Broadband dielectric spectroscopy on the molecular dynamics in thin polymer layers

PMSE 437

Friedrich Kremer, kremer@physik.uni-leipzig.de and Anatoli Serghei, serghei@rz.uni-leipzig.de. Institute for Experimental Physics I, Leipzig University, Linnestr. 5, Leipzig, 04103, Germany
The molecular dynamics in thin films of polymers having different (linear, hyperbrached and dendritic) macromolecular architectures is discussed. Based on measurements by means of broadband dielectric spectroscopy, capacitive scanning dilatometry and AC-calorimetry, the following issues are addressed: (i) What is the molecular mechanism of the confinement-effects? (ii) What role plays the macromolecular architecture in the dynamics of confined polymers? (iii) Do different experimental techniques deliver similar results when applied to investigate the dynamics of confined polymers? (iv) Does the presence of a free interface lead to shifts in the dynamics glass transition of thin polymer films? In order to address the last question, a novel experimental approach is demonstrated, which enables one to measure the molecular dynamics in ultra-thin organic layers having one free interface. [1] A. Serghei, M. Tress, and F. Kremer, Macromolecules, in press (2006). [2] A. Serghei, and F. Kremer, Rev. Sci. Instrum. 77, 116108 (2006).