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超疏水涂膜的研究进展 总被引:5,自引:0,他引:5
超疏水涂膜以其独特的性能,在国防、工农业生产和日常生活中有着广泛的应用前景。但目前的制备技术制约了其在建筑外墙涂料等大型设施方面的应用。探索如何采用简单有效的方法构造和调控涂膜的双微观结构,从而获得性能持久优异的超疏水性涂膜,并有效应用于生产和生活的各个方面是这一领域研究的最终目标。本文就超疏水材料表面理论的发展和近几年来超疏水膜制备技术取得的新成果进行了概括,并指出制备超疏水涂膜存在的问题和发展方向。利用表面能极低的含氟材料,将溶胶-凝胶、相分离技术和自组装梯度功能等技术有机结合,获得适宜的表面粗糙度和微观构造,是实现超疏水涂膜工业化生产的可行途径。 相似文献
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物体表面的润湿性能与其表面特殊的微观几何结构和理化性能相关,是固体表面一种重要的特征,可用接触角的量化值衡量。润湿性不仅影响自然界的动植物生命活动,在人类的日常生活中的应用也十分广泛。本科普实验通过展示自然界中荷叶、水黾等生物的超疏水表面,对超疏水原理进行阐述,以帮助人们了解生活中超疏水材料的由来和发展。然后,利用溶胶-凝胶法制备超疏水材料,并进行对比实验以展示疏水效果。最后,我们将基于靛蓝胭脂红变色的“红绿灯”实验在超疏水材料上进行绘画展示,让人们亲身感受化学之美、化学之趣,并以此激发其对化学的兴趣,引发人们对材料科学的探索和思考。 相似文献
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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. 相似文献
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采用简单的激光刻蚀方法制备了具有类“菜花”状多级结构的粗糙聚二甲基硅氧烷(PDMS)膜, 并用CCD与高敏感性微电力学天平观察和测量PDMS表面对水的吸附情况. 结果表明, 该膜表面具有超疏水性, 同时对水滴具有超低的吸附力. 还对其表面特殊多级结构产生的机理进行了分析, 并探讨了在化学组成和表面结构对超疏水性以及吸附性产生的影响. 相似文献
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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 总被引:3,自引:0,他引:3
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. 相似文献
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冬瓜是一种常见的蔬菜,大部分品种成熟时表面覆盖一层类似于"白霜"的粉末。本文使用扫描电镜、接触角测量仪、傅立叶变换红外光谱、X射线衍射仪等设备对冬瓜皮表面白霜的浸润性、结构形貌及其组成进行了研究,证实了冬瓜皮表面白霜的超疏水特性,水滴在其表面的接触角高达154.8±3.5°,且滚动角小于5°。研究表明,冬瓜皮表面的白霜呈现微纳米多级拓扑结构,主要由长链脂肪酸、长链烷烃酯类组成,这种微纳米拓扑结构和化学组成的协同作用决定了冬瓜皮表面的超疏水性。本工作可为进一步了解、设计此类结构材料提供数据积累。 相似文献
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Lienqueo ME Salazar O Henriquez K Calado CR Fonseca LP Cabral JM 《Journal of chromatography. A》2007,1154(1-2):460-463
Hydrophobic interaction chromatography (HIC) is an important technique for protein purification, which exploits the separation of proteins based on hydrophobic interactions between the stationary phase ligands and hydrophobic regions on the protein surface. One way of enhancing the purification efficiency by HIC is the addition of short sequences of peptide tags to the target protein by genetic engineering, which could reduce the need for extra and expensive chromatographic steps. In the present work, a methodology for predicting retention times of cutinases tagged with hydrophobic peptides in HIC is presented. Cutinase from Fusarium solani pisi fused to tryptophan-proline (WP) tags, namely (WP)2 and (WP)4, and produced in Saccharomyces cerevisiae strains, were used as model proteins. From the simulations, the methodology based on tagged hydrophobic definition proposed by Simeonidis et al. (Phitagged), associated to a quadratic model for predicting dimensionless retention times, showed small differences (RMSE<0.022) between observed and estimated retention times. The difference between observed and calculated retention times being lower than 2.0% (RMSE<0.022) for the two tagged cutinases at three different stationary phases, except for the case of cut_(wp)2 in octyl sepharose-2 M ammonium sulphate. Therefore, we consider that the proposed strategy, based on tagged surface hydrophobicity, allows prediction of acceptable retention times of cutinases tagged with hydrophobic peptides in HIC. 相似文献
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Fernández A 《The Journal of chemical physics》2004,121(22):11501-11502
Direct inspection of high-resolution protein structures reveals that backbone dehydration promotes extra conformational freedom in the peptide bond, especially when the residue is not involved in secondary structure. The results imply a buffering effect that lowers the entropic cost of hydrophobic collapse. (c) 2004 American Institute of Physics. 相似文献
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The potential energy surface for the migration of an extra Ga atom on the GaAs(001) β2(2×4) surface was mapped out by performing calculations at the level of analytical bond-order potential. Based on this calculations, we found some lower-energy sites for the adsorption of an extra Ga atom in the surface, which were in agreement with the experimental datMoreover, many possible pathways for an extra Ga atom diffusing in this surface were revealed. According to the relative energies of the possible pathways, the individual Ga adatoms preferably keep their diffusion in two pathways parallel to the As dimers. This result can be understood using the strain caused by the diffusing Ga atom in the pathways. In addition, the simulated kinetic processes of the extra Ga atom diffusing in different pathways at finite temperatures support the prediction from our calculated potential energy surface. 相似文献
