Metal organic hybrid lubricating glass coating with self-repairing function and preparation method thereof

Abstract

The invention discloses a metal organic hybrid glass coating material with water-triggered lubrication and self-repairing functions as well as a preparation method and application thereof, and belongs to the field of functional coating materials. The material is mainly formed by self-assembly of metal ions (such as zinc, cadmium, europium or terbium) and a histidine ligand through evaporation induction. In a dry state, the material is in a solid glassy state and can be stably attached to the surfaces of various substrates; after meeting water, the lubricating oil is dissolved to form a liquid lubricating layer on a friction interface, so that the friction coefficient is obviously reduced to 0.1 or below, and the lowest friction coefficient can reach 0.06 or so; and after the moisture is volatilized, the material can recover the solid state and realize structure self-repairing. The lubricating property of the material can be further improved by adding a two-dimensional material MXene (the content is 0.01-1.5 wt%). The preparation method is simple and convenient, the metal salt and the histidine ligand are self-assembled in water and then are ground and dispersed to form slurry, and the slurry is coated and dried. The material is suitable for occasions needing lubrication on demand such as precision machinery and medical equipment, realizes the crossing from passive protection to active response and self-repairing, and has important engineering application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional coating materials, in particular to a metal-organic hybrid glass coating material with water-triggered lubrication and self-repairing functions and a preparation method and application thereof. BACKGROUND

[0002] In a large number of mechanical moving parts, precision instruments and medical devices, lubrication is a key means to reduce friction, reduce wear and prolong service life. Traditional lubricating materials are mostly oils, solid lubricants or polymer coatings, which often have problems such as easy contamination, difficult replenishment, poor environmental adaptability, and inability to self-repair. Especially in some occasions requiring intermittent lubrication or changing environmental conditions, traditional lubrication methods are difficult to achieve "on-demand lubrication" and long-term protection.

[0003] In recent years, the development of intelligent responsive materials has provided new ideas for the lubrication field, such as switching the lubrication state through temperature, pH, light and other external stimuli. However, these materials are mostly single-function, often lack the ability to automatically restore the initial state after use, and it is even more difficult to simultaneously achieve the integration design of "triggered lubrication" and "damage self-repair".

[0004] Metal-organic hybrid glass is a kind of amorphous material formed by molecular self-assembly of metal ions and organic ligands, which has adjustable structure, excellent optical properties, and can exhibit dynamic reversible characteristics under certain conditions. This kind of material has been studied in the fields of optics, sensing, etc., but it has not been fully explored and systematically reported as an intelligent coating material that can respond to water triggers and has self-repairing functions in the field of lubrication.

[0005] Therefore, it is of great scientific research significance and engineering application value to develop an integrated glass coating material with simple structure, sensitive response, "on-demand lubrication" and "self-repairing" capabilities, and adaptability to complex environments. SUMMARY

[0006] The present application aims to provide a metal-organic hybrid glass coating material with water-triggered lubrication and self-repairing functions to solve the problem that existing lubricating materials cannot achieve on-demand triggering, long-term self-repairing and strong environmental adaptability.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A metal-organic hybrid glass coating material with water-triggered lubrication and self-repairing functions, characterized in that the material has the following properties:

[0009] Solid adhesion: in a dry state, it is a solid glass state and can be stably attached to the surface of various substrates;

[0010] Water-triggered lubricity: partial dissolution upon water exposure, forming a liquid lubricating layer at the friction interface, significantly reducing the friction coefficient;

[0011] Self-repairing: after water evaporation, the material can restore to solid glass state and realize structural self-repairing.

[0012] Preferably, the material is formed by evaporation-induced self-assembly of metal ions and organic ligands, wherein the metal ions are selected from at least one of zinc, cadmium, europium, and terbium, and the organic ligands are L-histidine or D-histidine.

[0013] More preferably, two-dimensional titanium carbide (MXene) is further dispersed in the material; in the dry solid state, the MXene is coated in the glass matrix; upon water exposure, the MXene is exposed to the interface as the glass matrix dissolves, cooperatively realizing low-friction liquid lubrication.

[0014] Further, the content of the MXene is 0.01-1.5wt%, and the thickness of the MXene sheet is 1-5nm. Experiments show that when the material is coated on the surface of a substrate and forms a liquid lubricating layer after water is added, the friction coefficient can be reduced to below 0.1, preferably below 0.06, when rubbing against stainless steel.

[0015] The present application also provides a preparation method of the material, comprising the following steps:

[0016] S1: dissolving a metal salt and a histidine ligand in water, and evaporating to induce self-assembly at room temperature to form a metal-organic hybrid glass;

[0017] S2: grinding the obtained glass material into a powder, and re-dissolving with water as a coating precursor;

[0018] S3: optionally, mixing a MXene dispersion with the precursor to obtain a composite slurry;

[0019] S4: coating the precursor or the slurry on the surface of a substrate to form a solid coating after drying.

