Provided are a surface treatment agent for powder capable of being used to produce a dispersion superior in dispersibility, fluidity and temporal stability; and a dispersion containing a powder treated with such surface treatment agent for powder. The agent is a diblock copolymer whose main chain is comprised of a silicone graft copolymer block represented by a formula [I] and a polar copolymer block represented by a formula [II], wherein one end structure of the main chain is represented by a formula [III], and the other end structure of the main chain is represented by a formula [IV], the formulae [I] to [IV] being expressed as

##STR00001##

wherein A represents an organopolysiloxane-containing group; B represents a polar group-containing monovalent hydrocarbon group having 1 to 20 carbon atoms, an amino group or a hydroxyl group.

The present invention is a method for producing a conjugated diene polymer comprising polymerizing at least a conjugated diene monomer using a living radical polymerization method to produce a conjugated diene polymer that comprises a halogen atom at a terminal of a polymer chain, a living radical polymerization reaction being initiated using a copper salt, a multidentate ligand that comprises a nitrogen atom having an sp.sup.2 hybridized orbital as a coordinating atom, and an organic halide, to produce the conjugated diene polymer having a number average molecular weight (Mn) of 1,000 to 1,000,000 and a molecular weight distribution (Mw/Mn) of less than 2.0. The present invention provides a method for efficiently and inexpensively producing a conjugated diene polymer that includes a halogen atom at the terminal of the polymer chain, and has the desired molecular weight and a narrow molecular weight distribution.

Disclosed herein are compositions and methods for reducing the antigenicity of molecules. The antigenicity of a molecule may be reduced or eliminated by conjugating at least one branched polymer to the molecule to form a molecule-polymer conjugate. The branched polymer may include a backbone and a plurality of side chains, each side chain covalently attached to the backbone.

Nanostructures and associated compositions, systems, and methods are provided. In some embodiments, a nanostructure may comprise polymers, intermolecular bonding groups, and a particle. The polymers may be associated with the particle and the intermolecular bonding groups may be associated with at least some of the polymers. In some embodiments, at least some of the intermolecular bonding groups may have a different chemical composition and/or chemical property than the polymers. In some embodiments, nanostructures may reversibly associate with each other via the intermolecular bonding groups to form a material. In some such cases, the intermolecular bonding groups on different nanostructures may reversibly associate with each other. In some embodiments, the nanostructures may be designed, such that the energy required to disassociate at least a portion of the nanostructures in the material is greater than the energy required to dissociate a single association between intermolecular bonding groups.

An organic tellurium compound is disclosed having a versatility that, when used as a living radical polymerization initiator, it is applicable to polymerization of a vinyl monomer in an aqueous vehicle without using any surfactant or dispersant. The organic tellurium compound is represented by a general formula (1), ##STR00001##
where R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, A represents an alkali metal atom or an alkaline earth metal atom, x=1 when A is monovalent, x=½ when A is divalent, and R.sup.3 is represented by a general formula (2), ##STR00002##
where in the general formula (2) R.sup.4 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R.sup.5 and R.sup.6 each independently represent an alkylene group having 2 to 8 carbon atoms, and a represents an integer from 0 to 10.

The present invention provides a pigment dispersant that exhibits high fine dispersibility, stability, and fluidity in a small amount, a pigment dispersion liquid including the pigment dispersant, and a process of producing the pigment dispersant and pigment dispersion liquid. The pigment dispersant contains as a main component, a graft copolymer formed through living radical polymerization using two or more monomers containing including a methacrylate A having an acidic group or a basic group and a methacrylate-based macromonomer B having a methacrylate residue at one terminal of a particular polymer chain that has a molecular weight of from 500 to 5000. A ratio of a total molar number of the methacrylate-based monomers relative to 1 mol of a polymerization-initiating compound in the raw material monomers is from 20 to 50 mol. A ratio of the B component-derived polymer chain to the graft copolymer is from 50 to 90 mass %.

An intracellular delivery vehicle of which surface is covered by a positive charge, an intracellular delivery complex in which a component or compound desired is loaded in the intracellular delivery vehicle, a temperature-sensitive probe comprising the intracellular delivery complex, and a method for measuring the intracellular temperature by the temperature-sensitive probe are disclosed. The intracellular delivery vehicle is useful on account of its capability of easily delivering the component or compound desired inside the cell without inhibiting cell proliferation.

In one embodiment the invention relates to a method of preparing a polyrotaxane, said method comprising: performing a radical copolymerization of at least (a) a first polymerizable monomer having a stopper group, and of at least (b) a second polymerizable hydrophobic monomer, wherein said second monomer is complexed by a ring-shaped molecule, and of at least (c) a third polymerizable hydrophilic monomer; wherein during said copolymerization a copolymer threading said ring-shaped molecule is formed, wherein during said copolymerization said first monomer having a stopper group is incorporated into the chain of said copolymer at least partially between the ends thereof, and wherein said stopper groups prevent said ring-shaped molecule from disassembling from the copolymer; and wherein the amount of said first monomer having a stopper group is of from 0.1 mol % to 20 mol % based on 100 mol % of the total amount of polymerizable monomers. In another embodiment the invention relates to a method of preparing a polyrotaxane, said method comprising: performing a radical copolymerization of at least (a) a first polymerizable monomer having a stopper group, and of at least (b) a second polymerizable partially hydrophilic monomer, wherein said second monomer is complexed by a ring-shaped molecule, and wherein said second monomer has a solubility in water at 20° C. of from 5 g/L to 40 g/L; wherein during said copolymerization a copolymer threading said ring-shaped molecule is formed, wherein during said copolymerization said first monomer having a stopper group is incorporated into the chain of said copolymer at least partially between the ends thereof, and wherein said stopper groups prevent said ring-shaped molecule from disassembling from the copolymer; and wherein the amount of said first monomer having a stopper group is of from 0.1 mol % to 20 mol % based on 100 mol % of the total amount of polymerizable monomers. Furthermore, the present invention relates to methods of preparing cross-linked polyrotaxanes and cross-linked polyrotaxanes which can be prepared using such methods. Thus, the present invention also relates to polyrotaxane and crosslinked polyrotaxanes. The invention also relates to products which contain the polyrotaxanes or cross-linked polyrotaxanes or which can be prepared from the polyrotaxanes or the cross-linked polyrotaxanes. The present invention further relates to the use of polyrotaxanes or cross-linked polyrotaxanes in various applications, such as the use as a self-healing material.

The present invention relates to methods of forming star polymers having configurable architecture in which arms are synthesized by means of living anionic polymerization, with the arms being conjugated with a core, the core comprising m coupling groups, each coupling group having n methylene groups. The invention further relates to star polymers produced therefrom.

Provided are a block copolymer having a narrow molecular weight distribution such that the copolymer can be used in a DSA technique, a block copolymer intermediate thereof, and methods for producing the same. A block copolymer intermediate represented by the general formula (1) or (2) is used:

##STR00001##

wherein, in the general formulae (1) and (2), each of R.sup.1 and R.sup.3 independently represents a polymerization initiator residue, each of R.sup.2 and R.sup.4 independently represents an aromatic group or an alkyl group, Y.sup.1 represents a polymer block of (a)an (meth)acrylic acid ester, Y.sup.2 represents a polymer block of styrene or a derivative thereof, L represents an alkylene group having 1 to 6 carbon atoms, X represents a halogen atom, and each of m and n independently represents an integer of 1 to 5.