Imperfect Focal Conic Domains in Asmectics: a Textural Analysis. - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Liquid Crystals Année : 2008

Imperfect Focal Conic Domains in Asmectics: a Textural Analysis.

Résumé

F o r P e e r R e Wehaveanalyzedoptical microscopyobservations of Focal ConicDomains (FCDs) withim- perfect ellipses onthebasis of thetheoretical concepts developedin[M. Klemanet al., Philos. Mag. 86, 4439(2006)]. Twotypes of imperfect ellipses are observed: withkinks (elementary imperfectionsresultingfromatopological interactionof adisclinationwithadislocation, attheir pointofjunction)beingeitherintheellipseplane('Mouse')orperpendiculartoit('Turtles'). The experimental conditions for theobservationof imperfect FCDs of bothtypes aredescribed. A model describingtheshapeofaMouse-typeellipseiscomparedtoobservations. Twoexperimental observationsinnematogenicsmectics(i.e., whichhaveasmectic →nematictransition)emphasize thepredominant roleof kinks indynamical phenomenainvolvingdislocations andFCDs: a)- a reversibleandsuddentemperatureinducedtransformationbetweentwoFCDtextures: FCDswith fewer kink-carryingdistortions (calledisometrictextures) andthehigher temperatureoneswith proliferationof kinks (callednon-isometric), b)- ashrinkingof theellipses uponheating, upto theirsuddenandtotal vanishingatatemperaturewell belowthephasetransition. Incontrast, in anon-nematogenicsmectic, theellipsesizedoesnotvaryuponheatinguntil theappearanceofthe isotropicphase.
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Dates et versions

hal-00270259 , version 1 (04-04-2008)

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  • HAL Id : hal-00270259 , version 1

Citer

Yu. A. Nastishin, Claire Meyer, M. Kleman. Imperfect Focal Conic Domains in Asmectics: a Textural Analysis.. Liquid Crystals, 2008, pp.1-43. ⟨hal-00270259⟩
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