256c Dynamics and Collapses of Colloidal Lattices at Oil - Water Interfaces

Sowmitri Tarimala, Chih-yuan Wu, and Lenore L. Dai. Texas Tech University, 6th & Canton, Dept. of Chemical Engineering, Lubbock, TX 79409

One interesting aspect of colloidal particles is the formation of colloidal crystals at the two-dimensional and three-dimensional level. Here we report the dynamics and collapses of ordered colloidal lattices at liquid-liquid interfaces using Pickering emulsions as an experimental template. The colloidal particles oscillate around their equilibrium positions. The short-time diffusion constant of single particles increases with increasing the lattice spacing; the oil phase viscosity only has an effect on diffusion at large inter-particle distances. Strikingly, we observe that the ordered equilibrium structure can be disturbed when increasing the output laser intensity in a confocal laser scanning microscope which leads to the collapse of colloidal lattices under small radiation pressure forces.