The water- and dirt-repellent properties of fluorinated products have been used primarily in waterproof coatings. The development of new materials or the definition of new functions for existing substances may extend the possible application of these systems to other specific uses, such as new anti-graffiti coatings to guarantee easy clean-up in the event of this kind of vandalism. The present study aimed to assess the anti-graffiti protection afforded by a fluoralkyl siloxane in limestone and granite. The results show that the surface of the substrates darkened and yellowed slightly under the treatment and that the total colour variations ()E*) found after the first cleaning were similar in the two substrates. After subsequent graffiti painting-cleaning cycles, )E* was greater in the granite, due to its more rugged surface.

This research was funded by the Spanish Ministry of Science and Technology under project MAT 2003-08343. The Spanish National Research Council, through the Heritage Subject Network, and the European Social Fund co-financed P.M. Carmona-Quiroga's pre-doctorate internship contract. The authors wish to thank Rafael Fort for the use of the contact angle equipment.

14 pages, 4 figures, 5 tables.

Peer reviewed