Regensburg 2004 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 14: SYMPOSIUM: Understanding and Controlling Complex Structures: From Synthetic Polymers to Biomaterials II

CPP 14.5: Vortrag

Dienstag, 9. März 2004, 15:30–15:45, H 37

Nanophase separation in side chain polymers and the dynamics in self-assembled confinements — •Mario Beiner — FB Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany

Structural and dynamic data for different series of amorphous side chain polymers with long alkyl groups show consistently that a nanophase separation of incompatible main and side chain parts on the one nanometer scale is a common feature of such materials [1]. Long alkyl groups – belonging to different monomeric units and chains – aggregate in the melt and form alkyl nanodomains with a typical size of 0.5-2 nm. The dynamics of the nanophase-separated side chain polymers is characterized by the presence of an additional polyethylene-like glass transition αPE within the alkyl nanodomains. Important features of this αPE process are main chain independent. With increasing size of the alkyl nanodomains a strong-to-fragile transition has been observed in the steepness index of the αPE process as obtained from relaxation spectroscopy measurements. This finding is discussed in the context of cooperative motions in self-assembled confinements and will be related to the long and controversial discussion about the size of dynamic heterogeneities in glasses. This is an interesting link between central questions in glass transition research and structural aspects in nanophase-separated materials. The general importance of nanophase separation effects for an understanding of the dynamics of complex materials in nanotechnology and nature is demonstrated.

[1] M. Beiner and H. Huth, Nature Materials 2, 595 (2003)
15 min. Pause

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