-containing groups corresponding to any one of the following: benzene, naphthalene, naphthoquinone, diphenylmethane, fluorene, anthracene, anthraquinone, phenanthrene, tetracene, tetracenedione, pyridine, quinoline, isoquinoline, indoles, isoindole, pyrrole, imidazole, oxazole, thiazole, pyrazole, pyrazine, pyrimidine, purine, benzimidazole, furans, benzofuran, dibenzofuran, carbazole, acridine, acridone, phenanthridine, thiophene, benzothiophene, dibenzothiophene, xanthene, xanthone, flavone, coumarin, azulene or anthracycline. As used herein, a group corresponding to the groups listed above expressly includes an aromatic or heterocyclic aromatic group, including monovalent, divalent and polyvalent groups, of the aromatic and heterocyclic aromatic groups listed herein are provided in a covalently bonded configuration in the compounds of the invention at any suitable point of attachment. In embodiments, aryl groups contain between 5 and 30 carbon atoms. In embodiments, aryl groups contain one aromatic or heteroaromatic six-membered ring and one or more additional five- or six-membered aromatic or heteroaromatic ring. In embodiments, aryl groups contain between five and eighteen carbon atoms in the rings. Aryl groups optionally have one or more aromatic rings or heterocyclic aromatic rings having one or more electron donating groups, electron withdrawing groups and/or targeting ligands provided as substituents. Compositions of some embodiments of the invention comprise aryl groups as terminating groups, such as polymer backbone terminating groups and/or polymer side chain terminating groups.
(48) Arylalkyl groups are alkyl groups substituted with one or more aryl groups wherein the alkyl groups optionally carry additional substituents and the aryl groups are optionally substituted. Specific alkylaryl groups are phenyl-substituted alkyl groups, e.g., phenylmethyl groups. Alkylaryl groups are alternatively described as aryl groups substituted with one or more alkyl groups wherein the alkyl groups optionally carry additional substituents and the aryl groups are optionally substituted. Specific alkylaryl groups are alkyl-substituted phenyl groups such as methylphenyl. Substituted arylalkyl groups include fully halogenated or semihalogenated arylalkyl groups, such as arylalkyl groups having one or more alkyl and/or aryl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Compositions of some embodiments of the invention comprise arylalkyl groups as terminating groups, such as polymer backbone terminating groups and/or polymer side chain terminating groups.
(49) As to any of the groups described herein which contain one or more substituents, it is understood that such groups do not contain any substitution or substitution patterns which are sterically impractical and/or synthetically non-feasible. Optional substitution of alkyl groups includes substitution with one or more alkenyl groups, aryl groups or both, wherein the alkenyl groups or aryl groups are optionally substituted. Optional substitution of alkenyl groups includes substitution with one or more alkyl groups, aryl groups, or both, wherein the alkyl groups or aryl groups are optionally substituted. Optional substitution of aryl groups includes substitution of the aryl ring with one or more alkyl groups, alkenyl groups, or both, wherein the alkyl groups or alkenyl groups are optionally substituted.
(50) Optional substituents for any alkyl, alkenyl and aryl group includes substitution with one or more of the following substituents, among others:
(51) halogen, including fluorine, chlorine, bromine or iodine;
(52) pseudohalides, including CN; COOR where R is a hydrogen or an alkyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, or phenyl group all of which groups are optionally substituted; COR where R is a hydrogen or an alkyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, or phenyl group all of which groups are optionally substituted; CON(R).sub.2 where each R, independently of each other R, is a hydrogen or an alkyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, or phenyl group all of which groups are optionally substituted; and where R and R can form a ring which can contain one or more double bonds and can contain one or more additional carbon atoms; OCON(R).sub.2 where each R, independently of each other R, is a hydrogen or an alkyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, or phenyl group all of which groups are optionally substituted; and where R and R can form a ring which can contain one or more double bonds and can contain one or more additional carbon atoms; N(R).sub.2 where each R, independently of each other R, is a hydrogen, or an alkyl group, or an acyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, phenyl or acetyl group, all of which are optionally substituted; and where R and R can form a ring which can contain one or more double bonds and can contain one or more additional carbon atoms; SR, where R is hydrogen or an alkyl group or an aryl group and more specifically where R is hydrogen, methyl, ethyl, propyl, butyl, or a phenyl group, which are optionally substituted;
(53) SO.sub.2R, or SOR where R is an alkyl group or an aryl group and more specifically where R is a methyl, ethyl, propyl, butyl, or phenyl group, all of which are optionally substituted; OCOOR where R is an alkyl group or an aryl group; SO.sub.2N(R).sub.2 where each R, independently of each other R, is a hydrogen, or an alkyl group, or an aryl group all of which are optionally substituted and wherein R and R can form a ring which can contain one or more double bonds and can contain one or more additional carbon atoms; OR where R is H, an alkyl group, an aryl group, or an acyl group all of which are optionally substituted. In a particular example R can be an acyl yieldingOCOR where R is a hydrogen or an alkyl group or an aryl group and more specifically where R is methyl, ethyl, propyl, butyl, or phenyl groups all of which groups are optionally substituted.
(54) Specific substituted alkyl groups include haloalkyl groups, particularly trihalomethyl groups and specifically trifluoromethyl groups. Specific substituted aryl groups include mono-, di-, tri, tetra- and pentahalo-substituted phenyl groups; mono-, di-, tri-, tetra-, penta-, hexa-, and hepta-halo-substituted naphthalene groups; 3- or 4-halo-substituted phenyl groups, 3- or 4-alkyl-substituted phenyl groups, 3- or 4-alkoxy-substituted phenyl groups, 3- or 4-RCO-substituted phenyl, 5- or 6-halo-substituted naphthalene groups. More specifically, substituted aryl groups include acetylphenyl groups, particularly 4-acetylphenyl groups; fluorophenyl groups, particularly 3-fluorophenyl and 4-fluorophenyl groups; chlorophenyl groups, particularly 3-chlorophenyl and 4-chlorophenyl groups; methylphenyl groups, particularly 4-methylphenyl groups; and methoxyphenyl groups, particularly 4-methoxyphenyl groups.
(55) As to any of the above groups which contain one or more substituents, it is understood that such groups do not contain any substitution or substitution patterns which are sterically impractical and/or synthetically non-feasible.
DETAILED DESCRIPTION OF THE INVENTION
(56) In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art.
