Aggregated States of Molecular Chains in Solid-State Films of Poly(γ-n-alkyl D-glutamate) Cast from Various Solutions

Abstract

The aggregated states of molecular chains in the crystalline region were studied for well annealed films of poly(γ-methyl D-glutamate) and poly(γ-n-hexyl D-glutamate) cast from various solutions. These crystalline regions were found to be composed of the α-helical chains in hexagonal array by means of the X-ray diffraction technique. Both a planar and a (1010) uniplanar orientations were found in the solid films of poly(γ-methyl D-glutamate), depending upon the kind of solvents and casting temperatures. Only a (1120) uniplanar orientation was observed in the solid film of poly(γ-n-hexyl D-glutamate). Viscosity measurements and optical microscopic observations revealed that the aggregated states of molecular chains in the solid were in close relation to those in solutions found in the evaporating process of solvents. In the case of poly(γ-methyl D-glutamate), a planar orientation was observed when a cholesteric solution was cast and dried, and also a (1010) uniplanar orientation was observed when a solution was gelatinized. On the other hand, in the case of poly(γ-n-hexyl D-glutamate), a liquid crystalline state was observed in any one solvent used for this report, resulting in a (1120) uniplanar orientation in the cast film.