Polydopamine-Ni-Graphene/Carboxylated Cellulose Nanofiber/Sodium Alginate/PEG Phase-Change Composite for Thermal Management in Microelectronics

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