(57) The invention is further detailed in the following Examples, which are offered by way of illustration and are not intended to limit the scope of the invention in any manner.
Example 1: Synthesis of Isocyanate-Based Brush Block Copolymers and their Rapid Self-Assembly to Infrared Reflecting Photonic Crystals
(58) Abstract
(59) The synthesis of rigid-rod, helical isocyanate-based macromonomers was achieved through the polymerization of hexyl isocyanate and 4-phenylbutyl isocyanate, initiated by an exo-norbornene functionalized half-titanocene complex. Sequential ruthenium-mediated ring-opening metathesis polymerization of these macromonomers readily afforded well-defined brush block copolymers, with precisely tunable molecular weights ranging from high (1512 kDa) to ultra-high (7119 kDa), while maintaining narrow molecular weight distributions (PDI=1.08-1.39). The self-assembly of these brush block copolymers to solid-state thin-films and their photonic properties were investigated. Due to the rigid architecture of these novel polymeric materials, they rapidly self-assemble through simple controlled evaporation to photonic crystal materials that reflect light from the UV, through the visible, to the near infrared. The wavelength of reflectance is linearly related to the brush block copolymer molecular weight, allowing for predictable tuning of the band gap through synthetic control of the polymer molecular weight. A combination of scanning electron microscopy and optical modeling were employed to explain the origin of reflectivity.
(60) Introduction
(61) Urbanization is causing a cascade of negative effects on the environment..sup.1 A readily apparent example on a local scale is the urban heat island (UHI) effect, the phenomenon that urban areas often have higher local temperatures than surrounding areas..sup.2 A major cause of UHIs is the absorption and thermalization of solar energy by modern building materials. A tremendous amount of money and energy is consumed towards cooling in these areas,.sup.3 resulting in increased pollution.sup.4 and degraded living conditions..sup.5 To minimize the negative effects of urbanization on the environment, great efforts have been directed towards urban design and the development of new technologies. Because the majority of solar energy is in the form of IR radiation, there is strong interest in developing IR-reflecting materials to prevent absorption and thermalization.
(62) Photonic crystals (PCs) are periodic composite materials with frequency specific reflection, which can be tuned to efficiently reflect IR light..sup.6 In these materials, the propagation of certain wavelengths of light is forbidden due to photonic band gaps that originate from the periodic modulation of the dielectric function. The wavelength of reflected light is related to the optical path length of the domains, which is determined by the size and refractive index of the components. PCs are most commonly synthesized through layer-by-layer depositions, lithography, or the self-assembly of colloidal crystals..sup.6 Unfortunately, these routes are expensive or impractical as large area PCs; a more desirable IR-reflective building material would be fabricated inexpensively from a commodity material, such as a polymer. In this context, the self-assembly of block copolymers (BCPs).sup.7 provides an attractive means to IR-reflecting PCs because of their low cost potential in terms of both raw material and bottom-up fabrication via self-assembly. However, most BCP PCs can only reflect short wavelengths of visible light..sup.8,9 This is because high molecular weight (MW) polymers, capable of forming large domains, exhibit extreme polymer chain entanglement that is detrimental to self-assembly and inhibits the formation of large, ordered morphologies. To overcome the inability of utilizing high MW BCPs to form polymer PCs that reflect long wavelengths of light, the domain sizes can be enlarged through swelling with additives, namely solvent molecules.sup.10 or homopolymers,.sup.11 although these approaches generally require complicated annealing procedures.
(63) Brush BCPs can self-assemble to long-wavelength reflecting PCs without the need for swelling agents..sup.12 By exploiting the advantageous characteristics (i.e. livingness, stability, as well as steric and functional group tolerance) of ruthenium (1) mediated ring-opening metathesis polymerization (ROMP).sup.13 we were able to synthesize well-defined brush BCPs constructed from lactide- and styrene-macromonomers (MMs)..sup.12,14 This grafting-through polymerization strategy of MMs affords highly uniform brush BCPs,.sup.15 where the sterically encumbered array of low MW side-chains greatly inhibits chain-entanglement and enforces the unifying main-chain to assume a highly elongated conformation..sup.16 As a result, these brush BCPs rapidly self-assembled to stacked lamellae of alternating layers of lactide and styrene domains, forming 1D PC architectures. Through controlled evaporation, the films exhibited a maximum peak wavelength (.sub.max) of reflectance as long as 540 nm, while thermal annealing under compression allowed ultra-high MW brush BCPs to self-assemble to PCs that reflected light as long as 1311 nm. Although the reported brush BCPs can assemble to IR-reflecting PCs after thermal annealing, we sought to develop a system that could assemble to such domain sizes under ambient conditions to enable widespread applications, including IR-reflecting paints. We envisioned that increasing the rigidity of the grafts would enhance the overall persistence length of the brush BCP, further decreasing chain-entanglement and promoting more rapid self-assembly of ultra-high MW BCPs to even larger domains. Reported herein is the synthesis of brush BCPs constructed from rigid isocyanate-based MMs and their rapid self-assembly through controlled evaporation to PCs that can reflect light from the UV, through the visible, and into the near-IR (see,
(64)
(65) Results and Discussion
(66) Chart 1.
(67) Structures of initiators and monomers utilized in this Example.
(68) ##STR00021##
Synthesis of Macromonomers and Brush (Block) Copolymers.
