When Acrylic Paints Get A Spa Day
When acrylic paint was introduced in the late 1940s it was a boon for artists with a penchant for instant gratification: Acrylics dry within hours, compared to the weeks and sometimes months it takes for oil paint to completely harden.
But few things in life are perfect, and acrylic paint is no exception. In order to keep pigments stable in the acrylic polymer base, paint makers had to include additives called surfactants. Unfortunately, after a few years or decades, the surfactants get itchy feet and rise out of the paint to the surface of the artwork.
Once there, these surfactants can leave a white film on priceless paintings and they can also be sticky, attracting dirt and grime to the artwork.
In this week's C&EN, my colleague Celia Arnaud digs deep in to acrylic paint chemistry and talks with conservation scientists about what they do to remedy the problem of wandering surfactant.
Unfortunately, many existing solvents that might be used to clean off the surface of acrylic artworks tend to make the paint swell... This makes museum staff nervous because it's not clear what long term consequence come from this swelling. Another problem is that solvents that don't cause acrylic paints to swell aren't typically good cleaners.
That's why researchers at the Tate Galleries in London, the Getty Conservation Institute in LA and the DOW chemical company have teamed up to try and find a solvent that cleans but does not swell acrylic paint. At the same time researchers at the University of Delaware are working with Golden Artist Colors, a paint company, to work out good cleaning conditions for acrylic paintings.
If these researchers hit paydirt, acrylic paintings around the world will finally get that facial treatment they've all been needing.
Andy Warhol's acrylic portrait of Brooke Hayward needed the surfactant that had exited the painting to be cleaned off. Conservation scientists used surface imaging technology to monitor the cleaning process. Credit: MOLAB.