The infuence of interchain compositional heterogeneity on the conformation in random copolymers of γ‐benzyl‐ L ‐glutamate and L ‐valine

Variation in the solvent used for the copolymerization of γ‐benzyl‐ L ‐glutamate and L ‐valine N ‐carboxyanhydrides provides copolymers which have variable interchain compositions, and this variation in interchain compositional heterogeneity is reflected in the solid‐state conformations of the respective copolymers. Poly[Glu(OBzl) 29 Val 71 ] prepared in dioxane exhibits a β‐structure, whereas a copolymer of the same average composition prepared in benzene/methylene chloride shows predominantly an β‐helix conformation with a small amount of β‐structure. The use of the monomer reactivity ratio permits the calculation of the average and incremental copolymer compositions at any conversion; thus, correlations between conformation and interchain compositional heterogeneity can be made. In general, copolymers prepared in dioxane show a greater distribution of chain composition and therefore permit a wider variety of conformation than copolymers prepared in benzene/methylene chloride under identical conditions.