Microscopic contact line dynamics dictate the emergent behaviors of particle rafts

Particle rafts --- fluid-fluid interfaces covered with particles --- form wrinkles and folds when compressed, like a crumpled piece of paper. Nevertheless, composed of discrete particles, rafts under compression can also fail by expelling single particles, which cannot be explained by existing continuum models. We develop a composite model that incorporates the contact line dynamics of individual particles to fully describe both the elastic and granular responses of the compressed particle rafts. By using this new model framework, we also demonstrate the control of raft behaviors by tuning the physicochemical properties of individual particles.