Preparation and characterization of superhydrophobic silica-based surfaces by using polypropylene glycol and tetraethoxysilane precursors

Preparation of superhydrophobic silica-based surfaces via sol-gel process by adding polypropylene glycol (PPG) polymer into the precursor solution has been developed. Surface roughness of the films was obtained by removing the organic polymer at 500 °C and then the hydrophobic groups bonded onto the films were obtained by chemical reaction with hexamethyldisilazane (HMDS). Physical properties of the as-prepared films were analyzed by contact angle measurements, scanning electron microscopy (SEM), UV-VIS scanning spectrophotometer and Fourier transform infrared (FT-IR) spectrophotometer. The experimental parameters were varied by the type of silane species, the weight ratio of PPG solution to precursor solution, the hydrolysis time of the precursor solution, the molecular weight of PPG, the casting temperature and the evaporation temperature. The phase separation of the PPG polymer rich domain occurred on the substrates at a lower temperature. The result showed that the contact angles of the films prepared at 5 °C were greater than 150° when the weight ratio of PPG solution to precursor solution was 5. In addition, the transmittance of the films was greater than 80% simultaneously.     

Fabrication of patterned TiO2 thin film by a wet process

Hydrophobic/hydrophilic patterned TiO₂ thin film was successfully fabricated on a glass substrate by a wet process. A micro-nano complex structure with a high roughness was fabricated by a layer-by-layer selfassembly and liquid phase deposition (LPD) method. To fabricate superhydrophobic TiO₂ thin films, TiO₂ nanoparticles were deposited on the surface of (PAH/PAA) thin film by a LPD method and the surface of TiO₂ was modified by a hydrophobic treatment using fluoroalkyltrimethoxysilane. The RMS roughness and water contact angle of the prepared TiO₂ thin film were ca. 65.6 nm and ca. 155°. The superhydrophobic surface exposed to UV light changed to a hydrophilic surface by the photocatalytic property of TiO₂ to decompose a hydrophobic group. Finally, hydrophobic/hydrophilic patterned TiO₂ thin film with a 300 ??m dot size was fabricated. The surface morphology, transmittance, surface roughness and water contact angle of the prepared thin films were measured by a field emission scanning electron microscope, an atomic force microscope, a UV-Vis spectrophotometer and a contact angle meter.     

Spray deposited superhydrophobic ZnO coatings via seed assisted growth

Superhydrophobic zinc oxide (ZnO) coatings were synthesized by a simple and cost-effective spray pyrolysis technique (SPT) via seed assisted growth onto the glass substrates at 723 K from an aqueous zinc acetate precursor solution. Initially, the ZnO seeds were synthesized from an aqueous 0.4 M zinc acetate solution onto the glass substrates at 723 K. For the seed assisted growth of ZnO, the solution concentrations (0.1 M to 0.4 M) were used and its effect on structural, morphological, optical and wettability properties of ZnO thin films was investigated. The synthesized films were found to be polycrystalline, with preferential growth along c-axis. Scanning electron microscopy (SEM) images show the uniform distribution of spherical grains of about 60-80 nm grain size. After seed assisted growth, film surface becomes very rough. The films were specular and transmittance of thin films decreases as the concentration of the precursor solution increases. The optical absorption spectrum shows a sharp absorption band-edge at 381 nm, corresponding to optical gap energy (Eg) of 3.25 eV. All samples are superhydrophobic in nature. The Zn4 sample shows the superhydrophobicity with highest value of the contact angle (CA) i.e. 165°. Such a superhydrophobic coatings can be useful in the anti-snow, anti-fog and self cleaning surfaces.     

