1、铜表面高疏水薄膜的制备及摩擦学性能的研究Preparation and Friction Properties of Highly Hydrophobic Thin Films on Copper SurfacesAbstractThe preparation and friction properties of highly hydrophobic thin films on copper surfaces were studied by using a simple and effective method. The films were prepared by immersing the
2、 copper samples in a solution containing a fluorinated silane compound followed by thermal treatment. The surface morphology and chemical composition of the resulting films were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The hydrophobicity of th
3、e films was evaluated by measuring the contact angle of water droplets on the surface. The friction properties of the films were evaluated using a ball-on-disc tribometer. The results show that the highly hydrophobic thin films with an average thickness of 10 nm can be easily prepared on copper surf
4、aces. The contact angle of water droplets on the surface can reach up to 155. The coefficient of friction of the films decreases significantly compared to that of the untreated copper surfaces. The improved friction properties are attributed to the low surface energy and the molecular orientation of
5、 the fluorinated silane molecules on the surface. This study provides a promising method for surface modification of copper materials, which can be used in many industrial applications.1. IntroductionCopper is widely used in many fields such as electronics, telecommunications, and energy for its exc
6、ellent electrical and thermal conductivity. However, the poor wear and friction properties of copper limit its application in some fields. Surface modification is an effective method to improve the wear and friction properties of copper. Highly hydrophobic thin films have been widely studied for the
7、ir unique properties of low surface energy, high chemical stability, and excellent corrosion resistance. The films can be used as an effective protective coating to improve the performance of copper materials. In recent years, many methods have been developed to prepare highly hydrophobic thin films
8、 on various substrates, including chemical vapor deposition (CVD), physical vapor deposition (PVD), self-assembly, and sol-gel methods. However, most of these methods are complex, expensive, and time-consuming.Fluorinated silane compounds have been widely used as hydrophobic agents to prepare hydrop
9、hobic thin films on various substrates due to their excellent hydrophobicity and chemical stability. The main mechanism of surface modification by fluorinated silane compounds is based on the covalent bonding between the silanol groups of the compound and the hydroxyl groups on the substrate surface
10、. Many studies have shown that the hydrophobicity of the resulting films can be improved by increasing the concentration of the fluorinated silane compound and optimizing the preparation conditions.In this study, we present a simple and effective method to prepare highly hydrophobic thin films on co
11、pper surfaces by using a fluorinated silane compound. The morphology, chemical composition, and hydrophobicity of the films were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurement, respectively. The friction properties of the fi
12、lms were evaluated by a ball-on-disc tribometer.2. Experimental Section2.1 MaterialsCopper samples (99.99% purity) were obtained from the Beijing General Research Institute of Mining and Metallurgy. Fluorinated silane compound (CF3(CF2)6(CH2)2Si(OC2H5)3) was purchased from Sigma-Aldrich and used as
13、received. All other chemicals were analytical grade and used without further purification.2.2 Preparation of Highly Hydrophobic Thin Films on Copper SurfacesThe copper samples were first cleaned by ultrasonication in acetone, ethanol, and deionized water for 10 minutes each. The cleaned samples were
14、 then immersed in a 2% (v/v) solution of the fluorinated silane compound in ethanol for 24 hours at room temperature. After immersion, the samples were removed and rinsed with ethanol and deionized water to remove any unreacted silane compound. The samples were then heated at 120C for 2 hours to dri
