溶胶凝胶法制备超疏水二氧化硅涂膜及其表面润湿行为

采用溶胶-凝胶法以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES)为前驱体制备超疏水SiO2涂层。红外光谱(FTIR)和热重分析(TGA)表征合成SiO2的化学组成,通过透射电镜(TEM)和扫描电镜(TEM)观察制备SiO2的结构形貌,扫描电镜(SEM)和原子力显微镜(AFM)观察SiO2涂膜的表面形貌,通过测试水接触角(WCA)讨论SiO2涂层的表面微观结构与其表面疏水性能的关系。结果表明以TEOS和MTES为共前驱体可以制备得到表面带-CH3基团的SiO2溶胶,SiO2溶胶在老化过程中纳米SiO2粒子由于自组装作用形成草莓状微米-纳米双微观结构,这种结构赋予SiO2涂膜表面不同等级的粗糙度,使得水滴与涂膜表面接触时能够形成高的空气捕捉率和较小的粗糙度因子,与SiO2表面疏水性的-CH3基团共同作用形成类荷叶超疏水结构。     

WC/CNT纳米复合材料制备及其对甲醇氧化的电催化性能

采用表面修饰技术将碳纳米管(CNT)表面羧基化, 通过羧基将钨离子基团修饰到碳纳米管的外表面, 再通过原位还原碳化技术, 将钨离子基团还原成碳化钨(WC)纳米微粒, 制备出WC/CNT纳米复合材料. 采用FTIR、XRD、SEM、HRTEM和N2吸附等分析测试手段对样品的形貌、晶相组成和微观结构特征进行了表征. FTIR和N2吸附结果表明, 硝化后, 在碳纳米管表面羧基化的同时比表面积增加; XRD结果表明, WC/CNT样品由碳纳米管、WC以及非化学计量比的氧化钨组成; SEM和HRTEM结果表明, WC纳米颗粒均匀地分散于碳纳米管的外表面,并与碳纳米管构成了复合材料. 采用循环伏安法测试了样品在碱性条件下对甲醇氧化的电催化性能, 结果表明, 复合材料对甲醇氧化的电催性能明显强于WC 和碳纳米管, 并在实验结果的基础上探讨了复合材料催化性能提高的原因.     

碳纤维微观结构表征方法

碳纤维作为高性能纤维的一种,是先进复合材料最重要的增强材料,碳纤维的微观结构是决定其性能的主要因素。综述了碳纤维微观结构的表征方法,主要包括表面形貌、形态结构、化学结构、晶态结构和孔结构。碳纤维表面形貌表征主要通过扫描电镜(SEM)和原子力显微镜(AFM);形态结构主要采用透射电镜(TEM)来表征;化学结构表征主要依靠拉曼光谱(Raman)和X射线光电子能谱(XPS);晶态结构和孔结构分别采用广角X射线衍射(WXRD)和小角X射线散射(SAXS)来分析,这为研究分析如何得到高性能碳纤维提供了参考。     

玫瑰花花瓣微观结构与水滴黏附性质的关系

利用环境扫描电镜(ESEM)分别观察了新鲜、枯萎的玫瑰花花瓣正、反两面的微观形貌,并通过测量样品的表观接触角表征了其浸润性,采用高敏感性微电力学天平测试了样品表面的粘附力,分析了玫瑰花花瓣微观结构与水滴粘附性质的关系.实验结果表明,微米结构主要影响玫瑰花花瓣的超疏水性,而纳米结构则是导致玫瑰花花瓣具有高粘附力的关键原因.     

含氟硅丙烯酸酯乳液超疏水膜中疏水基团的梯度分布与表面微观结构研究

利用含氟疏水基团的梯度分布,结合草莓形纳米SiO2粒子提供的双重粗糙表面,制备了具有类"荷叶效应"的超疏水涂膜,水接触角达(174.2±2)°,滞后角几乎接近0°.通过原子力显微镜、扫描电镜和水接触角的测试对膜表面形貌及疏水性能进行了表征;探讨了其表面微观结构与表面疏水性能的关系.草莓形复合粒子在膜表面的无规则排列赋予涂膜表面不同等级的粗糙度,使水滴与涂膜表面接触时能够形成高的空气捕捉率,这种微观结构与疏水基团的梯度分布相结合,赋予了含氟硅丙烯酸酯乳液涂膜表面超疏水性能.     

