Guina Ren

A novel superhydrophobic bulk material

To solve the mechanical damage and oil fouling problems, a novel superhydrophobic bulk material was fabricated by a simple approach. The superhydrophobic property of the resulting bulk material was retained after 20 abrasion cycles and even after cutting deep into it. The bulk material can thermally regenerate its superhydrophobicity for repeated use when fouled by oil. Exploiting this materials superhydrophobicity and thermal stability, the strongly oleophilic bulk material is demonstrated as a reusable oil sorbent scaffold in water.

Designing transparent superamphiphobic coatings directed by carbon nanotubes

Creating surfaces with superamphiphobic property and optical transparency simultaneously would have fundamental and practical significance but has been proven extremely challenging. Herein, we develop a transparent superamphiphobic coating using carbon nanotubes (CNTs) as the template by a facile approach. CNTs enwrapped with SiO2 coating was produced by a sol-gel method and then sprayed onto the glass slides to form coatings. Subsequent thermal treatment and surface fluoration allowed the sprayed coating to exhibit enhanced transparency across a broad spectrum of ultraviolet and visible wavelengths and also display superrepellency toward water and a number of organic liquids, such as dodecane. The obtained transparent coating can sustain its superamphiphobicity even after thermal treatment at 400 °C. Separate experiment demonstrated that the CNTs-directed geometrical structure played a key role in establishing superamphiphobicity.

Tribological Behaviors of Polyurethane Composite Coatings Filled with Ionic Liquid Core/Silica Gel Shell Microcapsules

Silica gel shell microcapsules containing ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) have been successfully synthesized through an interfacial self-assembly process and solgel reaction. They are further developed as filler to improve the tribological property of polyurethane composite coatings. The tribological behaviors of the polyurethane composite coatings filled with microcapsules have been systematically investigated using ball-on-disk tribological test. The results showed that the polyurethane composite coating filled with microcapsules displayed much lower friction coefficient and wear, compared with that of unfilled one. It is demonstrated that the ionic liquid released from the broken microcapsules during the friction process lubricates the rubbing surfaces and prevents a direct contact between steel ball and coating, leading to a lower friction coefficient and a lower wear width and depth.

Influence of lubricant filling on the dry sliding wear behaviors of hybrid PTFE/Nomex fabric composite

To improve the antiwear property and load carrying capacity of hybrid PTFE/Nomex fabric/phenolic composites, graphene and graphene oxide (GO) had been synthesized and were employed as fillers, together with graphite. Sliding wear tests show that the wear rates of filler-reinforced PTFE/Nomex fabric composites were reduced greatly when compared to unfilled fabric composite. Besides, it was found that the 2 wt% GO filled PTFE/Nomex fabric composites exhibited the optimal tribological properties. It was proposed that the self-lubrication of GO, the favorable interface stability of the composite, and the uniform transfer film on the counterpart pin contributed together to the reinforced tribological property of GO filled PTFE/Nomex fabric composite. We also investigated the influence of filler content, applied load, sliding speed, and tensile and bonding strength on the tribological properties of PTFE/Nomex fabric composites.

Tribological Behaviors of Hybrid PTFE/Nomex Fabric/Phenolic Composite under Dry and Water-Bathed Sliding Conditions

The tribological behaviors of hybrid polytetrafluoroethylene (PTFE)/Nomex fabric/phenolic composite under dry sliding condition and water-bathed sliding conditions were investigated using a pin-on-disk type tribometer. The results showed that this hybrid fabric reinforced composite exhibited a higher wear rate and a lower friction coefficient under water-bathed sliding conditions compared to that measured under dry sliding condition. Scanning electron microscopy (SEM) and X-ray photoelectron microscopy (XPS) analysis demonstrated that under water-bathed sliding conditions the transfer films formed on the counterpart pins surface were of high roughness and less PTFE transferred onto the pin surface, compared to that under dry sliding condition. Moreover, the hybrid fabric composite displayed varied tribological behaviors when distilled water-bathed sliding condition and seawater-bathed sliding condition were applied separately.

