Investigations on conformations of block and of random copolymers in dilute solution

Abstract

Abstract Investigations on the viscosity behavior of well characterized block and random copolymers were carried out in a number of solvents. Account was taken of the expansion of the corresponding individual homopolymers in each of the chosen solvents. It was shown thus that for block copolymers heterocontact interactions do not affect the dimensions of the macromolecular coils. This confirms the “segregated” conformations of block‐copolymers, characterized by a very low number of intramolecular heterocontacts. On the contrary, for random copolymers the χ AB term does not only affect the expansion but also the unperturbed dimensions of the molecule. The heterocontact interactions are, as expected, strongly solvent dependent, and a relation was established between the expansion increment and the critical demixtion volume of the corresponding homopolymers.