超疏水滤纸的制备与应用

对SiO2纳米粒子进行硅烷化改性,再将其修饰到滤纸上,制备出静态水接触角＞150°的超疏水滤纸,对制备条件进行了优化。 用热重分析及扫描电子显微镜对超疏水滤纸表征后发现,二氧化硅纳米粒子在滤纸纤维表面形成一层包裹层,即纳米级粗糙结构,这种结构对滤纸的疏水性具有关键作用。 对滤纸的油水分离性能进行了研究,发现其对非均相体系和高粘度油水混合物具有很好的分离效果。     

Zn片经水热反应和氟硅烷修饰构建超疏水ZnO表面

以乙二胺为溶剂, Zn片在120、140 及160 ℃经水热反应生长出具有蛋糕形、荷叶乳突状、棒状和仙人球状等微结构的ZnO表面. 扫描电镜研究表明, 反应时间越长越有利于形成完整的微纳米结构, 反应温度较高生成的微纳米结构更规整. 140 ℃反应4 h和160 ℃反应5 h的ZnO表面经过氟硅烷修饰后表现出良好的超疏水性, 与水滴的接触角分别达到154.6°和157.3°, 滚动角分别为5°和3°. 该方法因其操作简便、成本低廉, 在锌表面制备特殊微结构和构建超疏水表面具有潜在的应用.     

具有超疏水表面的硅/二氧化硅层次结构薄膜

目前报道的硅基材料的超疏水表面主要是通过制备粗糙微观结构,并在其表面修饰表面能相对较低的有机物两个步骤来实现的,在户外等实际环境中应用时存在由于表面修饰有机物的降解而逐渐失去超疏水性的问题.本工作以液态金属锡作为生长衬底,通过化学气相沉积(CVD)法制备了一种具有超疏水性能的硅基薄膜结构.利用扫描电镜(SEM),透射电镜(TEM)以及X射线衍射(XRD)等手段对产物的表面形貌和组成结构进行分析发现,薄膜表面由竖直生长的硅/二氧化硅(Si/SiO2)核壳层次结构组成.采用Cassie理论模型对其超疏水性能的产生提出了可能的解释.发现构成薄膜表面的Si/SiO2层次结构单元的形貌是影响超疏水性能的重要因素.相对于以前报道的硅基材料的超疏水表面,这种新结构的超疏水性能不依赖于表面化学修饰,有望拓宽硅基材料的应用环境.     

SDBS/HCl化学刻蚀法制备具有纳米-微米混合结构的铝基超疏水表面

采用阴离子表面活性剂十二烷基苯磺酸钠(SDBS)作为辅助刻蚀剂, 利用盐酸刻蚀, 在铝基质的表面形成了纳米-微米混合的粗糙结构; 化学刻蚀后的粗糙表面经过1H,1H,2H,2H-全氟癸烷基三乙氧基硅烷(FDTES)的修饰, 形成了接触角大于160°的超疏水表面. 扫描电镜表征结果显示, 所得到的超疏水表面具有纳米-微米混合结构; 基于此, 利用气泡辅助刻蚀机理初步解释了二级混合结构产生的原因, 认为是坑刻蚀和位错刻蚀的共同作用导致了混合结构的产生. 此外, 不同pH和长时间暴露实验证明所制备的铝基超疏水表面具有良好的稳定性.     

微纳米结构复合表面的疏水-冰性能

通过软复型和水热法制备出一种由有机材料和ZnO纳米棒组成的微纳米结构复合表面,这种表面的微米结构是周期为300μm、高度为70μm的锯齿状结构,ZnO纳米线的直径为300~500 nm,长度为2~3μm.这种有机材料和ZnO纳米线复合成的表面经过全氟硅烷修饰后,具有良好的低黏滞特性和低温超疏水性(约为150°)以及较长的结冰延时性(6000~7630 s),实验结果对设计表面低温疏水/疏冰材料具有参考价值.     

