聚偏氟乙烯膜的超疏水改性研究

为提高疏水膜的疏水性能,使其可在膜蒸馏、膜吸收等领域有更广泛的应用.采用溶液相转移法制备超疏水性聚偏氟乙烯(PVDF)分离膜,考察了铸膜液中PVDF和非溶剂(低分子二醇类化合物PG)的浓度对膜润湿性能的影响.结果表明,通过改变铸膜液中PVDF、PG的浓度,能使PVDF膜的表面静态接触角从75.1°提高到161.7°,滚动角仅为15.8°.还研究了PVDF复合膜的制备条件对膜润湿性能的影响,结果表明,在一定的非溶剂浓度范围,增加复合膜涂覆液中非溶剂PG的加入量,有利于得到较高的复合膜表面接触角,但膜丝在涂覆液中的浸泡时间也需要相应延长.当非溶剂PG的质量分数为39.1%、浸泡时间为50 s时,复合膜表面接触角达到了155°.

Fabrication and anti-corrosion performance of superhydrophobic silane film on sintered NdFeB

An eco-friendly superhydrophobic protective film(DTMS/TEOS silane film)was fabricated on sintered NdFeB substrate through the utilization of electrochemically assisted deposition technology.The structure,properties,and film-forming mechanism of dodecyltrime-thoxysilane(DTMS)/tetraethoxysilane(TEOS)silane films were comprehensively analyzed using Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).Based on the test results,it can be determined that this film has a superhydrophobic property with a hydrophobicity angle of 152°.This special property can be attributed to the long alkyl chains in the DTMS molecule,the rough morphology,and the low surface energy of the DTMS/TEOS silane film.The surface of sintered NdFeB is coated with a layered three-dimensional network silane film that forms through the condensation of silanol substances.This film provides excellent corrosion resistance to the sintered NdFeB substrate,reducing its corrosion current density to 2.02×10~(-6)A/cm~2.Moreover,the impact of film on the magnetic characteristics of sintered NdFeB was assessed and found to be minimal.

自清洁功能性纺织品研究进展

在当前环境污染日趋严峻的条件下,自清洁功能纺织品具有巨大的发展潜力和广阔的市场空间。文章综述了纺织纤维及其纺织品获取自清洁功能的两种技术途径,即超疏水化表面技术和光催化自清洁技术,并介绍了两种技术途径的工作原理;同时对自清洁功能性纺织品的开发现状进行了阐述,还展望了其发展趋势,指出在开发高性能低成本的自清洁材料领域仍需不断探索。

Enhanced corrosion resistance of micro-arc oxidation coated magnesium alloy by superhydrophobic Mg-Al layered double hydroxide coating

To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.

Preparation and corrosion resistance of superhydrophobic coatings on AZ31 magnesium alloy

In order to improve the corrosion resistance of the Mg alloys, the superhydrophobic coatings on AZ31 Mg alloy wereprepared by a two-step process of micro-arc oxidation treatment and superhydrophobic treatment in stearic acid ethanol solution. Theeffects of voltages, frequencies and treatment time on the contact angle of the superhydrophobic treated sample were investigated.The results showed that with increasing the voltage, frequency and treatment time, all of the contact angles of the superhydrophobictreated sample increased first, and then decreased, reaching the maximum values at 350 V, 1000 Hz and 5 min, respectively. Theoptimal superhydrophobic coating was mainly composed of MgO and Mg2SiO4 phases, with the pore diameter of ～900 nm, thethickness of ～6.86 μm and the contact angle of 156.96°. The corrosion current density of the superhydrophobic AZ31 sampledecreased by three orders of magnitude, and the amount of hydrogen evolution decreased by 94.77% compared with that of the AZ31substrate sample.

Anti⁃icing/De⁃icing Mechanism and Application Progress of Bio⁃inspired Surface for Aircraft

Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-icing surfaces have gained great attention recently due to their low-hysteresis,non-stick properties,slow nucleation rate and low ice adhesion strength.These bio-inspired anti-icing surfaces,such as superhydrophobic surfaces,slippery liquid-infused porous surfaces and quasi-liquid film surfaces,have realized excellent anti-icing performance at various stages of icing.However,for harsh environment,there are still many problems and challenges.From the perspective of bioinspiration,the mechanism of icing nucleation,liquid bounce and ice adhesion has been reviewed together with the application progress and bottleneck issues about anti-icing in view of the process of icing.Subsequently,the reliability and development prospect of active,passive and active-passive integrated anti-icing technology are discussed,respectively.

