Slow relaxation and solvent effects in the collapse of a polymer.
Using molecular dynamic simulations we study the quench of a homopolymer chain into a poor solvent at finite temperature. We show that, depending on the quench depth, there are different relaxation pathways to the collapsed state. Solvent effects are introduced through an effective Lennard-Jones potential depending on the local monomer density. The various relaxation regimes are characterized by the contact correlation function. As the quench depth increases, the system evolves towards a glassy state, and the relaxation dynamics continuously changes from an exponential to a stretched exponential law. The characteristic relaxation time diverges at low temperature following an Arrhenius law, like in the case of strong glasses. We found that the stretching exponent depends on aging in a nonuniversal way. The solvent modifies the globular state by diminishing the effects of frustration and glassy behavior.
Frisch
Thomas
T
Institut de Recherche sur les Phénomènes Hors Equilibre, UMR 6594, CNRS, Université d'Aix-Marseille, 49 rue F. Joliot-Curie, Boîte Postale 146, 13384 Marseille, France. frisch@irphe.univ-mrs.fr
Verga
Alberto
A