The contact angle is very important parameter in improving the self-cleaning property as well as in increasing the wear resistance of engineering surfaces in addition to improving the thermal transfer properties of materials in general. In this study, titanium dioxide nanoparticles were added to the epoxy resin and sprayed on a substrate of the brass tube used in heat exchangers for the purpose of studying its effect on the angle of contact of the substrate where different proportions of the nanomaterial were added to the epoxy resin in (1%, 3%, 5%, and 7%)wt. The results showed that the contact angle increased with increasing the rate of titanium dioxide nanoparticles.