Superhydrophobic surfaces have considerable technological potential for various applications due to their extreme water-repellent properties. When two hydrophilic bodies are brought in contact, any liquid present at the interface forms menisci, which increases adhesion/friction and the magnitude is dependent upon the contact angle. The superhydrophobic surfaces may be generated by the use of hydrophobic coating, roughness and air pockets between solid and liquid. The geometric effects and dynamic effects, such as surface waves, can destroy the composite solid-air-liquid interface. Studies on silicon surfaces patterned with pillars of varying diameter, height and pitch values and deposited with a hydrophobic coating were performed to demonstrate how the contact angles vary with the pitch. A criterion was developed to predict the transition from Cassie and Baxter regime to Wenzel regime, considering water droplet size as a parameter on the patterned surfaces with various distributions of geometrical parameters. The trends are explained based on the experimental data and the proposed transition criterion.
展开▼