尼龙表面的超疏水及高度疏油改性

在聚合物表面引入多级粗糙结构并降低表面能可以提高其表面的疏水疏油性. 采用三种不同方法在尼龙6(聚酰胺)表面引入活性基团, 即或将尼龙6材料表面的酰胺键还原成仲胺, 或硅羟基化, 或使用低温等离子体处理得到羟基, 并通过X-射线光电子能谱(XPS)进行验证. 实验结果表明, 表面含有仲胺基团的尼龙6可静电吸附硅球; 而表面含有硅羟基及羟基的尼龙6可原位生长纳米硅层, 再经过3-氨基丙基三甲氧基硅烷(APS)处理可达到硅球吸附的目的. 经比较了不同改性方法对在尼龙6表面构建粗糙结构的影响, 我们认为等离子体处理更利于方便快捷地制备稳定均匀的粗糙结构. 当被全氟十二烷基三氯硅烷(Rf-Si)氟化修饰后, 具有粗糙结构的尼龙6表面均具有超疏水性, 但其疏油性则与表面引入的硅球尺寸密切相关, 如在500～900 nm硅球构建的粗糙表面上, 十六烷烃(3 μL)的静态接触角为140°左右, 滚动角为20°; 而在20～200 nm硅球构建的粗糙表面上, 其静态接触角和滚动角则分别为125°和40°左右. 实验结果还显示, 这类具有一定双疏性的尼龙表面也有较好的抗细菌粘附性.     

微液滴在仿蛛丝结构TiO_2纤维表面的定向运动与粘附

制备了具有响应性的仿蛛丝周期纺锤节TiO2纤维。通过改变纤维表面微观结构、紫外光照和超声波等手段,仿蛛丝结构TiO2纤维表面浸润性会发生响应性变化。纤维表面的这种浸润性变化,不仅实现了水滴从纺锤节两端到中心处的定向运动,而且可以使得水滴被纤维纺锤节粘附。当仿蛛丝结构TiO2纤维表面为亲水状态时,无论纺锤节光滑还是粗糙,水都是从纺锤节两端向中心方向运动;当仿蛛丝结构TiO2纤维表面疏水时,水滴会被具有粗糙表面的纺锤节两端粘附。     

喷砂-阳极氧化-氟化处理构筑铝合金超疏水表面

为研究复合法制备超疏水表面过程中主要工艺参数对表面形貌及超疏水性能的影响, 开发了一种喷砂-阳极氧化复合方法, 在铝合金表面构筑了微米-纳米二级结构, 经氟化处理后获得了超疏水特性. 结果表明, 喷砂处理在铝合金表面通过冲蚀的凹坑构筑出微米结构, 阳极氧化则在铝合金表面通过蜂窝状氧化膜构筑纳米结构. 但单纯构筑粗糙结构或单纯改变表面化学组成均不能在铝合金表面获得超疏水特性. 单纯的微米结构或纳米结构, 即使有低表面能聚合物修饰也不能获得超疏水特性. 只有微米-纳米二级结构和低表面能聚合物的协同作用, 才能有效构筑铝合金超疏水表面. 这种铝合金与水滴接触时, 形成的气阱可减小固体表面与水滴的接触面积, 降低表面与水滴间的热量交换, 从而减缓水分子的凝结, 提高铝合金的抗霜冻性. 同时, 气阱还可有效减缓海水的腐蚀, 提高铝合金的耐海水腐蚀性.     

研究简报聚苯乙烯接枝TiO2有机无机杂化超疏水涂层的制备

采用自由基聚合的方法,在经乙烯基三乙氧基硅烷(VTEOS)修饰的纳米TiO2表面上接枝聚苯乙烯(PS),而后制得PS-g-TiO2有机无机纳米杂化超疏水薄膜。利用场发射扫描电子显微镜和傅里叶变换红外光谱仪对PS-g-TiO2进行了形貌和结构表征,并探讨了VTEOS修饰对TiO2纳米粉体表面浸润性能的影响。测试结果表明,纳米TiO2经VTEOS改性后所制备的PS-g-TiO2薄膜和仅用硅烷偶联剂修饰的TiO2薄膜都具有良好的超疏水性能,水滴在薄膜上的最大静态接触角分别为160°和154°,滑动角分别为3°和4°。     

铝合金表面原位自组装超疏水膜层的制备及耐蚀性能

采用阳极氧化法在铝合金表面原位构造粗糙结构, 经表面自组装硅氧烷后得到超疏水自清洁表面, 与水滴的接触角最大可达157.5°±2.0°, 接触角滞后小于3°. 通过傅立叶变换红外(FT-IR)光谱分析仪、场发射扫描电子显微镜(FE-SEM)、能谱仪(EDS)、原子力显微镜(AFM)和接触角测试对阳极氧化电流密度、硅氧烷溶液中水的含量和自组装时间等参数进行了分析, 并得到制备超疏水自清洁表面的最优工艺参数. FE-SEM及AFM的测试结果表明, 由自组装硅氧烷膜层的无序性形成的纳米结构和阳极氧化构造的微米级粗糙结构与硅氧烷膜层的低表面能的协同作用构成了稳定的超疏水表面. 电化学测试(动电位极化)的结果表明, 原位自组装超疏水膜层极大地提高了铝合金的耐蚀性.     