(69) Polyisocyanates are a class of polymers that adopt rigid helical secondary structures,.sup.17 and in the case of brush copolymers composed of a polystyrene main-chain and polyhexyl isocyanate side-chains, it has been shown that the rigid side-chains result in main-chain elongation, compared to similar graft copolymers with random-coil side-chains..sup.18 Thus, we found isocyanate-based MMs to be ideal candidates for investigating if increased side-chain rigidity would facilitate self-assembly to large domain sizes and long-wavelength reflecting PCs. Additionally, their controlled polymerization can be achieved utilizing half-titanocene (IV) alkoxide initiators, where the alkoxide group is quantitatively incorporated as a chain-end group on the polyisocyanate, providing an efficient means to prepare appropriately functionalized MMs..sup.19 Embracing this synthetic approach, an exo-norbornene half-titanocene derivative (2) was prepared in good yield from the reaction between CpTiCl.sub.3 and N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide in the presence of Et.sub.3N. Complex 2 was subsequently employed to produce exo-norbornene functionalized MMs from hexyl isocyanate (HICN, MM-1) and 4-phenyl butyl isocyanate (PBICN, MM-2). These MMs exhibited similar MWs (weight average MW (M.sub.w)=6.77 and 5.99 kDa for MM-1 and MM-2, respectively) and narrow molecular weight distributions (MWDs) (polydispersity index (PDI=M.sub.w/M.sub.n)=1.05 and 1.07 for MM-1 and MM-2, respectively). The ROMP of MM-1 and MM-2 initiated by 1 was efficient, and could be carried out over a broad range of [MM]:[1] ratios, achieving high MM conversion, producing high MW copolymers with narrow MWDs (Table 1). Closer examination of the ROMP of MM-1 shows that it exhibits living characteristics (i.e. linear increase in MW with increasing MM conversion, and a nearly constant PDI during the course of polymerization), necessary for successful synthesis of well-defined BCPs in a one-pot synthetic procedure (see,
(70)
(71) TABLE-US-00001 TABLE 1 Results of the ROMP of macromonomers mediated by 1..sup.a Run [MM]/ Time Conv M.sub.w PDI No. MM [1] (min) (%).sup.b (kDa).sup.b (M.sub.w/M.sub.n).sup.b 1 MM-1 50 50 98.5 364.9 1.03 2 MM-1 100 50 95.8 924.9 1.10 3 MM-1 150 70 95.7 1944 1.11 4 MM-1 200 90 97.0 2123 1.38 5 MM-1 250 150 93.7 3310 1.39 6 MM-2 150 100 90.7 1100 1.07 .sup.aPolymerizations performed in 3.01 mL THF at ambient temperature. [MM-1] = [MM-2] = 9.81 mM. .sup.bDetermined by Light Scattering.
(72) A similarly controlled ROMP of MM-2 was observed, although sluggish in comparison to the ROMP of MM-1. Nonetheless, ROMP of MM-2 reached high MM conversion, producing the well-defined brush copolymer (Run, 6, Table 1). To enable the production of well-defined brush BCPs a thorough characterization of the kinetic profile for the ROMP of the MM's is required. The kinetic study of the ROMP of MM-1 reveals a first-order dependence on [MM-1] for all [MM-1]:[1] ratios investigated (see,
(73) TABLE-US-00002 TABLE 2 Results of the block copolymerization of isocyanate macromonomers mediated by 1..sup.a PDI MM-1 Run [MM-1]:[MM- Time Yield M.sub.w (M.sub.w/ (mol .sub.max No. 2]:[1] (min).sup.b (%).sup.c (kDa).sup.d M.sub.n).sup.d %).sup.e (nm).sup.f 7 100:100:1 48 89.7 1512 1.08 52.4 334 8 150:150:1 64 86.7 2918 1.15 50.8 511 9 200:200:1 85 91.5 4167 1.20 49.9 664 10 215:215:1 94 85.4 5319 1.32 51.3 802 11 250:250:1 144 93.9 7119 1.39 52.3 1120 .sup.aPolymerizations performed in 3.01 mL THF at ambient temperature. [MM-1] = [MM-2] = 9.81 mM. .sup.bReaction time for polymerization of MM-1. Polymerization was allowed to proceed for 3 (runs 7-9) or 5 (runs 10 and 11) hours after the addition of MM-2. .sup.cIsolated Yield. .sup.dDetermined by Light Scattering. .sup.eDetermined by .sup.1H NMR. .sup.fMaximum peak wavelength of reflectance of the primary reflection for films prepared from the controlled evaporation from DCM.
(74) Self-Assembly and PC Properties of Brush BCPs.
(75) In this Example, we report the investigation into the ability of BCP polymers to rapidly self-assemble to PCs. Thin films of the polymers were prepared through controlled evaporation from DCM, THF, CHCl.sub.3, or toluene. In contrast to the previously reported lactide/styrene brush BCPs, no significant solvent effect was observed on self-assembly, as judged by the nearly identical reflectance spectra and .sub.max of the films. The self-assembly of these brush BCPs to ordered thin-films is dictated through a delicate interplay of factors, including solvent, kinetics, polymer interactions, as well as polymer/substrate interactions..sup.20 Our preliminary explanation for the negligible solvent effect is that the rigid architecture of the isocyanate brush BCPs promotes a highly elongated main-chain, minimizing solvent as well as polymer interactions. This represents a degree of pre-organization, which accelerates self-assembly to ordered morphologies. As such, films prepared from the controlled evaporation of DCM solutions were analyzed because it is the most volatile solvent and most strongly highlights the rapid self-assembly of the brush BCPs. The rapid self-assembly of the brush BCPs is qualitatively observed in that the samples with MWs of 1512, 2918, and 4167 kDa produced films that visually appeared violet, green, and red, respectively. Films fabricated from higher MW BCPs were white, suggesting that the ultra-high MW polymers were reflecting wavelengths of light beyond the visible spectrum.
(76)
(77) To quantitatively measure the PC crystal properties of these materials, reflectance measurements were acquired as a function of wavelength using a spectrophotometer with an integrating sphere diffuse reflectance accessory (see,
(78) To assign the morphology of the brush BCPs and gain insight into the origin of their PC properties, scanning electron microscopy (SEM) was performed on cross-sections of the films to directly image the polymer domains (see,
(79) When the polymer MW was increased further, unordered morphologies lacking any well-defined domains were observed in the SEM analysis (see,
(80)
(81) To further support the proposed origin of reflectivity, the polymer nanostructures were modeled using transfer matrix simulations (see,
Conclusion
(82) In conclusion, a series of well-defined (PDI=1.08-1.39) isocyanate-based brush block copolymers have been synthesized with high (1512 kDa) to ultra-high (7119 kDa) molecular weights. Due to the rigid-rod secondary structure of the isocyanate grafts, the self-assembly of these block copolymers is enhanced, such that they rapidly form well-ordered morphologies composed of stacked lamellae with large domain sizes. As the domain sizes are directly controlled by the polymer molecular weights, the wavelength of reflectance can be synthetically and predictably tuned from the UV to the near IR by manipulation of the polymer chain length. Visualization of the polymer morphology through SEM and optical modeling confirm that the origin of the reflective properties of these novel polymers is through their assembled into 1D photonic crystal architectures. These IR reflecting materials can be fabricated by the evaporation from a volatile solvent under ambient conditions, thus, they show promise as a new technology towards IR-reflecting coatings that can be applied as paints.
