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Abstract
Cholesteric pitch (P=2π/qc ) was measured for aqueous solutions of a triple-helical polysaccharide schizophyllan as a function of temperature (T), concentration (c) and molecular weight (M v). qc was substantially independent of M v but changed with T and c. At higher temperatures, qc changed monotonously with T but showed a sudden decrease around 7–18°C on lowering T, which was due to the order-disorder transition of aqueous schizophyllan. The concentration dependence of qc for D2O solutions in the high temperature disordered state is the same as that for H2O solutions, and interpreted theoretically using the threaded effective freely jointed chain model. On temperature jump experiments. qc did not follow immediately T, but changed with the time elapsed. The relaxation time τch was less than a few minutes. Since the conformation of the triple helix follows T much faster than τch, this relaxation comes from rotational diffusion of the triple helix.