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 160° 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 °C to −10 °C. Also, it was found that the capacitance of superhydrophobic surfaces decreased with increasing anodising voltage.

► A superhydrophobic surface was prepared via aluminium anodisation followed by silicone rubber coating. The anodisation voltage affects the size and form of the pore. ► An important delayed freezing time on the superhydrophobic surfaces was observed. Wettability behaviour of superhydrophobic surface depends strongly on substrate temperature. Increasing the anodising voltage reduced the capacitance of superhydrophobic surfaces.