A superhydrophobic cerium oxide film and a preparation method thereof

Abstract

The present invention belongs to the field of super-hydrophobic material technology, and in particular to a kind of super-hydrophobic cerium oxide film and preparation method thereof.The present invention, in the mixed gas atmosphere including argon and oxygen, using Ce simple substance as target material, carries out grazing incidence magnetron sputtering, and obtains the super-hydrophobic CeO on substrate surface2Film;The substrate surface has micron-level array structure;The grazing angle of the grazing incidence magnetron sputtering is 45~55 °.The present invention uses grazing angle magnetron sputtering method, prepares CeO on the substrate surface with micron-level array structure2Film, successfully builds micron-nano composite structure, and outwardly protruding nanostructure has larger specific surface area;Thus, the super-hydrophobic cerium oxide film prepared by the present invention and the contact angle with water reaches 154.2 °, with excellent super-hydrophobic performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of super-hydrophobic materials, and in particular relates to a super-hydrophobic cerium oxide film and a preparation method thereof. Background Art

[0002] Wettability is a key characteristic of a material surface, primarily determined by the chemical composition of the solid surface and its microscopic geometry. Surfaces are categorized as hydrophilic or hydrophobic based on their wettability. Generally, a liquid droplet does not fully spread out on a solid surface; when stable, it forms a certain angle with the surface, known as the contact angle θ. A contact angle less than 90° is considered hydrophilic, greater than 90° is considered hydrophobic, and a contact angle greater than 150° and a rolling angle less than 10° is considered superhydrophobic.

[0003] Superhydrophobic materials should generally have low surface free energy (SE) and a surface with micro-nano structure. The Tadanaga group prepared a superhydrophobic Al2O3 film. They synthesized a rough and porous Al2O3 film surface by using a sol-gel method, and then used fluorosilane to perform secondary modification on the surface to obtain a contact angle with water of 165°. The Yoshimitsu group prepared a superhydrophobic SiO2 film and obtained a silicon surface with micron-level roughness by mechanical etching. The surface was also modified by fluorosilane for a second time to obtain a contact angle with water of 150°. The Liu group prepared a surface with a multi-level structure. A layered coating was prepared on a glass substrate by a one-step hydrothermal method. The coated substrate was then immersed in a modified solvent by a phase separation method. Finally, a surface with a multi-level structure was obtained, and a contact angle with water of 153.6° was obtained. Yang's team created a honeycomb-shaped super-hydrophobic surface. They prepared a micron-sized emulsion using a microemulsion method. The emulsion, coated on a glass substrate, was then heated and dried to create a porous and rough surface structure. Finally, the rough structure was modified with octyltrimethoxysilane, resulting in a water contact angle of 156°. While these methods have yielded relatively ideal hydrophobic surfaces, these research results also present some challenges: The development of materials for preparing super-hydrophobic surfaces involves expensive, low-surface-energy materials (such as polyethylene and fluorosilane compounds), and these materials have poor mechanical strength and are easily damaged, limiting their use.

[0004] Subsequently, researchers discovered that rare earth oxides are intrinsically hydrophobic, and that their hydrophobic temperature is as high as 1000°C. This research result has opened up a broad space for the preparation of ceramic hydrophobic materials with corrosion resistance, high thermal stability, high mechanical properties, and simple preparation processes. The applicant disclosed in "Growth and roughness dependent wetting properties of CeO2 films prepared by glancing angle deposition[J]" (T An, X Deng, S Liu, S Wang, J Ju, C Dou., Ceramics International SCI 44 (2018) 9742-9745) that nanoscale CeO2 films were prepared on silicon substrates using glancing angle deposition. Although the film has hydrophobic properties, it cannot achieve super-hydrophobic properties. Summary of the Invention

[0005] The purpose of the present invention is to provide a super-hydrophobic cerium oxide film and a preparation method thereof. The super-hydrophobic cerium oxide film prepared by the present invention has a maximum contact angle of 154.2° and has more excellent hydrophobic properties; and the preparation method is simple, low-cost, and suitable for industrial production.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a super-hydrophobic cerium oxide film, comprising the following steps:

[0008] In a mixed gas atmosphere containing argon and oxygen, grazing incidence magnetron sputtering is performed using Ce as a target material to obtain the super-hydrophobic CeO2 film on the surface of a substrate; the surface of the substrate has a micron-scale array structure; the grazing angle of the grazing incidence magnetron sputtering is 45~55°.

