Preparation and basic property of superhydrophobic silicone rubber surfaces

Summary

In the outdoor insulating, the most important property of silicone rubber is its hydrophobicity. In recent research of interface and adhesion, wettability control has been widely investigated for technological applications such as self-cleaning surfaces by modifying both the geometric structure and the chemical composition of the surfaces. Water droplets on lotus-leaf-like superhydrophobic surface can pick up dirt particles and remove contamination. This property is an idea state for outdoor insulating material. In this article, we give a way to make a surface modification of silicone rubber. By using of high power picosecond laser in cooperated with a high speed scanning mirror, micro pit with nano substructures can be fabricated on mold steel. This kind of mold is used in the directly replicating process in which the surface morphology of silicone rubber (HTV) can be changed during the vulcanization by micro-nano structured protrusion. The superhydrophobic characteristics is achieved on composite insulating surface where its contact angle reaches 151°. From the SEM and theoretical analysis results, it can be found that the protrusion on silicone rubber having a low aspect ratio of an intrinsically hydrophobic material enhances the hydrophobicity of the solid surface through increasing surface roughness. At the same time, the contact area between the water and surface decreases significantly. Contact model of the water and the superhydrophobic surface obeys the Cassie-Baxter equation, the infiltration depth of water on the superhydrophobic silicone rubber is significantly shallow. The sliding angle of superhydrophobic surface reaches 5°, which means that this insulating surface has a good self-clean properties.

Additional informations

Authors

Lim Sung Woo, Lee Jong Geon, Tamus Zoltán Ádám, Khan Umer Amir, Csányi Gergely Márk