Method for preparing super-hydrophobic molybdenum disulfide through organic ion in-situ wrapping technology, product and application

Abstract

The invention provides a method for preparing super-hydrophobic molybdenum disulfide through an organic ion in-situ wrapping technology, a product and application, and belongs to the technical field of hydrophobic materials. The preparation method provided by the invention comprises the following steps: dispersing molybdate, a sulfur source and a cationic surface modifier in water to obtain a mixed solution; and carrying out a hydrothermal reaction on the mixed solution, and cooling to room temperature to obtain the super-hydrophobic organic ion in-situ coated molybdenum disulfide (MoS2). The method has the advantages that the raw materials are wide in source, the production process is environmentally friendly, the required reaction temperature is mild, and the product is easy to separate and purify and shows high purity and good form consistency. In addition, the whole preparation process is simple and efficient, and is suitable for industrial popularization and application. According to the organic ion in-situ coated super-hydrophobic molybdenum disulfide prepared by the method, the hydrophilic property of MoS2 is successfully overcome, and the obvious super-hydrophobic characteristic is endowed to the molybdenum disulfide.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrophobic materials, and in particular to a method, product and application of preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology. Background Art

[0002] The hydrophobicity of solid materials refers to the special wettability of solid materials to liquids. Superhydrophobic materials generally refer to materials that have a spherical shape when water drops fall on the surface of the material, with a contact angle greater than 150 degrees and a rolling angle less than 10 degrees. Water drops on the surface of superhydrophobic materials can carry away surface impurities, so they can also achieve self-cleaning. Superhydrophobic materials can also be cleverly applied to the surface of materials that are easily reactive with water, acting as an efficient protective barrier to effectively isolate moisture and protect the underlying materials from water erosion and damage.

[0003] MoS2 (molybdenum disulfide), as a typical transition metal sulfide, has a graphite-like two-dimensional layered structure. The weak van der Waals force between its layers makes MoS2 exhibit excellent lubrication properties in the field of tribology. As a dry lubricant, MoS2 has the advantages of high temperature resistance and strong pressure resistance, and is widely used in lubrication under extreme working conditions such as high temperature and heavy load. However, MoS2 also has some application limitations. Among them, the most significant problem is its water resistance. Under water erosion, MoS2 is prone to agglomeration, resulting in lubrication failure. In order to overcome this limitation, it is necessary to find an effective method to improve the hydrophobicity of MoS2. Summary of the invention

[0004] Based on the above content, the purpose of the present invention is to provide a method, product and application of preparing super hydrophobic molybdenum disulfide by in-situ encapsulation technology of organic ions. The present invention adopts organic cations (hexadecyltrimethylammonium ions, CTA + ) complexed with molybdate anions to form Mo7O 24 (CTA)6 complex. During the reaction, under the action of the reducing agent and the sulfur source, Mo7O 24 6- It is reduced to MoS2, and finally the organic ion in-situ encapsulated MoS2 (MoS2-CTA) is obtained. The hydrophobicity comes from the specific binding of the hydrophilic ammonium group of the modifier CTA ion with MoS2, and the hydrophobic end of the modified alkane long chain is arranged outward to form a hydrophobic layer. This hydrophobic layer can effectively prevent water from directly contacting MoS2, thereby improving its water resistance and extending the working life of MoS2 in humid and low temperature conditions.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is a method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology, comprising the following steps:

[0007] dispersing molybdate, sulfur source and cationic surface modifier in water to obtain a mixed solution;

[0008] The mixed solution is subjected to a hydrothermal reaction and then cooled to room temperature to obtain the super-hydrophobic molybdenum disulfide.

[0009] The second technical solution of the present invention is a superhydrophobic molybdenum disulfide prepared by the above-mentioned method for preparing superhydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology.

[0010] The third technical solution of the present invention is a super hydrophobic coating, the raw materials of which include the above-mentioned super hydrophobic molybdenum disulfide.

[0011] A fourth technical solution of the present invention is a super hydrophobic coating, which is prepared from the above-mentioned super hydrophobic coating.