[0009] Preferably, the micron-scale array structure is composed of array units, and the array units are micron-scale cones, and the bottom diameter of the micron-scale cones is 2-3µm and the height is 2-3µm.

[0010] Preferably, the grazing incidence magnetron sputtering time is 1 to 6 hours.

[0011] Preferably, the sputtering pressure of the grazing incidence magnetron sputtering is 0.5~1.0Pa.

[0012] Preferably, the deposition temperature of the grazing incidence magnetron sputtering is 300-500°C.

[0013] Preferably, during the grazing incidence magnetron sputtering, the radio frequency power of the Ce target is 80-120W.

[0014] Preferably, the volume flow ratio of argon to oxygen is 30:(8~12).

[0015] Preferably, the substrate is made of Al2O3.

[0016] The present invention provides a super-hydrophobic cerium oxide film prepared by the preparation method described in the above technical solution, wherein the super-hydrophobic cerium oxide film has a micron-scale array structure, the micron-scale array structure is composed of array units, and the surface of the array structure unit forms a nano-protrusion structure.

[0017] Preferably, the nano-protrusion structure is a nano-thorn-like protrusion structure.

[0018] The present invention provides a kind of preparation method of super-hydrophobic cerium oxide film, comprise the following steps:In a mixed gas atmosphere including argon and oxygen, using Ce simple substance as target material, grazing incidence magnetron sputtering is carried out, and the super-hydrophobic CeO is obtained on substrate surface2Film;The substrate surface has micron-scale array structure;The grazing angle of the grazing incidence magnetron sputtering is 45~55 °.The present invention adopts grazing angle magnetron sputtering method, prepares CeO on the substrate surface with micron-scale array structure2Film, by controlling the grazing angle of grazing incidence magnetron sputtering is 45~55 °, obtains the nanoscale CeO of outward protrusion at micron-scale array structure surface deposition2Film, this by micron-scale array structure is substrate, and by grazing incidence magnetron sputtering CeO deposited on surface2Film not only successfully constructs micron-nano composite structure, and outward protrusion nanostructure has larger specific surface area;Thus, the super-hydrophobic cerium oxide film prepared by the present invention has a contact angle with water of 154.2 °, with excellent super-hydrophobic performance.

[0019] Furthermore, in the present invention, the array units of the micron-scale array structure are micron-scale cones. The present invention preferably uses micron-scale cones as the array units on the surface of the array structure, and the CeO2 film deposited on the surface has a thorn-like protrusion shape, presenting a "hedgehog-shaped" nano-CeO2 film with a large specific surface area and strong superhydrophobic properties.

[0020] Furthermore, in the present invention, the grazing incidence magnetron sputtering time is 1 to 6 hours. By controlling the grazing incidence magnetron sputtering time to 1 to 6 hours, the present invention avoids the inability to form an effective convex morphology due to the grazing incidence magnetron sputtering time being too short, and also avoids the reduction of the film specific surface area due to the grazing incidence magnetron sputtering time being too long, thereby achieving optimal superhydrophobic properties.

