Flexural strength of glass with poly(methyl methacrylate)-silica nanoparticle composite coatings

Poly(methyl methacrylate) (PMMA) silica nanoparticle composite coatings are applied to glass for improved strength. The coatings are applied to glass slides via the dip-coating method, and the strength is evaluated using 4-point bend flexural tests. The improvement in strength from these coatings is found to be due to the flaw-filling mechanism. Additionally, the nanoparticles incorporated into the coating provide the PMMA matrix with a reinforcement effect that enhances the overall strength improvement of the coating. Five different coatings are tested with different weight percentages of nanoparticles, ranging from 0 to 2 wt%. All the coatings maintain high optical transparency across the visible spectrum and have thickness values ranging between 1 and 3 µm. Although there is evidence of other coatings providing strengthening to glass, this effect has never been shown with PMMA-silica nanoparticle composite coatings. These coatings are beneficial due to the biocompatibility of PMMA and the favorable mechanical properties of silica nanoparticles. In addition, these coatings can be processed via solution mixing in a one-pot method without the need for any additives.