Temperature adjustable thermal conductivity and thermal contact resistance for liquid metal/paraffin/olefin block copolymer interface material

Abstract: The adjustable thermal conductivity and thermal contact resistance are the key ways to realize efficient thermal management of electronic devices. In this work, a low melting-point alloy/paraffin/olefin block copolymer thermal interface material with the above properties was designed and prepared. Low melting-point alloy and paraffin undergo phase transformation with the increase of temperature, resulting in the significant decrease of thermal contact resistance. Moreover, the liquid phase low melting-point alloy particles are connected to reconstruct an efficient heat conduction path, which enhances the thermal conductivity of composites. In addition, this paper studied the thermal conductivity of composites at two different temperatures (30 °C/50 °C) and the effect of temperature or pressure on the thermal contact resistance. Furthermore, the heat dissipation effect of composites was evaluated by infrared thermal imager. The results prove that the thermal conductivity of composites (90 wt% filler) increases from 0.99 W/m⋅K to 1.87 W/m⋅K as the temperature increases from 30 °C to 50 °C. The thermal contact resistance of composites (90 wt% filler) is reduced to 0.024 K⋅cm2/W(60 °C, 40 Psi). Moreover, the results of heat dissipation experiments also confirm that the thermal contact resistance decreases with the enhancement of temperature. Therefore, all the results indicate that the thermal conductivity and thermal contact resistance of composites can be adjusted by changing the temperature.

Keywords: Thermal contact resistance, Thermal conductivity, Thermal interface materials, Low melting-point alloy, Phase change

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