Dependence of the molecular dynamics of comblike polyacrylates and polymethacrylates on the mesophase structure studied by dielectric spectroscopy

Andreas Schoenhals; Dietmar Wolff; Juergen Springer

doi:10.1117/12.237155

26 April 1996 Dependence of the molecular dynamics of comblike polyacrylates and polymethacrylates on the mesophase structure studied by dielectric spectroscopy

Andreas Schoenhals, Dietmar Wolff, Juergen Springer

Author Affiliations +

Proceedings Volume 2779, 3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials; (1996) https://doi.org/10.1117/12.237155
Event: 3rd International Conference on Intelligent Materials, 1996, Lyon, France

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.

Citation Download Citation

Andreas Schoenhals, Dietmar Wolff, and Juergen Springer "Dependence of the molecular dynamics of comblike polyacrylates and polymethacrylates on the mesophase structure studied by dielectric spectroscopy", Proc. SPIE 2779, 3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials, (26 April 1996); https://doi.org/10.1117/12.237155

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