Surface dispersive energy determined with IGC-ID in anti-graffiti-coated building materials

Coating building materials with anti-graffiti treatments hinders or prevents spray paint adherence by generating low energy surfaces. This paper describes the effect of coating cement paste, lime mortar, granite, limestone and brick with two anti-graffiti agents (a water-base fluoroalkylsiloxane, “Protectosil Antigraffiti®”, and a Zr ormosil) on the dispersive component of the surface energy of these five construction materials. The agents were rediluted in their respective solvents at concentrations of 5 and 75% and the values were determined with inverse gas chromatography at infinite dilution (IGC-ID).The dispersive energy of the five materials prior to coating, ranked from highest to lowest, was as follows: limestone > granite > cement paste > brick > lime mortar. After application of the two anti-graffiti compounds, CF3 terminals (Protectosil) were found to reduce the surface energy of both basic (limestone and lime mortar) and acidic (granite) substrates more effectively than CH3 (ormosil) terminals.