Broadband Dielectric Spectroscopy to Study the Molecular Dynamics of Polymers Having Different Molecular Architectures

Abstract

This chapter discusses broadband dielectric spectroscopy (BDS) which is used to study the molecular dynamics of polymeric systems. In its modern form BDS covers the extraordinary frequency range from 10-3 Hz to 109 Hz with the option to extend both limits to lower and higher values, respectively. This enables one to analyse the molecular dynamics on a large time scale especially if the temperature of the sample is varied as well. The dynamics of polymers having different molecular architectures (linear and cyclic chains, and star-branched systems) are discussed. Star-branched polymers of PI have in principle similar dynamics as linear chains: Two relaxation processes are observed being assigned to the segmental and normal mode. Mesogenic groups can be incorporated into polymeric systems. In side chain liquid crystalline polymers the mesogenic unit is connected to the main chain by a flexible spacer. Due to BDS broad frequency range of more than 10 decades a manifold of different molecular fluctuations can be studied from the dynamic glass transition (spanning already more than 10 decades in times) to secondary relaxations. Additionally one finds in chiral liquid crystals cooperative processes like soft and Goldstone modes.

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Title
Broadband Dielectric Spectroscopy to Study the Molecular Dynamics of Polymers Having Different Molecular Architectures
Book Title
Physical Properties of Polymers Handbook
Book DOI
10.1007/978-0-387-69002-5
Chapter DOI
10.1007/978-0-387-69002-5_21
Part of
Volume
Editors
  • James E. Mark Send Email (1)
  • Editor Affiliation
  • 1 Department of Chemistry, University of Cincinnati, Crosley Tower, Martin Luther King Drive, 45221-0172, Cincinnati, OH
  • Authors
  • F. Kremer Send Email (2)
  • Author Affiliation
  • 2 Fakultat f. Physik u. Geowissenschaften, Universitat Leipzig, Leipzig, Germany
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