Carboxylated cellulose composite film fabricated via layer‐by‐layer self‐sssembly for thermal management material with ultra‐high thermal conductivity

Abstract With the development of 5G equipment, aerospace, sensors, thermal management devices and other fields in the direction of high power, high performance and miniaturization, the heat released during usage increases significantly, leaving great application prospects for heat dissipation materials. In spite of great attention paid to film materials due to their light weight and flexibility, they have the obvious disadvantage of poor thermal conductivity. In this work, carboxylated cellulose (CNF‐C)/dopamine‐coated nickel‐coated graphene (PDA‐Ni@GNS) composite films with high in‐plane thermal conductivity (in‐plane TC) have been fabricated by a simple vacuum‐assisted filtration method. In the prepared composite films, the flaky packing layers were found to be stacked orderly and form an excellent thermally conductive network, resulting in an increase in in‐plane TC by 322.1% (sample W4) as compared with that of neat films. By comparing the in‐plane TCs of the composite films with that of a commercial gasket, it was readily seen that the present composite films had fairly excellent heat dissipation properties. The composite exhibits not only sufficiently high in‐plane TC and tensile strength of 149.02 MPa but also exhibits hydrophobic property, imparting the composite films good working stability under extreme conditions, which ensured of their potential applications in thermal management materials. Highlights The introduction of Ni promotes the construction of heat conduction path. High in‐plane TC is obtained through layer‐by‐layer self‐assembly. The modification of filler enhanced the mechanical properties of the films. The modification of fillers led to the hydrophobicity of the film. The introduction of PDA made the films have insulating properties.