靶材成分对磁控溅射PTFE超疏水薄膜的影响

目的了解靶材成分对磁控溅射PTFE薄膜性能的影响,以提升PTFE薄膜疏水性能。方法采用射频磁控溅射技术,在玻璃基片上一步制备了透明超疏水聚四氟乙烯薄膜,并研究了不同PTFE靶材对薄膜的影响。利用X射线光电子能谱仪(XPS)、接触角测试仪(Drop Meter)、紫外-可见分光光度计(UV-Vis)分别对靶材和薄膜的性能进行研究。结果两靶材的氟碳官能团含量有明显差异,且靶材1含有CF2O,靶材2中不含。靶材的成分影响了PTFE的溅射率,靶材1的溅射率为靶材2的2倍。相同溅射时间下,靶材不同的薄膜厚度不同,从而表现出不同的静态水接触角。薄膜的疏水性能与薄膜厚度呈现指数关系,最终稳定在170°水接触角平台。同时,溅射过程中,F离子刻蚀到玻璃基底而引入了Na F,但薄膜中Na F和氟碳基团的含量与靶材成分相关。薄膜中Na F的存在,提升了薄膜的F/C比,降低了薄膜表面能,提升了其疏水性能,但降低了薄膜的可见光透过率。结论一步制备透明超疏水聚四氟乙烯薄膜的技术具有广泛应用前景,了解靶材成分对薄膜性能的影响具有重要指导意义。     

Role of rf power on the properties of undoped SnOx films deposited by rf-PERTE at low substrate temperature

Transparent and conductive undoped tin oxide (SnO_x) thin films were deposited at low substrate temperature (< 140 °C) by radio frequency (rf) plasma enhanced reactive thermal evaporation (rf-PERTE) of tin (Sn) in the presence of oxygen The undoped SnO_x films were not submitted to any post-annealing treatments. The influence of rf power variation on the optical, electrical and structural properties of the as-grown films is presented. A variation in the films' structure was verified with the increase of rf power. Undoped SnO_x films, 90 nm average thick, deposited at rf power range of 60–70 W are nanocrystalline, show a conductive behaviour, an average visible transmittance of ≥ 80% and a maximum electrical conductivity of about 34.6 (Ω cm)^− 1. Films deposited at lower values of rf power (40 W) are amorphous and exhibit a semiconductive behaviour, showing an electrical conductivity of about 7.54 × 10^− 1 (Ω cm)^− 1. As a low substrate temperature deposition process is used, SnO_x thin films can be obtained on a wide range of substrates.     

电沉积法制备Co–LDHM超疏水膜及性能研究

目的 采用电沉积法在不锈钢网上构筑稳定的钴层状双氢氧化物微球(Co–LDHM)超疏水薄膜。方法 首先,通过第1次电沉积在不锈钢网上制备出ZIFs纳米片阵列结构(ZIF–NFA),并以此为牺牲模板,然后在第2次电沉积作用下制备出微纳米尺寸的Co–LDHM,最后通过浸泡硅烷降低其表面能。通过溅射试验、耐磨性实验、油水分离实验及电化学试验,分别评价经超疏水改性后不锈钢网的抗污、耐摩擦、油水分离及耐蚀性能,并通过接触角,用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)对不锈钢网表面的疏水程度及膜表面的形貌与结构进行分析。结果 经两步电沉积处理后的不锈钢网表面类似浴球状,具有微米/纳米多级表面形貌结构;接触角测试表明,所制备的薄膜呈现出良好的超疏水性能,静态接触角达到159.4°±2°;经过30个耐摩擦实验周期,其表面接触角为141.3°±2°,仍具有较高的疏水性;油水分离效率均大于97%,重复20次以上分离效率仍保持在96%,且具有一定耐蚀性能和良好的抗污性。结论 通过两步电沉积法构筑的Co-LDHM超疏水不锈钢网具有优异的超疏水性能,为MOFs在制备超疏水材料方面的应用提供了一个新的思路。     

Corrosion inhibition using superhydrophobic films

Neutron reflectivity (NR) was used to study the effectiveness of superhydrophobic (SH) films as corrosion inhibitors. A low-temperature, low-pressure technique was used to prepare a rough, highly porous organosilica aerogel-like film. UV/ozone treatments were used to control the surface coverage of hydrophobic organic ligands on the silica framework, allowing the contact angle with water to be continuously varied over the range of 160° (SH) to <10° (hydrophilic). Thin (∼5000 Å) nano-porous films were layered onto aluminium surfaces and submerged in 5 wt% NaCl in D₂O. NR measurements were taken over time to observe interfacial changes in thickness, density, and roughness, and therefore monitor the corrosion of the metal. NR shows that the SH nature of the surface prevents infiltration of water into the porous SH film and thus limits the exposure of corrosive elements to the metal surface.     

