Effects of surfactants and thickness of carbon nanotube film on conductive property for touch screen

Abstract

Conductive transparent film technology has been developed extensively for electronic industry such as touch panel and so on. In this study, single-wall carbon nanotubes (SWCNTs) was chosen to disperse in acrylic resin and homogenized by surfactant. The dispersion of SWNCT is one of the key factors that strongly influences the properties of these products. Thus Hydrocarbon and Silicone surfactant types were compared. The wire-bar coating technique was used to produce a conductive film PET base. Our objectives were to study the effects of surfactants and thickness of SWCNT film on conductivity and transparency. Surfactant concentration was varied 0.1 – 2.0 % w/w. Film formation samples were done by using wire K-bar rods varied the thickness using single and multi-coating method. Transparency and sheet resistance were analyzed. Results showed that the varying surfactant concentration and coating thickness did slightly affect obviously the change of transmittance of conductive films and sheet resistance varied between 10⁴ – 10⁵ Ω/square for both surfactants. While sheet resistance declined relevant to the increase of SWCNT thickness and the amount of surfactants. Results showed Silicone surfactant gave better results than Hydrocarbon surfactant, the optimum sheet resistance was at 8.91x10² Ω/square with 87% transmittance (including PET film) and 2.63x10³ Ω/square with 86% transmittance by using 2.0% of silicone and hydrocarbon surfactant respectively with the film thickness of 250 microns.