[0021] The present invention provides a super-hydrophobic cerium oxide film prepared by the preparation method described in the above technical solution, wherein the super-hydrophobic cerium oxide film has a micron-scale array structure, wherein the micron-scale array structure is composed of array units, and the surface of the array structure unit forms a nano-protrusion structure. The present invention successfully constructs a surface micro-nanostructure by growing a nano-scale CeO2 film on a micron-structured template, and achieves super-hydrophobic properties by creating a layered surface of microns and nanometers. The super-hydrophobic cerium oxide film prepared by the present invention has a larger contact angle than the CeO2 ceramic sheet prepared by a sintering method in "Hydrophobicity of rare-earth oxide ceramics" (Azimi, G., Dhiman, R., Kwon, HM. et al., Nature Materials, Mater 12, 315–320 (2013)). The contact angle of the superhydrophobic cerium oxide film is also greater than that of a single nanoscale CeO2 film prepared on a smooth silicon substrate ("Growth and roughness dependent wetting properties of CeO2 films prepared by glancing angle deposition[J]") (TAn, X Deng, S Liu, S Wang, J Ju, C Dou., Ceramics International SCI 44 (2018) 9742-9745). Therefore, the superhydrophobic cerium oxide film provided by the present invention has superior hydrophobic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 SEM images and cross-sectional morphology images of the sapphire substrate used in the embodiments of the present invention;

[0023] Figure 2 XRD patterns of CeO2 films prepared in Examples 1 to 4 of the present invention and Comparative Example 1;

[0024] Figure 3 This is a scanning electron microscope plan view of the CeO2 film deposited for 2 hours in Example 1 of the present invention;

[0025] Figure 4 This is a scanning electron microscope plan view of the CeO2 film deposited for 4 hours in Example 2 of the present invention;

[0026] Figure 5 This is a scanning electron microscope plan view of the CeO2 film deposited for 6 hours in Example 3 of the present invention;

[0027] Figure 6 This is a scanning electron microscope cross-sectional image of a CeO2 film deposited for 2 hours in Example 1 of the present invention;

[0028] Figure 7 This is a scanning electron microscope cross-sectional image of a CeO2 film deposited for 4 hours in Example 2 of the present invention;

[0029] Figure 8 This is a scanning electron microscope cross-sectional image of a CeO2 film deposited for 6 hours in Example 3 of the present invention;

[0030] Figure 9 This is a scanning electron microscope plan view of a CeO2 film deposited for 1 h in Example 4 of the present invention;

[0031] Figure 10 This is a scanning electron microscope plan view of a CeO2 film deposited for 0.5 h in Comparative Example 1 of the present invention;

[0032] Figure 11 Typical contact angle test images of CeO2 film surfaces and water prepared in Examples and Comparative Examples of the present invention;

[0033] Figure 12 The contact angle diagrams of CeO2 films prepared in Example 1 of the present invention and Comparative Example 1;

[0034] Figure 13 This is a comparison chart of the contact angles of CeO2 films prepared in Example 1 of the present invention and Comparative Example 2. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing a super-hydrophobic cerium oxide film, comprising the following steps:

[0036] In a mixed gas atmosphere containing argon and oxygen, grazing incidence magnetron sputtering is performed using Ce as a target material to obtain the super-hydrophobic CeO2 film on the surface of a substrate; the surface of the substrate has a micron-scale array structure; the grazing angle of the grazing incidence magnetron sputtering is 45~55°.

[0037] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0038] In the present invention, the material of the substrate is preferably Al2O3. In a specific embodiment of the present invention, the substrate is preferably sapphire.

[0039] In the present invention, the microscopic morphology of the sapphire substrate is closer to the surface morphology of the lotus leaf. The present invention uses the sapphire substrate to grow a nano-scale CeO2 film, and improves the hydrophobicity of the film by imitating the surface structure of the lotus leaf.

[0040] In the present invention, the substrate surface has a micron-scale array structure. In the present invention, the micron-scale array structure is composed of array units; the array units of the micron-scale array structure are preferably micron-scale cones, and the base diameter of the micron-scale cones is preferably 2-3µm, more preferably 2.3-2.7µm; the height is preferably 2-3µm, more preferably 2-2.3µm.

