Mg-Nd-Zn-Zr镁合金表面超疏水SiO2薄膜的制备及其表征

以微弧氧化层(MAO)为预处理过渡层,正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为主要原料,采用sol-gel和浸渍-提拉相结合的方法在Mg-Nd-Zn-Zr(NZ30K)镁合金表面获得甲基(-CH3)疏水基团表面修饰的超疏水SiO2薄膜,实现了NZ30K镁合金表面的超疏水改性.同时研究了微弧氧化层的表面特征、sol-gel过程中TEOS/乙醇摩尔比(TEOS/EtOH)和MTES添加量(MTES/TEOS摩尔比)对所制备超疏水SiO2薄膜表面形貌和润湿特性的影响.结果表明:NZ30K镁合金经过微弧氧化处理后,表面呈现的微米-纳米尺度上多孔的粗糙结构,其表面体现为亲水性,但有利于提高超疏水SiO2薄膜与NZ30K基材的结合力;当TEOS/EtOH摩尔比为1/30,MTES/TEOS摩尔比为1/2时,SiO2薄膜表面的静态接触角达到151°,其表面具有超疏水特性;而进一步提高MTES/TEOS摩尔比至1时,其静态接触角有所提高,达到153°.红外光谱(FT-IR)表明NZ30K镁合金表面SiO2薄膜的超疏水特性是由于MTES的引入使得-CH3疏水官能团能够成功地嫁接到SiO2粒子的表面.     

B10白铜表面超疏水膜的制备及其耐腐蚀性能研究

以B10白铜为基底,采用刻蚀、煅烧和表面改性的方法制备了超疏水膜,采用K100-MK2型张力仪测量超疏水膜的接触角,采用扫描电子显微镜观察超疏水膜的表面形貌,采用电化学工作站测试超疏水膜在3.5% NaCl（%表示质量分数）水溶液中的耐腐蚀性能。结果表明,刻蚀、煅烧后的B10白铜样品分别在溶液A中改性5 min、在溶液B中改性12 h后,得到的两种超疏水膜的接触角可分别达到153.2°和151.5°。将两种超疏水膜分别在3.5% NaCl水溶液中腐蚀10 d后,与裸B10白铜相比,仍表现出较好的耐腐蚀持久性。该方法为制备具有抗腐蚀和自清洁性能的超疏水表面提供了一条有效途径,可用于金属材料的表面改性。     

木材表面SiO2/环氧树脂/氟硅烷复合超疏水膜的构建

【目的】为获得具有良好机械耐磨性的超疏水木材,构建了木材表面SiO₂/环氧树脂/氟硅烷复合超疏水膜。【方法】采用两步法在木材表面构建有机/无机复合超疏水涂层,在木材基底预置透明环氧树脂底层以覆盖木材表面天然微沟槽结构,然后构建SiO₂/环氧树脂/氟硅烷(FAS)复合超疏水薄膜。采用场发射扫描电子显微镜、原子力显微镜以及傅里叶红外光谱仪对超疏水涂层的微观形貌和化学组成进行表征,并测试其疏水、疏油和机械耐磨性能。【结果】木材表面复合超疏水涂层具有精细的微/纳米二元粗糙结构,该结构协同低表面能物质FAS,使木材表面不仅具有良好的超疏水性能(水静态接触角为153°,滚动角低于4°),而且疏油(乙二醇接触角为146°,滚动角低于11°); 经砂纸多次磨擦后木材表面水接触角和滚动角基本不变,超疏水性能保持稳定,超疏水涂层的微纳米结构及疏水物质依然保留,表现出良好的机械耐磨性。【结论】有机/无机复合超疏水涂层体系中,环氧树脂由于黏结作用使得SiO₂纳米粒子与木材基底形成牢固的结合,从而赋予涂层良好的机械稳定性。     

