On the impact of a liquid crystal droplet upon a surface pre-treated by various liquids

The physical phenomena of a liquid crystal droplet hitting a surface has been investigated experimentally, with a set of observation equipment being established. The piezoelectric droplet generator is combined with a signal controller and a temperature controller to accurately generate liquid crystal droplets with the same volume. The precise moving platform and the rotating platform are used to control the position where the droplets fall and hit a glass slide. The surface is treated with various solutions of acetone, pure water, ethanol, n-propanol, n-heptanol, ethylene glycol, dodecane and hexadecane, by using different drying methods, including air drying, natural drying and forced drying.

The focus of the experiment is to observe the interaction between liquid crystal molecules and solids during the collision and expansion of liquid crystal droplets on various surfaces, resulting in different arrangements of liquid crystal molecules, which are discussed by measuring the static contact angle of the droplets. We intend to know the correlation between the liquid crystal droplet and various surfaces. If there is a solution on the glass slide, the liquid crystal molecules will align parallelly after the liquid crystal droplet hits the surface. The liquid crystal molecules align homeotropically to the surface on a completely dry surface.