Researchers from the University of Florence in Italy have developed a new technique for safely and quickly removing graffiti from street art.

Street art, which tends to be a magnet for graffiti, can, according to researchers, be cleaned with a nanostructured fluid derived from non-toxic solvents and surfactants incorporated into retentive hydrogels that slowly release cleaning agents, which remove the graffiti layer in just minutes without damaging the original artwork.

Making current methods for removing graffiti from street art challenging is that the paints used in both the artwork and the graffiti often feature one of three different paint binder types — acrylic, vinyl or alkyd polymers — all of which are of similar composition. As such, current methods for removing graffiti from street art require scraping, sand blasting or chemical cleaners.

To develop a technique that won’t destroy the original artwork, researchers used Fourier transform infrared spectroscopy to identify the binders, fillers and pigments in the three different paint class types. The team then used small angle X-ray scattering analyses to observe the behavior of four alkyl carbonate solvents and a biodegradable nonionic surfactant in water.

Based on their observations, the team determined that the nanostructured cleaning combination featuring 2-butanol and a biodegradable alkyl glycoside hydrotrope as co-solvents and co-surfactants worked well. That combination was then incorporated into the retentive hydrogels and tested on street art in Florence. During testing, the gel successfully removed graffiti covering the street art in just minutes without damaging the original artwork.

The research — Selective removal of over-paintings from “Street Art” using an environmentally friendly nanostructured fluid loaded in highly retentive hydrogels —appears in the Journal of Colloid and Interface Science.