一种多尺度仿生超疏水表面制备

A multi-dimension bionic super-hydrophobic surface was prepared by embedding nano-silicaon on the sandblasted aluminum surface. After surface modification by perfluoroalkyltriethoxysilame, the surface shows the similar capability and structure of lotus leaves. the super-hydrophobic surface shows static contact angle as high as 173° and tilt angle as low as 2.5° for 6.5 μL water droplet.     

SURFACE REARRANGEMENTS OF OXYGEN PLASMA TREATED POLYSTYRENE： SURFACE DYNAMICS AND HUMIDITY EFFECT

The time evolution of oxygen plasma treated polystyrene(PS)surfaces was investigated upon storing them in theair under controlled humidity conditions.The methods of water contact angle,X-ray photoelectron spectroscopy(XPS),sumfrequency generation(SFG)vibrational spectroscopy,and atomic force microscopy(AFM)were used to infer the surfaceproperties and structure.Chemical groups containing oxygen were formed on the PS surface with the plasma treatment,demonstrated by water contact angle and XPS.The surface polarity decayed markedly on time,as assessed by steady increasein the water contact angle as a function of storage time,from zero to around 60°.The observed decay is interpreted as arisingfrom surface rearrangement processes to burying polar groups away from the uppermost layer of the surfaces,which is incontact with air.On the other hand,XPS results show that the chemical composition in the first 3 nm surface layer isunaffected by the surface aging,and the depth profile of oxygen is essentially the same with time.A possible change of PSsurface roughness was examined by AFM,and it showed that the increase of water contact angle during surface aging couldnot be attributed to surface roughness.Thus,it is concluded that surface aging is attributable to surface reorganization andthe motion of oxygen containing groups is confined within the XPS probing depth.SFG spectroscopy,which is intrinsicallyinterface-specific,was used to detect the chemical structure of PS surface at the molecular level after various aging times.The results are interpreted as follows.During the aging of the plasma treated PS surfaces,the oxygen containing groupsundergo reorientation processes toward the polymer bulk and/or parallel to the surface,while the CH_2 moiety stands up onthe PS surface.Our results indicate that the surface configuration changes do not require large length scale segmentalmotions or migration of macromolecules.Motions that are responsible for surface configuration changes could be relativelysmall rotational motions.The aging behaviors under different relative humidity conditions were shown to be similar from18% to 91%,whereas the kinetics of surface polarity decays were faster in higher relative humidity.Here,the surfacerearrangement of polystyrene films that were previously treated by oxygen plasma and aged,and was investigated in terms ofcontact angle after the water immersion.The contact angles of the water-immersed samples were found to change andapproach the initial values before the immersion asymptotically.     

Reason for the loss of hydrophilicity of TiO_2 film and its photocatalytic regeneration

TiO2 film was prepared on soda-lime glass by sol-gel method. The water contact angle (θ) of the fresh TiO2 film is 0°. During storage in air, the surface of TiO2 film is gradually converted to the hydrophobic state. XPS and ITD results reveal that it is due to the adsorption of organic contaminants on TiO2 surface in air ambience. The lost hydrophilicity of TiO2 film can be regenerated by UV illumination.     

具有米状纳微阶层结构的仿生超疏水十二硫醇铅表面的简单制备

A superhydrophobic surface of lead dodecanethiolate with the water contact angle(CA) of 152.2°±1.2° and the sliding angle(SA) of 3.8°±1.0° was fabricated using a simple and relative inexpensive route based on our previous reported method. The procedure employed a one-pot reaction between lead salt and alkanethiolate to form a thermal stable superhydrophobic coating under mild conditions. SEM images revealed the lead dodecanethiolate surface morphology with packed aggregate “rice-like” particles of micrometer scale in length and nanometer scale in thickness. Also, Lead dodecanethiolate powder was investigated by TGA and XRD.     

Characterization and tribological investigation of self-assembled trimethoxysilyl-functionalized poly(phthalazinone ether ketone)thin films on glass substrates

<正>Trimethoxysilyl-functionalized PPEK(PKGS) films had been designed to serve as wear resistant coatings for silicon surfaces. These surface films were formed by a dip-coating technique applied to self-assembled monolayers(SAMs).The formation and wetting behavior of PKGS films were characterized by means of contact angle measurement.The friction coefficient of the film prepared is very low(about 0.1),and the anti-wear behavior is good,with a lack of failure after sliding over 1800 s.     

Removal of Cd（ Ⅱ ） from Aqueous Solutions by Natural Freshwater Surface Coatings

Natural freshwater surface coatings (biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434. 78μmol Cd/m^2 (being equal to 0. 17mmol Cd/g of surface coatings or 10. 38mmol Cd/g Fe) and the Cd(Ⅱ) remnoval from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0. 1mg/L (the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd (Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150min in solution under the controlied laboratory conditions (mineral salts solution with defined speciation, ionic strength 0. 05mol/L, and 25℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd(Ⅱ) from polluted water.     