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The effect of surface hydrophobicity distribution of proteins on retention in hydrophobic interaction chromatography (HIC) was investigated. Average surface hydrophobicity as well as hydrophobic contact area between protein and matrix were estimated using a classical thermodynamic model. The applicability of the model to predict protein retention in HIC was investigated on ribonucleases with similar average surface hydrophobicity but different surface hydrophobicity distribution. It was shown experimentally that surface hydrophobicity distribution could have an important effect on protein retention in HIC. The parameter "hydrophobic contact area," which comes from the thermodynamic model, was able to represent well the protein retention in HIC with salt gradient elution. Location and size of the hydrophobic patches can therefore have an important effect on protein retention in HIC, and the hydrophobic contact area adequately describes this. 相似文献
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Pal S Weiss H Keller H Müller-Plathe F 《Langmuir : the ACS journal of surfaces and colloids》2005,21(8):3699-3709
The local structure of water near hydrophobic surfaces of different surface topographies has been analyzed by molecular dynamics simulation. An alkane crystal has been taken as the parent model for a hydrophobic surface. Surface structures were created by placing pits into it, which were half a nanometer deep and several nanometers wide. Around all structures, the water has a lower density, less orientational ordering, fewer water-water hydrogen bonds, and fewer surface contacts than for a flat unstructured surface. This indicates that the structured surfaces are more hydrophobic than the flat surface. Of the structures investigated, pits with a diameter of approximately 2.5 nm were effective in increasing the hydrophobic character of the surface. 相似文献
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丙烯酰胺-苯乙烯双亲嵌段共聚物的微结构及水溶液行为 总被引:3,自引:0,他引:3
通过改变丙烯酰胺(AM)与苯乙烯(St)的投料比、苯乙烯与表面活性剂的加入量之比及引发剂加入量,在微乳液中制备了分子链微结构系列变化的丙烯酰胺-苯乙烯双亲嵌段共聚物(PAM-b-PSt),用荧光探针法与表面活性测定法详细地研究了共聚物中PSt嵌段长度、含量及分子量等微结构因素对共聚物在水溶液中的疏水缔合性与表面活性的影响.结果表明,当共聚物水溶液的浓度高于临界缔合浓度时,PAM-b-PSt的疏水缔合作用以分子间的缔合为主.若共聚物中PSt嵌段含量及分子链长一定时,随着PSt疏水嵌段长度增长,PAM-b-PSt的疏水缔合性增强,而对共聚物的表面活性影响很小.若共聚物中PSt疏水嵌段长度及分子链长一定时,PAM-b-PSt的疏水缔合性随着PSt嵌段含量的变化而变化,当PSt嵌段含量一定时,使大分子链之间产生最强的疏水缔合作用;而其表面活性则随着PSt嵌段含量的增大而增强.若共聚物中PSt疏水嵌段长度及含量一定时,分子量对其表面活性有较大的影响,分子量越高,表面活性越差;同时,在较稀的溶液浓度范围内,分子量对PAM-b-PSt的疏水缔合性的影响则很小. 相似文献
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L Qi J Fresnais P Muller O Theodoly JF Berret JP Chapel 《Langmuir : the ACS journal of surfaces and colloids》2012,28(31):11448-11456
In a recent publication, we have highlighted the potential of phosphonic acid terminated PEG oligomers to functionalize strong UV absorption cerium oxide nanoparticles, (1) which yield suspensions that are stable in aqueous or organic solvents and are redispersible in different solvents after freeze-drying. In the present work, we highlight the interfacial activity of the functional ceria nanoparticles and their potential to modify hydrophobic surfaces. We first investigated the phosphonated-PEG amphiphilic oligomers behavior as strong surface active species forming irreversibly adsorbed layers. We then show that the oligomers interfacial properties translate to the functional nanoparticles. In particular, the addition of a small fraction of phosphonated-PEG oligomers with an extra C16 aliphatic chain (stickers) into the formulation enabled the tuning of (i) the nanoparticles adsorption at the air/water, polystyrene/water, oil/water interfaces and (ii) the particle/particle interaction in aqueous solutions. We also found that dense and closely packed two-dimensional monolayers of nanoceria can be formed by spontaneous adsorption or surface compression using a Langmuir trough. A hexagonal organization controlled by reversible and repulsive interaction has been characterized by GISAXS. Mono- or multilayers can also be stably formed or transferred on solid surfaces. Our results are key features in the field of polymer surface modification, solid-stabilized emulsions (Pickering), or supracolloidal assemblies. 相似文献