[0012] A fifth technical solution of the present invention is an application of the above-mentioned super-hydrophobic molybdenum disulfide or the above-mentioned super-hydrophobic coating in the preparation of a super-hydrophobic coating.

[0013] The present invention discloses the following technical effects:

[0014] The raw materials used in the present invention are widely available and easily obtained, the production process is environmentally friendly, the reaction temperature is low, the product is easy to separate and exhibits high purity and good morphological consistency, and the preparation process is simple and efficient, which is suitable for industrial promotion and application.

[0015] The organic ion in-situ encapsulated super-hydrophobic molybdenum disulfide prepared by the present invention has super-hydrophobicity and effectively modifies the hydrophilic property of MoS2.

[0016] The MoS2 treated with CTAB in the present invention not only exhibits super-hydrophobic properties, but also has good lubricity compared with traditional MoS2 coatings. The coating made of MoS2 in the present invention also prolongs the working life of the MoS2 coating under humid and low-temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 Schematic diagram of the structure of unoptimized MoS2 and in-situ encapsulation of MoS2 by organic ions;

[0019] Figure 2 X-ray diffraction patterns of the unoptimized MoS2 in Comparative Example 1 and the organic ion in-situ encapsulated MoS2 in Example 1;

[0020] Figure 3 This is a scanning electron microscope image of the in-situ encapsulation of MoS2 by organic ions in Example 1;

[0021] Figure 4 This is a scanning electron microscope image of the unoptimized MoS2 in Comparative Example 1;

[0022] Figure 5 This is a water contact angle test of the unoptimized MoS2 in Comparative Example 1 and the organic ion in-situ encapsulated MoS2 in Example 1. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] Room temperature in the present invention means 15-35°C.

[0029] According to the hydrophobic characteristics of long-chain alkanes, the cationic surface modifier is used to modify the hydrophilic characteristics of MoS2. The present invention innovatively proposes to use the cationic surface modifier to in-situ encapsulate MoS2 during the MoS2 generation process to obtain a super-hydrophobic MoS2 nanosphere material. The MoS2 treated with the cationic surface modifier (CTAB) in the present invention exhibits super-hydrophobic properties, which prolongs the working life of the MoS2 dry lubricant under humid and low-temperature conditions.

[0030] The present invention provides a method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology, comprising the following steps:

[0031] dispersing molybdate, sulfur source and cationic surface modifier in water to obtain a mixed solution;

[0032] The mixed solution is subjected to a hydrothermal reaction and then cooled to room temperature to obtain the super-hydrophobic molybdenum disulfide.

[0033] In some embodiments of the present invention, the sulfur source is thiourea; the cationic surface modifier is hexadecyltrimethylammonium bromide (CTAB). The present invention does not limit the specific type of molybdate, as long as it can be used with the sulfur source in a subsequent hydrothermal process to obtain super-hydrophobic MoS2 nanospheres under the induction of the cationic surface modifier, such as sodium molybdate, magnesium molybdate, zinc molybdate or sodium molybdate.

[0034] Thiourea decomposes at high temperature to produce ammonia, carbon dioxide and hydrogen sulfide. In the reaction of the present invention, thiourea not only provides a sulfur source, but also produces CO2 which can increase the pressure of the reaction system and facilitate the chemical reaction, thereby obtaining micron-sized powders of uniform size. The cationic surface modifier is preferably an organic cation having a linear alkane long chain structure, and an organic cation having a non-linear alkane long chain structure cannot achieve a hydrophobic effect.

[0035] In some embodiments of the present invention, the molar ratio of the molybdate, the sulfur source and the cationic surface modifier is (6-9):45:(0.8-1.2)). Further preferably, the molar ratio of the molybdate, the sulfur source and the cationic surface modifier is 7:45:1.

[0036] In some embodiments of the present invention, the usage ratio of the cationic surface modifier to water is (0.24-0.37) g:45 mL.

[0037] The present invention limits the ratio of molybdate, sulfur source, cationic surface modifier and water to ensure that the cationic surface modifier can play an inducing role.

[0038] The present invention does not impose any particular limitation on the method of dispersing the molybdate, sulfur source and cationic surface modifier in water, as long as they can be dispersed evenly to obtain a mixed solution with uniform components. For example, they can be dispersed by ultrasound or stirring.

