Spatial organization of slit-confined melts of ring polymers with non-conserved topology: A lattice Monte Carlo study

TL;DR

This study uses lattice Monte Carlo simulations to investigate how slit confinement affects the structure and interactions of ring polymer melts, revealing confinement-induced changes in conformation, contact frequency, and potential for tuning mechanical properties.

Contribution

It provides new insights into the effects of slit confinement on ring polymer melts, including conformational changes and link formation, with implications for material design.

Findings

Confinement enlarges and elongates polymer chains.

Contact and knottedness increase with confinement.

Ring-ring links decrease as confinement increases.

Abstract

We present Monte Carlo computer simulations for melts of semiflexible randomly knotted and randomly concatenated ring polymers on the fcc lattice and in slit confinement. Through systematic variation of the slit width at fixed melt density, we first explore the influence of confinement on single-chain conformations and inter-chain interactions. We demonstrate that confinement makes chains globally larger and more elongated, while enhancing both contacts and knottedness propensities. As for multi-chain properties, we show that ring-ring contacts decrease with the confinement, yet neighbouring rings are more overlapped as confinement grows. These aspects are reflected on the decrease of the links formation between pairs of rings. The results suggest that confinement can be used to fine-tune the mechanical properties of the polymer network. In particular, confinement biases the synthesis of networks that are softer to mechanical stress. Finally, in connection with a previous study of us and recent simulations on two-dimensional polymer melts, our findings suggest that entanglements in polymer melts arise from pairwise ring-ring links alone.