Protective cleaning of Chinese paper artworks with strong hydrogels: An interfacial adhesion perspective

Up to now, it is always a delicate and challenging task to clean and protect Xuan paper ink painting. Xuan paper is composed of cellulose with a rough surface and easy to absorb dust, which leads to poor cleaning effect and irreversible damage in traditional cleaning process. Hydrogel is one of the most effective tools to clean the artworks. However, in the practice of cleaning Xuan paper, most hydrogels cannot achieve fine cleaning result due to the interfacial adhesion issues. Herein, to protectively and effectively clean Xuan paper, using physical yet strong poly(vinyl alcohol)/poly(N-(2-hydroxyethyl) acrylamide) (PVA/PHEAA) hydrogel with suitable stiffness as the model, the interfacial adhesion between hydrogel and Xuan paper was systematically investigated, and various technologies were used to evaluate the cleaning effect. A critical interfacial adhesive energy (< 4 J/m(2)) is found to achieve the protective and effective cleaning purpose. To the best of our knowledge, this is the first report to estimate the adhesion of hydrogel on the cleaning of paper artwork, which will provide a new viewport in the conservation practice.