Efficient one-pot synthesis of mussel-inspired Cu-doped polydopamine nanoparticles with enhanced lubrication under heavy loads

Nanoparticles (NPs) combined with mussel-inspired chemistry of Polydopamine (PDA) is a promising strategy for achieving robust lubrication under heavy loads. However, the in situ synthesis of metal NPs inside PDA network still remains a great challenge. Here, we propose a novel one-pot method for in situ synthesis of a Cu-doped polydopamine nanocomposite (PDA@Cu). The Cu NPs are uniformly doped in the long-chain networks rather than anchored on the surfaces of PDA, leading to the enhanced load capacity. Furthermore, our synthesis process has outstanding efficiency (only 3 h) compared with previous methods (over 24 h). PDA@Cu exhibits excellent lubricating performances even under a heavy load (550 N). The coefficient of friction and the wear depth are reduced by 45% and 97% respectively, owing to the unique nanostructure of a PDA@Cu tribofilm. Thus, this study has a great significance for increasingly growing industrial demands of energy conservation and emission reduction under extreme conditions.