segunda-feira, novembro 03, 2003

Adenda ao Trauma Nacional: Encomende-se!!!

«Researchers in Mexico have invented a new type of anti-graffiti paint.

The row over who will provide the anti-graffiti technology for Berlin's Holocaust memorial (see article) highlights a widespread and ancient problem. Even the Romans had to put up with slogans scratched on their fine new buildings by ungrateful locals. Ever since then, people have been struggling to deal with unofficial decorators who wish to express their opinions, or merely to catch the public eye.

Most existing anti-graffiti coatings work only a few times before they must be repainted; a nuisance when a newly cleaned surface gets redaubed almost immediately. But now, Víctor Castaño and his colleagues at the Autonomous National University of Mexico, in Santiago de Querétaro, believe they have a solution—a paint to which the daubings will not stick.

The group's research work has already led to one graffiti-proof coating, called Deletum 3000. But this is inconvenient to use as it has to be mixed just prior to use. The new product, Deletum 5000, which will be released in January, is a ready-mixed, and more effective, version, as Dr Castaño explained to the Nanotechnology in Crime Prevention and Detection conference held in London on October 28th.

Deletum 5000's special ingredient is silica. It is loaded with particles of the stuff that are but a few nanometres (billionths of a metre) across. These particles have had both oil-repellent and water-repellent molecules attached to their surfaces. Both are necessary, since the materials used by graffiti artists may be oil-based or water based. However, if merely mixed together, the two would end up repelling each other, and thus separating. By attaching them to the silica, this mutual loathing can be overcome and, as the paint dries, the changes that take place force the oil-and-water-proofing to the surface. The result is that most agents used by graffiti artists will not stick to that surface—and what does stick can be washed or brushed off easily.»

The Economist