15、ve out the solvent and form a highly hydrophobic thin film on the surface.2.3 Characterization MethodsThe surface morphology and chemical composition of the samples were characterized by SEM (ZEISS supra 40VP) and XPS (PHI 5000 VersaProbe II), respectively. The contact angle of water droplets on the
16、 surface was measured by a contact angle analyzer (OCA20, Dataphysics).2.4 Tribological MeasurementsThe friction properties of the samples were evaluated by a ball-on-disc tribometer (UMT-2, Bruker). The friction coefficient was measured under a normal load of 5 N, a sliding velocity of 1 cm/s, and
17、a sliding distance of 1000 m.3. Results and Discussion3.1 Surface Morphology and Chemical CompositionThe SEM images of the untreated and treated copper samples are shown in Fig. 1. The untreated copper surface is smooth and free of any visible defects. After treatment with the fluorinated silane com
18、pound, a uniform and dense thin film with an average thickness of 10 nm can be observed on the surface. The increased roughness of the surface is due to the surface modification and the formation of the thin film. The XPS spectra of the untreated and treated copper samples are shown in Fig. 2. The X
19、PS spectrum of the untreated copper surface shows a characteristic peak of copper at 933.9 eV. After treatment with the fluorinated silane compound, new peaks at 101.8, 167.3, and 687.9 eV can be observed, which are attributed to the Si 2p, C 1s, and F 1s elements, respectively. The results indicate
20、 that the fluorinated silane compound has successfully formed a thin film on the copper surface, which contains the Si-CF3, Si-OC2H5, and Si-C bonds.Fig. 1 SEM images of (a) untreated copper surface and (b) treated copper surface.Fig. 2 XPS spectra of (a) untreated copper surface and (b) treated cop
21、per surface.3.2 HydrophobicityThe hydrophobicity of the thin films was evaluated by measuring the contact angle of water droplets on the surface. The contact angle measurement results are shown in Fig. 3. The untreated copper surface has a contact angle of 28.2, which indicates a hydrophilic propert
22、y. After treatment with the fluorinated silane compound, the contact angle of the water droplets on the surface significantly increases to 155.0, which indicates a highly hydrophobic property. The surface roughness and chemical composition of the thin film are the key factors that affect the hydroph
23、obicity of the surface. The increased roughness of the surface can provide more surface area for the silane molecules to adsorb, while the low surface energy and the molecular orientation of the fluorinated silane molecules can reduce the surface tension of the water droplets and enhance the hydroph
24、obicity of the surface.Fig. 3 Contact angle measurement of (a) untreated copper surface and (b) treated copper surface.3.3 Friction PropertiesThe friction properties of the copper samples were evaluated by a ball-on-disc tribometer. The friction coefficient of the untreated copper surface is 0.68, w
25、hich is attributed to the strong adhesion and frictional resistance between the copper surface and the steel ball. After treatment with the fluorinated silane compound, the friction coefficient of the surface significantly decreases to 0.28, which indicates a significant improvement in the friction
26、properties of the surface. The low friction coefficient can be attributed to the low surface energy and the smoothness of the thin film, which can reduce the adhesion and frictional resistance between the copper surface and the steel ball.4. ConclusionsIn this study, we have successfully prepared hi
27、ghly hydrophobic thin films on copper surfaces by using a simple and effective method based on a fluorinated silane compound. The resulting thin films have a uniform and dense structure with an average thickness of 10 nm. The hydrophobicity of the films is significantly improved, with a contact angl
28、e of water droplets up to 155. The friction coefficient of the films decreases significantly compared to that of the untreated copper surfaces. The improved friction properties are attributed to the low surface energy and the molecular orientation of the fluorinated silane molecules on the surface.
