High Efficiency Fluorinated Oligo(ethylenesuccinamide) Coating for Stone

The protection of stone cultural assets is related to the transformation of the surface characteristic from hydrophilic to hydrophobic/superhydrophobic through the application of a coating.The suitability of a coating depends not only on its capability to dramatically change the surfacewettability, but also on other parameters such as the modification of kinetics of water absorption, thepermanence of vapor diffusivity, the resistance of the coating to aging and the low volatile organiccompound emissions during its application. In this work, an oligo(ethylensuccinamide) containinglow molecular pendant perfluoropolyether segments (SC2-PFPE) and soluble in environmentallyfriendly solvents was tested as a protective agent for historic stone artifacts. Magnetic resonanceimaging and relaxometry were employed to evaluate the effects of the surface wettability change,to follow the water diffusion inside the rock and to study the porous structure evolution after theapplication of SC2-PFPE. A sun-like irradiation test was used to investigate the photo-stability ofthe product. The results demonstrate that the highly photo-stable SC2-PFPE minimizes the surface wettability of the stone by modifying the water sorptivity without significantly affecting itsporous structure and vapor diffusivity. The improved performance of SC2-PFPE in comparison toother traditional coatings makes it a potential candidate as an advanced coating for stone culturalheritage protectio