Chemically derived Prussian Blue sol-gel composite thin films

A Prussian Blue (PB) sol-gel composite thin film was prepared via post-chem ical derivatization of a functionalizable sol-gel thin film. Bis[3-(trietho xysilyl)propyl] tetrasulfide (SIS) forms tough and crack-free films by sol- gel process with excellent adhesion on various solid surfaces. The sulfur c hain (-S-4-) can be chemically oxidized to sulfonic groups (-SO3-). After o xidation, PB sol-gel composite thin films were prepared by ion-exchange wit h ferrous ion followed by complexation with ferricyanide. The PB sol-gel co mposite thin films were characterized by electrochemistry, spectroscopy, an d microscopy. Applications in the development of a potassium ion-selective electrode and an optical pH indicator are demonstrated.