Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 640

Full Record for Micrograph 640

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Micrograph no
Brief description
Fracture surface in a liquid crystalline polymer, oriented by a magnetic field
alignment, fibre Link to MATTER Glossary entry for fibre, fibrillation Link to MATTER Glossary entry for fibrillation, fracture Link to MATTER Glossary entry for fracture, liquid crystalline polymer (LCP), lyotropic, magnetic, nematic, polymer Link to MATTER Glossary entry for polymer
Fracture, Polymer
Liquid crystalline polymer
Random copolyester of average molecular weight 14401
Standard codes
A 1.1T magnetic field has been applied for one hour (magnetic axis vertical)
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
Scanning electron microscopy (SEM)
Length bar
4 μm
Further information
Above their melting point, liquid crystalline polymers exhibit a mesophase within which, although able to flow and are not arranged in a crystal, they exhibit long range orientational order. This molecular alignment can be exploited to make high strength and stiffness fibres such as Kevlar, or even mouldable thermotropics such as Vectra. Molecular alignment can also be controlled by an external applied field; a property exploited in liquid crystal displays. This polymer has been subjected to a magnetic field of 1.1T (normal to the fracture plane) for one hour and the resulting alignment is evident in the fractured surface.
Prof A H Windle
Department of Materials Science and Metallurgy, University of Cambridge
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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