The cleaning of Modern paintings is a very delicate process, as the removal of dirt or grime deposited on rough, clotted and often water-sensitive surfaces can be challenging. Our work aims at providing solutions for the effective and selective cleaning of invaluable masterpieces, granting the transmission of our Cultural Heritage to future generations. In this regard, we developed cleaning hydrogels made of polyvinyl alcohol (H-PVA), semi-interpenetrated with a PVA of lower hydrolysis degree (L-PVA). Gelation was achieved through freeze-thawing (FT). Confocal Microscopy showed that the resulting Twin Chain Networks have a sponge-like structure and an interconnected porosity, provided by the polymer-polymer phase separation occurred in the pre-gel solution. Small Angle X-ray Scattering (SAXS) and rheology proved that both the presence of L-PVA and the number of FT cycles strongly affect polymer chains conformation and gels’ compliance. Fluorescence Correlation Spectroscopy (FCS) gave insights about the polymer dynamics, proving that not only L-PVA behaves as a structural component, but also it can partly diffuse in the gels’ pores and dangle from the walls, probably enhancing the networks’ ability to entrap soil. The gels showed high water retentiveness, despite their high equilibrium water content: such gels can be loaded with aqueous solutions or microemulsions, in order to allow the cleaning of different types of grime from water-sensitive substrates. All these features granted unprecedented cleaning performances: hydrophilic grime was successfully removed from the surfaces of “Two” and “Eyes in the Heat” by Jackson Pollock, while aged varnish and wax were easily detached from “The Studio” by Pablo Picasso (Peggy Guggenheim Collection, Venice). Twin-Chain Networks can pave the way to the application of new materials in the restoration practice, proving the effectiveness of a science-driven approach.

Twin-chain networks: A new class of hydrogels for the cleaning of modern and contemporary art

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.