工业化超疏水TiO2涂层的简易制备和性能研究

为探究适合工业化生产用超疏水纳米TiO₂的绿色改性工艺,以饱和脂肪酸A、硅烷B、纳米TiO₂（P25）等为原料制备超疏水TiO₂粉末,与环氧树脂混合后利用喷涂法制备出超疏水涂层。采用扫描电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪和接触角分析仪对超疏水粉末和超疏水涂层表面的形貌和疏水性进行了表征。结果表明：超疏水TiO₂粒子表面具有疏水性基团和微-纳米双重粗糙结构,粒子表面的静态水接触角为158°,滚动角为3°;当超疏水TiO₂与环氧树脂的质量比在3.2～3.5时,超疏水涂层既保持超疏水性,又与基底稳固结合,同时具有自清洁性和可修复性。该工艺操作简单方便,成本低,疏水性好,无需特殊设备,工艺环保,适应工业化生产,可用来大面积制备超疏水涂层,拥有较高的商业价值。     

High-temperature oxidation resistance of ceramic coatings on titanium alloy by micro-arc oxidation in aluminate solution

Ceramic coatings with aluminum titanuate (Al₂TiO₅) were prepared on Ti–6Al–4V alloy using pulsed bi-polar Micro-arc Oxidation (MAO). The micromorphology and phase composition of the micro-arc-oxidition ceramic coatings on the titanium alloy were characterized by X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) respectively. The results revealed that the distinct discharge channels and pores on the surface of the micro-arc-oxidition coatings appeared, and these channels were connected in the molten state. The electrolyte concentration was inversely proportional to the coating hardness; additionally, the coating prepared with sodium aluminate and sodium hypophosphite concentrations of 4 ?g/L and 0.5 ?g/L, respectively, was the most refined after high-temperature sintering, and it was demonstrated to better prevent oxidation. Increasing the electrolyte concentration coincided with fluctuating coating thermal shock resistance. The thermal shock resistance of the coating respectively prepared with sodium aluminate, and the sodium hypophosphite concentrations of 4 ?g/L and 0.5 ?g/L was the highest. Additionally, the high-concentration coatings performed significantly better than the low-concentration coatings. The oxidation resistance of the coating samples was also significantly higher than that of the TC4 titanium alloy substrate. The adhesion strength between the coatings and the substrate with and without the sealing treatment was measured by tensile tests. Then, the high-temperature oxidation performance of the coating samples with and without the sealing treatment was investigated by conducting a high-temperature oxidation experiment at a calcinating temperature of 500 ?°C. The results indicate that the adhesion strength between the coatings and substrate was high for the as-prepared and sealed micro-arc oxidation samples regardless of whether they were calcined. The high-temperature oxidation mass increase curves for the sealed and unsealed coating samples calcined at 500 ?°C for 500 ?h revealed that the high-temperature-oxidation-induced mass increase of the coating samples sealed with a sodium silicate solution was much lower than that of the titanium alloy substrate. Thus, the sealing treatment significantly improved the high-temperature oxidation resistance of the TC4 titanium alloy. Lastly, the high-temperature oxidation behavior at 500 ?°C was analyzed and discussed.     

Preparation,characterization and antibacterial property of naringin loaded PLGA nanospheres

Naringin is a predominant flavanone in grapefruit and shows a variety of biological effects such as antioxidative, anticancer, anti-inflammatory and antibacterial activity. However, its application in pharmaceutical field is limited by low water solubility, poor bioavailability and instability. To overcome the problem, naringin has been encapsulated in poly(lactic-co-glycolic acid) (PLGA) polymer by emulsion-diffusion-evaporation method in this work. Moreover, naringin loaded PLGA nanospheres were characterized by scanning electron microscope (SEM), dynamic light scatter method (DLS), fourier transform infrared (FTIR) spectra, UV–vis spectra and fluorescence spectra of DNA-EB competition displacement. The mean diameter of PLGA nanospheres and NRG/PLGA nanospheres was 123 ?± ?25 ?nm and 137 ?± ?30 ?nm, respectively. The drug encapsulation efficiency was 86.4% while the drug loading rate was 22.3%. The fluorescence spectra of the competitive DNA-binding experiments revealed that the functional activity of naringin was retained after loaded in PLGA. It is revealed that the initial burst effect happened in the initial 24 ?h and followed by sustained release lasting for 10 days. Moreover, the nanospheres exhibited strong antibacterial activity, and 99.9% of E. coli and S. aureus were killed when treated with naringin loaded PLGA nanospheres at the concentration of 0.2 ?mg ?mL^?1 within 24 ?h. Furthermore, the viable cells remained only 48% when the concentration of NRG/PLGA nanospheres was 32 ?μg ?mL^?1 and NRG/PLGA nanospheres was important for inhibition of cancer cells. It is concluded that the stable naringin loaded PLGA nanospheres could have potential application in food industry and nanomedicine field.     