A simple way to an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding property

HYPOTHESIS Development of an ultra-robust superhydrophobic fabric with mechanical stability, UV durability, and UV shielding by a simple method is highly desirable, yet it remains a challenge that current technologies have been unable to fully address. EXPERIMENTS Herein, the original fabric is immersed into the solution containing ZnO nanoparticle and PDMS (polydimethylsiloxane), and the fiber surfaces are uniformly covered by a ZnO-PDMS layer after thermal treatment at 110 °C for 30 min. FINDINGS Droplets of water and corrosive liquids including strong acid, strong alkali, and saturated salt solution display sphere shape on the ZnO-PDMS coated fabric surface. The stable binding of ZnO-PDMS layer onto the fibers allows for the fabric coating with robust superhydrophobicity, and the coated fabric still displays superhydrophobicity after hand twisting, knife scratching, finger touching, and even cycles of sandpaper abrasion. The ZnO-PDMS coated fabric can also keep its superhydrophobic property when exposed to long term UV illumination, demonstrating its UV resistance. Moreover, the uniformly distribution of ZnO nanoparticles on fibers allows the ZnO-PDMS coated fabric to display UV shielding property.

Tribological Behaviors of Molybdic Acid-Modified Phenolic/Polyfluo Wax Composite Coating

ABSTRACT Phenolic resin (PF) and molybdic acid–modified phenolic (Mo-PF) have been synthesized and developed and combined with polyfluo wax (PFW) to fabricate PF-PFW and Mo-PF-PFW composite coatings. The effects of applied load and sliding speed on the tribological properties of the phenolic composite coating were evaluated using a block-on-ring wear tester. Compared to the PF composite coating, the Mo-PF displayed a lower friction coefficient and a higher wear life under all tested conditions. Scanning electron microscope (SEM) investigation showed that the Mo-PF composite coating had a smooth worn surface after the friction test, and a continuous and uniform transfer film was formed on the surface of the counterpart ring. The improved tribological properties of Mo-PF composite coating resulted from its enhanced thermal properties.

Hybrid Fabric/Molybdic Acid-Modified Phenolic Resin Composites with Improved Antiwear Properties

ABSTRACT Molybdic acid–modified phenolic resin (Mo-PF) had been synthesized and was used to prepare fabric composites. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that the thermal properties were improved when the phenolic resin was modified by molybdic acid. The tribological properties of the fabric composites were evaluated by a pin-on-disk tribometer. Compared to the unmodified ones, the result showed that the fabric composites made by Mo-PF displayed a lower wear rate under all tested conditions. The optimal content of molybdic acid to modify the phenolic resin was obtained, as the correspondingly produced fabric composite displayed improved tribological properties. The effect of applied load, sliding speed, and environment temperature on tribological properties of the fabric composites and the related mechanisms were also discussed.

The effect of oil fouling on the mechanical and tribological properties of nomex fabric/phenolic composite

Research related to the effect of oil fouling on the mechanical and tribological properties of the fabric composite are rare. Herein, Nomex fabric/phenolic composites were soaked in aviation hydraulic fluid or jet fuel oil for 24 h, and their corresponding mechanical and tribological properties were investigated. It was found that the mechanical property of the oil-fouled Nomex fabric/phenolic composites decreased compared to that of untreated fabric composite. Moreover, sliding wear tests indicated that the lubricating effect of aviation hydraulic fluid and jet fuel oil improved the tribological property of the oil-fouled fabric composites obviously, allowing them to exhibit lower friction coefficients and wear rates, compared to the original fabric composite. We also found that the aviation hydraulic fluid-fouled fabric composite and the jet fuel oil-fouled fabric composite displayed varied tribological behaviors and wear mechanisms under the same sliding condition.