Controlling formation of silver/carbon nanotube networks for highly conductive film surface

Flexible polymer films with high electrical conductivity were prepared through a simple coating of well-dispersed silver nanoparticle (AgNP) and multiwalled carbon nanotube (CNT) solution. The hybrid film with surface resistance as low as 1 × 10(-2) Ω/sq was prepared by controlling the annealing temperature in air and by using a suitable composition of silver nitrate/CNT/poly(oxyethylene)-oligo(imide) (POE-imide) in the ratio 20:1:20 by weight. During the heating, color of the film surface changed from black to golden to milky white, indicating the accumulation of AgNPs through surface migration and melting into CNT-connected networks. Thermogravimetric measurements showed that the transition temperature of 170 °C was responsible for the POE-imide degeneration and the subsequent Ag melting with a decrease in the surface resistance from 2.1 × 10(5) to 2.0 × 10(-1) Ω/sq, which was able to illuminate light-emitting diode lamps because of the formation of a continuous Ag network.