Hexagonal boron nitride nanosheets (h‐BNNSs) are obtained by a chemical exfoliation method from bulk h‐BN powders. The surface of h‐BNNSs is functionalized with 3‐aminopropyltriethoxysilane (APTS). Further, the amino functional groups on the surface of APTS‐modified h‐BNNSs (APTS‐BNNSs) are reacted with 4‐carboxyphenylboronic acid (CPBA) to obtain the covalently linked CPBA‐BNNSs. The morphology and structure of h‐BNNSs, APTS‐BNNSs, and CPBA‐BNNSs are comprehensively discussed. Of all the above four additives, the CPBA‐BNNSs can most outstandingly improve friction‐reducing and antiwear capacities of 150N base oil. The CPBA‐BNNSs possess excellent dispersion stability in base oil due to the phenylboronic acid groups on the surface of h‐BNNSs. Only 0.075 wt% CPBA‐BNNSs is added into the base oil, the coefficient of friction is decreased by 32.3%, and the wear scar diameter and mean wear volume of the rubbing surface are reduced by 42.9% and 88.4%. The analysis of the worn scar surface demonstrates that CPBA‐BNNSs can form a protective tribofilm containing boron and nitrogen elements on the rubbing surfaces, thereby decreasing the friction and protecting the surfaces from wear. Thus, the CPBA‐BNNSs may be recommended as a potential lubricant additive in practical applications.
Hexagonal Boron nitride (BN) can be used as a lubricant additive, which can dramatically reduce friction energy. However, due to the accumulation of BN in the water-based lubricants and the difficulty of entering the friction contact area, the tribological performance of BN becomes worse. To address this issue, the atomically thin hydroxylated boron nitride nanosheets (HO-BNNS) were successfully prepared. The thickness of HO-BNNS is only 0.6-0.8 nm. Meanwhile, the HO-BNNS has excellent dispersion stability in water-based lubricants because of the hydroxyl group on the surface of HO-BNNS. The as-prepared HO-BNNS exhibits unique friction properties as a water-based dispersible lubricant additive. Additionally, the average wear scar diameter, average friction coefficient, and mean wear volume of HO-BNNS/water-based (0.05 wt%) drop by about 64.7%, 60%, and 95.73%. Finally, the introduction of HO-BNNS can well control the temperature of water-based lubricant.
With the development of soft electronics, conductive composites are garnering an increasing amount of attention. The electrical conductivity, thermal conductivity, and electrical stability of conductive composites are all very important. In particular, the thermal conductivity of conductive composites is critical to the stability of their conductive properties. However, little is reported on thermal management in conductive systems. Herein, sufficiently hydroxylated boron nitride nanosheets (BN‐OH)@polyaniline (PANI) composite nanosheets with a high thermal conductivity and outstanding conductance stability are reported. PANI nanowire arrays are aligned vertically on BN‐OH. This well‐ordered nanostructure provides the means to form a good conductive and thermally conductive path. Notably, the composite through‐plane thermal conductivity is 2.1 W m−1 K−1(≈1000% that of pure PANI) and that the resistivity of the composite is 1.38 Ω cm. Importantly, the resistivity of the composite remains unchanged after 1 h of work. The results show that this composite has prospective applications for use in soft electronics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.