Control of nanotexture and wetting properties of polydimethylsiloxane from very hydrophobic to super-hydrophobic by plasma processing

Oxygen plasma processing of thermally cured PDMS films results in controlled surface nano-texturing and wettability. Such treatment of thermally crosslinked PDMS produces spontaneously formed wavy structures on the surface with high nano-scale amplitude and with periodicity of a few 100 nm. With increasing plasma treatment duration, roughness increased while periodicity decreased, resulting in surfaces of enhanced surface area exploited for the enhancement and control of surface hydrophobicity when followed by Fluorocarbon (FC) film coating of the PDMS surface. We achieved hydrophobic surfaces and super-hydrophobic surfaces. The mechanisms responsible for the plasma-induced PDMS surface nanotexturing are discussed, and the variations of the wetting properties have been explained using the Wenzel or Cassie-Baxter models.