[0041] This invention mimics the lotus effect by growing a nanoscale film on a micron-scale surface, forming a micron-nano composite structure. Specifically, this invention utilizes a rough sapphire substrate, which is a super-hydrophobic material (water contact angle > 150°). The surface of the sapphire substrate with a micron-scale array structure used in this invention not only has low surface energy but also a certain degree of roughness (micron-scale array structure). Further increasing the microscopic roughness of the substrate surface can further increase its contact angle with water, thereby achieving a highly (super) hydrophobic effect. The cerium oxide film provided by this invention, due to its micron-nano composite structure, is more hydrophobic than a single micron- or nanoscale film. Because the hierarchical composite structure significantly reduces the contact area between the solid surface and the liquid surface, the smaller the contact area, the more hydrophobic it is.

[0042] The present invention uses a substrate with a micron-scale array structure on its surface to grow a nano-scale CeO2 film. By regulating the array structure units on the surface of the array structure to have a conical morphology, a nano-scale CeO2 film with a thorny morphology can be grown on the surface of the array structure units. This special thorny morphology of the CeO2 film gives it a relatively large specific surface area and improves its hydrophobic performance.

[0043] In a specific embodiment of the present invention, the size of the substrate is preferably 2 cm×2 cm.

[0044] Before performing the grazing incidence magnetron sputtering, the present invention preferably pre-treats the substrate and the Ce target separately. The present invention preferably pre-treats the substrate by ultrasonically cleaning the substrate in acetone, alcohol, and deionized water for 10 minutes respectively, and then drying it with a hair dryer. The present invention preferably pre-treats the Ce target by argon ion sputtering to clean away contaminants on the surface of the Ce target. The present invention does not have any special restrictions on the conditions of the argon ion sputtering, and the sputtering conditions familiar to those skilled in the art can be used.

[0045] In the present invention, before performing grazing incidence magnetron sputtering, the present invention preferably places the cleaned substrate on a sample holder in a vacuum chamber, and then pumps the background pressure of the vacuum chamber to 5×10 -4 Pa, then argon is introduced into the vacuum chamber as a sputtering gas and oxygen is introduced as a reaction gas. In the mixed gas atmosphere of argon and oxygen, a super-hydrophobic cerium oxide film is prepared using metal Ce as a target.

[0046] In the present invention, the volume flow ratio of argon to oxygen is preferably 30:(8-12), more preferably 30:10.

[0047] In the present invention, the grazing incidence angle of the grazing incidence magnetron sputtering is 45-55°, more preferably 48-52°, and most preferably 50°.

[0048] In the present invention, the sputtering pressure of the grazing incidence magnetron sputtering is preferably 0.5-1.0 Pa, more preferably 0.6-0.9 Pa, and most preferably 0.8 Pa.

[0049] In the present invention, the deposition temperature of the grazing incidence magnetron sputtering is preferably 300-500°C, more preferably 350-550°C, and most preferably 400°C.

[0050] In the present invention, during the grazing incidence magnetron sputtering, the radio frequency power of the Ce target is preferably 80-120 W, more preferably 90-110 W, and most preferably 100 W.

[0051] In the present invention, the grazing incidence magnetron sputtering time is preferably 1 to 6 hours, more preferably 1 to 4 hours, and most preferably 2 to 4 hours.

[0052] In the present invention, the time of the grazing incidence magnetron sputtering cannot be too short or too long. When the time of the grazing incidence magnetron sputtering is less than 1 hour, only a small granular cerium oxide film can be obtained on the surface of the micron-scale array structure of the substrate. The film is flat and has certain hydrophobicity, but the hydrophobicity is poor; when the time of the grazing incidence magnetron sputtering is greater than 6 hours, the thorn-like protrusion structure of the thorn-like cerium oxide film formed on the surface of the micron-scale array structure of the substrate is too large, and the gap between the thorns is also too large, resulting in the destruction of the micron-nano composite structure of the cerium oxide film, resulting in poor hydrophobicity.

