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Micrometer and Sub-Micrometer Structure Formation of Phase Separating Polymer Films

Micrometer and Sub-Micrometer Structure Formation of Phase Separating Polymer Films

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Prüfsumme: MD5:5cf0a928fc610b007e667cfb04a51a95

WALHEIM, Stefan, 2000. Micrometer and Sub-Micrometer Structure Formation of Phase Separating Polymer Films [Dissertation]. Konstanz: University of Konstanz

@phdthesis{Walheim2000Micro-8880, title={Micrometer and Sub-Micrometer Structure Formation of Phase Separating Polymer Films}, year={2000}, author={Walheim, Stefan}, address={Konstanz}, school={Universität Konstanz} }

Walheim, Stefan deposit-license Dissolving two incompatible polymers in a common solvent and spin-coating the solution leads to phase separation during the evaporation of the solvent. Spinodal decomposition is the underlying process. In the thin film geometry, surface directed spinodal decomposition and also wetting properties of the different phases play an important role during the structure formation process. Thus, the phase morphology can be organized normal or parallel to the film surface depending on the surface energy of the substrate. We make use of the substrate sensitivity of the demixing process. By using chemically heterogeneous pre-structured substrates made by micro-contact printing an arbitrary substrate pattern can be used to induce a lateral composition variation in the polymer film. Thus, by controlling the phase morphology, one can create surfaces with new properties, e.g. lithography masks, optical devices, or biological sensors. For instance this novel structuring technique can be applied to ion conducting organic-inorganic hybrid materials and polymer-metal precursors for high Tc superconductors. More complex morphologies are found after spin-casting ternary polymer blends. If one of the polymer-polymer interaction parameters exceeds the sum of the other two, the morphologies can be considered as two-dimensional emulsions. Simulation results performed by Nauman et al. closely resemble the morphologies observed in our study.<br />Laterally isotropic phase separated polymer films can feature new physical properties. For example if one of the two polymers of a phase morphology with a lateral length scale below 200 nm is removed, the resulting nano-porous film can be used as a high-performance anti-reflection coating. The refractive index of these films can be adjusted in a range from 1.6 down to 1.05 by varying the polymer composition of the solution. This allows the build up of multi-layer AR-coatings with a broad spectral transmission. Micrometer and Sub-Micrometer Structure Formation of Phase Separating Polymer Films Mikrometer- und Submikrometer-Strukturierung phasenseparierender Polymerfilme 2000 2011-03-24T17:51:18Z 2011-03-24T17:51:18Z eng Walheim, Stefan application/pdf

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

SWalheimDiss.pdf 164

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