Street art has become a mainstream cultural phenomenon thanks to artists like Jean-Michel Basquiat, Keith Haring, Banksy and Kaws.
However, outdoor murals are prone to vandals who spoil their beauty with unwanted graffiti.
A group of chemists in Italy developed a groundbreaking new way to wipe away graffiti while keeping the art underneath intact.
The procedure involves loading non-toxic cleaners onto a thin layer of polymers known as hydrogels and applying them to a surface of a destroyed street art piece of art.
The hydrogel slowly releases the detergent to the top layer, which is only a few microns deep, allowing the overpainting to be removed quickly without damaging the work.
Cleaning street art graffiti is difficult because the chemical makeup of both are so similar that one solvent can hardly erase them without the other
“For decades we have focused on cleaning or restoring classic works of art that have used colors that have lasted 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 should never stand the test of time.”
The difficulty with recreating 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.
This makes it almost impossible to come up with a solution that removes the former and preserves the latter.
Researchers at the University of Florence have developed an environmentally friendly solvent that can remove any covering of graffiti while preserving the art underneath.
Until now, restorers have 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 liquid using non-toxic solvents and loaded it into highly retentive hydrogels.
The hydrogels were formulated as thin sheets of film that can be cut and shaped as needed and that adhere to walls.
Once placed on a surface, they release detergent very slowly to the top layer of a surface that is only a few microns deep.
The solvent is loaded onto thin layers of hydrogels, which slowly release it only to the top layer, which is only a few micrometers deep
As a result, the unwanted top layer is removed in minutes, sometimes seconds, without harming the work underneath.
The research team announced their new method at a virtual meeting of the American Chemical Society last week.
In some ways, the process is easy, said co-creator Michele Baglioni, since scientists already knew what chemicals are in the paint.
“The challenge is to combine them in the right way to get all of the properties we need,” he said.
“We need to know exactly what is going on on the surface of the pictures if we are to design cleaners.”
The team used infrared spectroscopy to characterize the binders, fillers, and pigments in three common color classes.
They tried combinations of low-toxicity alkyl carbonate solvents and combined them with biodegradable surfactants that reduce the surface tension of a liquid.
The results were loaded onto thin layers of hydrogels that adhere 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 “soft and puffy,” reported Ars Technica, and easy to wipe off.
Scientists tested their detergents for counterfeit “art” in the laboratory and then tried their best option on a real piece of street art in Florence, successfully removing some black markings without affecting the original work.
The hydrogel that worked best included 2-butanol as the solvent and alkyl glycoside as the nonionic 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 nonionic surfactant.
The researchers say the process could also be used to remove topcoat from artwork that was supposed to restore the painting but damaged it.
“They seem pretty far apart, but science and art are very closely related,” Michele Baglioni told Ars Technica. “Talking about art restoration and preservation is like talking about materials.”
The researchers plan to make the hydrogels commercially available through their company CSGI Solutions for Conservation of Cultural Heritage.