Hypothesis: The development of gels capable to adapt and act at the interface of rough surfaces is a central topic in modern science for Cultural Heritage preservation. To overcome the limitations of solvents or polymer solutions, commonly used in the restoration practice, poly(vinyl alcohol) (PVA) "twin-chain" polymer networks (TC-PNs) have been recently proposed. The properties of this new class of gels, that are the most performing gels available for Cultural Heritage preservation, are mostly unexplored. This paper investigates how chemical modifications affect gels' structure and their rheological behavior, producing new gelled systems with enhanced and tunable properties for challenging applications, not restricted to Cultural Heritage preservation.
Experiments: In this study, the PVA-TC-PNs structural and functional properties were changed by functionalization with sebacic acid into a new class of TC-PNs. Functionalization affects the porosity and nanostructure of the network, changing its uptake/release of fluids and favoring the uptake of organic solvents with various polarity, a crucial feature to boost the versatility of TC-PNs in practical applications.
Findings: The functionalized gels exhibited unprecedented performances during the cleaning of contemporary paintings from the Peggy Gugghenheim collection (Venice), whose restoration with traditional solvents and swabs would be difficult to avoid possible disfigurements to the painted layers. These results candidate the functionalized TC-PNs as a new, highly promising class of gels in art preservation.
Keywords: Crosslinking; Cultural heritage preservation; Hydrogels; PVA; Polyvinyl alcohol; Porogen; Sebacic acid; “twin-chain” gels.
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