Dual Functionalization of Hexagonal Boron Nitride Nanosheets Using Pyrene-Tethered Poly(4-vinylpyridine) for Stable Dispersion and Facile Device Incorporation

Owing to its favorable solution processability, the development of a stable dispersion of two-dimensional (2D) boron nitride (BN) has received significant attention for cutting-edge optic/electronic applications. Herein, we report an efficient method to disperse BN nanosheets (BNNSs) in polar solvents via dual noncovalent interactions using pyrene-tethered poly(4-vinylpyridine) (P4VP-Py). As a dispersion agent, P4VP-Py enables bifunctionalization with BNNS through pi-pi and Lewis acid-base interactions arising from the pyrene and pyridine moiety, respectively, resulting in highly stable BNNS dispersions in different polar solvents. The blend of P4VP-Py-functionalized BNNS with the pristine P4VP matrix resulted in increased thermal conductivity and dielectric constant combined with superior thermal stability by forming a compatible interface between the P4VP-Py matrix and the BNNS adjacent to the P4VP-Py. We demonstrated that dual noncovalent functionalization of BNNSs based on molecular design presents a strategy to achieve high dispersion of 2D materials into various media, ranging from polar solvents to solid matrices, for the expansion of advanced optic/electronic applications using BNNSs.