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Lately, a fiber-based optical tweezer that traps and arranges the micro/nano-particles is crucial in practical applications, because such a device can trap the biological samples and drive them to the designated position in a microfluidic system or vessel without harming them. Here, we report a new type of fiber optical tweezer, which can trap and arrange erythrocytes. It is prepared by coating graphene on the cross section of a microfiber. Our results demonstrate that thermal-gradient-induced natural convection flow and thermophoresis can trap the erythrocytes under low incident power, and the optical scattering force can arrange them precisely under higher incident power. The proposed optical tweezer has high flexibility, easy fabrication, and high integration with lab-on-a-chip, and shows considerable potential for application in various fields, such as biophysics, biochemistry, and life sciences.

• Waterborne PAI-graphite coatings are green lubricating materials. • Waterborne PAI-graphite coatings exhibit superior mechanical and tribological properties. • Tribological mechanisms of waterborne coatings were systematically investigated. • Tribological properties of waterborne coatings under different experimental conditions were explored. The purpose of this work is to fabricate novel green waterborne PAI-graphite bonded solid-lubricating coatings (BSLCs) with superior mechanical and tribological properties so as to replace the reported organic-solvent BSLCs to some extent, and further investigate the lubricating mechanisms. The work indicates that, the preparation of the waterborne PAI-graphite BSLCs have greatly reduced the utilization rate of organic solvents (without the usage of organic solvent). The basic physicochemical properties of the coatings have reached the corresponding level of the organic-solvent BSLCs. When the mass ratio of waterborne PAI resin and graphite is 1.2, the waterborne graphite-based BSLCs exhibit superior mechanical and tribological properties, which are comparable to those of the reported organic-solvent BSLCs. The variation of tribological properties of the waterborne PAI-graphite coatings under diversified applied loads and reciprocating frequencies were explored systematically for the sake of the better understanding of environmental adaptability of the waterborne PAI-graphite BSLCs. [ABSTRACT FROM AUTHOR]

The bulk metallic glass has the potential application used in mechanical moving parts serving in corrosive environments because of its excellent mechanical, tribological properties and corrosion resistance. Here, Zr 48 Cu 36 Al 8 Ag 8 BMG/graphite composites with a 3D lubricating layer are prepared via an in-situ integrated technique. The synergism of the graphite lubrication and the micro-texture effect could significantly smooth the friction coefficient curve and reduce wear. Although seawater has a lubricating effect, the corrosion affects the reliability of BMG/graphite composites. By applying an external potential to the friction system, the effect of preventing galvanic phenomena at the interface between the alloy and graphite and improving the wear resistance of the composite material can be effectively achieved. • BMG/graphite self-lubricating composite was prepared via an in-situ integrated technique. • The material has a 3D lubricating layer near surface. • Graphite lubricating films and micro-textured effect improve tribological properties. • Corrosion and wear resistance in seawater can further improved by applying an potential. [ABSTRACT FROM AUTHOR]

• Aqueous PAI-MoS 2 -graphite bonded solid lubricating coatings are novel green lubricated materials. • Aqueous coating with the MRGM of 0.3 exhibits more excellent mechanical and tribological properties. • Tribological mechanisms of aqueous coatings are systematically investigated concerning the morphology, structure and chemical compositions of wear scars. In this paper, a series of the environmental-friendly aqueous PAI-MoS 2 -graphite bonded solid-lubricating coatings (BSLCs) are prepared depending on the design concept of the recombination of two-component lubricant and aqueous resin, and the mechanical strength and wear resistance of the coatings are deeply optimized by virtue of the synergy of the components of coatings. The experimental results demonstrate that the successful preparation of aqueous BSLCs greatly reduces the utilization of toxic organic solvents and is conducive to environmental protection and resource conservation. Doping an appropriate amount of graphite into the aqueous BSLCs is beneficial to maximize the promotion of the mechanical and tribological properties of the coating, and when the mass ratio of graphite to MoS 2 (MRGM) is 0.3, the mechanical strength, friction reduction and wear resistance of the coatings display the comparable level as that of the organic-solvent based BSLCs. Based on the analysis of the variations of the morphology, structure and chemical composition of the wear scars, the corresponding active mechanisms on the mechanical and tribological properties of the coating are investigated in depth. [ABSTRACT FROM AUTHOR]