Performance and durability of octadecyltrichlorosilane coated borosilicate glass

While a coating may alter the surface properties and the performance of a material, it is unclear if these thin barrier layers can effectively inhibit environmentally-assisted cracking processes. In this research a nanoscale, hydrophobic film of octadecyltrichlorosilane was applied to bulk borosilicate glass rods. The resistance of the coated and uncoated rods to environmentally-assisted cracking was then evaluated in a room temperature, deionized water environment. While the coating procedure did not damage the glass surface or affect the probability of completing a successful test, it did not provide protection the glass samples against environmentally-assisted cracking. Analytical models based on linear elastic fracture mechanics suggest that the coating thickness must be on the order of the crack mouth opening displacement for the barrier layer to be effective. This finding suggests that nanoscale barrier coatings are best suited for micron and nanometer-scale substrates when superior structural performance is required.