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Striolo A 《The Journal of chemical physics》2006,125(9):094709
The adsorption of polymers, copolymers, surfactants, and biopolymers is often used to engineer surfaces. Towards improving our understanding of polymer adsorption we report simulation results for the adsorption of model copolymers, resembling surfactants, on nanoscale patterned hydrophobic surfaces at infinitely dilute concentrations. The surfactants are composed by a hydrophobic tail and a hydrophilic head. Surfactant adsorption on the hydrophobic surface occurs in the tail-down configuration in which the tail segments are in contact with the surface. We investigate how the presence of a solid hard mask, used to create the nanoscale pattern on the underlying hydrophobic surface, affects the surfactant adsorption. We find that surfactant adsorption on the underlying hydrophobic surface is prevented when the characteristic dimensions of the solid hard mask are less than twice the radius of gyration. We also show that details about mask-surfactant head effective interactions have the potential to alter the characteristics of adsorption. When the mask repels the head segments, the surfactants hardly adsorb on the underlying hydrophobic surface. When the mask strongly attracts the surfactant heads, the surfactants may preferentially adsorb on the mask rather than on the underlying hydrophobic surface. Under these latter circumstances the adsorbed surfactants in some cases assume a head-down configuration in which the head segments are in contact with the mask and the tail segments extend towards the bulk solution. We explain our results in terms of enthalpy and entropy of adsorption and discuss practical implications. 相似文献
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Hedin J Löfroth JE Nydén M 《Langmuir : the ACS journal of surfaces and colloids》2007,23(11):6148-6155
The adsorption behavior of ethyl(hydroxyethyl) cellulose EHEC and hydrophobically modified EHEC (HM-EHEC) at hydrophilic and hydrophobic surfaces has been studied using surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation monitoring (QCM-D) methods. The adsorbed amounts measured with the different methods were different due to large amounts of water in the films. The slow adsorption process made it reasonable to assume a continuous polymer reconfiguration process at the surface. This was mostly seen for HM-EHEC at the hydrophobic surface, where a more flexible structure was adopted during the adsorption process. A cross-linking agent was seen to truly interpolymer cross-link EHEC at the hydrophilic surface and HM-EHEC at the hydrophobic surface. For EHEC at a hydrophobic surface and for HM-EHEC at a hydrophilic surface, the polymers adsorbed in an individually phase-separated manner, making an interpolymer cross-linking reaction unsuccessful. 相似文献
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Results of colloid chemical characterisation and stability measurements on electrostatically stabilised latex dispersions
made from emulsions of styrene and 4,4′-azobis-(4-cyanovaleric acid) are reported. The deviant stability of the hydrophobic
polystyrene particles at low pH and low ionic strength is related to a proton “tunable” hydration layer surrounding weakly
charged particles. The idea implies the formation of a polymer-supported surface phase that does not have any clear boundary,
either towards the polymer moiety or in the direction of the bulk solution. The formation of the surface phase is controlled
by Coulombic, hydrophobic and van der Waals interactions and by the contribution from the water structure at the hydrophobic
and hydrophilic domain of the polymer particles. Negative charges on the hydrophobic surface badly interfere with the water
structure at the hydrophobic moiety of the particle, whereas positive or uncharged surface groups do not damage the balance
of free and clustered water molecules at the interface. Because the hydrophobic nature of the surface changes with the degree
of dissociation of the surface charges, the degree of hydrophobicity of the carboxylic latices can be adjusted by changing
the pH; therefore, it may be concluded that the hydrated and discharged carboxylic particle is apparently more hydrophobic
relative to the ionised one. Thus, our concept can also explain differences in the hydrophobicity of colloidal polymer particles.
Received: 12 June 1999/Accepted in revised form: 24 September 1999 相似文献