Transparent CaF2 surface crystallized CaO–2B2O3 glass possessing efficient photocatalytic and antibacterial properties

Abstract

AbstractThis study aims to fabricate surface crystallized transparent calcium borate glass (CaO–2B2O3) for photocatalytic and antibacterial applications. The CaO–2B2O3 glass was fabricated by using the conventional melt‐quenching technique. Instead of using traditional high temperature and longer soaking time heat‐treatment, the acid etching method was adopted to get surface crystallization. Surface etching of as‐quenched glass was performed at room temperature by using three different concentrations of hydrogen fluoride in order to attain the different amount of calcium fluoride crystals at the surface. The characterization of surface crystallized glass was performed with an X‐ray diffraction pattern and scanning electron microscope‐EDS mapping system. Sufficient transparency (65%) was retained even at highest crystallization of glass surface. Surface crystallization with CaF2 induces hydrophilicity and photocatalytic character in glasses which was evaluated with contact angle measurements and smart resazurin (Rz) ink test. Around 68% of methylene blue (MB) dye degradation was also displayed by the crystallized glass. Crystallized glasses portrayed good antibacterial property against Escherichia coli (gram‐negative bacteria). Ninety‐nine per cent of bacterial depletion was recorded in 3 hours exposure time with surface crystallized glass without any external intervention. Interesting morphological changes were observed in bacterial shape and physical appearance under field emission scanning electron microscope after exposure to crystallized glasses.