Fabrication of Heterostructured BNNS‐g‐P4VP‐AuNPs Hybrid Fillers with Uniform and Dense Au Nanoparticles for Enhancing Thermal Conductivity of the Nanofibrillated Cellulose

Abstract

Fabrication of the metal nanoparticles decorated boron nitride nanosheets (BNNSs) is an effective method to reduce the interfacial thermal resistance between fillers and is beneficial to form thermally conductive pathways in the composite. However, due to the chemical inertness of BNNS, a large amount of metal nanoparticles is really difficult to be immobilized onto the surfaces of BNNS. To solve this problem, in this work, poly(4‐vinylpyridine) (P4VP), possessing lots of coordination sites with Au nanoparticles (AuNPs), is applied to modify the BNNS by the self‐initiated photografting and photopolymerization (SIPGP). Then, the heterostructured BNNS‐g‐P4VP‐AuNPs hybrid fillers are prepared through P4VP‐assisted metallization approach. Results demonstrate that a large amount of AuNPs with an average size of 3–5 nm is immobilized onto the surfaces of BNNS‐g‐P4VP successfully. Furthermore, the in‐plane thermal conductivity of the nanofibrillated cellulose (NFC)‐based composite film with 30 wt% BNNS‐g‐P4VP‐AuNPs can reach as high as 14.04 W m−1 K−1, due to the enhanced interfacial thermal conduction. Therefore, the proposed modification method promises opportunities for the fabrication of high‐efficiency thermally conductive fillers and composites.