Prof. Dr. Axel Müller

Anionic polymerization is the method of choice to synthesize linear and miktoarm-star block copolymers with high molecular weights and very narrow molecular weight distributions. We report on the synthesis of some new block co- and terpolymers and on the self-organized nanostructures they form in the bulk and in solution. Bulk structures are used as novel stimuli-sensitive membranes, whereas solution structures are soft nanoparticles, which have either a compartmentalized core or corona: new multicompartment-core micelles, Janus nanoparticles and cylinders with multicompartment corona. These nanoparticles can combine several properties or functionalities in close proximity.

Anionic polymerization has been used to synthesize new block copolymers using monomers like glycidyl ethers, ethylene oxide, or N,Ndimethylaminoethyl methacrylate (DMAEMA). These polymers find applications in smart hydrogels and membranes.

A triblock terpolymer of butadiene (B), 2-vinylpyridine (VP) and tert-butyl methacrylate (tBMA) forms multi-compartment core micelles in acetone solution via phase-separation of the insoluble PB and PVP blocks. The micelles are stabilized by crosslinking of the PB block. Hydrolysis of the tert-butyl ester of the tBMA and/or quaternization of the PVP block forms water-soluble particles with a poly(methacrylic acid) corona.

In contrast, Janus particles form in the bulk by crosslinking of the PB middle block of PS-b-PB-b-PtBMA or poly(methyl methacrylate) (PMMA). Janus spheres, cylinders, and disks have different upper and lower sides and form aggregates in organic solvents. After hydrolysis of the PtBMA or PMMA block they are promising interfacial agents. Janus particles have been successfully applied as efficient surfactants for emulsion polymerization and as Pickering-style compatibilizers for polymer blends.

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