[0039] In some embodiments of the present invention, the temperature of the hydrothermal reaction is 190-230° C., and the time is 15-24 h.

[0040] The generation temperature of MoS2 must be higher than 190°C, otherwise it cannot be successfully synthesized. However, when the temperature exceeds 230°C, there is a risk of carbonization of organic molecules, and the higher the temperature, the greater the safety risks during the experiment. In addition, insufficient reaction time may result in the product not being fully formed or in poor crystallization, which in turn has an adverse effect on the quality and yield of the product.

[0041] In some embodiments of the present invention, after cooling to room temperature, the reaction solution is filtered, the solid product obtained by filtration is collected, and the solid product is washed and dried. In the present invention, the washing method is to use deionized water and anhydrous ethanol for washing respectively; the drying is carried out in a vacuum drying oven, the drying temperature is 50-70°C, and the drying time is 36-60h.

[0042] The preparation principle of the present invention is as follows:

[0043] First, the cationic surface modifier (CTAB) is dispersed in deionized water. When the solution concentration exceeds the critical micelle concentration, the linear CTA ions exist in the aqueous solution in the form of spherical micelles with the hydrophobic groups facing inward and the hydrophilic groups facing outward. When the molybdate solution is added to the solution containing CTAB, Mo7O 24 6- The spontaneous adsorption and assembly between Mo7O and CTA ions can form a white flocculant complex. Subsequently, under the action of CH4N2S as a sulfur source and reducing agent, Mo7O 24 6- Reduced to MoS2, CTA + The in-situ wrapping of MoS2 nanosheets is achieved. At the same time, as the self-assembly proceeds layer by layer, some CTA + The relative position of is transferred to the middle layer of MoS2, realizing in-situ intercalation. Figure 1 Shown is a schematic diagram of the structure of in-situ encapsulation of organic ions.

[0044] The present invention also provides super-hydrophobic molybdenum disulfide prepared by the method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology as described in the above technical scheme.

[0045] The present invention also provides a super-hydrophobic coating, the raw materials of which include the super-hydrophobic molybdenum disulfide described in the above technical solution.

[0046] The present invention also provides a super-hydrophobic coating, which is prepared by the super-hydrophobic coating described in the above technical solution. The present invention does not specifically limit the method for preparing the super-hydrophobic coating by the super-hydrophobic coating, and the technical means well known to those skilled in the art can be selected, for example, after the super-hydrophobic coating is sprayed onto the surface of the substrate, it is dried.

[0047] The present invention also provides the application of the super-hydrophobic molybdenum disulfide or the above-mentioned super-hydrophobic coating in the preparation of super-hydrophobic coating described in the above technical solution. In addition, molybdenum disulfide and graphene are both raw materials commonly used in the production of transistors, but MoS2 and graphene are both hydrophilic, and the transistors produced may have reduced life or damage in an environment of high humidity and water. And the super-hydrophobic MoS2 proposed in the present invention may provide a solution for transistors in the above-mentioned special environment.

[0048] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0049] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0050] Example 1

[0051] This embodiment provides an organic ion in-situ encapsulated super-hydrophobic molybdenum disulfide, and the preparation method thereof is as follows:

[0052] (1) Accurately weigh 1.4484 g of ammonium molybdate tetrahydrate, 2.8418 g of thiourea, and 0.3 g of CTAB, disperse them in a beaker containing 45 mL of deionized water, and fully dissolve them under the action of magnetic stirring to form a uniform solution to obtain a reaction solution;

[0053] (2) The reaction solution was transferred to a 100 mL polytetrafluoroethylene-lined autoclave, heated at 210° C. in an oven for 18 h, and cooled naturally to room temperature after the reaction was completed;

[0054] (3) The black solid precipitate at the bottom of the polytetrafluoroethylene liner was taken out, washed with deionized water and anhydrous ethanol three times each, and then placed in a vacuum drying oven at 60° C. to dry to constant weight to obtain a solid powder, i.e., organic ions in situ encapsulated superhydrophobic molybdenum disulfide.

