Article Title: New sustainable polymers and oligomers for Cultural Heritage conservation†         

Authors: Damiano Bandelli, Rosangela Mastrangelo, Giovanna Poggi, David Chelazzi and  Piero Baglioni

Year Published: 2024

Journal: Chemical Science 

Article DOI: https://doi.org/10.1039/D3SC03909A

Cover image credit: RichardMcCoy

Paintings, murals, and other pieces of art held in museums and cultural institutions sometimes need treatment to address accumulated dirt, oils, unwanted modifications, or even vandalism. However this artifacts are often fragile, the components or the paint and other materials can be easily damaged by poorly controlled exposure to detergents, solvents, or other materials. To protect pieces of cultural heritage, there is a need for chemical formulations that allow very controlled applications of solvents for cleaning these products.

              Researchers at the University of Florence recently reported the development of new organogels to aid in the controlled administration of solvents for cleaning cultural artifacts. Organogels are three-dimensional structures that can swell up by absorbing organic solvents. That process allows the organic solvents to be applied to a potentially fragile surface in a very controlled way.

Figure 1: Organogels are 3D structures, often polymers, that form spaces where smaller molecules, like organic solvents, can be absorbed. (Image Credit: ChemDoc 2010)

              The authors combined polymers combining a ester functional group with caster oil. After synthesizing the polymers, the authors developed a method to calculate the log P, which is a measure of how well the polymers attract to polar or non-polar compounds. They used a NMR technique called DOSY, which measured how quickly the polymers were able to move through different solvents. By comparing the polymers speeds in different polarity solvents, they were able to determine that their organogels had a suitable log P for common solvents used to restore paintings.

              To test the actual performance of the organogel, the researchers prepared a frosted glass plate coated with wax. The non-polar wax was designed to simulate an impurity that might need to be removed from an artifact. The wax gives the normally cloudy appearance of frosted glass a transparent color, so the researchers were able to measure the success of the experiment by the return of the glasses frosted surface appearance.

              Three solvents commonly used to clean artwork were tested: acetone, diethyl ketone, and p-xylene. These solvents are popular because they have the appropriate polarity to dissolve and remove many contaminants on glass and acetone and diethyl ketone in particular are relatively environmentally benign. All three solvents were successful in removing the wax during a ten-minute application to the frosted glass and were successfully removed afterwards.

              While there’s a lot to consider when trying to conserve fragile and valuable artifacts, technologies like this can give researchers more options for cleaning and preserving art. The authors note that they can also potentially be applicable in other industrial settings, like 3D printing or textiles, where organogels are used. Overall, the paper demonstrates a novel way to make and study a new chemical material to help protect cultural artifacts into the future.