Super-Slippery Degraded Black Phosphorus/Silicon Dioxide Interface

Abstract

The interfaces between two-dimensional (2D) materials and the silicon dioxide (SiO2)/silicon (Si) substrate, generally considered as a solid–solid mechanical contact, have been especially emphasized for the structure design and the property optimization in microsystems and nanoengineering. The basic understanding of the interfacial structure and dynamics for 2D material-based systems still remains one of the inevitable challenges ahead. Here, an interfacial mobile water layer is indicated to insert into the interface of the degraded black phosphorus (BP) flake and the SiO2/Si substrate owing to the induced hydroxyl groups during the ambient degradation. A super-slippery degraded BP/SiO2 interface was observed with the interfacial shear stress (ISS) experimentally evaluated as low as 0.029 ± 0.004 MPa, being comparable to the ISS values of incommensurate rigid crystalline contacts. In-depth investigation of the interfacial structure through nuclear magnetic resonance spectroscopy and in situ X-ray photoelectron spectroscopy depth profiling revealed that the interfacial liquid water was responsible for the super-slippery BP/SiO2 interface with extremely low shear stress. This finding clarifies the strong interactions between degraded BP and water molecules, which supports the potential wider applications of the few-layer BP nanomaterial in biological lubrication.

Regulating the Nb2C nanosheets with different degrees of oxidation in water lubricated sliding toward an excellent tribological performance

“…In addition, some illustrations of the excellent tribological properties of black phosphorus (BP) with the same 2D layered structure, as determined by previous researchers, also significantly aided this study [39][40][41][42]. The interaction between the nanoparticles and water contributed to the lubrication.…”

A review on tribology of polymer composite coatings

“…Several studies have confirmed the effectiveness of hard ceramic nanoparticles in improving the tribological properties of the coating, which is expected to enhance the adhesion of the transfer film to its counterpart [147]. Song and Zhang [70] found that the wear life increased from 1,250 to 2,750 m/μm for the PU composite coating with 3 wt% nano-silica and polytetrafluorowax (PFW), and the coefficient of friction slightly increased by 0.01.…”

Mechanical and tribological properties of nanocomposites incorporated with two-dimensional materials

“…There are two main strategies for further enhancing the mechanical properties of polymer composites. First, the functionalization, using octa (aminophenyl) silsesquioxane, octadecylamine, fluoride, etc., is an efficient way [129][130][131][132][133][134][135], because both dispersion and stress transfer can significantly improve the strength. The functionalization of 2D nanomaterials is conducive to better dispersion [136].…”