锌基底上含金属锡的超疏水表面的制备

针对超疏水金属表面广阔的应用前景,采用氯化亚锡的丙酮溶液,十八硫醇的丙酮溶液为疏水剂在锌基底上构建了超疏水表面,通过X-射线衍射(XRD)和扫描电镜(SEM)进行了结构表征和疏水性能测试.结果表明,超疏水表面具有微纳米阶层结构,静态接触角为158°,滚动角小于5°.     

Chemically robust carbon nanotube – PTFE superhydrophobic thin films with enhanced ability of wear resistance

A chemically robust superhydrophobic nanocomposite thin film with enhanced wear resistance is prepared from a composite comprising polytetrafluoroethylene(PTFE) and carbon nanotubes.The superhydrophobic thin films with hierarchical structure are fabricated by spraying an environmentally friendly aqueous dispersion containing carbon nanotubes and PTFE resin on silicon wafer.Thin films with a contact angle of 154.1°± 2° and a sliding angle less than 2° remain superhydrophobic after abrading over 500 times under a pressure of 50 g/cm~2.The thin film is also extremely stable even under much stress conditions.To further the understanding of the enhancement of wear resistance,we investigated the formation of microsized structure and their effects.The growth of microbumps is caused by attracting solution droplet to the hydrophilic islands on hydrophobic surface.     

一步法合成耐久性水基超疏水TiO2/DTMS涂层

为制备具有优异自清洁功能的耐久性水基超疏水涂层,以十二烷基三甲氧基硅烷(n-dodecyltrimethoxysilane, DTMS)为有机改性物,通过一步法在纳米TiO₂表面嫁接长链烷基官能团得到超疏水TiO₂/DTMS涂层。分析了TiO₂涂层及TiO₂/DTMS涂层的表面润湿性、形貌和化学组成,并对所得超疏水TiO₂/DTMS涂层的自清洁性能、机械及化学稳定性进行了测试。结果表明：超疏水TiO₂/DTMS涂层表面水接触角(water contact angle, WCA)达到159°;以亚甲基蓝粉末作模拟污染物,涂覆有超疏水TiO₂/DTMS涂层的玻璃具有优异的自清洁性能;经机械磨损(10 min)、酸碱液(pH=1、3、5、7、9、11、13)浸泡、高低温(−20、30、60、90、120、150 ℃)处理后超疏水TiO₂/DTMS涂层的WCA仍大于150°,表明其具有优异的机械和化学稳定性,可用于室外防污,如建筑物外墙、玻璃、太阳能电池板等。     

沿海水工混凝土结构表面防水技术

随着经济的高速发展,对外贸易的日益繁盛,中国沿海港口、码头在国民经济增长过程中扮演着重要的角色,但港口水工建筑物的桩基与码头长期处于浪溅区与大气区,占水体总含量3%的盐分会对基础建设部位的钢筋混凝土造成严重的腐蚀破坏。因此,针对上述所提出的问题,利用超疏水防护层机理,采用接触角、抗氯离子渗透以及吸水率试验的方法验证硅烷疏水剂性能的优劣。结果表明:硅烷疏水剂在混凝土表面形成的膜状物既能够有效疏水,又能够有效地和混凝土材料相结合,起到隔绝水的作用,从而有效地降低混凝土材料受Cl~-、SO_4~2-的腐蚀。     

Microstructure and oxidation behavior of carbon fiber reinforced SiC composite (Cf/SiC) with Mo–57Si–10B oxidation protection coating

Mo–57Si–10B (at.%) coating was prepared by the spark plasma sintering (SPS) technique on a 2D woven C_f/SiC composite, and the oxidation behavior of the bare and the coated C_f/SiC samples at 1300 ?°C were investigated. The coating was composed of a fine MoSi₂/MoB/SiO₂/Mo₂B₅ out layer and the inner SiO₂ interface layer. The mass gain percentage was approximately 0.25% after oxidation at 1300 ?°C for 100 ?h. The coated C_f/SiC substrate was effectively protected, owing to the rapid formation of the dense and protective borosilicate layer on the coating, the excellent microstructure stability of the coating and the inner SiO₂ interface layer.     