层间距为1.44 nm层状氢氧化苯甲酸锌剥离重组行为研究

层间距为1.44 nm层状氢氧化苯甲酸锌在乙醇、正丙醇、正丁醇介质中可剥离成其基本组成单元纳米层. 用TG-DTA、XRD、SEM、TEM和元素分析等手段研究了剥离的纳米层重组得到样品的结构特征、形貌和化学组成. 结果表明: 水热合成样品和剥离的纳米层重组样品具有相同的层状结构, 它们的化学组成分别为Zn(OH)1.12(C6H5COO)0.88和Zn(OH)1.1(C6H5COO)0.9. 水热合成的纤维状粒子剥离重组后改变成为像纳米带和纳米花粒子形貌.     

碳化钨/碳化二钨核壳结构纳米复合材料的制备及电化学性能

以偏钨酸铵为钨源, 铁黄(FeOOH)为载体, 将表面包覆法与原位还原碳化技术相结合, 制备出了具有核壳结构的碳化钨(WC)/碳化二钨(W₂C)纳米复合材料; 应用X射线衍射(XRD)分析、透射电子显微镜(TEM)和X射线能量散射谱(EDS)等手段对不同阶段样品的晶相、形貌、微结构和化学组成等特征进行了表征. 结果表明, 负载体经煅烧后, 载体及包裹层的物相均发生了变化, 形貌也相应地发生了改变; 经盐酸处理及还原碳化后, 样品由WC和W₂C纳米颗粒构成, 并构成了以W₂C为壳, 以WC为核的典型核壳结构; 结合表征结果对核壳结构的形成机理进行了探讨. 采用三电极体系循环伏安法测试了样品在酸性、中性和碱性溶液中对甲醇的电催化氧化活性. 结果表明, 与颗粒状碳化钨和介孔空心球状碳化钨相比, 样品的电催化活性有了明显的提高. 这说明W₂C与WC构成核壳结构纳米复合材料后, 其电化学性能有了明显的提升, 核壳结构纳米复合材料是提高碳化钨催化材料活性的有效途径之一.     

化学气相沉积法制备氧化锡自组装纳米结构

采用化学气相沉积法在镀有5-10 nm厚金膜的SiO2衬底上, 通过控制生长条件, 实现了二氧化锡纳米结构的自组装生长, 成功制备出了莲花状和菊花状的二氧化锡自组装纳米结构. 利用扫描电子显微镜、X射线衍射等表征分析手段对样品的表面形貌、结构及成份进行表征和研究. 并在此基础上, 讨论了两种自组装纳米结构的生长机制.     

不同制备方法对氧化铈结构及甲苯催化燃烧性能的影响

采用溶胶-凝胶-超临界干燥法、水热法及共沉淀法分别合成了氧化铈气凝胶(CeO2-A)、纳米棒(CeO2-R)和纳米片(CeO2-F).考察了不同形貌氧化铈的催化燃烧甲苯性能,通过多种方法分析表征了氧化铈样品的微观结构,讨论了不同方法制得的CeO2形貌结构对催化性能的影响.结果表明,CeO2-R和CeO2-F比表面积较低...     

α-Co(OH)_2的制备及其超级电容特性

以氯化钴为原料,聚乙烯吡咯烷酮(PVP)为分散剂,采用化学沉淀的方法制备出由纳米粒子组成的片状α-Co(OH)2.用红外光谱对所制样品的组分进行分析,用X射线衍射和场发射扫描电子显微镜表征产物的结构和形貌,用循环伏安和恒电流充放电等测试方法对其电化学性能进行研究.研究结果表明,由纳米粒子组成的片状α-Co(OH)2表现出优良的电化学性能,单电极比电容高达1220 F/g.     

