Abstract

Broadband Dielectric Spectroscopy (BDS) as one of the maior tools in studying molecular dynamics benefits from the extraordinary advantage that its sensitivity increases with decreasing thickness of a sample capacitor and hence with a decreasing amount of sample material. By use of refined preparation techniques and with novel nanostructured electrodes it is possible to avoid the (conventional) evaporation of a metal counterelectrode onto the polymerlayer. This enables one to analyse the molecular dynamics of polymerlayers being thinner than 5 nm and poviding usually no full coverage of the underlying surface. Even measurements of the dynamics of quasi-isolated polymer coils are possible. This is demonstrated for a variety of polymers in a wide spectral range (10-2Hz – 106Hz) and at temperatures between 150 K to 350 K. Furthermore ellipsometric and AC-calorimetric studies are included. The results are analysed and discussed within the framework of the physical understanding of the dynamic glass transition.

References:

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