Effect of carbon nanotubes as thermal interface materials on thermal conductivity using electrophoretic deposition

Abstract

Thermal interface materials (TIM) involve heat removal from electronic devices. It is used to remove heat sink from the heat sources to prolong the operation system of a device. It normally replaces the thermally insulated air between the two surfaces and uses it as a secondary thermal conductive material. The current thermal conductivity of TIM is considered to be a limitation for the development of advance electronic devices. In this study, the performance of carbon nanotubes (CNTs) which were used as TIM was investigated by using electrophoretic deposition method. The deposition of CNTs was varied from one to six layers and the performance of deposition was evaluated. The stable suspension of CNTs in DMF with zeta potential reading of -35.87 mV give rise to a smooth and uniform deposition on nickel plated copper substrate (heat spreader) with the usage of electrophoretic deposition (EPD). Maximum layers of CNTs deposition were obtained at six layers with 56.95 μm of deposition thickness and 11.0 mg of deposition weight. Thermal conductivity was measured using a thermal analyser while the thickness of deposition was observed using scanning electron microscope (SEM). The employment of CNTs improved the heat removal of TIM with thermal conductivity reading of 27.08 W m-1 K-1. Optimisation studies revealed that EPD operated at an applied voltage of 175 V coupled with 10 min deposition time produced a single layer deposition with the thickness of 14.14 μm.