Street art has become a mainstream cultural phenomenon, thanks to artists such as Jean-Michel Basquiat, Keith Haring, Banksy and Kaws.
But exterior murals are vulnerable to vandals, spoiling their beauty with unwanted graffiti.
A group of chemists in Italy have developed a groundbreaking new method to wipe away graffiti while keeping the art underneath intact.
The process involves loading non-toxic cleaners onto a thin layer of polymers known as hydrogels and applying them to a surface of a destroyed piece of street art.
The hydrogel slowly releases the cleaning agents down to the top layer only, only a few microns deep, allowing quick removal of the overpainting without damaging the work.
Removing graffiti from street art is difficult because the chemical composition of both is so similar that it is nearly impossible for a solvent to erase one without the other
“For decades, we’ve focused on cleaning or restoring classical works of art with paints designed to last for centuries,” said Piero Baglioni, a chemist at the University of Florence who worked on the project.
‘In contrast, modern art and street art, as well as the coatings and graffiti applied to them, use materials that were never intended to stand the test of time.’
The difficulty in restoring street art is that the spray paint used by vandals is usually so chemically similar to the original work – both use acrylic, vinyl, or alkyd polymers as paint binders.
That makes it nearly impossible to develop a solution that removes the former and keeps the latter.
Researchers at the University of Florence have developed an environmentally friendly solvent that can remove an overcoating of graffiti while preserving the underlying art.
Previously, restorers had to resort to scraping, sandblasting, or chemical solvents, all of which damage the original work.
To address the problem, university researchers designed a nanostructured fluid with non-toxic solvents and loaded it into highly-retaining hydrogels.
The hydrogels are formulated as thin foil sheets, which can be cut and shaped as needed and adhered to walls.
Once placed on a surface, they release cleaning agents very slowly to just the top layer of a surface, only a few microns deep.
The solvent is loaded onto thin sheets of hydrogels that slowly release it onto the top layer only a few microns deep
This removes the unwanted top layer in minutes, sometimes even seconds, without damaging the underlying work.
The research team shared their new method at a virtual meeting of the American Chemical Society last week.
In some ways, the process is simple, said co-creator Michele Baglioni, because scientists already knew what chemicals are in the paint.
“The challenge is to combine them properly to get all the properties we need,” he said.
‘We need to know exactly what is happening on the surface of the paintings if we want to design cleaners.’
The team used infrared spectroscopy to characterize the binders, fillers and pigments in three common paint classes.
They tried combinations of low-toxic alkyl carbonate solvents and combined them with biodegradable surfactants, which reduce the surface tension of a liquid.
The results were loaded onto thin sheets of hydrogels, which stick to walls and can be cut and shaped as needed.
After a few minutes, you can peel off a sheet and the overcoat should be “ softened and puffy, ” Ars Technica reported, and easy to wipe off.
The scientists tested their cleaners for fake ‘art’ in the lab, then tried their best option on an actual piece of street art in Florence, successfully removing some black tags without affecting the original work.
The hydrogel that worked best included 2-butanol as the solvent and alkyl glycoside as the non-ionic surfactant. The researchers plan to make the hydrogels commercially available
The combination that worked best included 2-butanol as the solvent and alkyl glycoside as the non-ionic surfactant.
The researchers say the process can also be used to remove top coats of paint on artwork that was intended to restore the painting but ultimately damage it.
“They seem to be quite far apart, but science and art are closely linked,” said Michele Baglioni Ars Technica. ‘Talking about art restoration, art conservation, is like talking about materials.’
The researchers plan to make the hydrogels commercially available through their company, CSGI Solutions for Conservation of Cultural Heritage.