蒙脱土/二氧化钛复合颗粒电流变液材料的制备及其性能

利用溶胶-凝胶法制备了一种新型的蒙脱土/二氧化钛(MMT/TiO_2)复合电流变 颗粒材料，FT-IR，XRD，SEM分析表明TiO_2以纳米晶的形态包覆于蒙脱土表面。电 流变性能测试表明，MMT/TiO_2复合颗粒的电流变效应比纯蒙脱土电流变液有显著 提高，当颗粒体积分数为25%，直流电场强度为3kV/mm时，TiO_2质量分数为22.7% 的MMT/TiO_2复合颗粒电流变液的静态屈服应力达8.3kPa，此值约为纯蒙脱土电流 变液的4倍。同时发现TiO_2包覆量对电流变效应有重要影响。     

Superhydrophobic Micro/Nanostructured Copper Mesh with Self-Cleaning Property for E ective Oil/Water Separation

In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39^° and oil contact angle near 0^°. Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m^-2, which could be used to separate various organic solvents/water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.     

MCM-41分子筛担载纳米TiO2复合材料光催化降解罗丹明B

采用溶胶-凝胶法将TiO2担载在介孔MCM-41分子筛上, 制备了不同TiO2含量的系列TiO2/MCM-41复合材料, 利用X射线衍射、N2吸附、紫外-可见光谱和透射电镜等方法对其进行表征. TiO2的晶型为锐钛矿相, 复合材料的比表面积和孔体积随其中TiO2担载量(复合材料中TiO2与MCM-41的质量比)的增加而减小, TiO2的平均粒径随其担载量的增加而增大. 以罗丹明B的光催化降解为探针反应, 评价了TiO2/MCM-41复合材料的光催化降解活性. 结果表明, 在紫外光照射下, 罗丹明B在该复合材料上的光催化降解反应遵循一级反应动力学, 复合材料对罗丹明B的光催化降解活性明显高于商用TiO2 (P-25), 复合材料的光催化降解活性由复合材料的吸附能力和所含TiO2的光催化活性共同决定.     

Facilely preparing various new titania electrospun fibers with controllable nanostructures using a three-step method

A facile three-step method is developed to prepare new titania fibers with various special structures using a standard electrospinning equipment. After the traditional electrospinning, a treatment process, such as storing in air and soaking in water, for electrospun composite fibers is added before the calcination. Based on a given electrospinning solution and corresponding composite fiber, the structure of titania fiber is easily adjusted to be rough surface, fiber-in-tube, or a string of many particles by controlling the treating parameters and the calcination temperature, so this method shows a great potential of producing ceramic nanofibers with controlled structures for a large-scale production using a standard electrospinning equipment. The origin behind the morphological change of titania electrospun fibers is intensely studied. The results indicate that the surface structure of titania electrospun fiber formed during the storing period, will become the key factor on the formation of special titania fiber structure during the calcination process with different temperatures.     

真空离子溅射法制备TiO2∶Au复合纳米纤维新型光催化剂及其 降解乙醛性能研究

采用静电纺丝技术与真空离子溅射相结合的方法制备了TiO2∶Au复合纳米纤维, 并采用SEM和X射线电子能谱仪对其进行了表征. 结果表明TiO2∶Au纳米纤维的表面形态能通过Au沉积时间得到很好的控制. 同时在紫外光照射下采用乙醛体系考察了TiO2纳米纤维和TiO2∶Au复合纳米纤维催化剂降解乙醛性能, 结果证明TiO2∶Au复合纳米纤维具有更好的催化效率, 紫外光照射70 min后乙醛被完全降解.     