Removal of Cd(Ⅱ) from Aqueous Solutions by Natural Freshwater Surface Coatings

Natural freshwater surface coatings(biofilms and associated minerals), which were developed in the Nanhu Lake, Changchun, P. R. China, were used as an efficient biosorbent for the removal of Cd(Ⅱ) from aqueous solutions. The batch experiments were carried out to determine the adsorption properties of Cd(Ⅱ) onto the natural surface coatings. The classical Langmuir adsorption isotherm was applied to estimating the equilibrium coefficients of Cd(Ⅱ) adsorbed on the surface coatings. The results show that the maximum adsorption capacity of the surface coatings is 434.78 μmol Cd/m2(being equal to 0.17 mmol Cd/g of surface coatings or 10.38 mmol Cd/g Fe) and the Cd(Ⅱ) removal from solution media by the natural surface coatings was shown to be strongly affected by solution pH and ion strength. The resulted information also indicates that the maximum Cd removal efficiency(CRE) was determined to be approximately 90% at initial Cd mass concentration of 0.1 mg/L(the concentration limit of Cd (Ⅱ) in wastewaters for discharge in aquatic media in Chinese legislation), and the kinetic adsorption of Cd(Ⅱ) onto the surface coatings is fast with around 70% of the total adsorption-taking place in 150 min in solution under the controlled laboratory conditions (mineral salts solution with defined speciation, ionic strength 0.05 mol/L, and 25 ℃). With the advantage of high Cd adsorption capacity, the natural surface coatings appear to be a potentially effective biosorbent for the removal and recovery of Cd (Ⅱ) from polluted water.     

Influence of Pretreatment on the Interaction of Oxygen with Silver and the Catalytic Activity of Ag／SiO2 Catalysts for CO Selective Oxidation in H2

The interactions of oxygen with pre~reduced silver catalysts as well as their catalytic propertiesfor CO selective oxidation in H2 after oxygen pre-treatment are studied in this paper. It is found that the pretreatment exerts a strong influence on the activity and selectivity of the silver catalyst. A drop in activity and selectivity is observed after treating a pre-reduced catalyst with oxygen at low temperatures,whereas a converse result is obtained after an oxidizing treatment at high temperatures (T≥350℃). O2-TPD results show that surface oxygen species adsorbs on silver surface after the oxygen treatment at low temperatures. However, penetration of oxygen into the silver is enhanced by a high temperature treatment, meanwhile the surface oxygen species disappear. No other silver species except metallic silver are observed on all the catalysts by XRD, and the size of silver particle is not changed after the treatment with oxygen at low temperatures. The surface oxygen species formed by oxygen treatment can also be removed by hydrogen reduction. The strongly-adsorbed surface oxygen species prohibit the adsorption and diffusion of oxygen species in reaction gas on the surface of silver catalyst, causing the decrease in CO oxidation activity, in other words, it is important to obtain a clean silver surface for increasing the catalyst activity in CO removal from H2-rich feed gas. The differences in activity and selectivity due to the oxygen pretreatment at different temperatures axe discussed in terms of the changes in the surface/subsurface oxygen species of the silver particles.     

Structures and antifouling properties of low surface energy non-toxic antifouling coatings modified by nano-SiO_2 powder

Antifouling coatings are used to improve the speed and energy efficiency of ships by preventing or- ganisms, such as barnacles and weed, building up on the underwater hull and helping the ships movement through the water. Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating bio- fouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. The low surface energy marine coating is an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. In this paper, the novel low surface energy non-toxic marine antifouling coatings were prepared with modified acrylic resin, nano-SiO2, and other pigments. The effects of nano-SiO2 on the surface structure and elastic modulus of coating films have been studied, and the seawater test has been carried out in the Dalian Bay. The results showed that micro-nano layered structures on the coating films and the lowest surface energy and elastic modulus could be obtained when an appropriate mass ratio of resin, nano-SiO2, and other pigments in coatings approached. The seawater exposure test has shown that the lower the sur- face energy and elastic modulus of coatings are, the less the marine biofouling adheres on the coating films.     

Kinetics of wetting of liquid on a solid surface

To consider a sessile drop on an ideal solid surface in equilibrium with a vapor phase, the classic Young equation was given. The derivation of the Young equation was based on both the mechanics and the energy knowledge. According to the constant volume of the liquid in the wetting process of the liquid on a smooth and homogeneous solid surface and the low energy law, Young equation was ob-tained through the mathematic method in this paper. The previous work indicated that the contact angle θ was a function...     

