Application and drying at ambient temperature of thick organic–inorganic hybrid coatings on glass

Abstract

Organic–inorganic hybrid coatings have achieved success in scientific environments because they can be designed using the sol–gel route to combine the high hardness and chemical stability typical of glass-like or ceramic materials (i.e., the inorganic side) with the toughness and ductility typical of organic materials (i.e., the organic side). Nevertheless, organic–inorganic hybrid coatings are often very brittle, and they can collapse if applied as thick film on rigid substrates because of the shrinkage during the drying/curing process. However, the manufacturing of a thick coating is compulsory, when stringent requirements for scratch performance and wear endurance must be met. In this respect, the present investigation proposes the design of self-drying silicone–epoxy resins and the manufacturing of the corresponding thick coatings (approximately ~120μm thick) on as-received and micro-corrugated glass using an automatic drawdown applicator. The scratch performance of the coatings was tested using progressive- and constant-mode scratch tests, and the wear resistance was examined using dry sliding linear reciprocating tribological tests. The experimental findings demonstrate how the role of the interface is crucial and how micro-corrugation is extremely beneficial in increasing the threshold of the maximum thickness beyond that at which coating bulging and delamination occur.