Superhydrophobic surface produced on polyimide and silicon by plasma enhanced chemical vapour deposition from hexamethyldisiloxane precursor

Plasma polymerisation of hexamethyldisiloxane (PPHMDSO) has been used to deposit micro- and nanostructured thin layers on silicon and polyimide substrates, using low-pressure and low-frequency plasma discharge. The effects of plasma chamber pressure and deposition time on film characteristics have been studied. Thickness, surface properties and chemical structure of the deposited thin layers were analysed by means of profilo-meter, scanning electron microscopy (SEM), static contact angle and Fourier transform infrared spectroscopy measurements. For some deposition parameters, nanopowders of different concentrations and size were observed on the elaborated thin layer surface. Fourier transform infrared spectroscopy analysis has revealed thin layers with chemical formula close to SiOxCyHz, with more organic character when the chamber pressure and the deposition time were increased. Water contact angle (WCA) measurements show that increasing deposition pressure and deposition time lead to the growth of a superhydrophobic surface on both polyimide and silicon substrates, owing to the increase in the nanopowders concentration over the coated surface.