Coating of carbon nano-tube filled epoxy resin and its surface conductivity

The aim of this study is to fabricate nanotubes (CNT)/epoxy nano-composites and coat them onto epoxy insulating substrates in order to reduce the surface resistivity. Dispersion agent was uniquely and newly prepared for uniform dispersion of CNT in an epoxy resin as polymer powder. An ultrasonic homogenizer was used for mixing an epoxy resin with commercial CNT and the prepared dispersion agent. The prepared suspension was coated on an epoxy insulating substrate using a spin coater under certain conditions. Cracked surface was observed with the field emission scanning electron microscope (FE-SEM) to check the dispersion of CNT. Surface resistivity was measured by an electrometer with a special test fixture at measurement. As a result, it was elucidated that grafting polymer molecules onto the CNT surface improves the dispersion of CNT in epoxy matrix compared to those containing CNT without functionalization. It was also shown that the surface resistivity of the nano-composites decreases because of more uniform dispersion of CNT. It was found that an addition of just 0.1 wt% CNT with the dispersion agent allows us to decrease the surface resistivity in two-digit.