Experimental Section
(83) Materials and Methods.
(84) (H.sub.2IMes)(PPh.sub.3).sub.2(Cl).sub.2RuCHPh was recieved as a research gift from Materia Inc. and converted to 1 via literature procedure..sup.23 All other chemicals were purchased from Sigma Aldrich. Solvents were purified by passage through solvent purification columns and further degassed with argon..sup.24 Hexyl isocyanate and 4-phenylbutyl isocyanate were dried over CaH.sub.2 overnight and vacuum distilled. N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide was prepared according to literature procedure..sup.25
(85) All reactions were carried out in flamed Schlenk-type glassware on a dual-manifold Schlenk line or in a nitrogen-filled glovebox. NMR spectra were recorded on a Varian Inova 300 MHz spectrometer. Chemical shifts were referenced to internal solvent resonances and are reported as parts per million relative to tetramethylsilane. Polymer molecular weights were determined utilizing THF as the eluent by multi-angle light scattering (MALS) gel permeation chromatography (GPC) using a miniDAWN TREOS light scattering detector, a Viscostar viscometer, and an OptilabRex refractive index detector, all from Wyatt Technology. An Agilent 1200 UV-Vis detector was also present in the detector stack. Absolute molecular weights were determined using dn/dc values calculated by assuming 100% mass recovery of the polymer sample injected into the GPC. Polymer thin films were prepared from the controlled evaporation of polymer solutions (1.5 g/L) in dichloromethane onto glass slides that had been previously washed with methanol and hexane. After the solvent was allowed to evaporate, the samples were dried under vacuum overnight. SEM images were taken on a ZEISS 1550 VP Field Emission SEM. Reflection measurements were performed on a Cary 5000 UV/Vis/NIR spectrophotometer, equipped with an integrating sphere diffuse reflectance accessory (Internal DRA 1800). All measurements were referenced to a LabSphere Spectralon 99% certified reflectance standard. The samples were illuminated through a Spectralon-coated aperature with a diameter of 1 cm, with a beam area of approximately 0.5 cm.sup.2. The samples were scanned at a rate of 600 nm/min, with a 1 nm data interval, from 1800 to 200 nm, with a detector crossover (InGaAs to PMT) at 800 nm.
(86) Synthesis of CpTiCl.sub.2(C.sub.11H.sub.12NO.sub.3) (2):
(87) In a glovebox, a 25 mL flask was charged with 483 mg of CpTiCl.sub.3 (2.20 mmol), 10 mL benzene, and a stir bar. To the rapidly stirred solution was added dropwise a solution of N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide (457 mg, 2.20 mmol) and triethyl amine (223 mg, 2.20 mmol) in 10 mL of benzene. The reaction was allowed to stir for 2 h and was then filtered through a glass frit. The volatiles were removed from the filtrate affording a yellow solid. The solid was recrystallized from a toluene/pentane solvent mixture to afford 350 mg (40.7%) of the pure product.
(88) .sup.1H NMR (C.sub.6D.sub.6, 300 MHz, 25 C.): 6.16 (s, 5H), 5.70 (t, J=1.86 Hz, 2H), 4.28 (t, J=5.58 Hz, 2H), 3.40 (t, J=14.3 Hz, 2H), 3.05-3.03 (m, 2H), 2.29 (d, J=1.00 Hz, 2H), 1.29-1.21 (m, 2H). .sup.13C NMR (C.sub.6D.sub.6, 75 MHz, 25 C.): 177, 138, 120, 78.9, 48.4, 45.8, 43.6, 40.5. HRMS (FAB+): Calculated: 390.0149. Found: 390.0143.
(89) Poly(Hexyl Isocyanate) Macromonomer (MM-1):
(90) A 10 mL round bottom flask was charged with 460 mg of 2 (1.18 mmol), 250 L of THF, and a stir bar. To the stirred suspension was added 6.87 mL of hexyl isocyanate (47.2 mmol, 40 equiv.). The reaction was allowed to proceed for 21 h before being poured into 50 mL of methanol. The polymer was isolated by filtration, redissolved in methylene chloride, and precipitated again into 50 mL of methanol. MM-1 was isolated by filtration and dried under vacuum at ambient temperature to a constant weight (5.53 g, 92.2%).
(91) .sup.1H NMR (CDCl.sub.3, 300 MHz, 25 C.): 6.30 (bs), 4.28 (bs), 3.68 (bs), 3.08 (bs), 2.71 (bs), 1.62 (bs), 1.28 (bs), 1.12-1.01 (m). M.sub.w=6.77 kDa; PDI=1.05. dn/dc=0.0829 mL/g.
(92) Poly(4-Phenyl Butyl Isocyanate) Macromonomer (MM-2):
(93) A 10 mL round bottom flask was charged with 445 mg of 2 (1.14 mmol), 250 L of THF, and a stir bar. To the stirred suspension was added 1.94 mL of 4-phenyl butyl isocyanate (11.3 mmol, 10 equiv.). The reaction was allowed to proceed for 21 h before being poured into 50 mL of methanol. The polymer was isolated by filtration, redissolved in methylene chloride, and precipitated again into 50 mL of methanol. The polymer was isolated by filtration and dried under vacuum at ambient temperature to a constant weight (1.69 g, 84.4%).
(94) .sup.1H NMR (CDCl.sub.3, 300 MHz, 25 C.): 7.31-7.14 (m), 6.29 (bs), 4.20 (bs), 3.72 (bs), 3.25 (bs), 2.59 (bs), 1.63 (bs), 1.29-1.19 (m). M.sub.w=5.99 kDa; PDI=1.07. dn/dc=0.140 mL/g.
(95) Synthesis of Homo-Brush Polymers:
(96) A 20 mL vial was charged with a stir bar, 200 mg of MM-1 (29.5 mol) or 177 mg MM-2 (29.5 mol), and 3.0 mL of THF. With rapid stirring 10 L of an appropriate concentration of 1 in THF was quickly added via syringe. For kinetic analysis a 0.2 mL aliquot of the reaction solution was taken at pre-determined time intervals and injected into a 2.0 mL septum sealed vial containing a solution of 25 L of ethyl vinyl ether in 0.7 mL of THF. The aliquot was analyzed by GPC to determine the percent macromonomer conversion by comparing the peaks corresponding to the brush polymer and the unreacted macromonomer. The polymerization was quenched by the addition of 200 L of ethyl vinyl ether and addition of 25 mL of methanol. The mixture was allowed to stir for 1 hour, and the polymer was isolated by filtration and dried under vacuum at ambient temperature to a constant weight.