氧流量对铟锡氧化物薄膜光电性能的影响

采用射频磁控溅射法，在不同氧流量（0～10sccm）的条件下沉积了铟锡氧化物（In2O3-SnO2）透明导电薄膜。紫外分光光度计测试薄膜的透射率，四点探针测试薄膜的方阻，椭偏仪测试薄膜的复折射率和薄膜厚度，XPS测试ITO薄膜的成分和电子结构。结果表明：薄膜的沉积速率和折射率与氧流量有关，薄膜厚度为60nm，氧流量在9sccm时，透射率超过80％（波长λ=400nm～700nm，包括玻璃基体），退火后透射率、方阻明显改善。XPS分析表明，薄膜中的亚氧化物的存在降低了薄膜的光电性能，控制氧流量可减少亚氧化物。     

Superhydrophobic fluoropolymer-modified copper surface via surface graft polymerisation for corrosion protection

With the objective of developing materials with repellent surfaces by combining both low surface energy and rough structure, superhydrophobic fluoropolymer films were prepared via surface graft polymerisation from copper substrates. A vinyl-terminated trimethoxysilane was firstly immobilised on the etched-copper surface to introduce active carbon–carbon double bonds. Subsequent graft polymerisation of 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA), in the presence of a polymerisation initiator 4,4′-azobis-(4-cyanpentanoic acid), yielded the fluoropolymer films on the copper substrates. The resultant P(HFBA)-grafted surfaces not only exhibited desired superhydrophobic property with water contact angle above 150°, but substantially improved the corrosion resistance of copper substrates.     

Effects of the solution temperature and the pH on the electrochemical properties of the surface oxide films formed on Alloy 600

The surface oxide films on Alloy 600 have been investigated as a function of the solution temperature and the pH by using a cyclic voltammetry, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a depth profiling by Auger electron spectroscopy (AES). H₃BO₃, Na₂SO₄ and NaOH aqueous solutions with temperatures in the range of 30–300 °C were used as the test solutions. As the solution temperature of the 0.5 M H₃BO₃ increased, the thickness of the passive film increased but the resistance of the passive film was diminished, which is coincident with a solution temperature dependency of the passive current in the potentiodynamic curve. The inner oxide film on Alloy 600 was distinguishable from the Cr-rich outer oxide film above 100 °C. From the Mott–Schottky relation, the oxide formed in 0.5 M H₃BO₃ at 300 °C showed a p-type semiconductor property, accompanied by a Cr-rich oxide film throughout the whole oxide film unlike the n-type oxide films up to 250 °C. The oxide resistance of the passive film decreased in the order of 0.5 M H₃BO₃, 0.1 M NaOH and 0.5 M Na₂SO₄, which is consistent with the pH dependency of the passive current. Ni-rich oxide films of a p-type were formed in the 0.5 M Na₂SO₄ or 0.1 M NaOH.     

MB8镁合金表面超疏水复合膜层的制备与表征

利用微弧氧化技术在镁合金表面制备微米级粗糙结构,采用环氧树脂溶液和纳米二氧化硅分散液对该表面进行涂覆处理,得到二氧化硅纳米颗粒均匀分布的粗糙表面,再利用全氟硅烷改性,制备得到具有超疏水性的复合膜层。采用扫描电镜、X射线衍射仪、接触角测量仪、高速摄影系统评价膜层的形貌结构和润湿性。结果表明,微弧氧化层所具有的微米级结构和纳米二氧化硅颗粒组成的微/纳二元粗糙结构对疏水性的提高具有重要作用;复合膜层表面的接触角随二氧化硅分散液浓度的提高呈现先增加后减小趋势,并最终逐渐稳定在150o左右;在二氧化硅分散液浓度为10.0g/L时,复合表面的接触角最大,可达161o,在此条件下获取的复合表面对不同pH值的液滴均具有超疏水性。同时该表面对水滴呈现低黏附特性。     

