Efficient proton conduction of nanometer-thick film of porous silica as prepared by oxygen plasma treatment

A highly proton-conducting silica film (thickness, 150 nm) was successfully fabricated by combination of template synthesis with a nonionic surfactant and subsequent oxygen plasma treatment. This ultrathin silica film is mechanically and thermally stable and possesses abundant silanol groups in the nanopore. It exhibited proton conductivities greater by 1–2 orders of magnitude than those of the corresponding heat-treated silica film in humid air.