Unilateral NMR investigation of multifunctional treatments on stones based on colloidal inorganic and organic nanoparticles

Abstract

Consolidation and protection are among the most important treatments usually carried out in conservation of stone artifacts and monuments. In this paper, portable unilateral NMR and conventional techniques were used for investigating new multifunctional treatments based on tetraethoxysilane, silica, and polytetrafluoroethylene nanoparticles. The study was carried out on a very complex and heterogeneous porous stone such as tuff. NMR study allowed to obtain detailed information on the penetration depth of treatments, the hydrophobic effect, and changes in the open porosity caused by treatments. Physical and chemical inhomogeneities between the impregnated layers of tuff and the layers underneath were also detected. The average pores radius and pores interconnection obtained from NMR diffusion measurements were used for the first time to compare effects of different consolidating and/or protective treatments on stone. Because unilateral NMR technique is neither destructive nor invasive, investigation of treatments can be also carried out and optimized directly on buildings and monuments of interest for Cultural Heritage.

Mesoporous silica nanoparticles as carriers of active agents for smart anticorrosive organic coatings: a critical review

“…For barrier properties, the most relevant effects were obtained using 2D nanoadditives, such as lamellar clay, 169,170 or graphene derivatives. 171,172 Then, different types of nanoparticles were used to impart peculiar physical-chemical properties, such as hydrophobicity, 173 UV blocking 174 and antibacterial properties. 175,176 In most cases the effectiveness of the smart coating was optimized by improving the nanoparticles dispersion into the coating and the nanoparticle/coating interfacial adhesion, key factors to obtain high performance nanocomposite materials.…”

The Influence of 30 Years Outdoor Weathering on the Durability of Hydrophobic Agents Applied on Obernkirchener Sandstones

“…On the other hand, the possible decrease of water vapour diffusion through the pore system can lead to hygric expansion inside the stone, which causes in combination with freeze-thaw cycles spalling of the treated stone area. Furthermore, the long-term behaviour and efficiency of these stone treatments depends on diverse aspects and is still a scientific issue [4][5][6][7]. The type of stone (e.g., sandstone, limestone, igneous or metamorphic rocks) as well as the chemical composition of the used conservative (e.g., acrylic polymers or organosilicon compounds) and also its application have a significant influence on the success of a conservation action, e.g., an incorrect performance or a poor adhesion of the water repellent with the stone substrate can lead to severe damage over time [8][9][10].…”

1H NMR study of the phase behavior of aqueous eutectic solutions using the inverse Laplace transform analysis of T2 relaxation

“…The wettability of the rocks was determined by comparing the amount of water on the rock surface with the total amount of water present. ILT can be used in a similar manner to measure water percolation and pore size distribution in rocks and other porous materials . Blümich et al .…”