Comparison of Conformational Phase Behavior for Flexible and Semiflexible Polymers

TL;DR

This study uses a novel microcanonical analysis method and extensive simulations to explore how bending stiffness influences phase transitions in flexible and semiflexible polymers, revealing qualitative changes in transition behavior.

Contribution

It introduces the application of the generalized microcanonical inflection point method to analyze phase transitions in polymers with varying stiffness.

Findings

Transition into compact phases changes qualitatively with stiffness.

The $ heta$ collapse transition remains largely unaffected.

The first-order liquid-solid transition disappears with increased bending stiffness.

Abstract

We employ the recently introduced generalized microcanonical inflection point method for the statistical analysis of phase transitions in flexible and semiflexible polymers and study the impact of the bending stiffness upon the character and order of transitions between random-coil, globules, and pseudocrystalline conformations. The high-accuracy estimates of the microcanonical entropy and its derivatives required for this study were obtained by extensive replica-exchange Monte Carlo simulations. We observe that the transition behavior into the compact phases changes qualitatively with increasing bending stiffness. Whereas the $\Theta$ collapse transition is less affected, the first-order liquid-solid transition characteristic for flexible polymers ceases to exist once bending effects dominate over attractive monomer-monomer interactions.