The effect of plasma treatment on structure and properties of poly(1-butene) surface

This paper is focused on the chemical and morphology changes in the surface of poly(1-butene) (PB-1) generated by plasma treatment. The radio frequency capacitively coupled plasma (air, argon, argon then allylamine, argon containing ammonia and argon with octafluorocyclobutane) was used. Modified surface of PB-1 was characterized by contact angle measurements, X-ray photoelectron spectroscopy, and atomic force microscopy. The surface hydrophilization by air and argon with ammonia plasmas was evaluated as most sufficient. Oppositely, a high level of hydrophobicity of PB-1 surface was reached by combination of argon with octafluorocyclobutane plasma. Upon plasma modification, hydrophilicity/hydrophobicity of treated surfaces remained stable within three days under air atmosphere and then values of contact angle slowly recovered to those of unmodified PB-1. However, morphology and surface chemical composition of plasma-modified samples remained generally unchanged during observed time. Changes in surface hydrophilicity/hydrophobicity of plasma-treated PB-1 were attributed to variance of conformation of the surface molecules.     

Protein adsorption and cell adhesion on polyurethane/Pluronic® surface with lotus leaf-like topography

Lotus leaf-like polyurethane/Pluronic^® F-127 surface was fabricated via replica molding using a natural lotus leaf as the template. Water contact angle measurements showed that both the hydrophobicity of the unmodified polyurethane (PU) surface and the hydrophilicity of the PU/Pluronic^® surface were enhanced by the construction of lotus leaf-like topography. Protein adsorption on the PU/Pluronic^® surface without topographic modification was significantly lower than on the PU surface. Adsorption was further reduced when lotus leaf-like topography was constructed on the PU/Pluronic^® surface. Cell culture experiments with L929 cells showed that adhesion on the PU/Pluronic^® surface with lotus leaf-like topography was low and adherent cells were spherical and of low viability. The PU/Pluronic^® surface with lotus leaf-like topography thus appears to be resistant to nonspecific protein adsorption and to cell adhesion, and these effects derive from the both chemical composition and topography. The results suggest a new strategy based on surface topography for the design of antifouling materials.     

人造玫瑰花花瓣的微结构分布与水滴黏附性质的关系

本文采用模板印刷法制备得到了“人造玫瑰花花瓣”,即具有玫瑰花花瓣结构的PDMS薄膜,通过对该薄膜逐级拉伸改变微观结构的分布;采用环境扫描电镜（ESEM）观察了不同拉伸程度下薄膜表面微观结构的变化,采用高敏感性微电力学天平测试了样品表面微观结构变化过程中水滴的粘附力,分析了微观结构分布与水滴粘附性质的关系;采用接触角测量仪表征不同拉伸条件下薄膜的浸润性.实验结果表明随着PDMS薄膜被逐次拉伸,单位面积内玫瑰花花瓣乳突的数目减少,纳米褶皱面积不断增加,而纳米级褶皱结构尺寸随着拉伸基本上不发生变化,直到样品破坏;与微观结构变化相对应的,该表面对水滴的粘附力先增大后减小,直到该表面彻底破坏.由此可见,微米结构及纳米结构的分布是影响玫瑰花花瓣对水滴粘附的主要因素.     

Fabrication of superhydrophobic sponge with hierarchical structure and application for oil/water separation

Oil/water separation polyurethane sponge with hierarchically structured surface similar to the chemical/topological structures of lotus leaf has been successfully developed by combining mussel-inspired one-step copolymerization approach. The chemical structure, surface topography, and surface wettability of the sponge were characterized by FTIR, SEM, and contact angle experiments, respectively. The results showed that as-prepared sponge exhibited high oil absorption rate because of the expansion in oil and collapse in water of the polymer molecular brushes. Meanwhile, it also possessed high absorption capacity (20 times of the self-weight), high oil retention (93.7%), and good recyclability. It had excellent potential in practical applications.     

