Modelling realistic microgels in an explicit solvent

TL;DR

This paper advances microgel modeling by explicitly simulating solvent interactions, providing deeper insights into solvent effects on microgel behavior and collapse dynamics, which are crucial for applications like liquid-liquid interfaces.

Contribution

It introduces an explicit solvent simulation approach for realistic microgels, enhancing understanding of solvent uptake and collapse kinetics beyond implicit models.

Findings

Explicit solvent model captures key features of implicit models.

Provides detailed insights into solvent uptake within microgels.

Facilitates study of microgel behavior at liquid-liquid interfaces.

Abstract

Thermoresponsive microgels are polymeric colloidal networks that can change their size in response to a temperature variation. This peculiar feature is driven by the nature of the solvent-polymer interactions, which triggers the so-called volume phase transition from a swollen to a collapsed state above a characteristic temperature. Recently, an advanced modelling protocol to assemble realistic, disordered microgels has been shown to reproduce experimental swelling behavior and form factors. In the original framework, the solvent was taken into account in an implicit way, condensing solvent-polymer interactions in an effective attraction between monomers. To go one step further, in this work we perform simulations of realistic microgels in an explicit solvent. We identify a suitable model which fully captures the main features of the implicit model and further provides information on the solvent uptake by the interior of the microgel network and on its role in the collapse kinetics. These results pave the way for addressing problems where solvent effects are dominant, such as the case of microgels at liquid-liquid interfaces.