High-Temperature Skin Softening Materials Overcoming the Trade-Off between Thermal Conductivity and Thermal Contact Resistance

The trade-off between thermal conductivity (kappa) and thermal contact resistance (R-c) is regarded as a hurdle to develop superior interface materials for thermal management. Here a high-temperature skin softening material to overcome the trade-off relationship, realizing a record-high total thermal conductance (254.92 mW mm(-2)K(-1)) for isotropic pad-type interface materials is introduced. A highly conductive hard core is constructed by incorporating Ag flakes and silver nanoparticle-decorated multiwalled carbon nanotubes in thermosetting epoxy (EP). The thin soft skin is composed of filler-embedded thermoplastic poly(ethylene-co-vinyl acetate) (PEVA). The kappa (82.8 W m(-1)K(-1)) of the PEVA-EP-PEVA interface material is only slightly compromised, compared with that (106.5 W m(-1)K(-1)) of the EP core (386 mu m). However, the elastic modulus (E = 2.10 GPa) at the skin is significantly smaller than the EP (26.28 GPa), enhancing conformality and decreasing R-c from 108.41 to 78.73 mm(2) K W-1. The thermoplastic skin is further softened at an elevated temperature (100 degrees C), dramatically decreasing E (0.19 GPa) and R-c (0.17 mm(2) K W-1) with little change in kappa, overcoming the trade-off relationship and enhancing the total thermal conductance by 2030%. The successful heat dissipation and applicability to the continuous manufacturing process demonstrate excellent feasibility as future thermal management materials.