(97) Homo-Brush Polymer from MM-1: .sup.1H NMR (CDCl.sub.3, 300 MHz, 25 C.): 5.78 (bs), 3.94-3.3 (m), 3.68 (bs), 3.22 (bs), 1.85-1.45 (m), 1.28 (bs), 1.11-1.01 (bs), 0.87 (bs). dn/dc=0.0800 mL/g.
(98) Homo-Brush Polymer from MM-2: .sup.1H NMR (CDCl.sub.3, 300 MHz, 25 C.): 7.35-6.96 (m), 5.67 (bs), 3.91 (bs), 3.67 (bs), 3.25 (bs), 2.57 (bs), 1.52 (bs), 1.27 (bs). dn/dc=0.143 mL/g.
(99) Synthesis of Brush Block Copolymers:
(100) A 20 mL vial was charged with a stir bar, 200 mg of MM-1 (29.5 mol), and 3.0 mL of THF. With rapid stirring 10 L of an appropriate concentration of 1 in THF was quickly added via syringe. At predetermined time intervals 177 mg of MM-2 (29.5 mol) was added as a solid and the solution was allowed to react as specified in the polymerization tables. The polymerization was quenched by the addition of 200 L of ethyl vinyl ether and addition of 25 mL of methanol. The mixture was allowed to stir for 1 hour, and the polymer was isolated by filtration and dried under vacuum at ambient temperature to a constant weight. No unreacted macromonomer was present in the isolated brush block copolymer, as determined by GPC analysis.
(101) .sup.1H NMR (CDCl.sub.3, 300 MHz, 25 C.): 7.35-6.96 (m), 5.67 (bs), 4.18-3.33 (m), 3.23 (bs), 2.54 (bs), 1.94-1.42 (m), 1.28 (bs), 1.13-0.99 (m), 0.87 (bs). dn/dc values for runs 7-11 in Table 2=0.128, 0.108, 0.124, 0.110, and 0.0909 mL/g, respectively.
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(c) Wang, J.; Zhang, Y.; Wang, S.; Song, Y.; Jiang, L. Acc. Chem. Res. 2011, 44, 405-415. (d) Aguirre, C. I.; Reguera, E.; Stein, A. Adv. Funct. Mater. 2010, 20, 2565-2578. (d) Moon, J. H.; Yang, S. Chem. Rev. 2010, 110, 547-574. 7. (a) Bates, F. S.; Hillmyer, M. A.; Lodge, T. P.; Bates, C. M.; Delaney, K. T.; Fredrickson, G. H. Science 2012, 336, 434-440. (b) Park, C.; Yoon, J.; Thomas, E. L. Polymer 2003, 44, 6725-6760. 8. For selected reviews see: (a) Paquet, C.; Kumacheva, E. Materials Today 2008, 11, 48-56. (b) Yoon, J.; Lee, W.; Thomas, E. L. MRS Bull. 2005, 30, 721-726. (c) Edrington, A. C.; Urbas, A. M.; DeRege, P.; Chen, C. X.; Swager, T. M.; Hadjichristidis, N.; Xenidou, M.; Fetters, L. J.; Joannopoulos, J. D.; Fink, Y.; Thomas, E. L. Adv. Mater. 2001, 13, 421-425. (d) Fink, Y.; Urbas, A. M.; Bawendi, M. G.; Joannopoulos, J. D.; Thomas, E. L. J. Lightwave Technol. 1999, 17, 1963-1969. 9. For selected examples see: (a) Hustad, P. D.; Marchand, G. R.; Garcia-Meitin, E. I.; Roberts, P. L.; Weinhold, J. D. Macromolecules 2009, 42, 3788-3794. (b) Rzayev, J. Macromolecules 2009, 42, 2135-2141. (c) Runge, M. B.; Bowden, N. B. J. Am. Chem. Soc. 2007, 129, 10551-10560. (d) Yoon, J.; Mathers, R. T.; Coates, G. W.; Thomas, E. L. Macromolecules 2006, 39, 1913-1919. 10. (a) Parnell, A. J.; Pryke, A.; Mykhaylyk, O. O.; Howse, J. R.; Adawi, A. M.; Terrill, N. J.; Fairclough, J. P. A. Soft Mater 2011, 7, 3721-3725. (b) Kang, C.; Kim, E.; Baek, H.; Hwang, K.; Kwak, D.; Kang, Y.; Thomas, E. L. J. Am. Chem. Soc. 2009, 131, 7538-7539. (c) Yoon, J.; Lee, W.; Thomas, E. L. Macromolecules 2008, 41, 4582-4584. (d) Kang, Y.; Walish, J. J.; Gorishnyy, T.; Thomas, E. L. Nature Mater. 2007, 6, 957-960. 11. (a) Urbas, A.; Sharp, R.; Fink, Y.; Thomas, E. L.; Xenidou, M.; Fetters, L. J. Adv. Mater. 2000, 12, 812-814. (b) Urbas, A.; Fink, Y.; Thomas, E. L. Macromolecules 1999, 32, 4748-4750. 12. Sveinbjornsson, B. R.; Weitekamp, R. A.; Miyake, G. M.; Xia, Y.; Atwater, H. A.; Grubbs, R. H. Submitted 2012. 13. (a) Vougioukalakis, G. C.; Grubbs, R. H. Chem. Rev. 2010, 110, 1746-1787. (b) Leitgeb, A.; Wappel, J.; Slugovc, C. Polymer 2010, 51, 2927-2946. (c) Bielawski, C. W.; Grubbs, R. H. in Controlled and Living Polymerizations. Mller, A. H. E.; Matyjaszewski, K. Eds.; Wiley-VCH: Weinheim, Germany. 2009; pp 297-342. (d) Bielawski, C. W.; Grubbs, R. H. Prog. Polym. Sci. 2007, 32, 1-29. (e) Slugovc, C. Macromol. Rapid Commun. 2004, 25, 1283-1297. 14. (a) Xia, Y.; Olsen, B. D.; Kornfield, J. A.; Grubbs, R. H. J. Am. Chem. Soc. 2009, 131, 18525-18532. (b) Xia, Y.; Kornfield, J. A.; Grubbs, R. H. Macromolecules 2009, 42, 3761-3766. 15. Sumerlin, B. S.; Matyjaszewski, K. (2007) in Macromolecular Engineering: Precise Synthesis, Materials Properties, Applications. Matyjaszewski, K.; Gnanou, Y.; Leibler, L. Eds.; Wiley-VCH: Weinheim, Germany. 2007. 16. Hu, M.; Xia, Y.; McKenna, G. B.; Kornfield, J. A.; Grubbs, R. H. Macromolecules 2011, 44, 6935-6934. 17. (a) Yashima, E.; Maeda, K.; Iida, H.; Furusho, Y.; Nagai, K. Chem. Rev. 2009, 109, 6102-6211. (b) Green, M. M.; Park. J.; Sato, T.; Teramoto, A.; Lifson, S.; Selinger, R. L. B.; Selinger, J. V. Angew. Chem. Int. Ed. 1999, 38, 3138-3154. (c) Mayer, S.; Zentel, R. Prog. Polym. Sci. 2001, 26, 1973-2013. 18. Kikuchi, M.; Lien, L. T. N.; Narumi, A.; Jinbo, Y.; Izumi, Y.; Nagai, K.; Kawaguchi, S. Macromolecules 2008, 41, 6564-6572. 19. (a) Patten, T.; Novak, B. M. J. Am. Chem. Soc. 1996, 118, 1906-1916. (b) Patten, T. E.; Novak, B. M. J. Am. Chem. Soc. 1991, 113, 5065-5066. 20. Albert, J. N. L.; Epps, T. H. Materials Today 2010, 13, 24-33. 21. Matsen, M. W.; Bates, F. S. J. Poly. Sci. Part B: Polym. Phys. 1997, 35, 945-952. 22. Orfanidis, S. J. Electromagnetic Waves and Antennas. Online book, retrieved May 2012. http://http://www.ece.rutgers.edu/orfanidi/ewa 23. Love, J. A.; Morgan, J. P.; Trnka, T. M.; Grubbs, R. H. Angew. Chem., Int. Ed. 2002, 41, 4035-4037. 24. Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.; Timmer, F. J. Organometallics 1996, 15, 1518-1520. 25. Matson, J. B.; Grubbs, R. H. J. Am. Chem. Soc. 2008, 130, 6731-6733.