[0053] The present invention controls the volume flow ratio, pressure, temperature, radio frequency power and time of grazing incidence magnetron sputtering of argon and oxygen, so as to increase the specific surface area of the super-hydrophobic cerium oxide film and improve the hydrophobicity of the super-hydrophobic cerium oxide film.

[0054] This invention uses grazing-angle magnetron sputtering to produce nanoscale CeO2 materials with unique morphologies on rough, micron-sized sapphire substrates. By manipulating the deposition time during the film preparation process, CeO2 films with controllable roughness and morphology, while also exhibiting excellent hydrophobic properties, are produced. This invention provides experimental and theoretical guidance for the research of ceramic hydrophobic membrane materials.

[0055] The present invention provides a super-hydrophobic cerium oxide film prepared by the preparation method described in the above technical solution, wherein the super-hydrophobic cerium oxide film has a micron-scale array structure, the micron-scale array structure is composed of array units, and the surface of the array structure unit forms a nano-protrusion structure.

[0056] In the present invention, the nano-protrusion structure is preferably a nano-thorn-like protrusion structure.

[0057] like Figures 3 to 9 As shown, the super-hydrophobic cerium oxide film deposited on the micron-scale array structure surface of the substrate of the present invention also has a micron-scale array structure. The CeO2 prepared by grazing incidence magnetron sputtering initially grows in the form of particles on the micron-scale array structure surface of the substrate. As the deposition time increases, CeO2 forms a surface with a micron-scale array structure as well as a thorn-like protrusion structure on the surface of the micron-scale array structure of the substrate, thereby forming a cerium oxide film with a "hedgehog morphology". It not only has a micron-nano composite structure, but also the thorn-like protrusions have the characteristics of a large specific surface area. Therefore, the cerium oxide film prepared by the present invention has super-hydrophobic characteristics.

[0058] The present invention adopts a grazing-incidence magnetron sputtering method and selects a sapphire substrate with a micron-scale array structure surface to construct a cerium oxide film with a micro-nano hierarchical structure. A micro-nano CeO2 film is prepared on a rough micron-scale sapphire substrate (with a micron-scale array structure surface). The surface morphology of the film presents a "hedgehog shape" and has excellent hydrophobic properties. The contact angle of the CeO2 film prepared by the present invention with water reaches 154.2°, which is the current maximum contact angle value of CeO2 material.

[0059] In order to further illustrate the present invention, the technical solution provided by the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0060] Example 1

[0061] A sapphire substrate with a size of 2 cm × 2 cm and a micron-scale array structure on the surface (the array unit is a cone with a bottom diameter of 2 µm and a height of 2 µm) was ultrasonically cleaned in acetone, alcohol, and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0062] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0063] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and oxygen (the flow ratio of argon and oxygen was 30:10), a CeO2 film was obtained by grazing incidence magnetron sputtering (the grazing angle was fixed at 50°) with a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a Ce target RF power of 100 W, and a sputtering time of 2 hours using cleaned metal Ce as the target.

[0064] Figure 1 This is a microscopic topography of the sapphire substrate used in this embodiment. Figure 1 (a) is the SEM image of the sapphire substrate surface. Figure 1 (b) is the cross-sectional morphology of the sapphire substrate. Figure 1 It can be concluded that the surface of the sapphire substrate is composed of a regular array of cones of the same size, uniform size, and micron-sized, shaped like small hills. The bottom diameter of the hill is 2µm and the height is 2µm. Figure 1 When (b) in the figure is naturally broken by the sapphire substrate, the fracture surface is along the depression of the regularly arranged small hills. The side of the intact regularly arranged small hills is intercepted and the cross section is obtained by SEM characterization.

[0065] Figure 3 This is a scanning electron microscope plan view of the CeO2 film prepared under the conditions of a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a RF power of 100 W, an argon to oxygen gas flow ratio of 30:10, and a sputtering time of 2 h in this embodiment.

[0066] Figure 6 This is a scanning electron microscope cross-sectional image of the CeO2 film deposited for 2 hours in this example.

