Effects of field on temperature-induced segregation and folding of polymer chains

Segregation of polymer chains and their conformations are studied as a function of temperature and field in two dimensions using a hybrid (discrete-to-continuum) simulation method. Temperature-induced segregation occurs on decreasing the temperature, i. e., from T=5 (desegregation) to T=1 (segregation) followed by chains folding (T less than or equal to 0.5) in the absence of field. The amplitude of folding increases on reducing the temperature. While the presence of field induces orientational ordering and anisotropy in the mass segregation of chains, it leads to desegregation as the field is increased above a characteristic value (E-c). Radius of gyration exhibits conformational crossover from extended (SAW) (high T) to collapse (low T) in the absence of field, but anisotropy sets in its spread in the presence of field. Variation of the radial distribution is consistent with these observations. (C) 1999 American Institute of Physics. [S0021-9606(99)51512-2].