Durable, high conductivity, superhydrophobicity bamboo timber surface for nanoimprint stamps

Superhydrophobic bamboo timber was fabricated by magnetron sputtering and nanoimprint stamps. Conductive copper film was deposited on the surface of bamboo timber, followed by transferring lotus leaf structure pattern to the Cu-bamboo timber surface. Modified by stearic acid, the as-prepared surface with lotus leaf structure showed superhydrophobic property with the water contact angle of 152°, and the sliding angle was only 5°. The coating showed excellent mechanical resistance, environmental stability and high conductivity. It was expected that this work could promote the applications of superhydrophobic and conductive bamboo products.     

Preparation and properties of chitosan-VC loaded nano-silver-doped natural latex

As one kind of the modern medical devices, various catheters are commonly used in interventional therapy, but they are prone to infection in the human body, which is a defect in clinical treatment. At present, the commonly used catheters are mostly treated with antibacterial coatings on the rubber catheters. However, there are some problems for their application, such as, easy peeling of the coating and poor durability of antibacterial properties. In order to solve the above problems, a kind of nano-silver antibacterial agent reduced and stabilized by Vitamin C modified chitosan was prepared, and then added into natural latex to produce an antibacterial latex with antibacterial properties from the inside to the outside. The chemical properties, mechanical properties and antibacterial properties of the samples were characterized, and the antibacterial mechanism of VC modified chitosan/nano silver was analyzed. The results showed that the antibacterial rates of the latex samples against E. coli and S. aureus reached 97.38% and 98.45%.     

硅烷改性三聚氰胺海绵的制备及其油水分离性能研究

利用甲基三甲氧基硅烷和二甲基二甲氧基硅烷水解后形成的水解液涂覆于三聚氰胺海绵上,成功制备了疏水亲油海绵。通过扫描电镜、X射线光电子能谱、傅里叶红外光谱、接触角和吸油能力测试等方法,对硅烷改性三聚氰胺海绵进行了表征。结果表明,硅烷改性使得本身亲水的三聚氰胺海绵表面转变为疏水状态,水的接触角可达149±0.5°,对八种油品或有机试剂的吸油能力可达到自重的47-60倍,使用达200次后吸附容量仅降低了17.7%,分离效率在96%以上。除此外,改性的海绵还具有较好的耐酸碱、耐盐和耐有机溶剂的特性,在溢油回收方面展现了良好的应用前景。     

Enhanced low-humidity performance of proton-exchange membrane fuel cell by introducing hydrophilic CNTs in membrane electrode assembly

Hydrophilic carbon nanotubes (HCNTs) were introduced into the membrane electrode assembly (MEA) to improve its low-humidity performance. The effects of types, placement, loading, and relative humidity on the MEA performance were investigated. It has been found that the MEA with 20 ?wt% HCNTs loading both in anode and cathode achieved the best self-humidifying performance. Its current density reached 1550 ?mA ?cm^?2 at 0.6 ?V, with a maximum power density of 953 ?mW/cm² at 70 ?°C, 30 psi and 30% relative humidity conditions. Besides, the stability test shows that its current density at 0.6 ?V only decreased by 6.4% after 44 ?h performance test, while the performance of blank MEA without HCNTs decreased by 45% within 6 ?h testing period. This extraordinary performance under low humidity condition is ascribed to that the HCNTs contained in the MEA improve the water management and mass transportation by functioning as a dispersant and hydrophilic agent.     

Hydrothermal synthesis of hydroxyapatite coating on the surface of medical magnesium alloy and its corrosion resistance

