Nanoengineered transparent, free-standing, conductive nanofibrous membranes

Transparent conductive nanofibrous membranes have been successfully fabricated by sputter-coating a metal (Au, Pd, Pt, Ni, Ag, or Au/Pd alloy) onto a water-soluble-polymer nanofibrous template, followed by the dissolution of the template in a water bath. The size of the conductive nanofibers can be facilely controlled by adjusting the diameter of the polymer nanofibers as well as the sputter-coating time. The as-prepared samples were characterized by SEM, TEM, FTIR, and TGA, and the results reveal that the as-prepared conductive nanofibers consist of many metal nanoparticles held together after the dissolution of the polymer template, which is likely due to the coalescence of the metal nanoparticles as well as the bridging effect of the polymer chains between the adjoining metal nanoparticles. The transmittance of the film decreases but the conductivity of the film increases with the time of sputter-coating. The as-prepared transparent nanofibrous membrane also shows good mechanical and metallic properties, and its resistance displays humidity-dependent behavior most likely attributed to the swelling effect of the highly hydrophilic polymer chain that bridges the metal nanoparticles. This study provides a promising route to the facile synthesis of conductive nanofibers, which may have great potential in various applications. © 2009 American Chemical Society.