Continuum theory of swelling material surfaces with applications to thermo-responsive gel membranes and surface mass transport

TL;DR

This paper develops a continuum theory for swelling material surfaces, specifically polymer gel membranes, to model shape morphing and surface properties, with applications in biomedicine, micro-motility, and coatings, including thermo-responsive gels.

Contribution

The paper introduces a novel continuum model for swelling surfaces, incorporating thermo-responsive behavior, and demonstrates its application through numerical studies in various fields.

Findings

Model accurately predicts shape changes in swelling membranes.

Thermo-responsive gels alter surface properties with temperature.

Applications include targeted drug delivery and adaptive coatings.

Abstract

Soft membranes are commonly employed in shape-morphing applications, where the material is programmed to achieve a target shape upon activation by an external trigger, and as coating layers that alter the surface characteristics of bulk materials, such as the properties of spreading and absorption of liquids. In particular, polymer gel membranes experience swelling or shrinking when their solvent content change, and the non-homogeneous swelling field may be exploited to control their shape. Here, we develop a theory of swelling material surfaces to model polymer gel membranes and demonstrate its features by numerically studying applications in the contexts of biomedicine, micro-motility, and coating technology. We also specialize the theory to thermo-responsive gels, which are made of polymers that change their affinity with a solvent when temperature varies.