Chemically Derived Prussian Blue Sol−Gel Composite Thin Films

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