Compositionally Graded Hydrophobic UV-Cured Coatings for the Prevention of Glass Stress Corrosion

Sara Dalle Vacche,Alessandra Vitale,Roberta Bongiovanni,Mauro Corrado,Gregorio Mariggiò

doi:10.3390/coatings9070424

Abstract

The use of glass in architecture is growing and is moving towards structural applications. However, the tensile strength of glass cannot be fully exploited because of stress corrosion. This is a corrosion triggered by stress applied to the material and dependent on environmental factors such as humidity and temperature. To protect glass from stress corrosion, we developed a UV-cured coating, characterized by hydrophobicity, barrier to water vapor properties, and good adhesion to glass, thanks to a compositional profile. The coating was obtained by combining a cycloaliphatic diacrylate resin with a very low amount of a perfluoropolyether methacrylate co-monomer, which migrated to the free surface, creating a compositionally graded coating. The adhesion to glass was improved, using as a primer an acrylated silane able to co-react with the resins. With a mechanical load test using the coaxial double ring set-up, we proved that the coating is effective in the inhibition of stress corrosion of glass plates, with an increase of 76% of tensile strength.

Highlights

The use of glass in architecture is growing, for grand facades of modern buildings, and for new structural applications, such as, for instance, glass-made staircases, roofs, load-bearing beams, and walkways [1]
Gauss distribution: A coating prepared with a cycloaliphatic UV-curable resin, a fluorinated methacrylate co-monomer, a co-reactive silane primer, showing a good barrier to water vapor, hydrophobicity, transparency, and adhesion properties
Good adhesion and high water repellency were present at the same time, thanks to a compositional gradient

Summary

Introduction

The use of glass in architecture is growing, for grand facades of modern buildings, and for new structural applications, such as, for instance, glass-made staircases, roofs, load-bearing beams, and walkways [1]. Such challenging applications are pushed forward by the aesthetic value conferred to the material, which allows architects to find innovative and minimalist solutions to fulfill their creative ideas. The construction of glass structures saves energy and improves wellbeing, as it maximizes the use of sunlight and exploits insulation properties Thanks to this trend, the studies in this field are increasing and different solutions for structural application of glass have been found [2,3]. Stress-raising flaws (known as Griffith flaws) accumulate on the glass surface as a result of manufacturing, transportation, and surface damage during its service life

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Conclusion