New orientationally ordered phases of a homopolymer

We present results of Monte Carlo simulations of a homopolymer with three-body interactions on a lattice. At equilibrium we find three collapsed phases with different orientational order. The first one may be described as a conventional phase with effective three-body attraction. Two other phases are observed in the region of the phase diagram corresponding to three-body repulsion. The second phase is characterized by local orientational order within the globule. The third one possesses global orientational order and it appears to be analogous to nematic phase of a liquid crystal. Kinetics of the collapse transition to the phase III is crucially different from that of phase I and II due to formation of clusters with different orientations at the intermediate stage. This is the origin of a metastable long-lived state in kinetics. (C) 1996 American Institute of Physics.