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KEY WORDSThermotropic Mesophase / Polyglutamate / Cholesteric Liquid Crystal / Circular Dichroism / Rodlike Macromolecule / Paper I of this series 1 reported the first observation of thermotropic liquid crystals on ex-helical poly(y-methyl o-glutamate-co-y-hexyl o-glutamate)s. In that paper, it was found that the thermotropic liquid crystalline phase arises in copolymers with intermediate hexyl contents of 30-70% and an appreciable difference in side chain length between the monomer components is attributable to the appearance of thermotropic nature in copolymers. In the same vein, thermotropic mesophases were successfully attained in poly(y-benzyl Lglutamate-co-y-dodecyl L-glutamate)s and the details of their cholesteric mesophase properties were reported in Paper III. 2 On the other hand, paper 11 3 indicated that even in homopolymers of L-glutamates, the thermotropic nature can be induced if n-alkyl groups longer than decyl are attached to the side chain. Induction of thermotropic phase has been also reported in poly(4-substituted y-benzyl Lglutamate)s with similar alkyl groups as substituents.4 In all cases, the long flexible side chains may be responsible for the occurrence ofthermotropic liquid crystals where they may play the role of solvent in familiar lyotropic liquid crystals. These novel thermotropic liquid crystalline (TLC) polymers, having a mesogenic ex-helical rod surrounded by flexible side chains, should be differentiated from two kinds of TLC polymers-the so called mainchain TLC polymers and the side-chain TLC polymers, and classified into a third kind of TLC polymer. 2 In this work, we prepared several kinds of copolyglutamates composed of two comonomers, a familiar y-benzyl Lglutamate and y-alkyl L-glutamates, with the objective of seeking new thermotropic polypeptides. Thermotropic mesophases were easily attained in the copolymers in which the alkyl L-glutamates have the side chains longer than decyl group. In this communication, we report some of their mesogenic properties.Five series of poly(y-benzyl L-glutamate-coy-alkyl L-glutamate)s, were synthesized by ester exchange reactions of poly(y-benzyl Lglutamate) (M w= 170,000) with the respective n-alkyl alcohols; octyl (n = 8), decyl (n = 10), (the carbon number of alkyl group: n=8, 10, 12, 14 or 16) 781

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