Depth profiling of the glass transition dynamics and diffusion in ultra-thin polymer films using dielectric probes

50000403v316
Promoter: Michael Wübbenhorst

details
Description: Glass forming liquids show deviations from their cooperative bulk-dynamics (finite size effects) when they are geometrically confined to dimensions comparable to the intrinsic length of cooperativity. Ultra-thin polymer films represent an attractive system for the study of size effects on the glass transition dynamics because of large reported Tg-shifts (> 70 K) and the ease with which nm-thick samples can be prepared.

This project aims to investigate the position dependence in the glass transition and related dynamics in ultrathin polymer films by employing “dielectric probes” or labels at specific depths in supported or freely-standing polymer films. Polymer films with a desired probe concentration profile will be achieved by assembling multilayers or, alternatively, by employing organic molecular beam deposition. Dielectric spectroscopy will be the principal technique to gather depth-specific dynamic information, which is complemented by structural investigations using ellipsometry and scanning probe techniques.
The ultimate goal of the project is to relate experimental mobility profiles in terms of intrinsic dynamic length scales, specific polymer-interface interactions and polymer conformation issues.

This position is related to the project “Depth profiling of the glass transition dynamics and diffusion in ultra-thin polymer films using dielectric probe techniques” and is open for a starting PhD student. The successful candidate should preferably have a Master degree in Physics, Applied Physics, Materials Science or Physical Chemistry.


Key words: glass transition, polymer dynamics, ultrathin films, nanometer confinement, dielectric spectroscopy

Latest application date: 2009-12-31

Financing: available

Type of Position: scholarship

Duration of the Project : 4 years


Research group: Department of Physics and Astronomy