Characterizing the Interplay between Polymer Solvation and Conformation

Conformational transitions of flexible molecules, especially those driven by hydrophobic effects, tend to be hindered by desolvation barriers. For such transitions, it is thus important to characterize and understand the interplay between solvation and conformation. Using specialized molecular simulations, here we perform such a characterization for a hydrophobic polymer solvated in water. We find that an external potential, which unfavorably perturbs the polymer hydration waters, can trigger a coil-to-globule or collapse transition, and that the relative stabilities of the collapsed and extended states can be quantified by the strength of the requisite potential. Our results also provide mechanistic insights into the collapse transition, highlighting that the bottleneck to polymer collapse is the formation of a sufficiently large cluster, and the collective dewetting of such a cluster. We also study the collapse of the hydrophobic polymer in octane, a nonpolar solvent, and interestingly, we find that the mechanistic details of the transition are qualitatively similar to that in water.

Automated summary

This study investigates the collapse transition of a hydrophobic polymer solvated in water and in a nonpolar solvent through molecular simulations. The results show that an external potential can trigger the transition by perturbing the hydration waters of the polymer, and the bottleneck to collapse is the formation of a sufficiently large cluster and its collective dewetting process. Interestingly, the mechanistic details of the collapse transition are qualitatively similar in water and in octane.