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Proceedings Paper

Dependence of the molecular dynamics of comblike polyacrylates and polymethacrylates on the mesophase structure studied by dielectric spectroscopy
Author(s): Andreas Schoenhals; Dietmar Wolff; Juergen Springer
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Paper Abstract

Dielectric spectroscopy is employed to study the dependence of the molecular dynamics of liquid-crystalline polyacrylates on the mesophase structure. The temperature dependence of the rate of the (beta) -relaxation which was assigned to rotational fluctuations of the mesogenic unit around its long axis can be described by an Arrhenius equation. Both the preexponential factor and the activation energy increase with the order of the mesophase which is discussed in the frame of the cooperativity of the (beta) -relaxation. It is shown that the activation parameters of this process correlate to lateral distance of mesogenic groups. The (alpha) - relaxation is related to the dynamic glass transition. Its independence on the mesophase structure is interpreted in terms of microphase separation. The rate of the (delta) -relaxation caused by rotational fluctuations of the mesogenic unit around its short axis is reduced by that of the (alpha) -process. The temperature dependence of this ratio is related to that of a molecular order parameter.

Paper Details

Date Published: 26 April 1996
PDF: 6 pages
Proc. SPIE 2779, 3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials, (26 April 1996); doi: 10.1117/12.237155
Show Author Affiliations
Andreas Schoenhals, Institut fuer Angewandte Chemie Berlin-Adlershof eV (Germany)
Dietmar Wolff, Technische Univ. Berlin (Germany)
Juergen Springer, Technische Univ. Berlin (Germany)


Published in SPIE Proceedings Vol. 2779:
3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials
Pierre Francois Gobin; Jacques Tatibouet, Editor(s)

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