[0067] Example 2

[0068] A sapphire substrate with a size of 2 cm × 2 cm and a micron-scale array structure on the surface (the array unit is a cone with a bottom diameter of 2 µm and a height of 2 µm) was ultrasonically cleaned in acetone, alcohol, and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0069] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0070] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and O2 (the flow ratio of argon and oxygen was 30:10), a CeO2 film was obtained by grazing incidence magnetron sputtering (the grazing angle was fixed at 50°) with a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a Ce target RF power of 100 W, and a sputtering time of 4 hours using cleaned metal Ce as the target.

[0071] The microscopic morphology of the sapphire substrate used in this embodiment is the same as that in Example 1.

[0072] Figure 4 This is a scanning electron microscope plan view of the CeO2 film prepared under the conditions of a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a RF power of 100 W, an argon to oxygen gas flow ratio of 30:10, and a sputtering time of 4 h in this embodiment.

[0073] Figure 7 This is a scanning electron microscope cross-sectional image of the CeO2 film prepared by deposition for 4 hours in Example 2 of the present invention.

[0074] Example 3

[0075] A sapphire substrate with a size of 2 cm × 2 cm and a micron-scale array structure on the surface (the array unit is a cone with a bottom diameter of 2 µm and a height of 2 µm) was ultrasonically cleaned in acetone, alcohol, and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0076] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0077] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4 Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and O2 (the flow ratio of argon to oxygen was 30:10), a CeO2 film was obtained by grazing incidence magnetron sputtering (the grazing angle was fixed at 50°) with a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a Ce target RF power of 100 W, and a sputtering time of 6 hours using cleaned metal Ce as the target.

[0078] The microscopic morphology of the sapphire substrate used in this embodiment is the same as that in Example 1.

[0079] Figure 5 This is a scanning electron microscope plan view of the CeO2 film prepared under the conditions of a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a RF power of 100 W, an argon to oxygen gas flow ratio of 30:10, and a sputtering time of 6 h in this embodiment.

[0080] Figure 8 This is a scanning electron microscope cross-sectional image of the CeO2 film prepared by deposition for 6 hours in Example 3 of the present invention.

[0081] Example 4

[0082] A sapphire substrate with a size of 2 cm × 2 cm and a micron-scale array structure on the surface (the array unit is a cone with a bottom diameter of 2 µm and a height of 2 µm) was ultrasonically cleaned in acetone, alcohol, and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0083] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0084] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4 Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and O2 (the flow ratio of argon to oxygen was 30:10), a CeO2 film was obtained by grazing incidence magnetron sputtering (the grazing angle was fixed at 50°) with a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a Ce target RF power of 100 W, and a sputtering time of 1 hour using cleaned metal Ce as the target.

[0085] The microscopic morphology of the sapphire substrate used in this embodiment is the same as that in Example 1.

[0086] Figure 9 This is a scanning electron microscope plan view of the CeO2 film prepared under the conditions of a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a RF power of 100 W, an argon to oxygen gas flow ratio of 30:10, and a sputtering time of 1 h in this embodiment.

[0087] Comparative Example 1

[0088] A sapphire substrate with a size of 2 cm × 2 cm and a micron-scale array structure on the surface (the array unit is a cone with a bottom diameter of 2 µm and a height of 2 µm) was ultrasonically cleaned in acetone, alcohol, and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0089] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0090] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and O2 (the flow ratio of argon and oxygen was 30:10), a CeO2 film was obtained by grazing incidence magnetron sputtering (the grazing angle was fixed at 50°) with a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a Ce target RF power of 100 W, and a sputtering time of 0.5 h using cleaned metal Ce as the target.

[0091] The microscopic morphology of the sapphire substrate used in this embodiment is the same as that in Example 1.

