Compression and reswelling of microgel particles after an osmotic shock

TL;DR

This study investigates how microgel particles respond to osmotic shocks using microfluidic devices, revealing a non-monotonic compression-reswelling behavior and extracting key material properties through modeling.

Contribution

It introduces a microfluidic-based method to analyze microgel response to osmotic shocks and extracts material properties from a single experiment.

Findings

Microgel particles exhibit non-monotonic compression and reswelling behavior.

Material properties like compressive modulus and permeability are extracted.

The approach is applicable to controlled release and responsive materials.

Abstract

We use dedicated microfluidic devices to expose soft hydrogel particles to a rapid change in the externally applied osmotic pressure and observe a non-monotonic response: After an initial rapid compression the particle slowly reswells to approximately its original size. Using a simple phenomenological and a more elaborate poroelastic model, we extract important material properties from a single microfluidic experiment, including the compressive modulus, the gel permeability and the diffusivity of the osmolyte inside the gel. We expect our approach to be relevant to applications such as controlled release, chromatography, and responsive materials.