Anomalous Critical Slowdown at a First Order Phase Transition in Single Polymer Chains

TL;DR

This study reveals that polymer chains exhibit a critical slowdown near a first-order phase transition, combining features of both first-order jumps and critical point divergences, supported by simulations and a theoretical model.

Contribution

The paper introduces a dynamic effective interface model that explains anomalous slowdown phenomena in force-driven polymer phase transitions.

Findings

Relaxation time diverges as the transition is approached.

The model accurately reproduces simulation data.

Unconventional features may be common in macromolecular phase transitions.

Abstract

Using Brownian Dynamics, we study the dynamical behavior of a polymer grafted onto an adhesive surface close to the mechanically induced adsorption-stretching transition. Even though the transition is first order, (in the infinite chain length limit, the stretching degree of the chain jumps discontinuously), the characteristic relaxation time is found to grow according to a power law as the transition point is approached. We present a dynamic effective interface model which reproduces these observations and provides an excellent quantitaive description of the simulations data. The generic nature of the theoretical model suggests that the unconventional mixing of features that are characteristic for first-order transitions (a jump in an order parameter) and features that are characteristic of critical points (anomalous slowdown) may be a common phenomenon in force-driven phase transitions of macromolecules.