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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 16: Interfaces and Thin Films II (joint session with DECHEMA and VDI)

CPP 16.8: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H40

Nano-scale Roughness of Phase Boundaries in Heterogeneous Polymers: The rigid-mobile Interphase — •Matthias Roos and Kay Saalwächter — Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Germany

Many macroscopic features of polymers rely on microscopic and nano-scale characteristics, so their morphology, in particular nano-scale dynamic heterogeneities, is of great importance. Based on the possible distinction of differently mobile parts of the sample by proton NMR, we use an effect called spin diffusion (i.e, transport of spin magnetization among the nuclei) to investigate neighborhood relations between rigid and mobile (below or above Tg, respectively) components in semi-crystalline polymers and block copolymers. In addition, a phase of intermediate mobility can be identified.

If there is a selective magnetization of the rigid phase, first the magnetization induced signal of the interphase rises, followed by the magnetization of the mobile phase. That is to say, the magnetization diffuses from the rigid phase to the mobile one but must cross the respective interphase. Contrary to this, if a selective magnetization of the mobile phase is created, the rigid phase will gain its magnetization simultaneously with the interphase.

It was possible to replicate this effect by simulating the diffusive behavior of magnetization when taking into account a thickness variation of the rigid phase, where the interphase is mainly situated in ``depressions" of the rigid phase, i.e., in regions that are less exposed to the mobile phase.