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1.
Superhydrophobic films mainly based on poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) polyelectrolyte multilayer have been deposited onto cleaned glass substrate by a layer-by-layer dip coating method. 3 bilayers of the PAH and PAA was directly coated onto the substrate as an underlying layer for subsequent coating. Desired surface roughness on the polyelectrolyte bilayers was created by etching the bilayers in hydrochloric acid solution so as to create the open pore having suitable size at the surface. Then, nanoparticles such as SiO2 and TiO2 of various sizes were deposited onto the etched polyelectrolyte bilayers. Finally, the surfaces were further modified with semifluorinated silane followed by cross-linking at 180 °C for 2 h to obtain desirable surface morphological features. The effect of etching time and addition of nanoparticles on surface morphology was investigated using an atomic force microscope (AFM). Wetting ability of the prepared film was determined by measuring water droplet contact angle using a goniometer. Adhesion between the superhydrophobic films and the substrate was evaluated by using a standard tape test method (D3359). The adhesion was improved by reducing the organic content in the films.  相似文献   

2.
In many medical and industrial applications, some strategies are needed to control the adhesion forces between the materials, because surface forces can activate or hinder the function of the device. All actual surfaces present some levels of roughness and the contact between two surfaces is transferred by the asperities on the surfaces. The force of the adhesion, which depends on the operating situations, can be influenced by the contact region. The aim of the present study is to predict the adhesion force in MEMS surfaces using the JKR and DMT models. The surfaces of the coating material in this research consisted of the single-layer coating of Gold and Silver, and the double-layer coating of TiO2/Gold and TiO2/Silver on the silicon (100) substrates. The depositing was done by the thermal evaporation method. The results showed that the double-layer coating developed by the new deposition method helped the reduction of the adhesion forces between the probe tip and the specimen surface. The predicted adhesion forces between the probe and the specimens with DMT and JKR models were compared with the experimental results. For all specimens, the simulated data by applying the JKR theory were in a good agreement with the adhesion force experimental values.  相似文献   

3.
To enhance the poor scratch resistance of polycarbonate, a silica (SiO2) and titania (TiO2) transparent inorganic coatings was designed and synthesized using a microwave assisted sol–gel heating. Due to the transparency of PC to microwave, the idea was to obtain a localized heating only on the coating film. The obtained films were fully characterized to mainly evaluate the effect of titania content, added both as nanoparticles and from tetraethyl orthotitanate, TEOT, on scratch resistance and surface morphology. Particular attention was paid to preserve the transparency of the final product. The results allowed to define that TEOT addition enhances the adhesion between coating and polycarbonate, even if the optimized quantity have to be defined in order to avoid a decrease of coating mechanical resistance. In this work optimized TEOT level results to be the associated to 5 wt% of TiO2, which enable the better balancing between adhesion and mechanical resistance performances.  相似文献   

4.
Adhesion force is one of the most important factors in microelectromechanical systems (MEMS), especially for microassembly. It depends on operating conditions and is affected by the contact area. In this study, the adhesion force between MEMS materials and AFM tips was analysed using AFM's point-mode spectroscopy. The aim was to study the effectiveness of various coatings in MEMS adhesion surfaces. For this purpose, five silicon surfaces were used, four of which were coated, and one was noncoated. Two of them were deposited by single-layer coating (Au and Ag). The other two were deposited by double-layer coating (TiO2/Au, TiO2/Ag) on a Si (1 0 0) substrate. The depositing was accomplished by the thermal evaporation method. Composite materials and analysis were reviewed by observing the SEM image. The experimental results showed that the method of deposition helped to decrease the adhesion force between the probe tip and the surface of the specimens, and double-layer coating had stronger effect on decreasing the adhesion force than the single-layer coating.  相似文献   

