Aggregation of theta-polymers in spherical confinement

TL;DR

This study uses multicanonical simulations to analyze how density influences the aggregation transition temperature of theta polymers confined in a spherical cavity, revealing the interplay between single-polymer collapse and aggregation.

Contribution

It provides a systematic analysis of density effects on polymer aggregation transition temperatures using advanced simulation techniques.

Findings

Aggregation temperature depends on density.

Polymers behave as isolated above the aggregation temperature.

Finite-size effects influence the transition.

Abstract

We investigate the aggregation transition of theta polymers in spherical confinement with multicanonical simulations. This allows for a systematic study of the effect of density on the aggregation transition temperature for up to 24 monodisperse polymers. Our results for solutions in the dilute regime show that polymers can be considered isolated for all temperatures larger than the aggregation temperature, which is shown to be a function of the density. The resulting competition between single-polymer collapse and aggregation yields the lower temperature bound of the isolated chain approximation. We provide entropic and energetic arguments to describe the density dependence and finite-size effects of the aggregation transition for monodisperse solutions in finite systems. This allows us to estimate the aggregation transition temperature of dilute systems in a spherical cavity, using a few simulations of small, sufficiently dilute polymer systems.