Facile method to prepare a novel honeycomb-like superhydrophobic Polydimethylsiloxan surface

A novel honeycomb-like superhydrophobic Polydimethylsiloxan surface with interesting hierarchical micro- and nanostructures was obtained using a facile template method. The water contact angle and sliding angle of the superhydrophobic Polydimethylsiloxan surface were 155 ± 1.7° and 5°, respectively. The superhydrophobic Polydimethylsiloxan surface showed high stability in the pH range from 1 to 14. After several frictions, the superhydrophobic Polydimethylsiloxan surface also maintained high superhydrophobicity. When the superhydrophobic Polydimethylsiloxan surface was contaminated, 99.5% contaminant particles were removed from the superhydrophobic Polydimethylsiloxan surface by artificial rain, showing an excellent self-cleaning property. After being stored in an ambient environment for 6 months, no decrease in water contact angle was observed.     

可切换润湿性超疏水表面制备方法及应用

目的 制备可切换润湿性的智能超疏水表面,并探索该表面潜在的应用前景。方法 利用模板法,基于热响应形状记忆聚合物（Shape Memory Polymer,SMP）制备具有条状微结构阵列的可切换润湿性智能超疏水表面,并对其润湿性可逆转换能力及循环使用稳定性进行测试。结果 通过扫描电子显微镜观察到所制备表面微结构完整且轮廓清晰,液滴接触角在该表面可达到（150±3）°。通过加热使该表面达到玻璃化转变温度,此时对其施加外载荷使表面上条状微结构向一侧倾倒,由于微结构形态的改变,SMP表面疏水性减弱、水黏附性增强,再通过简单加热就可以使表面形态恢复至原始状态。通过试验测得环氧SMP的形状固定率为98.8%、形状回复率为96.3%,均达到95%以上,由于其优异的形状记忆特性,条状微结构的形态可以在原始直立状态和受到外载荷时的倾倒状态之间产生热响应而自由转变,且这种润湿性转换循环10次以上后,该表面依然保持着相对良好的润湿性可逆转换能力。结论 基于形状记忆聚合物制备出的可切换润湿性智能超疏水表面具有良好的润湿性可逆转换能力和循环使用能力,且在液滴微反应器、生物检测、可重写液体图案、无损失液滴转移和芯...     

Fabrication of superhydrophobic surfaces on Mg alloy substrates via primary cell corrosion and fluoroalkylsilane modification

The present work reports a simple and safe two‐step process to render magnesium (Mg) alloy surfaces superhydrophobic via primary cell corrosion and subsequently cover it with a fluoroalkylsilane (FAS) film. The surfaces were characterized by scanning electron microscopy (SEM), optical microscopy, energy‐dispersive X‐ray spectroscopy (EDS), Fourier‐transform infrared spectrophotometry (FTIR), X‐ray diffraction (XRD), and optical contact angle measurements. The power generated via the primary cell corrosion of copper and Mg alloys was also measured using a digital multimeter. The results show that micro/nanometer‐scale binary rough structures and an FAS film with a low surface energy were present on the Mg alloy surfaces, both of which confer good superhydrophobicity with a water contact angle of 162.8° and a tilting angle of 2°. The micro/nanometer‐scale binary rough structures consisted of micrometer‐scale grains, cluster‐like structures composed of nanometer‐scale needles, and network‐like structures composed of nanometer‐scale sheets. Superhydrophobicity was analyzed by the Cassie–Baxter theory. Findings show that only about 6.3% of the water surface was in contact with the Mg alloy substrates, while the remaining 93.7% was in contact with the air cushion. The unique advantage of the proposed method is that power can be generated during the machining process of the superhydrophobic surfaces on the Mg alloy substrates.     