5.
Implantable medical devices (IMDs) are susceptible to microbial adhesion and biofilm formation, which lead to several clinical complications, including the occurrence of implant-associated infections. Polylactic acid (PLA) and its composites are currently used for the construction of IMDs. In addition, chitosan (CS) is a natural polymer that has been widely used in the medical field due to its antimicrobial and antibiofilm properties, which can be dependent on molecular weight (Mw). The present study aims to evaluate the performance of CS-based surfaces of different Mw to inhibit bacterial biofilm formation. For this purpose, CS-based surfaces were produced by dip-coating and the presence of CS and its derivatives onto PLA films, as well surface homogeneity were confirmed by contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antimicrobial activity of the functionalized surfaces was evaluated against single- and dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan-based surfaces were able to inhibit the development of single- and dual-species biofilms by reducing the number of total, viable, culturable, and viable but nonculturable cells up to 79%, 90%, 81%, and 96%, respectively, being their activity dependent on chitosan Mw. The effect of CS-based surfaces on the inhibition of biofilm formation was corroborated by biofilm structure analysis using confocal laser scanning microscopy (CLSM), which revealed a decrease in the biovolume and thickness of the biofilm formed on CS-based surfaces compared to PLA. Overall, these results support the potential of low Mw CS for coating polymeric devices such as IMDs where the two bacteria tested are common colonizers and reduce their biofilm formation.  相似文献   

6.
This study describes a facile breath‐figure method for the preparation of honeycomb‐like porous TiO2 films with an organometallic small‐molecule precursor. Multiple characterization techniques have been used to investigate the porous films and a mechanism for the formation process of porous TiO2 films through the breath‐figure method is proposed. The pore size of the TiO2 films could be modulated by varying the experimental parameters, such as the concentration of titanium n‐butoxide (TBT) solution, the content of cosolvent, and the air flow rate. In vitro cell‐culture experiments indicate that NIH 3T3 fibroblast cells seeded on the honeycomb‐like porous TiO2 films show good adhesion, spreading, and proliferation behaviors, which suggests that honeycomb‐like porous TiO2 films are an attractive biomaterial for surface modification of titanium and its alloys implants in tissue engineering to enhance their biocompatibility and bioactivity.  相似文献   

7.
Al2O3 and TiO2 thin films were deposited by atomic layer deposition at 80-250 °C on various polymeric substrates such as polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and ethylenetetrafluoroethylene (ETFE). The films were studied with FESEM, EDX, XRD, contact angle measurements and adhesion tests. The film growth rates on the thermoplastics were close to the corresponding growth rates on Si substrates. The adhesion of the films was good on PEEK and poor on PTFE. All coated surfaces showed lower water contact angles than the uncoated thermoplastics. Furthermore, the water contact angles on all TiO2-coated surfaces decreased upon UV illumination, most efficiently with crystalline TiO2 coatings.  相似文献   

8.
TiO2 thin film photocatalysts coated onto soda lime glass were prepared by a dip coating process using a highly viscous solvent. The source of the TiO2 was tetraisopropyl orthotitanate, and -terpineol was used as the solvent. Two types of thin film preparation procedures based on dip coating (a sol-gel system and thermal decomposition system) were used to prepare the samples. TiO2 thin films were obtained after calcination at 450°C for 1 hour. The film thickness obtained with a single dipping was proportional to the viscosity of the dip coating solutions. The obtained thin films were transparent with a thickness of 1 m. The crystal form of the obtained photocatalyst films was anatase alone. The thin films were formed with aggregated nano-sized TiO2 single crystals (7–15 nm). The photocatalytic activity of the TiO2 thin films, as evaluated by the photooxidation of NO (1 ppm) in dry air, was as high as our previous TiO2 thin films prepared by the sol-gel method.  相似文献   

9.
A novel technique has been developed to fabricate surface-relief gratings using sol-gel derived porous coating on plastic foil substrates. Organically modified TiO2 sol was prepared by roll-coating on OPP foil substrates. The plastic films coated with TiO2 nano-particles were embossed to form surface-relief gratings with micro-structures. The morphology of the porous coatings and the micro-structures were investigated using electron scanning microscopy (SEM). Optical transmission of the films was measured using UV-VIS and IR spectroscopy. The diffraction efficiency of the gratings on the coated plastic foil was examined in terms of fabrication conditions. It was shown that special figures could be seen in the films when the angle of view was changed. The final products of the composite films are transparent and suitable for industry manufacture and applications.  相似文献   

10.
采用化学方法处理微弧氧化(MAO)制备的含Si、Ca元素的TiO2涂层(SC), 获得钛氢氧钠(Na0.8H1.2Ti3O7)生物活性纳米线结构。化学处理过程中, SC涂料表面出现了Ca、Na元素溶解, Si元素沉积的现象。化学处理后的SC涂层比SC涂料具有更好的吸水性和诱导磷灰石形成能力。这与处理后涂层(SHTO)特殊的纳米结构有关, 在模拟体液浸泡过程中更容易形成Ti-OH。同时, 钠氢氧钛纳米线的表面形貌、相组成、OH基团以及良好的湿润能力使其更加适合于MC3T3-E1细胞的粘附和增值。  相似文献   

