Soft, Peelable Organogels from Partially Hydrolyzed Poly(vinyl acetate) and Benzene-1,4-diboronic Acid: Applications to Clean Works of Art

• Published in: ACS applied materials & interfaces 2017-08, Vol.9 (33), p.28069-28078
• Main Authors: Duncan, Teresa T, Berrie, Barbara H, Weiss, Richard G
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.7b09473

We have developed soft, peelable organogels from 40% hydrolyzed poly­(vinyl acetate) (40PVAc) and benzene-1,4-diboronic acid (BDBA). The organic liquids gelated include dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, 2-ethoxyethanol, and methanol. The rheology of these soft materials can be tuned by altering the concentration of the polymer and/or crosslinker. Insights into the mechanisms leading to gelation were obtained from 1H NMR experiments, fluorescence measurements, and studies comparing properties of materials made from BDBA and phenylboronic acid, a molecule incapable of forming covalent crosslinks between the polymer chains. These organogels can be easily peeled off a surface, leaving no residue detectable by UV–vis spectroscopy. They are demonstrated to be effective at softening and removing deteriorated coatings from water-sensitive works of art and delicate surfaces. They have the needed characteristics to clean topographically complex surfaces: good contact with the surface, easy removal, and little to no residue after removal. A 2-ethoxyethanol organogel was used to remove oxidized varnish from a 16th century reliquary decorated with painted gold leaf, and an ethanol gel was used to remove solvent-resistant coatings from 16th and 18th century oil paintings.