ZnO/PS core-shell hybrid microspheres prepared with miniemulsion polymerization

The hybrid microspheres of ZnO/PS with different core-shell structures were prepared in miniemulsion polymerization. 3-(trimethoxysilyl)propyl methacrylate (MPS) was used as a functional co-monomer to enhance the surface polarity of ZnO nanoparticles and to prevent water from quenching the luminescent properties of ZnO. The morphology of hybrid particles was examined with a transmission electron microscope. The luminescence spectra were measured using a Shimadzu RF-5301 PC spectrofluorimeter (Xe source) at room temperature. The crystallization structure of samples was characterized with a Rigaku wide-angle X-ray diffractometer. The chemical composition and structure of the ZnO colloids, MPS-modified ZnO colloids, and ZnO/PS hybrid microspheres were analyzed with IR.     

Development and characterization of poly ethyl metha acrylate–iron oxide(III) based hydrophobic liquid nanocomposite films

Select applications of hydrophobic nanocomposites include preparation of robust self-cleaning surfaces, water-repellent glass surfaces, and waterproofing textiles. Various nanocomposites have been reported in the literature; however, the relationship between the nanocomposite surface morphology and its hydrophobicity needs to be understood better. In the present work Fe₂O₃ nanoparticles and poly ethyl metha acrylate (PEMA) were used in varying proportions to obtain a series of model hydrophobic surfaces (spin-coated on glass substrate). The hydrophobicity of these surfaces was measured by static contact angle; a maximum of 103° was obtained at highest loading of iron oxide nanoparticles. These surfaces were also characterized using AFM. The contact angle and characterization data were used to test some of the models which have been proposed in the recent literature on prediction of contact angle for composite surfaces. It is proposed that the hydrophobicity of the iron oxide–PEMA surface is due to the physical roughness causing air entrapment as well as the chemical heterogeneity. Based on the experimental studies and the simulations using the recent models on contact angle, some general features of relationship between a composite surface morphology and its hydrophobicity is proposed.     

类荷叶结构聚全氟乙丙烯的超疏水性

以聚二甲基硅氧烷（PDMS）复制的荷叶表面微结构为阴模模板,将聚全氟乙丙烯（FEP）粉体置于该阴模模板上,在约0.3 N/cm2的压力,280 ℃和-0.1 Mpa真空度的条件下热压成型,成功制备了具有类荷叶结构的FEP表面。扫描电镜观察结果表明, FEP表面与荷叶表面微结构具有很大的相似性,该表面具有良好的超疏水性,与水的接触角达到168°,滚动角小于3°,而且具有良好的疏酸、疏碱、疏盐溶液性能和稳定性,即使在溶液中长期浸泡而失活后,经piranha洗液处理约10 min,其表面超疏水、疏酸、疏碱性能也可迅速恢复。PDMS的热重分析结果表明,PDMS阴模在热压条件下失重极小,可重复使用。因此,将FEP的耐酸、耐碱、耐腐蚀和低表面能的特性与荷叶表面的特殊结构有机结合,在制备抗粘附、自清洁容器等方面具有广泛的应用前景。     

