New block copolymers of α‐amino acids

Abstract

Triblock cepolypeptides of γ‐benzyl‐L‐glutamate and L‐leucine or L‐valine of high molecular weight have been prepared. The solid state structure of the block copolymers cast from preferential solvents has been compared with that of random copolymers of similar composition as well as the appropriate homopolymers. Infrared and solid state circular dichroism measurements indicate that the γ‐benzyl‐L‐glutamate and L‐leucine blocks assume an α‐helical conformation and L‐valine blocks a β‐sheet structure. The WAXD patterns of the block copolymers show overlapping reflections characteristic of the individual homopolymers. Further evidence for a phase separated morphology is provided by dynamic mechanical spectroscopy.