Development of a nanosecond time-resolved Brewster angle microscope to observe phase change at an interface

A nanosecond time-resolved Brewster angle microscope was developed in order to observe pulsed-laser-induced spinodal de-mixing of binary liquid mixtures of triethylamine (TEA)-water and 2-butoxyethanol (2BE)-water at interfaces. At an air-liquid interface the phase changing regions spread across the liquid surface due to convection, which also resulted in the formation of larger domain areas than were observed at a quartz-liquid interface, for which convectional spreading was not observed. In the case of 2BE-water, de-mixing at an air-liquid interface, the domains developed a branched structure in the late stages of coarsening. At the same time the Reynolds numbers of the growing phases were estimated to be >3, which may account for the morphological changes that were observed in this time.