The temperature dependence of nematic liquid crystalline polymer melt diffusion |
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| Authors: | E Hall C K Ober G Galli |
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| Institution: | 1. Department of Materials Science and Engineering , Cornell University , Ithaca, New York , 14853-1501 , U.S.A.;2. Department of Chemistry and Industrial Chemistry , University of Pisa , 56126 , Pisa , Italy |
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| Abstract: | Abstract Polymer chain diffusion in the nematic mesophase was studied using a model main chain liquid crystalline (LC) polyether based on 2,2′-dimethyl-4,4′-dihydroxyazoxybenzene and mixed alkane spacers. A side chain LC polymethacrylate containing an azobenzene mesogenic group was also investigated. Tracer diffusion coefficients were determined as a function of temperature by an ion-beam depth profiling technique, forward recoil spectrometry. The results confirm that main chain LC polymer chain dynamics are dramatically affected by phase transitions and sample geometry. This behaviour is in marked contrast to the side chain LC polymer which exhibited no phase dependence on the part of the tracer diffusion coefficient. |
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