浸渍式提拉法制备TiO2薄膜的微观结构和润湿性

目的研究工艺参数与TiO_2薄膜的微观结构、光学性质及润湿性的关系。方法以钛酸四丁酯为原料,乙醇为溶剂,采用溶胶-凝胶浸渍式提拉法,改变工艺参数(提拉次数、提拉速度),在玻璃衬底上制备了TiO_2薄膜,并通过光学表面形貌仪、紫外可见分光光度计及接触角测试仪分析了不同参数下制备的TiO_2薄膜的微观结构、光学性质和润湿性。结果提拉次数和提拉速度都会影响薄膜的微观结构,提拉2次,提拉速度在3~7 cm/min之间制备的TiO_2薄膜表面平整、致密。在提拉方向上,存在厚度梯度,厚度梯度为1 nm/μm。透射光谱显示TiO_2薄膜在可见光区透明,吸收边与提拉工艺有关,提拉速度为7 cm/min,提拉2次制备的TiO_2薄膜,禁带宽度为3.57 e V,此时,接触角为14.8°。结论提拉速度、提拉次数影响TiO_2薄膜的微观结构、光学性质和润湿性。通过提拉工艺参数的调整,可以制备均匀致密、具有亲水性的半导体TiO_2薄膜。     

Fabrication of super-hydrophobic surface on copper surface by polymer plating

The 6-(N-allyl-1,1,2,2-tetrahydroperfluorodecyl)amino-1,3,5-triazine-2,4-dithiol monosodium) (ATP) was used to fabricate polymeric thin film on pure copper plate to achieve super-hydrophobic surface. The copper plates were pretreated to gain rough surfaces by chemical etching before polymer plating. The polymer plating process of ATP on copper in Na₂CO₃ aqueous solution and the growth mechanism of poly(6-(N-allyl-1,1,2,2-tetrahydro-perfluorodecyl) amino-1,3,5-triazine-2,4-dithiol) (PAT) thin film was studied by means of cyclic voltammetry. The polymeric film was investigated by using X-ray photoelectron spectroscopy (XPS), and the etched surfaces were observed by atomic force microscopy (AFM). A contact angle meter was applied to measure the contact angles with distilled water drops at ambient temperature. The experimental results indicated that the polymeric film formed on rough copper surface exhibits super-hydrophobic property with a distilled water contact angle of 155°. The wettability of copper surfaces was discussed on the basis of both Wenzel and Cassie theories. The etching and polymer plating processes are time-saving, inexpensive, environmental and fairly convenient to carry out. It is expected that this technique will advance the production of super-hydrophobic materials with new applications in large scale. Moreover, this kind of thin film can be used as a dielectric material due to its insulated feature.     

基于静电喷雾法制备油水分离的超疏水表面研究

目的 提出一种静电喷雾法制备超疏水表面而实现油水分离的方法。方法 利用静电喷雾法将二氧化硅微粒喷涂到不锈钢网表面以构建微粗糙结构,利用氟硅烷降低二氧化硅微结构涂层的表面能。探讨静电喷雾的电压、喷涂时间、二氧化硅粒径、溶液pH、浸泡时间等参数,对表面微结构和疏水性能的影响。通过扫描电镜表征样件表面形貌,通过接触角测量仪测量超疏水不锈钢网表面的疏水性能。利用超疏水不锈钢网实现油水分离以检验装置的浮油收集能力。结果 二氧化硅微粒能够在不锈钢网表面喷涂形成均匀粗糙的微结构。在6 kV静电压下,雾化喷涂粒径为25 nm的二氧化硅所获得的超疏水不锈钢网的接触角达161°,在不同pH溶液中浸泡15 d后,接触角仍大于150°,浸泡35 d后,接触角仍大于未处理的不锈钢网。该网可以收集97%以上的柴油和煤油及90%以上的汽油和茶油,且重复使用20次后,仍保持粗糙的表面微结构和高油水分离率。结论 采用静电喷雾法能简单高效地获得超疏水表面,且具有较好的化学稳定性和有效的油水分离能力,具有很广的应用前景。     

