Collapse Dynamics of a Homo-Polymer in Poor Solvent: Influence of Hydrodynamic Interactions and Quench Depth
The collapse dynamics of a homo-polymer in dilute solution, as the solvent quality is abruptly changed from good to poor, has always been an interesting and challenging physical problem. Understanding the collapse transition would enable us to obtain insight into the conformational transitions in many complex biological systems, such as protein and DNA folding, and how other such bio-molecules react to changes in their environment.
In this work, Brownian dynamics simulations of a bead-spring chain model with and without hydrodynamic interactions (HI) are carried out to investigate the role play by the solvent in mediating the dynamics of collapse. It is found that hydrodynamic interactions speed up the rate of collapse significantly. The polymer molecule often gets trapped in metastable states for long periods before going to its native globular state at deep quench. This trapping effect is also observed in the presence of HI. The collapse pathways from a good solvent state to a poor solvent state are found to be independent of HI. However, these pathways are significantly different for shallow and deep quench.