Electric wetting of ZnO surface

Abstract

Wettability is an important property of solid materials and is governed by both the surface chemical composition and the surface geometrical structure. The modifiable wetting properties has aroused much interest due to the wide practical applications in distinct technological industry such as microelectronics, food technology and cell manipulation. Hydrophobic surface refers to a surface with water contact angle of larger than 90° whereas a water contact angle smaller than 90° is referred to hydrophilic surface.

In this project work, the wettability of the zinc oxide (ZnO) was investigated. Zinc oxide has been widely exploited due to its unique optical, electrical and large bandgap properties for potential applications like chemical and biological sensors, solar cells and low friction/wear coatings for wide temperature range sliding applications. Application of external stimuli such as ultraviolet illumination, thermal excitation and electric field to the zinc oxide has been explored to realize surfaces that can display modified and switchable wettability. The enhancement of the roughness of the substrate surface would result in an extended water contact angle.