Construction of boron nitride nanosheets-based nanohybrids by electrostatic self-assembly for highly thermally conductive composites

Highly thermally conductive yet electrically insulating polymer/boron nitride nanosheets (BNNS) composites are crucially significant to tackle the “overheating” concern of microelectronics. However, the superiority of BNNS has not been fully exploited due to the large thermal resistance in polymer-fillers and fillers-fillers interfaces. Rational construction of BNNS-based nanohybrids is considered as a feasible and promising strategy, but often suffers from complicated preparation process and high cost. Herein, we reported a facile electrostatic self-assembly approach to successfully construct the BNNS-based nanohybrids, and fabricated a series of highly thermally conductive cellulose nanofibers (CNFs)-based composites. It was found that the positively charged thermally conductive nanoparticles (e.g., nanodiamond and modified Al2O3) can be stably adsorbed on the surface of BNNS, serving as a “bridge” to effectively strengthen the thermal conduction pathway in both CNF/BNNS and BNNS/BNNS interfaces. Moreover, benefiting from their highly oriented “brick–mortar” layered structure and strong interfacial interaction between CNFs matrix and BNNS-based nanohybrids, the resultant flexible CNFs-based composites exhibit superior thermal conductivity. This work offers a general approach for constructing BNNS-based nanohybrids, which shows great promise in developing advanced thermally conductive composites for practical applications in thermal management field.Graphical abstractBNNS-based nanohybrids were constructed by electrostatic self-assembly for fabricating highly thermally conductive composites.