Microheterophase structure of A-B-A type block copolymer consisting of poly(γ-benzyl l-glutamate) as the a component and polyisoprene as the B component

Abstract

A-B-A type block copolymers (GIG) composed of poly(γ-benzyl l-glutamate) (PBLG) as the A component and polyisoprene (PI) as the B component were synthesized. From the i.r. spectra measurements in the solid state, it has been found that the polypeptide chain block exists in the α-helix conformation in the same manner as PBLG. By using wide-angle X-ray diffraction (WAXD) and electron microscopy it could be shown that the block copolymers exhibit mesophase behaviour in different solvents. In this case, PI chains are in a random coil conformation and form domains embedded in the matrix phase formed by PBLG chains in the α-helix conformation. Model analysis of the complex modulus of the membrane cast from solution suggested the occurrence of spherical and cylindrical domain structures in the membrane.