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Thermal interface materials (TIMs) are the key to solving heat dissipation problems in high-power electrical equipment. TIMs with high thermal conductivity and low thermal contact resistance (TCR) will enhance interfacial heat transfer. In this work, a phase-change mediated graphene composite hydrogel with low TCR and high thermal conductivity is designed. In addition, by introducing the hydrogel cross-linked network into the phase change material, the phase change material leakage problem is effectively solved. The thermal conductivity of the phase change hydrogel is enhanced by 324% from 0.3 W m − 1 K − 1 to 1.23 W m − 1 K − 1 at a filling rate of 7 wt% of graphene. The effects of temperature and pressure on phase change composite hydrogels are investigated. When the temperature is increased from 50 °C to 80 °C, TCR decreases rapidly from 90 K ∙ c m 2 / W to 0.2–0.5 K ∙ c m 2 / W , which is attributed to the improved interfacial wettability mediated by the phase change. When the pressure is increased from 10 Psi to 50 Psi with 80 °C, TCR decrease from 20 K ∙ c m 2 / W to 0.5 K ∙ c m 2 / W , improving interfacial contact and enhancing interfacial heat transfer. Combining a hydrogel with a cross-linked structure with the phase change material resulted in an excellent encapsulation of the phase change material. The thermal management performance of the phase change hydrogel is evaluated using infrared thermography and shows good thermal response behavior as the temperature rose to 68.7 °C after 120 s of heating. The strategy of combining phase change materials with hydrogels will provide new ideas for the design of TIMs. [Display omitted] [ABSTRACT FROM AUTHOR]

Reducing thermal contact resistance (TCR) is an important way to enhance heat dissipation of electronic devices. Elastomer is easy to deform, increase the contact area and reduce the TCR, but its wetting condition is not satisfying. In this work, a novel elastomeric thermal interface materials (TIMs) polyethylene glycol/unsaturated polyester resin/graphene (PEG/UPR/G) was designed and prepared. With the increase of temperature, PEG near surface of PEG/UPR/G was released due to phase transformation, and a thin molten layer would be attached to the surface. By this way, the micro bumps on the solid surface were all soaked by the thin layer of molten PEG, which greatly reduced the TCR. In addition, the effect of temperature and pressure on TCR of elastomeric PEG/UPR/G were studied. When the pressure increases from 10 Psi to 50 Psi (65 °C), TCR decreases from 11–14 K ∙ cm 2/ W to 2–4 K ∙ cm 2/ W. The TCR will be further reduced to 0.7–0.9 K ∙ cm 2/ W (75 °C) due to the phase transition of PEG. Moreover, the heat dissipation effect of PEG/UPR/G was evaluated by infrared thermal imager. These results demonstrate that the total thermal resistance is the decisive factor for the final steady-state temperature and the time of unsteady heat transfer. [ABSTRACT FROM AUTHOR]