Interfaces and interfacial phenomena like nucleation, droplet coalescence and capillarity are amongst the most widely experienced phenomena in life, with relevance to areas as diverse as oil recovery, food and inkjet printing. The importance of interfacial phenomena has been further prompted by the recent and rapid emergence of micro- and nano-fluidics, because at these small length scales, interfacial phenomena are particularly dominant and interface dynamics strongly affect the transport and response of fluids in such devices. Actively controlling interfacial phenomena is therefore becoming increasingly desirable, both for providing new and fundamental insights into interfacial phenomena and for the successful implementation of micro- and nano-fluidic devices. The interfacial roughness in atomic and molecular systems is, however, typically in the (sub)nanometre range, making the relevant interfacial phenomena experimentally very hard to access. Colloidal systems, which consist of particles with a size between roughly one nanometre and several micrometres dispersed in a molecular solvent, provide a unique model system to explore interfacial phenomena in great detail due to their ultralow interfacial tension.
In this project, we use optical tweezing and confocal microscopy to gain fundamental insight into interfacial phenomena by actively manipulating colloidal interfaces, droplets, crystallites and liquid crystalline droplets. In particular, we plan to address phenomena like nucleation, evaporation, coalescence and capillary condensation and nematisation in colloidal liquids, crystallites and liquid crystals. We believe this will be a very rewarding approach that opens up a range of exciting possibilities to actively investigate and manipulate interfaces, droplets and crystallites, thereby providing a new perspective on interfacial phenomena in complex fluids.