Klemens Mathauer

Block copolymer micelles as seed in emulsion polymerization

The size of aggregates formed by poly(acrylic acid)-block-poly(methyl methacrylate) block copolymers was determined and the applicability of these block copolymers as stabilizers in emulsion polymerization was investigated. The analytical methods included transmission electron microscopy, light scattering, and analytical ultracentrifugation. Polymers with a hydrophilic poly(acrylic acid) block of equal or larger size than the hydrophobic poly(methyl methacrylate) block are efficient as stabilizers down to block copolymer-to-monomer ratios of less than 1 wt.-%. From the influence of the block copolymer-to-monomer ratio on the latex particle size, from the relation between the number of block copolymer molecules per latex particle and the aggregation number of the block copolymer micelles, and from fluorescence studies we conclude that micelles consisting of block copolymers with 35 or more hydrophobic MMA units act as a seed in the emulsion polymerization of acrylic and methacrylic monomers.

Low temperature plasma treatment of monomolecular Langmuir-Blodgett films

Abstract The structure of the surface layer of materials is usually quite different from the bulk. Detailed information about the surface structure is often not available. This, together with the complex nature of low temperature plasma treatment, hinders the investigations of plasma chemical processes on solid surfaces. Monomolecular Langmuir-Blodgett (LB) structures offer a unique opportunity to prepare model surfaces with known thickness and molecular architecture. From the data obtained, the depth of the Ar plasma influence on solid organic surfaces was estimated to be about 400–1000 A depending on the nature of the surface layer. An oxygen plasma penetrates deeper with a penetration limit greater than 1000 A. Using plasma treatment, one can improve or regulate the properties of the LB structure, e.g. one can introduce new functionalities and improve thermostability. It is shown that by plasma treatment it is possible to prepare thin organoceramic films from metal- or silicon-containing LB films.

Structure, Properties and Applications of Polymeric Langmuir–Blodgett Films

Two methods exist for the preparation of ultrathin polymer films; the self-assembly technique1, 2 and the Langmuir-Blodgett (LB) technique. For the self-assembly technique special molecular systems(α,ω-functionalized long alkyl chains) are required to build up multilayer systems, whereas for the Langmuir-Blodgett technique a large range of different molecular structures are suitable. The classical substances for the LB technique are amphiphilic molecules consisting of a long alkyl chain with a hydrophilic head group. They form monomolecular layers at the air/water interface that can be transferred onto solid substrates.