University of Oxford

Susan Perkin

Lauriane Pierrot-Deseilligny

Liquid liquid phase separations are a ubiquitous process in many natural processes. Examples include the formation of protein condensates inside cells, which regulate gene expression and cellular organization, and the nucleation of amorphous carbonate in coccolith vesicles of marine microalgae. Such environment are characterized by confined geometries, which means steric constraints limit molecular mobility and the high surface-to-volume ratio enhances interfacial effects. In such environments, deviations from bulk behaviour are expected. Theories predict that stability domains in confinement differ from bulk. Confinement should therfore be treated as a thermodynamic parameter and not only a simple boundary conditions. We use a surface force balance to study how nanoconfinement induces demixing in mixtures of simple molecular liquids. We developed a method to map concentration variations of nanoconfined fluids to identify how the equilibrium phases of a demixed mixture in confinement differ from those in bulk. With surface force measurements, we investigate the interplay between wetting transitions and confinement induced phase separation.