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Ferroelectric liquid crystalline elastomers, 1. Variation of network topology and orientation
Author(s) -
Gebhard Elisabeth,
Zentel Rudolf
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(20000501)201:8<902::aid-macp902>3.0.co;2-9
Subject(s) - ferroelectricity , elastomer , materials science , topology (electrical circuits) , polar , phase (matter) , electric field , hysteresis , liquid crystal , phase transition , field (mathematics) , condensed matter physics , composite material , chemical physics , optoelectronics , physics , dielectric , chemistry , electrical engineering , organic chemistry , mathematics , quantum mechanics , astronomy , pure mathematics , engineering
In order to evaluate structure‐property relations in ferroelectric LC‐elastomers concerning netpoint topology and netpoint density, three different elastomers were investigated. As far as the netpoint topology is concerned systems with a crosslinking within the smectic layers (intra‐layer) and between different layers (inter‐ layers) behave differently. Only the inter‐layer systems (elastomer E2 ) are able to stabilize the polar order of the smectic‐C* phase. Increasing the crosslinking density by stepwise crosslinking leads to a continuous shift of the ferroelectric hysteresis. Two switching times with and against the elastic field of the network are observed. The difference between these switching times increases with increasing crosslinking density. From this difference an electric field can be calculated, which is necessary for a compensation of the elastic field of the network. Crosslinking of elastomer E2 in the smectic A‐phase leads to a stabilization of a macroscopically untilted state. If a tilt is induced in the crosslinked smectic A‐phase by application of an electric field (electroclinic effect) the network keeps a memory of the polar state present during crosslinking.