Wettability behaviour of RTV silicone rubber coated on nanostructured aluminium surface

A nanostructutered superhydrophobic surface was elaborated by applying an RTV silicone rubber coating on electrochemically processed aluminium substrates. Study of anodisation voltage on surface morphology showed that higher anodising voltage led to larger pore sizes. Scanning electron microscopy image analysis showed bird's nest and beehive structures formed on anodised surfaces at 50 V and 80 V. Water static contact angle on the treated surfaces reached up to 160o at room temperature. Study of superhydrophobic surfaces at super cooled temperature showed important delayed freezing time for RTV hydrophobic surfaces when compared to non-treated aluminium. However, lower wettability was observed when surface temperature went down from 20 deg. C to -10 deg. C. Also, it was found that the capacitance of superhydrophobic surfaces decreased with increasing anodising voltage.