Runaway Transition in Irreversible Polymer Condensation with Cyclisation

TL;DR

This paper investigates the transition in polymer condensation processes where cyclisation competes with chain growth, revealing a phase change from ring-dominated to linear polymer-dominated regimes with significant implications for material properties.

Contribution

The study introduces a unified approach combining theory, simulations, and experiments to characterize the transition in irreversible polymer condensation with cyclisation.

Findings

Identifies a transition from ring-dominated to linear polymer regimes.

Shows fluids near the transition have distinct compositions and rheology.

Demonstrates the relevance of the transition in practical polymer systems.

Abstract

The process of polymer condensation, i.e. the formation of bonds between reactive end-groups, is ubiquitous in both industry and biology. Here we study generic systems undergoing polymer condensation in competition with cyclisation. Using a generalised Smoluchowski theory, molecular dynamics simulations and experiments using DNA and T4 ligase, we find that this system displays a transition, from a regime with finite-length chains at infinite time and dominated by rings to one dominated by linear polymers that grow in time. Finally, we show that fluids prepared close to the transition may have profoundly different compositions and rheology at large condensation times.