A MONTE-CARLO STUDY OF COPOLYMER CHAIN CONFORMATIONS IN DILUTE-SOLUTIONS IN GOOD AND SELECTIVE SOLVENTS

Conformations of symmetric diblock copolymers AB in dilute solutions i n good and selective solvents were studied by Monte Carlo simulations on a simple cubic lattice, Individual chain conformations were created by the self-avoiding walk algorithm. A modified thermal equilibration of the system based on the Metropolis acceptance criteria for energie s of the system and the Rosenbluth weights of chain conformations was applied. Interactions of the nearest neighbours (r = l), where l is th e lattice distance, and interactions for r = root 2l and r = root 3l w ere considered. Various structural characteristics of the whole copoly mer chain and individual blocks A, B were obtained in the course of co mputer simulations. It was found that a moderate contraction of the wo rse soluble block B and a certain segregation of blocks occurs in dilu te solutions in selective solvents for the block A, however neither th at contraction, nor the segregation of blocks are extensive.