MEASUREMENT OF THE SHAPE OF A LIQUID-LIQUID INTERFACE BY THE METHOD OF LIGHT-REFLECTION

An apparatus has been developed to measure the shape of the liquid-liquid interface of a phase-separated binary mixture after a temperature quench. The working principle of the apparatus is to measure the shape of the interface by using the reflection of a scanning light beam to find out the slope of the interface at various positions, and then the shape of the interface is obtained by a numerical integration. A real-time display sensitive to the shape of the interface is also provided to facilitate alignment of the optics. Results from calibrations show that a vertical resolution of 1 mum over a horizontal distance of 5 cm can easily be attained.