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Lookup NU author(s): Dr Naoko Sano
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We investigated the thermotropic phase behavior of rigid-rod poly(γ-octadecyl L-glutamate) (PG18) with an average molecular weight Mw=36,000. Two polymers with narrow molecular weight distributions (Mw/Mn), PG18-A with Mw/Mn=1.12 and PG18-B with Mw/Mn=1.05, were prepared by gel permeation chromatography (GPC) fractionation. Both were found to form a smectic A phase by means of microscopic observations of the focal conic texture and by the small-angle X-ray method. The smectic A phase of PG18-A was transformed into a cholesteric phase at approximately 140–170°C while that of PG18-B stably existed in the entire thermotropic temperature range from 60°C to 220°C (decomposition temperature). This dependence of smectic stability on the molecular weight polydispersity qualitatively corresponds to the theoretical prediction based on the excluded volume effect.
Author(s): Okoshi K, Sano N, Suzaki G, Tokita M, Magoshi J, Watanabe J
Publication type: Letter
Publication status: Published
Journal: Japanese Journal of Applied Physics
Year: 2002
Volume: 41
Pages: L720-L722
ISSN (print): 0021-4922
ISSN (electronic): 1347-4065
URL: http://dx.doi.org/10.1143/JJAP.41.L720
DOI: 10.1143/JJAP.41.L720