Example 2: Precisely Tunable Photonic Crystals from Rapidly Self-Assembling Brush Block Copolymer Blends
(103) Block copolymers (BCPs) are ideal large area photonic band gap materials because of their low cost potential in terms of both raw material and bottom-up fabrication via self-assembly..sup.[1] The microphase segregation of chemically distinct polymer blocks.sup.[2] to materials possessing a periodic dielectric function can form a photonic band gap that forbids the propagation of certain wavelengths of light through the bulk. Such materials are termed photonic crystals (PCs) and have many applications as optical filters, mirrors, and cavities..sup.[3] In the simplest scenario, 1-D PCs are constructed from alternating layers of materials, where the reflected wavelength is determined by the thickness and refractive index of each layer. Unfortunately, chain-entanglement, a definitive polymer characteristic, most often restricts the ability of ultra-high molecular weight (MW) BCPs to self-assemble to ordered domains large enough to reflect long wavelengths of light. Thus, BCP based PCs usually only reflect wavelengths of light as long as green,.sup.[4] while longer wavelengths are only accessible with domain swelling with added components (i.e. solvent.sup.[5] or homo-polymers.sup.[6]), typically requiring complex annealing procedures, which greatly reduces their potential applications.
(104) High MW brush BCPs are able to rapidly self-assemble, due to their reduced chain-entanglement, to PCs that can reflect all wavelengths of light from the UV to the near infrared without relying on any additional swelling components..sup.[7] Utilizing ruthenium mediated ring-opening metathesis polymerization (ROMP).sup.[8] we have developed a grafting-through polymerization of macromonomers (MMs) to ultra-high MW brush polymers..sup.[9] The grafting-through polymerization of MMs affords highly uniform brush BCP's, where the sterically demanding array of low MW side-chains greatly reduces chain-entanglement, enforcing the unifying main-chain to assume a highly elongated conformation..sup.[10] As such, symmetric brush BCP's readily self-assemble without complicated annealing methods to stacked lamellae composed of alternating layers of the different blocks, providing a facile means to 1-D PC architectures (Scheme 1)..sup.[7] The domain sizes directly scale with the MW of the BCP enabling the wavelength of reflected light to be predictably modulated by synthetically controlling the polymer MW..sup.[7] Although this approach successfully produces PCs that reflect target wavelengths of light, it requires that a specific MW brush BCP must be synthesized to reflect each wavelength of light; a more flexible and desirable technology would be post-synthetically tunable, bypassing such application-specific synthetic requirements.
(105) ##STR00022##
(106) In the case of linear random coil, symmetric BCPs it has been demonstrated that polymer blends of two different MW BCPs can self-assemble to uniform stacked lamellar morphologies, if the ratio of the polymer MWs is less than five..sup.[11] The resulting size is an average of the relative ratio of the two components and is permitted by the conforming and flexible characteristics of random coil linear BCPs as they access morphologies that minimize enthalpy interaction parameters through a proposed mechanism involving stretching of the low MW BCP and a compression of the high MW BCP. Additionally, similar blends of linear BCPs, in the presence of a swelling solvent and shear alignment, can exhibit temporary photonic crystal characteristics, reflecting light across the visible spectrum, which are lost upon solvent evaporation..sup.[5a] In this Example, we report a study of blends of brush BCPs of different MW and the ability of these materials to assume similar conforming morphologies, despite their inherently rigid architectures, as a means to readily modulate the domain sizes, and thus the bandgaps of the PCs. Using this technique, it was found that the wavelength of reflected light is precisely tunable across the visible spectrum of light and into the near infrared (NIR), simply through controlling the relative incorporation of the two polymers, greatly enhancing the practicality of brush BCP PCs.