[0055] Comparative Example 1

[0056] This embodiment provides a MoS2 nanomaterial, and the preparation method thereof is different from that of Embodiment 1 only in that cetyltrimethylammonium bromide (CTAB) is not added.

[0057] Effect verification:

[0058] 1. Figure 1 Schematic diagram of in-situ encapsulation of organic ions in MoS2 to achieve hydrophobic properties: the ammonium groups of the CTA ions are bridged with the MoS2 surface, and the long hydrophobic alkane chains are arranged outward, thus giving the material hydrophobicity. Figure 2 The X-ray diffraction patterns of the unoptimized MoS2 in comparative example 1 and the organic ion in-situ encapsulated MoS2 in Example 1 (in the figure, the organic ion in-situ encapsulated MoS2 represents Example 1, and the unoptimized MoS2 represents comparative example 1). It can be seen that the organic ion in-situ encapsulated MoS2 shows a significantly expanded interlayer spacing, which is due to the fact that the growth mechanism of MoS2 is layer-by-layer self-assembly. After the MoS2 nanosheets are encapsulated by organic ions, part of the organic ions originally on the surface are transferred to the interlayer after self-assembly. The expanded interlayer spacing also shows the stable combination of CTA ions and MoS2 nanosheets.

[0059] 2. Figure 3 is a scanning electron microscope image of the in-situ encapsulation of MoS2 by organic ions in Example 1 (in the figure, the broken shell-like microspheres of MoS2 in-situ encapsulated by organic ions represent Example 1), Figure 4 This is a scanning electron microscope image of the unoptimized MoS2 in comparative example 1 (in the figure, the unoptimized MoS2 nanoflower represents comparative example 1). It can be seen that the MoS2 in situ encapsulated by organic ions exhibits a hollow microsphere inside. The unoptimized MoS2 exhibits clusters composed of nanosheets.

[0060] 3. Figure 5 The water contact angle test of the unoptimized MoS2 in comparative example 1 and the organic ion in-situ encapsulated MoS2 in Example 1 (in the figure, the organic ion in-situ encapsulated MoS2 represents Example 1, and the unoptimized MoS2 represents comparative example 1). It can be seen that the contact angle measured by the CTAB optimized MoS2 nanosphere powder material prepared in Example 1 is 158°, reaching the contact angle standard of super hydrophobic material; the contact angle of the MoS2 nanomaterial prepared in comparative example 1 is 53°.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology, characterized in that: The following steps are involved: dispersing molybdate, sulfur source and cationic surface modifier in water to obtain a mixed solution; The mixed solution is subjected to a hydrothermal reaction and then cooled to room temperature to obtain the super-hydrophobic molybdenum disulfide.

2. The method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to claim 1, characterized in that: The molybdate is ammonium molybdate, magnesium molybdate, zinc molybdate or sodium molybdate; the sulfur source is thiourea; and the cationic surface modifier is hexadecyltrimethylammonium bromide.

3. The method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to claim 1 or 2, characterized in that, The molar ratio of the molybdate, the sulfur source and the cationic surface modifier is (6-9):45:(0.8-1.2).

4. The method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to claim 1 or 2, characterized in that, The usage ratio of the cationic surface modifier to water is (0.24-0.37) g:45 mL.

5. The method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 190-230° C. and the time is 15-24 hours.

6. The method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to claim 1, characterized in that: After cooling to room temperature, the method further includes filtering the reaction solution, collecting the solid product obtained by filtration, and washing and drying the solid product.

7. A super-hydrophobic molybdenum disulfide prepared by the method for preparing super-hydrophobic molybdenum disulfide by organic ion in-situ encapsulation technology according to any one of claims 1 to 6.

8. A super hydrophobic coating, characterized in that: The raw material comprises the super-hydrophobic molybdenum disulfide as described in claim 7.

9. A super hydrophobic coating, characterized in that: Prepared from the superphobic coating according to claim 8.

10. Use of the super-hydrophobic molybdenum disulfide according to claim 7 or the super-hydrophobic coating according to claim 8 in preparing a super-hydrophobic coating.

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