11.
采用化学方法处理微弧氧化(MAO)制备的含Si、Ca元素的Ti O2涂层(SC),获得钛氢氧钠(Na0.8H1.2Ti3O7)生物活性纳米线结构。化学处理过程中,SC涂料表面出现了Ca、Na元素溶解,Si元素沉积的现象。化学处理后的SC涂层比SC涂料具有更好的吸水性和诱导磷灰石形成能力。这与处理后涂层(SHTO)特殊的纳米结构有关,在模拟体液浸泡过程中更容易形成Ti-OH。同时,钠氢氧钛纳米线的表面形貌、相组成、OH基团以及良好的湿润能力使其更加适合于MC3T3-E1细胞的粘附和增值。  相似文献   

12.
Amorphous precursor powders have proven to be highly advantageous for the sol–gel processing of TiO2 thin films. Oxide yield, density, solubility, and thermal degradation of powders prepared under various conditions were determined; the thermoanalytical data could be assigned to the oxidative decomposition of different organic constituents. Certain powders are suitable for the preparation of alcohol-based sols, whereas also aqueous coating solutions can be prepared from others. Thin films prepared from both systems show excellent adhesion and optical properties when deposited on borosilicate glass substrates.  相似文献   

13.
在弱碱性和空气条件下, 以多巴胺(DA)为多重相互作用模型分子, 调控羧甲基壳聚糖(CMC)和侧基含 伯氨基(—NH2)的磷酰胆碱基聚合物(PMA)与DA之间的相互作用, 采用一步共沉积法构筑表面富含磷酰胆碱两性离子基团和CMC杀菌性聚合物的双重抗菌涂层. 研究发现, DA分子的万能黏附特性有利于诱导CMC 和PMA在基材表面发生共沉积, 增强涂层中各组分及其与基材之间的界面结合力, 所得涂层在体积分数为75%的乙醇水溶液中超声2 h后, 表面水接触角数值几乎保持不变, 稳定性良好; 而CMC和PMA聚合物链中的—NH2侧基与DA及其衍生物之间发生氢键、 席夫碱和/或迈克尔加成反应等多重相互作用, 协同改善DA分子氧化-自聚行为和沉积过程, 获得形貌较为均一的涂层表面. 所得表面同时含有两性离子基团和CMC聚合物链, 兼具良好抗生物污染和杀菌活性, 能够有效抑制细菌生物膜的形成.  相似文献   

14.
It has been recently proved that RuO2 can act as an effective surface activator of aluminum alloy sacrificial anodes. TiO2 has the property of stabilizing RuO2 coating and resisting biofouling on metal surfaces. Hence, a mixed oxide catalytic coating of TiO2 and RuO2 can enhance the galvanic performance of aluminum alloy sacrificial anodes and resists biofouling on the anode surface. In the present work RuO2–TiO2 mixed oxide was coated on aluminum alloy sacrificial anodes. The large and uniform porous nature of the coating was found to facilitate efficient ion diffusion. The coating was found to persist on the anode even after 3 months of galvanic exposure. The anode having an optimum combination of the mixed oxide had 70% TiO2 as the major component in the coating. The catalytic coating significantly improved the performance of the anodes to a large extent.  相似文献   

15.
The search for coatings that extend the useful life of biomedical devices has been of great interest, and titanium has been of great relevance due to its innocuousness and low reactivity. This study contributes to the investigation of Ti/Ag films in different configurations (monolayer and multilayer) deposited by magnetron sputtering. The sessile droplet technique was applied to study wettability; greater film penetrability was obtained when Ag is the external layer, conferring high efficiency in cell adhesion. The morphological properties were characterized by SEM, which showed porous nuclei on the surface in the Ag coating and crystals embedded in the Ti film. The structural properties were studied by XRD, revealing the presence of TiO2 in the anatase crystalline phase in a proportion of 49.9% and the formation of a silver cubic network centered on the faces. Tafel polarization curves demonstrated improvements in the corrosion current densities of Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti and Ti/Ag compared to the Ag coating, with values of 0.1749, 0.4802, and 2.044 nA.m−2, respectively. Antimicrobial activity was evaluated against the bacteria Pseudomonas aeruginosa and Bacillus subtilis and the yeasts Candida krusei and Candida albicans, revealing that the Ti/Ag and Ag/Ti/Ag/Ti/Ag/Ti/Ag/Ti coatings exhibit promise in biomedical material applications.  相似文献   

