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Scientists applying magnetic resonance techniques to cultural heritage are now a quite vast and international community, even if these applications are not yet well known outside this community. Not only laboratory experiments but also measurements in the field are now possible, with the use of portable nuclear magnetic resonance (NMR) instruments that enable non-invasive and non-destructive studies on items of any size, of high artistic and historical value as well as diagnosis of their conservation state. The situation was completely different in the second half of the 1990s when our group started working on applications of NMR to cultural heritage, by combining the knowledge of NMR for fluids in porous media at the University of Bologna, with the skilfulness of the chemists for cultural heritage of CNR and University of Florence, and Safeguarding Cultural Heritage Department of Aosta. Since then, our interest has been mainly devoted to develop methods to study the structure of pore space and their changes as a result of the decay, as well as to evaluate performance of the protective and conservative treatments of porous materials like stone, ceramic, cements and wood. In this paper, we will review the pathway that led us from the first tentative experiments, in the second half of the 1990s to the current work on these topics. [ABSTRACT FROM AUTHOR]

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 surface wettability, but also on other parameters such as the modification of kinetics of water absorption, the permanence of vapor diffusivity, the resistance of the coating to aging and the low volatile organic compound emissions during its application. In this work, an oligo(ethylensuccinamide) containing low molecular pendant perfluoropolyether segments (SC2-PFPE) and soluble in environmentally friendly solvents was tested as a protective agent for historic stone artifacts. Magnetic resonance imaging 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 the application of SC2-PFPE. A sun-like irradiation test was used to investigate the photo-stability of the 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 its porous structure and vapor diffusivity. The improved performance of SC2-PFPE in comparison to other traditional coatings makes it a potential candidate as an advanced coating for stone cultural heritage protection. [ABSTRACT FROM AUTHOR]