Boron nitride nanosheets (BNNSs) are two dimensional crystals composed of boron and nitrogen atoms covalently bonded in a hexagonal manner with exceptional physiochemical properties. However, the researches on BNNS are rather limited due to the lack of an efficient method to prepare BNNS. In this study, we report a facile and efficient method for the fabrication of BNNS through liquid-phase exfoliation of hexagonal boron nitride particles (h-BNs) in methanesulfonic acid. The resultant BNNS can be readily disperse in a number of organic solvents, such as N-methyl-2-pyrrolidone. Transmission electron microscopy and atomic force microscopy confirms that the obtained BNNSs are mainly single or few-layered with a thickness less than 3 nm. X-Ray photoelectron and infrared spectroscopy reveal that almost no compositional change occurred in BNNS during the superacid-assistant exfoliation process. The BNNS holds great promise in a number of important applications as demonstrated in this study of poly [2,2′-(p-oxydiphenylene)-5,5′-bibenzimidazole] (OPBI)/BNNS composites. The OPBI/BNNS composites showed superior mechanical and thermal properties as compared to neat OPBI and h-BN reinforced ones.

Polydopamine particles were used as fillers for constructing multifunctional composites for the first time.

Nitrogen-doped hierarchical porous carbon nanospheres (NHPCNs) with mesoscale and microscale pores are reported herein for their application in high-performance supercapacitor electrode materials (SCMs). The NHPCNs were facilely prepared via the carbonization of mesoporous polydopamine nanospheres (MPNSs) fabricated by one-step self-polymerization of dopamine using Pluronic F127 as a soft template. The influence of polymerization and carbonation temperatures on the morphologies, structures, and capacitor performances of the as-prepared NHPCNs was investigated systematically. The specific surface area of the NHPCNs can be achieved as high as 1725 m² g⁻¹, together with a pore volume of 1.85 cm³ g⁻¹. Due to their unique structure, the NHPCNs can act as high-performance SCMs and exhibit high charge storage capacity with a high specific capacitance of 433 F g⁻¹ in 6 M KOH at a current density of 0.5 A g⁻¹ and excellent stability with 95.7% of the initial capacitance after 10 000 cycles.