Drastic Dependence of the pH Sensitivity of Fe₂O₃-Bi₂O₃-B₂O₃ Hydrophobic Glasses with Composition.

Fe₂O₃-Bi₂O₃-B₂O₃ (FeBiB) glasses were developed as novel pH responsive hydrophobic glasses. The influence of the glass composition on the pH sensitivity of FeBiB glasses was investigated. The pH sensitivity drastically decreased with decreasing B₂O₃ content. A moderate amount of Fe₂O₃ and a small amount of B₂O₃ respectively produces bulk electronic conduction and a pH response on glass surfaces. Because the remaining components of the glass can be selected freely, this discovery could prove very useful in developing novel pH glass electrodes that are self-cleaning and resist fouling.