Structural correlations in comb heteropolymers in good and backbone-selective solvents

摘要

Molecular dynamics (MD) simulations of coarse-grained regular comb heteropolymers have been performed to explore structural correlations at equilibrium in a nonselective solvent and during the transition from coil to micelle in a backbone-selective solvent. We primarily consider the static structure factor measured directly from the simulations. In the good solvent, we consider cases ranging from short to long side chains, with respect to the spacer length. Reasonable agreement with a previously published theoretical structure factor is observed for a limited subset of the comb architectures in a small wavevector range. When the side chains are much longer than the spacers, the side-chain structure factor approaches that of starlike polymers. Additionally, plateau values of the structure factor scale with the sidechain length to the power of 0.736 when the side chains are shorter than the spacers. The transition from an open coil to a collapsed micelle is examined in MD simulations with explicit-solvent particles. Upon a sudden quench the from nonselective solvent to the backbone -selective solvent, the coil-to-micelle transition occurs via a sidechain clusterization mechanism. The time-dependent structure factors measured during the collapse process have plateau values that scale with the average cluster size to the power of 0.9. The origin of these two scaling exponents is still unknown. 0 2005 Wiley Periodicals, Inc.