Confined-immigration enhances water resistance and weatherability of highly transparent coatings for cultural heritage preservation

Ultra-transparent polyacrylic (PA) coatings are widely used in cultural heritage conservation but often face issues like whitening from phase separation due to poor water resistance and weatherability. This leads to frequent need for replacement, complicating the preservation of cultural artifacts. In this study, we propose a core/shell polyacrylic emulsion coating (PA-DFMA) with enhanced water resistance and weatherability by confining fluorinated polymers within the shell section. The core/shell structure of PA-DFMA is designed to prevent phase-separation-induced whitening and improve transparency, thanks to the strategic confinement of fluorinated polymers which also mitigates fluorine aggregation and enhances film formation at low temperatures. On the other hand, the introduction of fluorine refines the phase domains during the aging process, further ensuring the transparency of coating and greatly prolonging its durability. Chemically, the strong C-F bonds in the coating offer excellent UV aging resistance, and the lack of a chemical bonding network structure allows for the easy and safe removal of the coating, facilitating reversible treatment of artifacts. The performance test showed that PA-DFMA coatings outperform traditional cultural heritage protection products such as Golden and Rustins in transparency, weatherability, hardness, and reversibility. This eco-friendly coating is proven to offer substantial potential for the preservation of cultural heritage and maintenance of archaeological objects, providing new insights into the design of materials for this purpose