(107)
(108) The two different MW brush BCPs employed in this study were constructed through sequential ROMP of equal amounts of exo-norbornene functionalized hexyl isocyanate (MM-1) and 4-phenyl butyl isocyanate (MM-2) MMs (see,
(109)
(110) These results strongly suggest that despite the rigid architecture of the brush BCPs, the blends of the two different MW polymers are able to conform to uniform domains where the size is dictated by the relative ratio of the two components. We have previously established that the brush BCP's rapidly self-assemble to stacked lamellae. However, the mechanism of the blends to form such uniform domains remained unclear. The two most obvious routes would include the conforming assembly of the blends to stacked lamellae where the domains scale as an average of the two BCPs, similar to the mechanism followed by linear BCPs or through a gradual change in polymer morphology to compensate for the varying ratios of the two BCPs. To gain insight into the blending mechanism, scanning electron microscopy (SEM) was utilized to visually image the morphologies of the films.
(111)
(112) For all BCP blends, highly ordered stacked lamellae were observed in the SEM analysis (see,
(113) Blending of two different molecular weight brush block copolymers affords an effective means to simply control the domain sizes, and thus photonic properties of these materials. This blending strategy can be applied to any type of system with a brush copolymer that can be synthesized from any means with varying amounts of grafting density. It could also include the incorporation of other materials, including but not limited to, other homo-polymers, or any type of copolymer (di, tri, statistical, etc.) that are constructed from organic or inorganic materials. The brush copolymer does not need to be a di-block copolymer, but can also include statistical copolymers, or tri-block, or any number of blocks. Additionally, the ratio in MWs can be varied to access different morphologies. It can also apply to non-symmetric brush block copolymers, including asymmetry in molecular weight of the macromonomer, grafting density, or the relative incorporation of the macromonomers. The number of blending components can exceed 2, and be any combination of the above mentioned components. The materials can also be swelled with solvents or small molecules and may or may not be cross-linked with covalent or non-covalent interactions. Furthermore, blending of two different molecular weight brush block copolymers provided an alternative means to readily modulate the domain sizes and photonic properties of these materials.
(114) We have shown that blends between different MW brush BCPs form highly uniform, stacked lamellar morphologies. The resulting domains of the 1-D PC architectures scale linearly with the weight percent incorporation of the two polymers. Thus, a wide range of readily tunable photonic band gap materials can be easily fabricated simply through blending of two polymers. Because the brush BCP's rigid architecture greatly minimizes chain-entanglement, these blends rapidly self-assemble through controlled solvent evaporation of a volatile solvent, however, there appears to be sufficient flexibility to conform to precise layered structures. We foresee that this simple, bottom-up, readily tunable approach provides an attractive means to precisely tunable photonic band gap materials through the rapid self-assembly of brush BCP blends.
Experimental Section
(115) The synthesis and characterization of the macromonomers and brush block copolymers has been described previously..sup.[7b] Blends were prepared by mixing stock solutions (c=1.5 g/L; DCM) of BCP-1 and BCP-2 (10 mL total volume) in a 20 mL vial. A glass slide that had been previously washed with methanol and hexanes was placed vertically into the vial as the solvent was allowed to evaporate. Reflection measurements were performed on a Cary 5000 UV/Vis/NIR spectrophotometer, equipped with an integrating sphere diffuse reflectance accessory (Internal DRA 1800). All measurements were referenced to a LabSphere Spectralon 99% certified reflectance standard. The samples were illuminated through a Spectralon-coated aperature with a diameter of 1 cm, with a beam area of approximately 0.5 cm.sup.2. The samples were scanned at a rate of 600 nm/min, with a 1 nm data interval, from 1800 to 200 nm, with a detector crossover (InGaAs to PMT) at 875 nm. SEM images of freeze-fractured samples that were stained with RuO.sub.4 and carbon coated were taken on a ZEISS 1550 VP Field Emission SEM.
REFERENCES
(116) [1] For selected reviews see: a) C. Paquet, E. Kumacheva, Materials Today 2008, 11, 48-56; b) J. Yoon, W. Lee, E. L. Thomas, MRS Bull. 2005, 30, 721-726; c) A. C. Edrington, A. M. Urbas, P. DeRege, C. X. Chen, T. M. Swager, N. Hadjichristidis, M. Xenidou, L. J. Fetters, J. D. Joannopoulos, Y. Fink, E. L. Thomas, Adv. Mater. 2001, 13, 421-425; d) Y. Fink, A. M. Urbas, M. G. Bawendi, J. D. Joannopoulos, E. L. Thomas, J. Lightwave Technol. 1999, 17, 1963-1969. [2] a) F. S. Bates, M. A. Hillmyer, T. P. Lodge, C. M. Bates, K. T. Delaney, G. H. Fredrickson, Science 2012, 336, 434-440; b) C. Park, J. Yoon, E. L. Thomas, Polymer 2003, 44, 6725-6760. [3] a) J. Ge, Y. Yin, Angew. Chem. Int. Ed. 2011, 50, 1492-1522; b) J. F. Galisteo-Lpez, M. Ibisate, R. Sapienza, L. S. Froufe-Prez, . Blanco, C. Lpez, Adv. Mater. 2011, 23, 30-69; c) J. Wang, Y. Zhang, S. Wang, Y. Song, L. Jiang, Acc. Chem. Res. 2011, 44, 405-415; d) C. I. Aguirre, E. Reguera, A. Stein, Adv. Funct. Mater. 2010, 20, 2565-2578; d) J. H. Moon, S. Yang, Chem. Rev. 2010, 110, 547-574. [4] For selected examples see: a) P. D. Hustad, G. R. Marchand, E. I. Garcia-Meitin, P. L. Roberts, J. D. Weinhold, Macromolecules 2009, 42, 3788-3794; b) J. Rzayev, Macromolecules 2009, 42, 2135-2141; c) M. B. Runge, N. B. Bowden, J. Am. Chem. Soc. 2007, 129, 10551-10560; d) J. Yoon, R. T. Mathers, G. W. Coates, E. L. Thomas, Macromolecules 2006, 39, 1913-1919. [5] a) A. J. Parnell, A. Pryke, O. O. Mykhaylyk, J. R. Howse, A. M. Adawi, N. J. Terrill, J. P. A. Fairclough, Soft Mater 2011, 7, 3721-3725; b) C. Kang, E. Kim, H. Baek, K. Hwang, D. Kwak, Y. Kang, E. L. Thomas, J. Am. Chem. Soc. 2009, 131, 7538-7539; c) J. Yoon, W. Lee, E. L. Thomas, Macromolecules 2008, 41, 4582-4584; d) Y. Kang, J. J. Walish, T. Gorishnyy, E. L. Thomas, Nature Mater. 2007, 6, 957-960. [6] a) A. Urbas, R. Sharp, Y. Fink, E. L. Thomas, M. Xenidou, L. J. Fetters, Adv. Mater. 