RFOT theory for glassy dynamics in a single condensed polymer

TL;DR

This paper applies RFOT theory to a single condensed polymer, showing it exhibits glassy dynamics with a thermodynamic transition and Vogel-Fulcher-Tamman relaxation, similar to structural glasses.

Contribution

It extends RFOT theory to describe glassy behavior in a single condensed polymer, revealing universal characteristics with structural glasses.

Findings

SCP exhibits slow dynamics below a dynamical transition temperature.

A thermodynamic glass transition occurs at a lower temperature where configurational entropy vanishes.

Relaxation times follow the Vogel-Fulcher-Tamman law, diverging at a finite temperature.

Abstract

The number of compact structures of a single condensed polymer (SCP), with similar free energies, grows exponentially with the degree of polymerization. In analogy with structural glasses (SGs), we expect that at low temperatures chain relaxation should occur by activated transitions between the compact metastable states. By evolving the states of the SCP that is linearly coupled to a reference state, we show that, below a dynamical transition temperature ($T_d$), the SCP is trapped in a metastable state leading to slow dynamics. At a lower temperature, $T_K \ne 0$, the configurational entropy vanishes, resulting in a thermodynamic random first order ideal glass transition. The relaxation time obeys the Vogel-Fulcher-Tamman law, diverging at $T=T_0 \approx T_K$. These findings, accord well with the random first order transition theory, establishing that SCP and SG exhibit similar universal characteristics.