Nanosized ZnO/SiO₂-Based Amphiphobic Coatings for Stone Heritage Protection

Abstract

Exploring and developing an efficient protective coating for precious stone heritages that have been exposed to sunlight and rain for a long time is crucial. The UV resistance properties of nano-ZnO are apparent. Nano-SiO2 has a stable chemical structure and is one of the main components of stone. This paper introduces the synergistic protective effect of ZnO nanoparticles (ZnO-NPs) and SiO2 nanoparticles (SiO2-NPs) on stone, which is novel in this field. The functional nanocomposite coating (FZS coating) was obtained by spraying the ultrasonic mixture of ZnO-NPs and SiO2-NPs, cross-linked with a silane coupling agent, and modified by fluorocarbon. Wettability and UV aging tests showed that the sandstone deposited by FZS coating had excellent amphiphobicity (water contact angle (WCA) > 160°, oil contact angle (OCA) < 140°). The hydrophobicity was almost changeless after 300 h of UV irradiation, indicating high UV absorption capacity and durability. Interestingly, the amphiphobicity remains unchanged after alternating treatments of temperature and humidity, expressing superior weathering stability. This facile functional coating has potential applications protecting outdoor stone heritages.

Research on the Reinforcement and Inhibition of Water–Salt Activity in Mural Ground Layers by Superhydrophobic SiO2 Particles

“…SiO 2 is a common material for the protection of cultural relics [20][21][22][23][24][25], owing to its excellent compatibility, durability and weather resistance. Wang et al [20] prepared hydrophobic coatings on ancient bricks via a nano-SiO 2 /TiO 2 hybrid fluorinated B-72 composite, effectively avoiding the adhesion of air pollutants.…”

“…Wang et al [20] prepared hydrophobic coatings on ancient bricks via a nano-SiO 2 /TiO 2 hybrid fluorinated B-72 composite, effectively avoiding the adhesion of air pollutants. Zhu et al [22] studied nanosized ZnO/SiO 2 -based amphiphobic coatings for stone heritage protection, and the hydrophobicity was almost unchanged after 300 h of UV irradiation, indicating the composite possessed a good UV absorption capacity and durability. Although most cases of SiO 2 application in heritage protection have involved the conservation of ancient bricks and stones [20,22,26,27], there are very few pieces of research related to murals.…”

“…Zhu et al [22] studied nanosized ZnO/SiO 2 -based amphiphobic coatings for stone heritage protection, and the hydrophobicity was almost unchanged after 300 h of UV irradiation, indicating the composite possessed a good UV absorption capacity and durability. Although most cases of SiO 2 application in heritage protection have involved the conservation of ancient bricks and stones [20,22,26,27], there are very few pieces of research related to murals. Herein, we chose superhydrophobic SiO 2 to improve the wettability and reinforcement properties of mural ground layers.…”