2000, 12, 812-814; b) A. Urbas, Y. Fink, E. L. Thomas, Macromolecules 1999, 32, 4748-4750. [7] a) B. R. Sveinbjrnsson, R. A. Weitekamp, G. M. Miyake, Y. Xia, H. A. Atwater, R. H. Grubbs, Submitted 2012; b) G. M. Miyake, R. A. Weitekamp, V. A. Piunova, R. H. Grubbs, Submitted 2012. [8] a) G. C. Vougioukalakis, R. H. Grubbs, Chem. Rev. 2010, 110, 1746-1787; b) A. Leitgeb, J. Wappel, C. Slugovc, Polymer 2010, 51, 2927-2946; (c) C. W. Bielawski, R. H. Grubbs in Controlled and Living Polymerizations. Mller, A. H. E.; Matyjaszewski, K. Eds.; Wiley-VCH: Weinheim, Germany. 2009; pp 297-342; d) C. W. Bielawski, R. H. Grubbs, Prog. Polym. Sci. 2007, 32, 1-29; e) C. Slugovc, Macromol. Rapid Commun. 2004, 25, 1283-1297. [9] a) Y. Xia, B. D. Olsen, J. A. Kornfield, R. H. Grubbs, J. Am. Chem. Soc. 2009, 131, 18525-18532; b) Y. Xia, J. A. Kornfield, R. H. Grubbs, Macromolecules 2009, 42, 3761-3766. [10] M. Hu, Y. Xia, G. B. McKenna, J. A. Kornfield, R. H. Grubbs, Macromolecules 2011, 44, 6935-6934. [11] (a) D. Yamaguchi, T. Hashimoto. Macromolecules 2001, 34, 6495-6505. (b) L. Kane, M. M. Satkowski, S. D. Smith, R. J. Spontak. Macromolecules 1996, 29, 8862-8870. (c) T. Hashimoto, K. Yamasaki, S. Koizumi, H. Hasegawa. Macromolecules 1993, 26, 2895-2904.
Example 3: Blending of Different Molecular Weight Polymers
(117) We report fabrication of photonic crystals by brush block-copolymer (BCPs) blending. By incrementally changing the ratio between two components in the blend we were able to access photonic crystals that reflected across the spectrum, anywhere from UV into near IR. A similar strategy was pursued using on dendronized block-copolymers, where macromolecular pendant chain was replaced with Newkome-type dendritic group, functionalized with either benzyl ether group or long aliphatic chain.
(118)
(119) According to the earlier reported data on certain linear symmetrical BCPs a blend will maintain stacked lamellae morphology as long as the ratio between molecular weight of two components is less than 5. Thus for our study we chose two dendronized BCPs samples with M.sub.w: 480 kDa (PDI=1.05) reflecting in UV (.sub.max=330 nm) and 1250 kDa (PDI=1.10) reflecting red (.sub.max=768 nm). Films were prepared by controlled evaporation from dichloromethane solution in weight percent ratios of 25:75, 50:50 and 75:25. All films exhibited a primary reflection peak with .sub.max increasing linearly with increasing incorporation of higher molecular weight component (see,
(120)
(121) TABLE-US-00003 TABLE 3 Summary of reflectance data Weight fraction .sub.max (%) (nm) 0 330 25 490 50 586 75 755 100 768
(122) To get understanding of the blending mechanism scanning electron microscopy (SEM) was employed. Stacked lamellar morphology was observed for 75:25 and 50:50 blends while morphology of 75:25 appeared to be amorphous (see,
(123)
(124)
(125) The brush block copolymer was constructed through the sequential ruthenium mediated ring-opening metathesis polymerization of a polyhexylisocyanate and polystyrene macromonomer. This polymer had a molecular weight (weight average molecular weight [M.sub.w=1547 kDa]) and a polydispersity index (PDI) of 1.58. A thin film of this polymer was fabricated through controlled evaporation to yield a uniform nanostructured dielectric mirror that reflected light around 400 nm (see,
(126)
(127)
(128) This brush block copolymer was mixed with a linear polystyrene polymer (Mw=13.6 kDa; PDI=1.03). Blends were composed of weight fractions of 63:35, 73:27, and 85:15% of linear polystyrene to brush block copolymer. Altering the weight incorporation of the two components can alter the light reflecting properties and alter the nanostructured morphology (see,
(129) This brush block copolymer was blended with a polynorbornene-graft-polystyrene (M.sub.w=1716 kDa; PDI=1.65) [
STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS
(130) All references cited throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).
(131) The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.
(132) When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure. Additionally, unless otherwise specified, all isotopic variants of compounds disclosed herein are intended to be encompassed by the disclosure. For example, it will be understood that any one or more hydrogens in a molecule disclosed can be replaced with deuterium or tritium. Isotopic variants of a molecule are generally useful as standards in assays for the molecule and in chemical and biological research related to the molecule or its use. Methods for making such isotopic variants are known in the art. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently.
(133) It must be noted that as used herein and in the appended claims, the singular forms a, an, and the include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to a cell includes a plurality of such cells and equivalents thereof known to those skilled in the art, and so forth. As well, the terms a (or an), one or more and at least one can be used interchangeably herein. It is also to be noted that the terms comprising, including, and having can be used interchangeably. The expression of any of claims XX-YY (wherein XX and YY refer to claim numbers) is intended to provide a multiple dependent claim in the alternative form, and in some embodiments is interchangeable with the expression as in any one of claims XX-YY.
(134) Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention.
(135) Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. As used herein, ranges specifically include the values provided as endpoint values of the range. For example, a range of 1 to 100 specifically includes the end point values of 1 and 100. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.
(136) As used herein, comprising is synonymous with including, containing, or characterized by, and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, consisting of excludes any element, step, or ingredient not specified in the claim element. As used herein, consisting essentially of does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms comprising, consisting essentially of and consisting of may be replaced with either of the other two terms.
(137) One of ordinary skill in the art will appreciate that starting materials, biological materials, reagents, synthetic methods, purification methods, analytical methods, assay methods, and biological methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.