Search

Severe plastic deformation and lateral flow during machining of pure iron surface resulted in relatively serious tool wear and poor surface quality. Although several methods proposed could improve machinability of pure iron to some extent, poor wettability and high plasticity of pure iron cannot be changed, and further improvement of surface quality may be therefore restrained. In this paper, we propose a new machining method using atmospheric pressure plasma jet to adjust material properties of pure iron during precision turning process. The influence mechanism of plasma jet on surface wettability of pure iron is investigated by plasma modification experiment, scanning electron microscope, and X-ray photoelectron spectroscopy. On the basis of the influence mechanism, precision turning experiments are performed under different lubricating conditions. The experimental results indicate that plasma jet can effectively improve pure iron surface wettability by changing surface composition while not influencing surface microstructures. Under plasma atmosphere, surface roughness and cutting force are obviously reduced, and tool wear is effectively alleviated. [ABSTRACT FROM AUTHOR]

Wettability patterns have significant application potential in liquid transportation and water collection. Plasma hydrophilization is high-efficient and less-destructive, and has been widely used for preparing wettability patterns. However, the plasma-treated surfaces tend to recover to its original wettability, causing invalidation of the patterns. As a green treatment method, boiled water treatment could construct nanostructures, which is favorable for hydrophilicity-retaining; while the hydrophilization effect of plasma treatment would promote the reaction. Therefore, it should be possible to combine plasma and boiled water treatments to prepare long-lasting wettability patterns. In this paper, superhydrophobic aluminum surfaces were modified by plasma jet followed by boiled water treatment. The time stability, microstructures and chemical compositions of the treated surfaces were investigated by testing contact angles, scanning electron microscope, X-ray diffractometer, and X-ray photoelectron spectroscopy. The surfaces treated by plasma jet and boiled water could retain superhydrophilicity for a long time under various storage conditions, including normal ambient, high temperature or high humidity. On the basis of this technique, long-lasting patterns could be prepared on different metal substrates. The green method proposed is expected to have promising application potential in fabricating wettability patterns and lab-on-chip devices, especially for those used in severe conditions. Unlabelled Image • Long-lasting water/oil wettability patterns are prepared on metal substrates. • The patterns show good time stability under high temperature/humidity. • The patterns are obtained by using plasma and boiled water to modify substrates. • The modification method is reversible. [ABSTRACT FROM AUTHOR]

Plasma treatment is a versatile tool for surface modifications, and plasma-induced hydrophilicity has a well-known aging behavior. In this paper, plasma hydrophilization and the subsequent aging behavior of superhydrophobic and hydrophobic surfaces are comparatively investigated. Static water contact angle measurement and X-ray photoelectron spectroscopy show that, compared with the hydrophobic surface, the superhydrophobic surface requires more plasma dose to completely change its wettability even after considering the difference in their initial wettability, and the corresponding aging speed is also obviously retarded. A tentative model based on the surface micro/nanostructures is presented to explain the results. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Patterned surfaces that show different wettabilities on same substrates have important application value in fields like fog collection and liquid transportation. However, superhydrophilic regions on the patterned surfaces prepared tend to become superhydrophobic, which restrains their further applications. Therefore, it is of great significance to explore wettability change of the superhydrophilic regions. In this paper, we prepare patterned aluminum (Al) surfaces by nanosceond laser texturing and fluorosilane modification, and investigate the wettability change of the patterned surfaces (laser parameters: a pulse repetition rate of 20 kHz, a scanning speed of 300 mm/s, a power of 6 W, a pulse width of 100 ns, a beam waist diameter of 46 μm, an optical wavelength of 1064 ± 5 nm, a pulse energy of 0.3 mJ and a laser fluence of 18 J/cm2). Contact angles, surface morphologies and surface chemical compositions are measured and analyzed by an optical angle meter, a scanning electron microscope, and X-ray photoelectron spectroscopy. Compared with a uniform superhydrophilic surface, the superhydrophilic area on a patterned surface becomes superhydrophobic more rapidly, indicating that cross contamination of low surface energy functional groups from the superhydrophobic region promotes wettability change of the superhydrophilic region. In addition, the wettability change rate gradually accelerates when storing under a higher temperature of 100 °C; we perform fog collection experiments on patterned surfaces storing under different temperatures, and find that low temperature can hinder wettability change of functional patterned surfaces, thereby improving service life. Unlabelled Image • Wettability change of patterned surfaces is studied. • The wettability change was slower under low temperature in contaminated air. • Cross contamination from superhydrophobic area causes faster wettability change. • Temperature of 100 °C results in faster wettability transition in contaminated air. [ABSTRACT FROM AUTHOR]

[Display omitted] • An anti-adhesion electrotome with good conductivity and durability is developed. • The electrotome is coated by ceramic coating, silicone oil, and carbon nanotubes. • The electrotome shows good slippery performance with a water rolling angle of ∼10°. • The electrotome possesses excellent anti-blood and anti-tissue adhesion properties. • The electrotome has high endurability for low-temperature storage. Possessing advantages of simple operation, less postoperative pain, etc., high-frequency electrotomes have significant application values in electrosurgical field. However, during practical applications, the electrotomes suffer from blood and tissue adhesion, which may result in secondary tissue tear and bleeding. Although researchers have proposed to alleviate the problems by methods including coating and slippery liquid-infused porous surface, demerits like low conductivity and poor durability still exist. Here, we develop an innovative electrotome using nano-hydrophobic ceramic coating, medical silicone oil and multi-walled carbon nanotubes (MWCNTS) (mass ratio 50:25:1), and the electrotome demonstrates excellent anti-blood, anti-tissue adhesion properties, high conductivity, and good stability under different humidity environment conditions. We then investigate the mechanisms contributing to the good performance by scanning electron morphologies (SEM) and X-ray photoelectron spectroscopy (XPS). In addition, the developed electrotome also has high endurability for low-temperature storage, and may have promising application prospect in electrosurgical field. [ABSTRACT FROM AUTHOR]