Preparation and characterization of porous TiO_2/ZnO composite nanofibers via electrospinning

<正>Porous TiO_2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO_2/ZnCl_2/PVP[PVP:polyvinyl pyrrolidone)]nanofibers,which were electrospun from a mixture solution of TiO_2,ZnCl_2 and PVP.Transmission electron microscopy(TEM) and X-ray diffraction(XRD) analyses were used to identify the morphology of the TiO_2/ZnO nanofibers and a formation of inorganic TiO_2/ZnO fibers.The porous structure of the TiO_2/ZnO fibers was characterized by N_2 adsoption/desorption isotherm.Surface photovoltage spectroscopy(SPS) and photocatalytic activity measurements revealed advance properties of the porous TiO_2/ZnO composite nanofibers and the results were compared with pure TiO_2 nanofibers,pure ZnO nanofibers and TiO_2/ZnO nanoparticles.     

Preparation and characterization of silver/TiO2 composite hollow spheres

Silver-coated poly(methyl acrylic acid) (PSA) core-shell colloid particles were prepared by an in situ chemical reduction method. Crystalline silver/titania composite hollow spheres were obtained by coating the as-prepared PSA/silver particles with an amorphous titania layer and subsequently calcining in Ar atmosphere. SEM and TEM investigation indicated that the size of the as-prepared PSA/silver and PSA/silver/TiO(2) core-shell particles and silver/titania composite hollow particles was fairly uniform and the wall thickness of the hollow spheres was in the range of 40-80 nm. UV-vis absorption spectra were recorded to investigate their optical properties.     

Green Approach to the Fabrication of Superhydrophobic Mesh Surface for Oil/Water Separation

We report a simple and environment friendly method to fabricate superhydrophobic metallic mesh surfaces for oil/water separation. The obtained mesh surface exhibits superhydrophobicity and superoleophilicity after it was dried in an oven at 200 °C for 10 min. A rough silver layer is formed on the mesh surface after immersion, and the spontaneous adsorption of airborne carbon contaminants on the silver surface lower the surface free energy of the mesh. No low‐surface‐energy reagents and/or volatile organic solvents are used. In addition, we demonstrate that by using the mesh box, oils can be separated and collected from the surface of water repeatedly, and that high separation efficiencies of larger than 92 % are retained for various oils. Moreover, the superhydrophobic mesh also possesses excellent corrosion resistance and thermal stability. Hence, these superhydrophobic meshes might be good candidates for the practical separation of oil from the surface of water.     

Reversible superhydrophobic to superhydrophilic conversion of Ag@TiO2 composite nanofiber surfaces

A new type of superhydrophobic material consisting of a surface with supported Ag@TiO(2) core-shell nanofibers has been prepared at low temperature by plasma-enhanced chemical vapor deposition (PECVD). The fibers are formed by an inner nanocrystalline silver thread which is covered by a TiO(2) overlayer. Water contact angles depend on the width of the fibers and on their surface concentration, reaching a maximum wetting angle close to 180 degrees for a surface concentration of approximately 15 fibers microm(-2) and a thickness of 200 nm. When irradiated with UV light, these surfaces become superhydrophilic (i.e., 0 degrees contact angle). The decrease rate of the contact angle depends on both the crystalline state of the titania and on the size of the individual TiO(2) domains covering the fibers. To the best of our knowledge, this is one of the few examples existing in the literature where a superhydrophobic surface transforms reversibly into a superhydrophilic one as an effect of light irradiation.     

Multiscale characterization of antimicrobial poly(vinyl butyral)/titania nanofibrous composites

Titania nanofillers were used to reinforce nanofibers in composite mats produced by electrospinning of poly(vinyl butyral) with two different concentrations of polymers. The titania nanoparticles and titania nanotubes were added into an acetic acid/ethanol solution in different contents of 3 and 1 wt%, respectively. The effect of the processing system on the morphology of the produced fibers was analyzed. The antimicrobial poly(vinyl butyral) composite fibers with titanium dioxide nanoparticles and titanium dioxide nanotubes were produced by single and multineedle electrospinning systems. This study reports fabrication of composite nanofibrous mats with significant mechanical and antimicrobial properties at a high production speed, which is promising for commercial applications (health care, photocatalysis, protective clothing, etc.). The reported result revealed an outstanding correlation between values of elastic modulus derived from nanoindentation and dynamic mechanical techniques. Copyright © 2017 John Wiley & Sons, Ltd.