The early corrosion control of biomedical magnesium alloy is an important measure to determine its good performance during implantation into human body. The deposition of calcium phosphate biological coating is the most effective solution at present. In this paper, hydroxyapatite (HAP) coating was hydrothermal synthesized on the surface of AZ31B magnesium alloy, and the influence mechanism of hydrothermal synthesis temperature, time and solution concentration was investigated. The synthesis conditions and deposition mechanism of hydroxyapatite coating without DCPA (CaHPO₄) were proposed. The surface morphology of the coating was observed by field emission electron scanning microscope (FESEM). The types and contents of microelements in the material were analyzed by energy disperse spectroscopy (EDS). Fourier transform infrared spectroscopy (FTIR) was used to analyze the functional group information of the coating surface. The corrosion resistance of different experimental groups was studied by electrochemical test. The results showed that when the calcium phosphate solution concentration was 0.1 ?mol/L and the calcium/phosphorus ratio was 1.67, the coating had better morphology structure and corrosion resistance, and the calcium/phosphorus ratio of HAP crystals reached 1.58, the epit of the prepared AZ31B-HAP coating by bare metal increased from ?1.51 ?V to ?1.18 ?V, the impedance value reached 1.0 ?× ?10⁵ ?Ω?cm², and the early corrosion of magnesium alloy substrate was effectively delayed.     

改性纳米SiO2成膜复合涂层对混凝土疏水和抗碳化性能的影响

为了研究改性纳米Si O2+有机成膜涂层对混凝土疏水和抗碳化性能的影响,配制了6种改性和未改性纳米Si O2有机成膜复合涂料,测定了涂覆复合涂料后混凝土的表面接触角,确定了涂料中纳米Si O2的最佳添加量。通过测定涂层混凝土的吸水率发现,改性和未改性纳米Si O2可以显著提高涂层混凝土的憎水性,其中改性纳米Si O2的改善幅度更大,同时混凝土的吸水率与其接触角呈一阶线性负相关的关系;通过涂层混凝土的加速碳化试验发现,改性和未改性纳米Si O2可以有效改善涂层混凝土的抗碳化性能,其中改性纳米Si O2的改善效果更好,而且还发现涂层混凝土的疏水能力和抗碳化性能之间存在正相关关系,即表面涂层疏水性能越强,混凝土抗碳化性能越好。     

Mangosteen peel-derived activated carbon for supercapacitors

This work reports the effects of activation temperatures on the porous development and electrochemical performance of activated carbons. Herein, activated carbons were prepared from the biowaste of mangosteen peel by using KOH activation at temperatures of 400, 600, and 800 ?°C. The results demonstrate that the specific surface area increases with increasing the activation temperatures in which the well-developed porous structure after KOH activation at 800 ?°C provides the highest specific surface area of 1039 ?m² ?g^?1. At 600 ?°C, the activated carbon delivers the highest specific capacitance value of 182 ?F ?g^?1 ?at a current density of 0.5 ?A ?g^?1 in 3 ?M KOH aqueous electrolyte. This is correlated well with its high micropore fractions (99%). Moreover, it was found that the activation temperature changes the major contribution of oxygen-containing functional group on surface of activated carbon, which is beneficial for the enhancement of the specific capacitance value of activated carbon at the temperature of 600 ?°C. This work suggests that the activation temperature is a key to optimizing the electrochemical performance of activated carbons. Overall, our activated carbons can be considered as a strong candidate for use as electrode materials in supercapacitors.     

仿生超疏水导电竹材的制备及其耐久性

 采用银镜反应及分子自组装技术,在竹材表面原位负载一层纯单质银纳米粒子,赋予竹材导电功能,再经十七氟癸基三甲氧基硅烷（FAS-17）的进一步处理,制备出具有导电功能的仿生超疏水竹材试样,并通过实验观察研究了其稳定性及耐久性。结果表明,制备竹材表面拥有亚微米/纳米二维等级粗糙结构,该结构协同低表面能物质FAS-17共同决定了竹材的超疏水性,竹材表面与水的接触角为155°,滚动角小于10°;制备竹材能够抵抗pH 1~14溶液及强浓度NaCl溶液,且经强烈的溶液搅拌及蒸煮,依旧保持超疏水性和导电性。     

热交换器翅片用亲水铝箔预处理工艺控制

亲水铝箔用作热交换器时,在加工及使用过程中对其附着力、耐腐蚀性及亲水性等涂层性能要求较高,为确保亲水铝箔涂层性能,涂覆前的清洗预处理尤为重要。通过中性盐雾试验、附着力测试及持续亲水性测试等手段,分析了亲水铝箔预处理工艺参数的制定及优化控制,涂覆前预处理按照脱脂液浓度2%～5%（质量分数）,脱脂液温度20～40℃,pH 10～13,热水清洗温度40～60℃,处理后铝箔板面清洁度达因值≥56即可满足亲水铝箔的生产需求。