We use dedicated microuidic devices to expose soft hydrogel particles to a rapid change in the externally applied osmotic pressure and observe a surprising, non-monotonic response: After an initial rapid compression, the particle slowly reswells to approximately its original size. We the- oretically account for this behavior, enabling us to extract important material properties from a single microuidic 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.

Unilever , NWO
Phys. Rev. Lett.
Theory of Biomolecular Matter

Sleeboom, J., Voudouris, P., Punter, M., Aangenendt, F., Florea, D., van der Schoot, P., & Wyss, H. (2017). Compression and reswelling of microgel particles after an osmotic shock. Phys.Rev.Lett., 119(9, Article number: 098001), 1–5. doi:10.1103/PhysRevLett.119.098001