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Fracture surface in a liquid crystalline polymer | by CORE-Materials
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Fracture surface in a liquid crystalline polymer

DoITPoMS, University of Cambridge

 

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 specimen has not had a magnetic field applied to it and it exhibits only local molecular self-alignment, without any overall orientation alignment. It is to be compared with a similar sample which has been subjected to a magnetic field of 1.1T for one hour and in which there is a high level of fibrillar alignment.

 

System

Liquid crystalline polymer

 

Composition

Random copolyester of average molecular weight 14402

 

Reaction

  

Processing

No external field has been applied

 

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

Scanning electron microscopy (SEM)

 

Contributor

Prof A H Windle

 

Organisation

Department of Materials Science and Metallurgy, University of Cambridge

 

View micrograph in DoITPoMS website

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Taken on October 3, 2002