Control of drop motion by means of optical patterns imprinted on Fe:LiNbO3 crystals.

Controlling and predicting the mobility of sessile droplets in contact with a solid surface has fundamental implications and technological applications. In the last decade, the use of liquid impregnated surfaces has become the best way to improve the wettability of a substrate and promote the motion of sessile droplets. In this thesis we will couple the realization of a liquid impregnated surface with the photovoltaic effect exhibited by Lithium Niobate crystals to control in an active way the motion of sessile droplets. The resulting method is simple and versatile, enabling the successful manipulation of many consecutive drops having typical volumes of micro-liters, without the need for electrodes or power supplies. In particular, the pattern of illumination arriving on the Lithium Niobate is generated by a spatial light modulator which permits to write any shape to control the droplet. After a preliminary exploration of the dynamics of the system, the main goal of this thesis work consists in finding the best parameters to realize and control the motion of a train of droplets in a reproducible way.