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DoITPoMS Micrograph Library Full Record for Micrograph 638

Full Record for Micrograph 638

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Micrograph no
638
Brief description
Disclinations in a smectic LCP, revealed by decoration
Keywords
alignment, decoration, disclination, dislocation Link to MATTER Glossary entry for dislocation, liquid crystalline polymer (LCP), polymer Link to MATTER Glossary entry for polymer, smectic, spontaneous band texture, texture
Categories
Polymer
System
Liquid crystalline polymer
Composition
Semi-flexible LCP, Cl-8
Standard codes
Reaction
Processing
The band texture forms spontaneously during the solidification of smectic melts of some semi-flexible polymers. It may also be induced by shear.
Applications
The molecules in a LCP mesophase can be steered by external fields; a property used in display technology. Alignment is also exploited in high strength fibres like Kevlar and mouldable Vectra.
Sample preparation
Technique
Cross-polarised light microscopy
Length bar
10 μm
Further information
Detailed configurations of disclinations and their interactions have been elucidated by band texture decoration. The positive value of elastic anisotropy of a semi-flexible LCP, Cl-6, shows that bend distortion is favoured. The obvious variations of elastic anisotropy values measured from the different disclinations is probably related to the polydispersity of the polymer. The majority of disclination pairs showing random configurations indicate that that defect interactions are far from equilibrium in polymeric smectics.
Contributor
Prof A H Windle
Organisation
Department of Materials Science and Metallurgy, University of Cambridge
Date
03/10/02
Licence for re-use
Attribution-NonCommercial-ShareAlike 4.0 International
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