Experimental Soft Condensed Matter Physics

We employ optical microscopy, light scattering, optical tweezing, and analytical centrifugation, to study phases and phase transitions in systems of colloids, micron-sized particles in a solvent. These systems exhibit liquid, crystalline, glass, gel and liquid-crystalline phases, where the colloidal particles mimick atoms and molecules. Employing confocal microscopy, we follow tens of thousands of individual particles in real time, in either two or three spatial dimensions. This unprecedentedly-detailed experimental information, which is not available with any other experimental technique, allows a much deeper understanding of collective phenomena, such as crystal nucleation, glass formation, and random solid packing to be achieved.

We also study the interfacial physics of liquid emulsion droplets. Recently, we have discovered a unique interfacial phase transition, which allows the droplet shapes to be temperature-tuned from spherical to faceted, with their bulk remaining liquid.