Development of Bionic Polymers

Bionics, an artificial imitation of natural products, has always been a forever dream in the fairy tale or scientific fiction when we were childhood and children live now. However, the development of science in molecular scale makes this dream of childhood and manhood realize today.Bionics, a branch of science concerned with application the data about the functioning of biological system to the solution of engineering problems, become top-priority of science in the 21st century.However, few examples are given in molecular-level or nano-scale controlling lotus-like surface (a bionic surface for vast potential application). In the same time, such a typical bionic surface (as well known, so called "Lotus-effect") is a symbol or a totem that scientists can develop a novel approach to prepare desired surface and to control its microstructure or morphology at one's pleasure.In general, a film with a water contact angle (CA) higher than 150° can be defined as a superhydrophobic surface. The Langmuir-Blodgett film prepared by using CF3(CF2)10COOH possesses the lowest surface tension, which is 6 mJ/m2 (1). However, the water CA on a smooth surface with regularly aligned C20F42 with close-hexagonal packed -CF3 groups is only 119° (2).Obviously, only adjusting chemical composition is not enough to produce a superhydrophobic surface. Wenzel et al (3) suggested that the contact angle θ' of a liquid droplet on a rough solid surface should be written as:cosθ, =γcosθ = γ(γs-γsl)/γl, here γ is a roughness factor and γsl, γs and γl denote the interfacial tensions of the solid-liquid, the solid-gas, and the liquid-gas interfaces,respectively. This γ is always larger than 1 and a rough surface will be more water-repellent or more wettable to a liquid when intrinsic contact angle θ is bigger or smaller than 90°, respectively.Therefore, a general approach to obtain superhydrophobic surfaces is using a combination of depressing surface energy and enhancing surface roughness (4-17).Super-hydrophobic polymeric surface has been prepared in this case with a mixture of low-cost fluorine-end-capped polyurethane(FPU) and commonly available polymethyarylates(PMA) under ambient conditions. No obvious structures were observed by SEM for the pure FPU coated surface.The surface morphology is uniformly smooth at both low and high magnifications. The CA on the surface is about 95°, which indicates that FPU film has better hydrophobicity than pure polyurethane without fluorine-group, whose CA is about 65°. However, the hydrophobicity of polymer surface changes dramatically as the film is directly prepared through a one-step coating of a FPU/PMA solution between 10-30℃. The CA is up to 166 . The result shows that the SA can be dramatically decreased with small amount of FPU, and the SA reached a limiting value of 3.4 ± 2.0 ° when the FPU content in the FPU/PMA mixture is between 20 ～ 60 wt%. The water drop is unstable on these surfaces, and with a very small tilt-angle, the water drop will roll off the surface.It means that such a polymeric surface exhibits an excellent superhydrophobicity. In addition, the polymer surface possesses not only a better hydrophobicity than that of natural lotus leaf (CA measured is about 160°), but also a lypophobic property: the oil contact angle on the same surface is 140°, while the surface of lotus is lypophilic. Most interestingly, we have found that the coated film prepared by FPU/PMA mixture has a two-length scaled rough micro-nano-binary structure, that is, every micro-papilla (300-700nm) on the polymeric surface is also covered by nano-papillae ranging from 30-40nm. These MNBs is very much the same as the natural lotus-leaf surface in micro- and nano-scales. Compared with lotus surface structure, the NMBs structure on this bionic polymeric surface prepared is in less scale. The results clearly demonstrated that a bionic polymeric surface similar to the natural lotus-leaf surface can be obtained by a one-step coating process. The results showed also that such a bionic polymeric surface possess of some "self-repairing" properties similar to that of natural surfaces and the effects of preparation temperature and concentration as well as substrate made no obvious difference on the hydrophobicity of the bionic polymeric surfaces..In conclusion, we demonstrated that the MNBs of a bionic polymeric film has been one-step obtained with the use of the self-aggregation of PMA combining with a nano-scaled phase separation of amphiphilic copolymer during the drying process in ambient atmosphere. This remarkable result provides many potential possibilities, including coating, hygienic, medical,environmental, and industrial processing applications.     

Calcium Carbonate@silica Composite with Superhydrophobic Properties

In this paper, spherical calcium carbonate particles were prepared by using CaCl₂ aqueous solution + NH₃·H₂O + polyoxyethylene octyl phenol ether-10 (OP-10) + n-butyl alcohol + cyclohexane inverse micro emulsion system. Then, nanoscale spherical silica was deposited on the surface of micron calcium carbonate by Stöber method to form the composite material. Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and structure of the composite material. It is found that the surface of the composite material has a micro-nano complex structure similar to the surface of a “lotus leaf”, making the composite material show hydrophobicity. The contact angle of the cubic calcium carbonate, spherical calcium carbonate and CaCO₃@SiO₂ composite material were measured. They were 51.6°, 73.5°, and 76.8°, respectively. After modification with stearic acid, the contact angle of cubic and spherical CaCO₃ were 127.1° and 136.1°, respectively, while the contact angle of CaCO₃@SiO₂ composite was 151.3°. These results showed that CaCO₃@SiO₂ composite had good superhydrophobicity, and the influence of material roughness on its hydrophobicity was investigated using the Cassie model theory.