Loss and recovery of hydrophobicity of RTV silicone rubber coating

The loss of surface hydrophobicity of room temperature vulcanized (RTV) silicone rubber (SIR) due to immersion in acid, alkali and saline solutions has been studied as a function of immersion time and concentration. The loss and recovery of the hydrophobicity is correlated with the solute and the absorption of water during immersion and its subsequent desorption in air. The hydrophobicity is determined by measuring the static contact angle between the tangent to a droplet of distilled water and the horizontal RTV-SIR coating surface. The surface tensions of solutions were measured before and after the RTV-SIR coatings were immersed in solutions. The values show the effect of solution on RTV-SIR coating.