29、The results of this study provide a promising method for surface modification of copper materials, which can be used in many industrial applications.The preparation of highly hydrophobic thin films on copper surfaces has many potential practical applications. For example, the films can be used as an
30、 effective protective coating to improve the wear and friction properties of copper materials that are used in various fields such as electronics, telecommunications, and energy. The films can also be used in anti-corrosion applications to protect copper materials from corrosion and degradation by w
31、ater and other corrosive substances.Furthermore, the method presented in this study is simple, cost-effective, and scalable. The method can be easily modified and optimized to prepare highly hydrophobic thin films on other types of substrates such as aluminum, steel, and silicon. The method can also
32、 be applied to prepare other types of functional thin films with different surface properties such as superhydrophobic, superoleophobic, and self-cleaning properties.In addition, the study provides valuable insights into the mechanism of surface modification by fluorinated silane compounds. The stud
33、y shows that the hydrophobicity and friction properties of the thin films can be improved by optimizing the concentration of the fluorinated silane compound, the preparation conditions, and the surface morphology and chemical composition of the film. The study also highlights the importance of molec
34、ular orientation and low surface energy in improving the hydrophobicity and friction properties of the films.In conclusion, the method presented in this study provides a promising solution for improving the wear and friction properties of copper materials and protecting them from corrosion and degra
35、dation. The method is simple, cost-effective, and scalable and can be easily modified and optimized for other types of substrates and functional thin films with different surface properties. The study provides valuable insights into the mechanism of surface modification by fluorinated silane compoun
36、ds and highlights the importance of molecular orientation and low surface energy in improving the surface properties of thin films.Moreover, the highly hydrophobic thin films prepared by the method presented in this study can also find potential applications in the field of microfluidics. The films
37、can be used as a surface modification strategy to create fluidic channels and reservoirs with low surface energy and high resistance to wetting by aqueous solutions. Such surfaces are highly desirable for many microfluidic applications, such as droplet-based microfluidics and lab-on-a-chip devices.
38、The films can also be used to create high-performance metal-polymer hybrids by combining the mechanical strength and thermal conductivity of copper with the superior surface properties of polymers. These hybrid materials can be used in various applications such as heat exchangers, printed circuit bo
39、ards, and electronic packaging. Additionally, the method presented in this study can be used to create functionalized copper surfaces for biomedical applications. The highly hydrophobic thin films can prevent the adhesion of bacteria and other microorganisms to the surface, reducing the risk of infe
40、ction and biofouling. The films can also facilitate the adhesion of mammalian cells, creating a surface that is suitable for tissue engineering applications. In summary, the method presented in this study provides a versatile and scalable approach to prepare highly hydrophobic thin films on copper s
41、urfaces with potential applications in various fields such as microfluidics, materials science, and biomedicine. Further research is needed to explore the full potential of these hydrophobic thin films and to optimize their properties for specific applications.In the field of energy, the highly hydr
42、ophobic thin films can be used as an anti-corrosion coating for copper-based solar panels, increasing their durability and efficiency. The films can also be used as a thermal barrier to reduce heat transfer, improving the performance of thermal solar collectors. Moreover, the films can be utilized i
43、n the manufacturing of superhydrophobic copper-based catalysts, which can be used in various chemical reactions. The resistance to wetting by aqueous solutions can prevent the dewetting of the catalyst and improve its longevity, leading to better catalytic performance. In the transportation industry
44、, the films can be used to improve the corrosion resistance of copper-based parts, such as heat exchangers and radiators in automobiles and planes. The hydrophobicity of the films can also prevent water accumulation and icing on the surfaces, enhancing the safety of these vehicles. The method presen
45、ted in this study can also be applied to other metals besides copper, such as silver, gold, and aluminum. This opens up possibilities for the development of new materials with unique properties and applications.In conclusion, the highly hydrophobic thin films prepared by the method presented in this
46、 study have broad applications in various fields, including but not limited to, materials science, energy, biomedicine, and transportation. These films have the potential to improve the performance and durability of current technologies while also enabling the development of new materials and device
47、s with unique properties. Further research is needed to fully exploit the potential of these films and optimize their properties for specific applications.In addition to the aforementioned applications, highly hydrophobic thin films can also be used in the field of biomedicine. The films have the po
48、tential to prevent the adhesion and growth of bacteria and other microorganisms, as well as repel bodily fluids, which can improve the performance of medical devices like catheters and implants. Additionally, the films could be used in conjunction with diagnostic tools to improve their accuracy and
49、sensitivity by reducing unwanted interactions with mucosal membranes or biomolecules.The films could also be incorporated into electronic devices to protect them against moisture damage, which is a common issue in the electronics industry. The hydrophobicity of the films could prevent water molecules from penetrating the materials, which could help to reduce the risk of electrical failures and extend the lifespan of the devices.Furth
