Towards Hybrid 2D Nanomaterials: Covalent Functionalization of Boron Nitride Nanosheets

In contrast to the typically electrically conductive nanocarbon systems, boron nitride nanosheets (BNNSs) are particularly attractive for the fabrication of polymers that require high thermal conductivity while maintaining electrical insulation. However, their tendency to aggregate and the weak interfacial interaction with the polymer matrix limit their effectiveness in enhancing thermal conductivity. To address these challenges, BNNSs can be chemically modified to improve dispersion and compatibility within the matrix. Nonetheless, the inherent chemical inertness of boron nitride poses a significant obstacle to functionalization. In this work, we demonstrate the successful covalent modification of BNNSs using three different silane coupling agents: (3-aminopropyl)dimethylmethoxysilane, (3-aminopropyl)diethoxymethylsilane, and (3-aminopropyl)trimethoxysilane. FT-IR, SEM/EDX, and WAXS confirm the successful functionalization and reveal that the number of alkoxy groups in the silane strongly influences siloxane network formation and the extent of surface coverage on BNNSs.