Vertically aligned carbon fibers-penetrated phase change thermal interface materials with high thermal conductivity for chip heat dissipation

Phase change thermal interface materials (PCTIMs) are receiving increasing attention but suffer from low thermal conductivity and are challenging to improve significantly. Here, vertically aligned short-cut carbon fibers (VASCFs) were employed for the first time to develop PCTIMs with high thermal conductivity. The most effective thermal conductivity enhancement was achieved by VASCFs, which were attributed to providing complete heat transfer paths, further verified by the finite element simulation. VASCFs were thus incorporated into an optimized mixture of silicon rubber (SR) and paraffin (PA) to fabricate form-stable phase change thermal pads. The VASCFs/PA/SR thermal pads achieved a thermal conductivity of as high as 7.00 W/(m·K), much higher than that of the previously reported PCTIMs. More significantly, it is revealed that the reduction in thermal impedance induced by the phase change of PA, led to the better heat dissipation performance of VASCFs/PA/SR, thus making the VASCFs/PA/SR phase change thermal pads show potential in practical applications.