Sonochemical Functionalization of Glass

Functionalized glass plays a crucial role in various fields, including materials and biomedical sciences. Traditionally, it has been produced through silanization reactions or by coating the glass with polymers. But these approaches involve toxic chemicals and result in films that are prone to hydrolysis upon long-term exposure to water. In this report, a novel, simple method for functionalizing glass using ultrasonication of aryl diazonium salts is introduced. When these salts are exposed to ultrasound under mild conditions (24 kHz/400 W), aryl radicals are generated, which spontaneously react with the glass surface. This reaction forms a thin organic polymeric film whose surface properties, such as hydrophobicity or charge, can be tailored by the terminal group of the diazonium salt employed. The film is covalently bonded to the glass surface via Si–O–C bonds, which offer enhanced stability compared to the more hydrolysis-prone Si–O–Si bonds that govern traditional silanization techniques. This newly functionalized glass is shown to adhere microorganisms such as microalgae (Chlorella vulgaris C. vulgaris), bacteria (Escherichia coli, E. coli), and yeast (Saccharomyces cerevisiae, S. cerevisiae), suggesting potential applications in enzyme production, filtration, environmental remediation technologies, biofuels, and biofuel cells.