16.
The combination of low friction, wear resistance, high hardness, biocompatibility, and chemical inertness makes diamond-like carbon (DLC) films suitable in numerous applications in biomedical engineering. The cytotoxicity of DLC films containing TiO2 nanoparticles was practical and theoretically evaluated. The films were grown on 316L stainless steel substrates from a dispersion of TiO2 nanopowder in hexane. Raman spectroscopy shows that the presence of TiO2 increased the graphite-like bonds in the films. The incorporation of TiO2 nanoparticles into DLC films increases surface roughness, decreases water contact angle (increased hydrophilic character), and increases the total free surface energy due to the higher polar component. As the concentration of TiO2 increased, the films increased the cell viability (MTT assay), becoming more thermodynamically favorable to cell spreading (??F Adh values became more negative). This was evidenced through the increasing number of projections (philopodia and lamellipodia), indicating a higher adhesion between the L929 cells and the films. The practical and theoretical findings of this study show that the incorporation of TiO2 into DLC films is effective in enhancing cell viability. These results show the potential use of DLC and TiO2-DLC films in biomedical applications.  相似文献   

17.
锐钛矿型多孔TiO2薄膜的溶解法制备及性能表征   总被引:2,自引:0,他引:2  
在具有锐钛矿晶粒的TiO2溶胶中加入苯丙乳液粒子,使用该混合液浸渍提拉涂膜,然后利用甲苯将薄膜中的苯丙乳液粒子溶解去除,并通过重复涂膜,在室温下获得了具有良好多孔性的锐钛矿型TiO2薄膜。考察了多孔薄膜的表面形貌、光学性能、吸附性能和光催化性能。结果表明:随薄膜涂膜次数的增加,TiO2多孔薄膜的吸光度增大,透光率减小,光吸收边波长向长波方向移动。罗丹明B在TiO2多孔薄膜上的吸附量随涂膜次数的增加先升高,后降低;多次涂膜会在薄膜中产生半封闭的孔洞,经过长时间的毛细渗透等作用能进一步增加薄膜对罗丹明B的吸附。TiO2多孔薄膜通过吸附+光催化氧化的模式快速分解罗丹明B,其活性主要受到薄膜在光催化反应初期的吸附能力的影响。此外,TiO2的负载量、光的利用效率、以及光生电荷迁移及其分离等也是影响薄膜光催化活性的因素。  相似文献   

18.
In order to more easily separate TiO2 photocatalyst from the treated wastewater, TiO2 film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO2-coated ACFs (TiO2/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO2 film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO2/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO2/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO2 films and ACFs, which endowed the as-obtained TiO2/ACFs photocatalyst with improved reusable performance, and TiO2/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity.  相似文献   

19.
We demonstrate that the biomimetic method—which has been used for the formation of silica thin films—also could be applied directly to the formation of titanium dioxide (TiO2) thin films, which are technologically important materials because of their applications to photocatalytic purifiers, photochemical solar cells, and others. After generation of poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) films on gold surfaces by surface‐initiated polymerization, titanium bis(ammonium lactato)dihydroxide was used as a precursor of TiO2. The TiO2/PDMAEMA films were successfully formed on the surfaces in aqueous solution at neutral pH (pH 6.7) and room temperature, and were characterized by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy, and X‐ray diffractometry. The formed TiO2 films have an amorphous nature and large area uniformity in thickness. The degree of crystallization was controlled by annealing. We also investigated the pH effect and the phosphate incorporation in the films by using phosphate‐buffered solutions. The TiO2 films were formed in all the employed pH values in the range of 2 to 12, but phosphate anions were found to be incorporated into the films facilely only at low pH.  相似文献   

20.
In this work, Sn and Nb co-doped TiO2 were coated on glazed porcelain substrates via sol–gel dip coating method. Field emission-scanning electron microscopy, transmission electron microscopy, and UV–vis spectrophotometer were used to evaluate thickness and optical properties of the thin films. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy. Water contact angle on the film surfaces was measured by a contact angle analyzer under solar light irradiation. The optical results indicated that Sn/Nb dopant in TiO2 thin film changed the absorption edge from ultraviolet to visible light and exhibited excellent photo-catalytic ability for degradation of methylene blue solution under solar irradiation. Wettability results indicated that Sn and Nb dopant ions had significant effect on the hydrophilicity property of thin films.  相似文献   

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