[0092] Figure 10 This is a scanning electron microscope plan view of the CeO2 film prepared under the conditions of a sputtering pressure of 0.8 Pa, a deposition temperature of 400°C, a RF power of 100 W, an argon to oxygen gas flow ratio of 30:10, and a sputtering time of 0.5 h in this embodiment.

[0093] Test Example 1

[0094] Figure 2 The XRD patterns of CeO2 films prepared in Examples 1 to 4 and Comparative Example 1 of the present invention are shown in FIG. Figure 2 It can be concluded that: in the XRD diagram, Figure 2 It can be seen that under the conditions of sputtering time of 0.5h, 1h, 2h and 4h respectively, the (200) and (311) diffraction peaks of cerium oxide crystals gradually increase. When the deposition time is 2 hours, the strongest peak changes from the original (111) to (200).

[0095] Depend on Figures 3 to 10 It can be concluded that when the deposition time is 0.5, 1h, and 2h, the surface becomes rougher and rougher as the deposition time increases. It is the roughest between the mountains, where you can see bumpy particles growing on the hills, which are relatively flat. When the deposition time is 4h and 6h, the shape becomes thorn-like, and the size of the thorns increases with the deposition time, and they become very rough. Figure 6 、 7 Figures 8 and 8 are scanning electron microscope cross-sectional images of CeO2 films prepared under the conditions of sputtering pressure of 0.8 Pa, deposition temperature of 400℃, RF power of 100 W, argon and oxygen gas flow ratio of 30:10, and sputtering time of 2 h, 4 h, and 6 h, respectively. Figures 6-8 It can be concluded that the SEM cross section when the deposition time is 2h Figure 6 It can be seen that the small lumpy particles growing on the hill, when the deposition time is 4h and 6h, Figure 7 、 8 The hills are covered with small three-dimensional thorns, which are very rough. As the deposition time increases, the size of the CeO2 film thorns prepared under 6h conditions becomes larger, and the gaps between the thorns also become larger.

[0096] Comparative Example 2

[0097] A Si (100) substrate with a size of 2 cm × 2 cm and a smooth surface was ultrasonically cleaned in acetone, alcohol and deionized water for 10 minutes respectively, and then dried with a hair dryer.

[0098] Argon ion sputtering is used to clean the contaminants on the surface of the Ce target.

[0099] The cleaned sapphire substrate was placed on the sample holder in the vacuum chamber. Before preparation, the background pressure in the vacuum chamber was pumped to 5×10 -4 Pa, then argon was introduced into the vacuum chamber as the sputtering gas and oxygen as the reaction gas. In a mixed atmosphere of argon and O2 (the flow ratio of argon and oxygen was 30:10), cleaned metal Ce was used as the target material, and the grazing incidence magnetron sputtering method (the grazing angle was fixed at 50°) was adopted. The sputtering pressure was 0.8 Pa, the deposition temperature was 400°C, the RF power of the Ce target was 100W, and the sputtering time was 0.5h, 1h, and 2h, respectively, to obtain CeO2 films on Si precipitates.

[0100] Test Example 2

[0101] In this test, the contact angles of CeO2 films prepared in Examples 1-4 and Comparative Examples 1-2 were measured with water. An optical contact angle meter was used to test the CeO2 films. A 5μL drop of deionized water was placed on the surface of the sample. After the droplet stabilized, a photograph was taken. Software was then used to calculate the contact angle between the droplet and the sample surface. At least five points were measured for each sample, and the average was calculated. Figure 11 This is a photo of the water contact angle of the sample.

