Transparent thin films of multiwalled carbon nanotubes self-assembled on polyamide 11 nanofibers

Electrospun polyamide 11 (PA11) nanofiber films are used as a guide for the deposition of two-dimensional networks of multiwalled carbon nanotubes (MWNTs). This method allows for the manufacturing of transparent and electrically conductive thin films. It is demonstrated that the sheet resistance (Rs) and transmittance (T) decrease, as the films become thicker due to longer electrospinning times or larger fibers. The transmittance could be improved by fusing (melting) the fibers at moderate temperatures or impregnating the film with a resin, showing that light scattering rather than absorption by the MWNTs or the polymer was responsible for a low transmittance. As the number of MWNT deposition cycles increases, the Rs decreases with a constant transmittance. A fused 100 nm film obtained after 10 min of electrospinning of the 2 wt % PA11 solution shows Rs = 154 k Omega sq(-1) and T = 83% after ten MWNT deposition cycles. A 95% transmittance was achieved after removing the polymer fibers by heating the glass plate in air (Rs = 440 k Omega sq(-1) after five MWNT deposition cycles).