Synthesis and characterization of novel polyimides containing stilbene unit in the side chain and their controllability of nematic liquid crystal alignment on the rubbed surfaces

Four polyimides containing hexylene spacer and a fluorostilbene unit in the side chains were prepared in thin‐film form by two‐step condensation of 3,3′‐bis[(4′‐fluoro‐4‐stilbenyl)oxyhexyloxy]‐4,4′‐biphenyldiamine (FS6B) with pyromellitic dianhydride (PMDA), benzophenone‐3,3′,4,4′‐tetracarboxylic dianydride (BTDA), 4,4′‐oxydi(phthalic anhydride) (ODPA), and 4,4′‐hexafluoroisopropylidenedi(phthalic anhydride) (6FDA), respectively, and their controllability of liquid crystal (LC) alignment on rubbed surfaces was investigated. Pretilt angles of LCs were achieved in the 2–9° range, depending on the rubbing density and backbone structures. The effect of the mesogenic stilbene group on the pretilting of LCs was distinctive in FS6B‐PMDA. Contact‐angle measurements on thin films annealed at 120 °C revealed that FS6B‐PMDA potentially had the better alignment stability than FS6B‐6FDA. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3622–3632, 2001     

Radiation Damage of Crystal Polyesters

The change of crystal structures in polyethylene terephthalate (PET) and polyhexa methylene terephthalate (PHT) irradiated by γ-ray were investigated by using the methods of WAXD and SAXS. It was found that irradiation caused the crystal parameters of PET and PHT to lengthen, and the cell to expand; and at the same time, the long period and the thickness of lamellae were unchanged. These results indicate that the radiation damage of crystal polyesters causes the increase of lacunaries within the crystal polyester.     

Physical significance of contact angles

Summary The physical significance of contact angles has been interpreted on the basis of a model derived from known surface energy relationships. The degrees of non-spreading and spreading have been expressed in terms of the magnitude of contact angles. On the basis of the physical picture, hysteresis of contact angle has been calculated from the experimental values of equilibrium contact angle and surface tension of the liquid. It has been suggested that it is not necessary to assume that hysteresis of contact angles is due to surface roughness of solids. The picture also explains why apparent contact angle on a non-flat solid surface is more than that on a flat solid.With 2 figures and 1 table     

超疏水性生物表面的研究进展

介绍了几种天然超疏水生物表面的研究进展,包括蛾翅膀、蝉翼、蝴蝶翅膀、白蚁翅膀、甲虫,蚊子的腿、翅及其复眼,水黾的腿部和荷叶的表面。 对现有的仿生超疏水材料的制备方法及常用作表面修饰的低表面能材料做了简单的归纳与总结。 对超疏水材料研究面临的挑战及以后的发展趋势做了展望。     

Covalently Attached Liquids: Instant Omniphobic Surfaces with Unprecedented Repellency

Recent strategies to prepare “omniphobic” surfaces have demonstrated that minimizing contact angle hysteresis (CAH) is the key criterion for effectiveness. CAH is affected by chemistry and topography defects at the molecular and higher levels, thus most surfaces exhibit significant CAH. Preparative methods for stable coatings on smooth substrates with negligible CAH (<2°) for a broad range of liquids have not been reported. In this work, we describe a simple and rapid procedure to prepare omniphobic surfaces that are stable under pressure and durable at elevated temperatures. Consistent with theory, they exhibit sliding angles that decrease with liquid surface tension. Slippery omniphobic covalently attached liquid (SOCAL) surfaces are obtained through acid‐catalyzed graft polycondensation of dimethyldimethoxysilane. The smooth, stable, and temperature‐resistant coatings show extremely low CAH (≤1°) and low sliding angles for liquids that span surface tensions from 78.2 to 18.4 mN m^?1.     

超疏水表面的研究进展

表面的浸润性是决定材料应用的一个重要性质,许多物理化学过程,如吸附、润滑、黏合、分散和摩擦等均与表面的浸润性密切相关.近年来,由于超疏水表面在自清洁表面、微流体系统和生物相容性等方面的潜在应用,有关超疏水表面的研究引起了极大的关注.本文综述了超疏水表面研究的新进展:简单介绍了表面浸润性的表征手段和影响因素,归纳了超疏水表面的制备方法和相关的理论分析,对超疏水表面研究的发展进行了展望.     

仿荷叶表面研究进展

近年来,荷叶表面的自清洁功能引起人们极大的研究兴趣,这种自清洁功能源自于表面形貌与低表面能物质的共同作用.目前,已用不少方法来制备仿荷叶表面.本文回顾近年来仿荷叶表面研究成果,探讨仿荷叶表面研究与发展趋势.     

柱状结构阵列碳纳米管膜的超疏水性研究

浸润性是固体表面的重要性质之一 .决定固体表面的浸润性的两个主要因素中 ,化学性质是内因 ,而几何结构形貌也是不可缺少的重要因素 .通过改变固体表面的粗糙度可以改变其浸润性 [1～ 5] .通常 ,人们用水接触角的大小来衡量固体表面水的浸润性 ,水与固体表面的接触角大于 1 5     

二氧化硅／环氧树脂复合涂层的制备及其疏水性能

采用喷涂技术,在马口铁表面喷涂环氧树脂和二氧化硅复合涂层,研究了二氧化硅的含量对表面疏水性的影响,复合涂层的疏水性随二氧化硅含量的增加而增加．当二氧化硅质量分数增大到40％时,所制备的复合涂层与水的接触角约为141°且具有较小的滚动角．