A Miniature Droplet Reactor Built on Nanoparticle-Derived Superhydrophobic Pedestals

The capability to design and modulate materials, shapes, heat transfer, and mass mixing during the process of developing chemical reactors has allowed researchers to explore millions of chemical reactions and assays. However, despite the advantages in engineering array-based microreactors or microfluidic systems, the wetting attachment between solutions of reagents/products and the glass or polymer substrates of containers leads to difficulties in collecting products effectively and preventing channel blockage. Herein we present a miniature droplet reactor which takes advantage of the anti-wetting and low-adhesive properties of nanoparticle-derived superhydrophobic pedestals, allowing aqueous droplets to be manipulated freely but also providing a confined environment for performing a series of aqueous phase chemical reactions on a small scale. Gas- or precipitate- forming reactions can also be performed inside this miniature reactor. Most importantly, reaction products in liquid, solid or gaseous states can be collected effectively, which allows the harvesting of valuable products formed in limited amounts. Such a miniature reactor built on superhydrophobic pedestals provides a new way of performing common chemical reactions and may open the door to the design of next-generation microreaction systems.

“Petal effect”-inspired superhydrophobic and highly adhesive coating on magnesium with enhanced corrosion resistance and biocompatibility

With properties of complete degradation and favorable mechanical behavior, Mg and its alloys are regarded as the next generation medical metal materials. However, fast degradation and poor surface biocompatibility hinder their clinical applications. Inspired by the ＂petal effect＂, we successfully constructed a superhydrophobic and highly adhesive coating on pure Mg via a simple hydrothermal treatment in a solution containing sodium oleate. The superhydrophobicity of the fabricated coating results from its flake-like micro-nanostructure and the low-surface-energy oleate group. Water droplet on the superhydrophobic coating cannot roll off even when the sample is turned upside down, owing to the sealed air-pockets and the van der Waals’ attraction at the solidliquid interface, indicating a highly adhesive force. The chemical and mechanical stability of the superhydrophobic coating were measured. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements suggest enhanced corrosion resistance of the as-prepared sample.Furthermore, cell cytotoxicity, migration and adhesion data of human umbilical vein endothelial cells（HUVECs） reveal an improved cytocompatibility of the modified surface. Finally,hemolysis assay and platelet adhesion assay suggest an improved hemocompatibility. It is believed that the facile and low-cost method can expand the new application of superhydrophobic surface with highly adhesive on Mg in biomedical fields.

Robust superhydrophobicity of hierarchical ZnO hollow microspheres fabricated by two-step self-assembly

Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light

Superhydrophobic conductive rubber band with synergistic dual conductive layer for wide-range sensitive strain sensor

Wearable electronic devices have received increasing interests because of their excellent flexibility,stretchability,and human friendliness.As the core components,flexible strain sensors integrated with wide working range,high sensitivity,and environment stability,especially in moisture or corrosive environments,remain a huge challenge.Herein,synergistic carbon nanotubes(CNTs)/reduced graphene oxide(rGO)dual conductive layer decorated elastic rubber band(RB)was successfully developed and treated with hydrophobic fumed silica(Hf-SiO_(2))for preparing superhydrophobic strain sensor.As expected,stable entangled CNTs layer and ultrasensitive microcracked rGO layer endow the sensor with extremely low detection limit(0.1%),high sensitivity(gauge factor is 685.3 at 482%strain),wide workable strain range(0–482%),fast response/recovery(200 ms/200 ms)and favorable reliability and reproducibility over 1000 cycles.Besides,the constructed Hf-SiO_(2) coating also makes the sensor exhibit excellent superhydrophobicity,self-cleaning property,and corrosion-resistance.As a proof of concept,our prepared high-performance strain sensor can realize the full-range monitoring of human motions and physiological signals even in the water environment,including pulse,vocalization,joint bending,running,and gesture recognition.Interestingly,it can also be knitted into a tactile electronic textile for spatial pressure distribution measurement.Thus,this study provides a universal technique for the preparation of high-performance strain sensors with great potential applications in the field of next-generation intelligent wearable electronics.

A general, rapid and solvent-free approach to fabricating nanostructured polymer surfaces

A general, rapid and solvent-free approach is proposed to fabricate nanostructured polymer surfaces by coupling ultrasonic vi- bration and anodized aluminum oxide templating. With our approach, hollow nanorods or nanofibers with controlled diameter and length are prepared on polymer surfaces. The whole fabrication process is completed in ～30 s and equally applicable to polymers of different crystalline structures. The wettability of the as-fabricated polymer surfaces （being hydrophilic, hydro- phobic, highly hydrophobic or even superhydrophobic） is readily regulated by adjusting the welding time from 0 s to a maxi- mum of 10 s. Our approach can be a promising industrial basis for manufacturing functional nanomaterials in the fields of electronics, optics, sensors, biology, medicine, coating, or fluidic technologies.