Surface attachment of protonated polyimidazolium monolayer on titanate nanotubes as a novel proton conductor

A novel proton conductor has been designed by the surface immobilization of protonated polyimidazolium monolayer on titanate nanotubes (TiNTs) through a polymer brush strategy. 2,2'-Azobis(2-methylpropionitrile) (AIBN)-type initiators are first attached to TiNTs followed by a free radical polymerization of protonated 1-vinylimidazole (VyImBF(4)) on the surface. The chemical structure of the resulting poly(VyImBF(4))-modified TiNTs is verified by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). TGA curve indicates their good thermal stability. The maximum proton conductivity achieves 6.74 x 10(-4) S cm(-1) at 200 degrees C under dry condition and 3.60 x 10(-2) S cm(-1) at 120 degrees C under 100% humidity, respectively, when the polymerization is carried out under a polymerization time of 3 h and an immobilized initiator concentration of approximately 42.4 mmol L-1. The proposed preparation of poly(VyImBF(4))-modified TiNTs would give a new idea for the design of other ion conductors.