Thermally activated breakdown in a simple polymer model

TL;DR

This paper models the thermally activated fragmentation of homopolymer chains, analyzing bond-breaking times as a first passage problem and confirming results with simulations.

Contribution

It introduces a simple polymer model using a first passage framework to calculate bond activation times, highlighting the influence of chain length and bond position.

Findings

Bond activation times depend on chain length and bond position.

Minimum activation times occur at free chain ends.

Theoretical results are supported by Brownian dynamics simulations.

Abstract

We consider the thermally activated fragmentation of a homopolymer chain. In our simple model the dynamics of the intact chain is a Rouse one until a bond breaks and bond breakdown is considered as a first passage problem over a barrier to an absorbing boundary. Using the framework of the Wilemski-Fixman approximation we calculate activation times of individual bonds for free and grafted chains. We show that these times crucially depend on the length of the chain and the location of the bond yielding a minimum at the free chain ends. Theoretical findings are qualitatively confirmed by Brownian dynamics simulations.