Polydopamine-Ni-Graphene/Carboxylated\nCellulose Nanofiber/Sodium\nAlginate/PEG Phase-Change Composite for Thermal Management in Microelectronics

Phase-change composites (PCCs) absorb and release heat\nin the process\nof phase change without changes in temperature, which makes them a\nhot spot in the field of heat storage applications. However, in practical\napplications, there still exist some shortcomings such as poor thermal\nconductivity and easy leakage. Based upon this, a three-dimensional\n(3D) porous aerogel with point-surface heat conduction pathway was\nprepared in this work using polydopamine-Ni-graphene (PDA-Ni-GNS),\ncarboxylated cellulose nanofiber (CNF-C), and sodium alginate (SA)\nby a combination of prefreezing orientation and freeze-drying. The\nthermally conductive PPCs were prepared by introducing PEG into the\naerogel matrix via vacuum impregnation. Thanks to the successful preparation\nof PDA-Ni-GNS, the contact area between fillers is greatly enlarged\nand dispersed in the matrix, which provides a prerequisite for reducing\nthe interface thermal resistance between filler–filler and\nfiller–matrix. Meanwhile, the aerogel from freeze-drying formed\na vertically arranged layered 3D thermal network structure inside\nthe composite. The network structure makes the thermal conductivity\n(TC) in both vertical and horizontal directions of the PDA-Ni-GNS/CNF-C/SA/PEG\nPCCs greatly improved (at a filler loading of 4 wt %) without any\nobvious PEG leakage. In the LED lamp heat dissipation and CPU heat\ndissipation tests, it was also seen that the PDA-Ni-GNS/CNF-C/SA/PEG\nPCCs had rather excellent TC values. In addition, it was jointly confirmed\nby TG, DSC, and cyclic DSC that the prepared thermally conductive\nPCCs also had excellent heat storage performance, high latent heat,\ngood thermal stability, as well as low degree of supercooling. The\nPCCs prepared by this work have good application prospects in the\nfield of thermal management of microelectronic devices.