氮气流量对磁控溅射法沉积NGZO薄膜性能的影响

目的通过磁控溅射镀膜工艺,在玻璃上制备高质量的氮镓共掺杂氧化锌(NGZO)薄膜。方法采用射频磁控溅射法,同时通入氩气和氮气,在流量比分别为25/10、25/20、25/25、25/30((m L/min)/(m L/min))条件下制备NGZO薄膜。通过XRD和SEM对薄膜的物相结构和表面形貌进行分析,通过紫外/可见分光光度计和霍尔效应测试仪对薄膜透过率和载流子浓度、迁移率及薄膜电阻率进行研究。结果与未掺入N的Ga掺杂氧化锌(GZO)薄膜相比,在可见光区,尤其是600~800 nm范围内,NGZO薄膜平均透过率在80%以上,符合透明导电薄膜透过率的要求。GZO薄膜载流子浓度较高,电阻率较低,而掺入N后薄膜的载流子浓度和迁移率有所下降,电阻率有所增加。结论在N-Ga共掺杂薄膜中,N的掺杂主要占据O空位,并吸引空位周围的电子,这减小了薄膜晶格畸变,并产生电子空穴,最终使得薄膜中电子载流子浓度降低,空穴载流子浓度增加,电阻率有所增加。随着氮气流量的变化,发现在25 m L/min时,薄膜具有最佳的综合性能。这种薄膜可用于紫外光探测器等需较大电阻率的应用中,并有望实现n-p型转化。     

耐久超疏水涂层的制备及其防冰防腐自清洁性能

超疏水涂层在防结冰、防腐蚀等领域具有广阔的应用前景,然而目前仍无法大规模制备稳定的超疏水表面。提出一种操作简单、成本低廉的方法,在铝合金基材上通过一步喷涂法制备出耐磨超疏水涂层。首先在铝合金基体表面涂覆环氧树脂粘结层,待其达到半固化状态时,喷涂硬脂酸修饰的微米 SiO₂ 和纳米 TiO₂ 粒子混合悬浮液,固化后该涂层与水的接触角为~ 155.4°,滚动角为~3°,实现了超疏水性。试验结果表明,该超疏水涂层具有较好的耐磨耐久性,在胶带剥离、砂纸摩擦、 紫外光长时间照射以及不同 pH 液滴等多种测试条件下仍具有良好的超疏水性。此外,此超疏水涂层在极端寒冷的天气下可以显著延缓水的冻结时间。环氧树脂和疏水颗粒的协同防腐作用使超疏水涂层在海水中表现出良好的防腐蚀性能。所制备的超疏水涂层还具有优异的自清洁特性,且因 TiO₂ 粒子本身的光降解性能,该涂层还可用于光降解污染物和净化水质。这种简单、环保的超疏水涂层在防结冰、防腐蚀等方面具有潜在的应用前景,可为克服传统超疏水表面使用耐久性差的问题提供解决思路。     

浸润性可转变的超疏水织物用于油水分离研究

目的制备超亲疏可逆转换实现油水分离的纺织品。方法首先利用化学镀铜的方法在涤棉织物表面构筑微米-亚微米粗糙结构,然后浸入十二酸乙醇溶液中通过低表面能物质的修饰得到超疏水织物。采用扫描电子显微镜(SEM)、能量色散X射线光谱仪(EDXS)和接触角测试仪对其表面形貌、表面元素和浸润性能进行测试。结果十二酸修饰镀铜涤棉织物具有超疏水性能,与水的接触角达到151.9°;此外,改变超疏水织物所处环境的p H可实现浸润性的可逆转变,从而达到不同密度的油与水的分离,且分离效率高达98%,分离循环次数在80次以上。结论通过化学镀铜构造粗糙表面,再用低表面能物质十二酸修饰,可成功制备超疏水织物。增大织物所处环境的p H值,可得到超亲水织物。超疏水织物和超亲水织物都可用于油水分离。