Effective lubrication under extreme conditions such as high temperature is of considerable importance to ensure the reliability of a mechanical system. New lubricants that can endure high temperatures should be studied and employed as alternatives to traditional oil-based lubricant. In this paper, a thermocapillary model of a silicone-oil droplet is developed by solving the Navier–Stokes and energy equations to obtain the flow, pressure, and temperature fields. This is accomplished using a conservative microfluidic two-phase flow level set method designed to track the interface between two immiscible fluids. The numerical simulation accuracy is examined by comparing the numerical results with experimental results obtained for a silicone-oil droplet. Hence, the movement and deformation of molten silicon droplets on graphite and corundum are numerically simulated. The results show that a temperature gradient causes a tension gradient on the droplet surface, which in turn creates a thermocapillary vortex. As the vortex develops, the droplet migrates to the low-temperature zone. In the initial stage, the molten silicon droplet on the corundum substrate forms two opposite vortex cells, whereas two pairs of opposite vortices are formed in the silicone fluid on the graphite substrate. Multiple vortex cells gradually develop into a single vortex cell, and the migration velocity tends to be stable. The greater the basal temperature gradient, the stronger the internal thermocapillary convection of the molten silicon droplet has, which yields higher speeds.

Nickel (Ni) films with positive and negative textured surfaces of lotus and rice leaf patterns were fabricated through an inexpensive and effective method. The as-prepared Ni films were superhydrophobic and exhibited excellent tribological properties after chemical treatment. Experimental results indicated that the water contact angles (WCAs) on the surfaces of biomimetic textured Ni films (approximately 120°) were far greater than those on smooth films (65°). The biomimetic textured surfaces became superhydrophobic (WCA of approximately 150°) after perfluoropolyether (PFPE) treatment, which could be due to the combined effects of the special texture and the PFPE. The as-prepared biomimetic-textured Ni films modified with PFPE were improved with a low friction coefficient and excellent antiwear properties, which were due to the combination of the effective lubrication of PFPE and the special textures that served as a good lubricant and a debris reservoir. Moreover, the antiwear properties of the as-prepared Ni films with negative biomimetic microtextures modified with PFPE were much better than those of films with positive biomimetic microtextures modified with PFPE.