[0102] The contact angles of CeO2 films prepared in Examples 1 to 4 and Comparative Example 1 with water ranged from 133.5° to 154.2°. Figure 12 The deposition time of the CeO2 film prepared in Example 1 is 2 hours, and the contact angle of the material is 152.8°C. The deposition time of the CeO2 film prepared in Example 2 is 4 hours, and the contact angle of the material is 154.2°C. The deposition time of the CeO2 film prepared in Example 3 is 6 hours, and the contact angle of the material is 146.3°C. The deposition time of the CeO2 film prepared in Example 4 is 1 hour, and the contact angle of the material is 148.4°C. The deposition time of the CeO2 film prepared in Comparative Example 1 is 0.5 hours, and the contact angle of the material is 133.5°C. Figure 12It can be seen that the contact angle of the super-hydrophobic material (>150°) has been achieved when the deposition time of the CeO2 film prepared by the present invention is 2h~4h, and high hydrophobic performance can also be obtained when the deposition time is 1h and 6h. When the deposition time of the present invention is 0.5, 1h, 2h, and 4h, the film surface becomes more and more hydrophobic as the deposition time increases. The contact angle value of the CeO2 film prepared under the 4h condition reaches the maximum value, which is 154.2°. 154.2° is the maximum contact angle of CeO2 material with water found so far. When the deposition time is 6h, it is found that the hydrophobicity deteriorates, and the contact angle value only reaches 146.3°. This is because the gaps between the particles on the surface of the CeO2 film with a deposition time of 6 hours become larger, resulting in an increase in the contact area between the water droplet and the film, a decrease in the contact angle, and thus a deterioration in the hydrophobicity. Figure 12 To demonstrate that the present invention uses a grazing incidence magnetron sputtering method to prepare a nanoscale CeO2 film on a rough micron-sized sapphire substrate, a super-hydrophobic CeO2 film is prepared when the deposition time is 2h and 4h. Compared with a single nanoscale CeO2 film prepared on a smooth silicon wafer (Comparative Example 2), as shown in FIG. Figure 13 The contact angle value of a single nanoscale CeO2 film prepared on a smooth silicon wafer did not exceed 150°, showing hydrophobicity, proving that the CeO2 film prepared by constructing a micro-nano rough structure in the present invention has a very large contribution to hydrophobicity. The membrane constructed with a micron-nano composite structure is more hydrophobic than a single nanoscale membrane and shows superhydrophobicity. Since the hierarchical composite structure can greatly reduce the contact area between the solid surface and the liquid surface, the smaller the contact area, the more hydrophobic it is.

[0103] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a super-hydrophobic cerium oxide film, characterized in that: The following steps are involved: In a mixed gas atmosphere comprising argon and oxygen, grazing incidence magnetron sputtering is performed using Ce as a target material to obtain the super-hydrophobic CeO2 film on the surface of a substrate; the substrate surface has a micron-scale array structure, the micron-scale array structure is composed of array units, and the array units are micron-scale cones; the grazing incidence magnetron sputtering has a grazing angle of 45 to 55 degrees and a grazing incidence magnetron sputtering time of 2 to 4 hours; The super-hydrophobic cerium oxide film has a micron-scale array structure, which is composed of array units. The array units are micron-scale cones. Nano-protrusion structures are formed on the surfaces of the array units. The nano-protrusion structures are nano-thorn-like protrusion structures.

2. The preparation method according to claim 1, characterized in that The bottom diameter of the micron-scale cone is 2-3 μm, and the height is 2-3 μm.

3. The preparation method according to claim 1, characterized in that The sputtering pressure of the grazing incidence magnetron sputtering is 0.5-1.0 Pa.

4. The preparation method according to claim 1, characterized in that The deposition temperature of the grazing incidence magnetron sputtering is 300-500°C.

5. The preparation method according to claim 1, characterized in that During the grazing incidence magnetron sputtering, the radio frequency power of the target material is 80-120W.

6. The preparation method according to claim 1, characterized in that The volume flow ratio of the argon gas to the oxygen gas is 30:(8-12).

7. The preparation method according to claim 1, characterized in that The material of the substrate is Al2O3.

8. The super-hydrophobic cerium oxide film prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The super-hydrophobic cerium oxide film has a micron-scale array structure, which is composed of array units. The array units are micron-scale cones. Nano-protrusion structures are formed on the surfaces of the array units. The nano-protrusion structures are nano-thorn-like protrusion structures.

Images