Electrospun polymer nanotibers coated with metal oxides by liquid phase deposition

Polyacrylonitrile fibers were electrospun yielding diameters in the range of 50 to 200 nm. These nanotibers were then immersed in an aqueous coating solution to deposit a continuous film of titanium dioxide on the surface. In order to shorten the coating time and optimize the metal oxide layer thickness, the fibers were surface functionalized by immersion in sodium hydroxide to have carboxylic acid groups. Polyelectrolytes were electrostatically adsorbed to some of the functionalized fiber surface samples prior to metal oxide deposition. The metal oxide nucleation density was compared after three hours for nanofibers with a cationic surface, an anionic surface, a carboxylic acid surface, and an untreated surface. Fibers with the carboxylic acid surface exhibited the highest nucleation density, which led to the shortest coating time. Such polymer-metal oxide nanoscale composite structures are expected to be of great utility in a number of applications, including sensors, photovoltaic cells, and catalytic surfaces.