[0020] In addition, the present application also provides the use of the material for preparing a "on-demand lubrication" functional coating, which is particularly suitable for precision machinery, medical devices, micro-electro-mechanical systems, or moving parts that require intermittent lubrication.

[0021] The present application also provides a lubrication method using the material as a lubrication functional layer to provide basic protection in the dry state; triggering liquid lubrication by adding water when lubrication is needed; after use, the water evaporates, and the coating restores to a solid state and self-repairs. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1The Zn-L-histidine hybrid glass manufactured in the silica gel template shows good plasticity and forming ability;

[0023] Figure 2 a and Figure 2 b are respectively the Zn-L-histidine hybrid glass manufactured on the surface of stainless steel and the MXene@Zn-L-histidine hybrid glass, and compared with each other, the color of the glass becomes darker after the addition of Mxene;

[0024] Figure 3 The friction coefficient curves of the Zn-L-histidine hybrid glass and the MXene@Zn-L-histidine hybrid glass after the addition of water, the load is 5N, 2Hz, 5mm stainless steel ball, and it is proved that the addition of MXene can further reduce the friction coefficient;

[0025] Figure 4 The friction coefficient and the comparison curve of deionized water of the MXene@Zn-L-histidine hybrid glass after the addition of water on the self-lubricating polyether ether ketone (PEEK) surface, and it is proved that the coating can significantly prolong the wear life of the self-lubricating substrate. DETAILED DESCRIPTION

[0026] The application will be further described below in combination with the drawings and specific examples, but the protection scope of the application is not limited to the following examples.

[0027] Example 1: Preparation of Zn-L-histidine hybrid glass coating

[0028] (1) Zn(NO3)2·6H2O and L-histidine were dissolved in deionized water according to a molar ratio of 1:2, poured into a silica gel template, and evaporated at room temperature for 5 days to form a hydrogel;

[0029] (2) The hydrogel was further dried at room temperature for 25 days to obtain Zn-L-histidine hybrid glass as shown in Figure 1 , which was ground into fine powder;

[0030] (3) The glass powder was dispersed in water again, and the coating slurry was obtained after ultrasonic treatment;

[0031] (4) The slurry was sprayed on the surface of a stainless steel sheet, and a solid coating was formed after drying at room temperature, as shown in Figure 2 a;

[0032] (5) After adding water, the friction coefficient rapidly decreased to below 0.1, as shown in Figure 3 ;

[0033] (6) After the friction test, the sample was naturally dried in air for 24 hours, and it was recovered to the glass state again, indicating that the coating has self-repairing ability.

[0034] Example 2: Preparation and performance of MXene-containing composite coating

[0035] (1) Prepare a single-layer MXene dispersion liquid. The method refers to the etching method known in the literature (Two-dimensional carbonitride MXenes: from synthesis to properties and applications. Carbon Energy. 2024; 6: e609. doi: 10.1002 / cey2.609);

[0036] (2) Mix the Zn-L-histidine hybrid glass powder obtained in Example 1 with the MXene dispersion liquid at a mass ratio of 99.5:0.5, and stir uniformly to obtain a composite slurry;

[0037] (3) Spray on the surface of 304 stainless steel and dry to obtain a composite coating, as shown in Figure 2 b;

[0038] (4) Tests show that the friction coefficient is further reduced to about 0.06 after adding water, and the coating exhibits a photothermal heating effect under near-infrared light irradiation, which is beneficial to the volatilization of water in a low-temperature environment and the self-repairing of the coating.

[0039] Example 3: Effect of coating on wear resistance of self-lubricating PEEK substrate

[0040] The slurry described in Example 1 is coated on the surface of a self-lubricating PEEK engineering plastic, and after drying, a friction experiment is performed, as shown in Figure 4 The friction coefficient of the self-lubricating PEEK surface containing only water rapidly increases after 15 min, indicating that the self-lubricating structure is damaged by wear. However, the MXene@Zn-L-histidine hybrid glass coating still has self-lubricating properties after 60 min of friction under the same conditions, and the friction coefficient is reduced.

[0041] Example 4: Cycle test of self-repairing performance

[0042] The coating of Example 1 is subjected to a "water lubrication-drying self-repairing" cycle test, and after 10 repetitions, the glass coating can still restore the initial friction performance and surface integrity, indicating that it has good cycle use stability.

[0043] The above examples are only to illustrate the technical solutions of the present application, and are not limiting. Those skilled in the art can make several modifications or equivalent replacements based on the concept of the present application, and these should also be considered within the protection scope of the present application.

Claims

1. A metal-organic hybrid glass coating material with water-triggered lubrication and self-healing functions, characterized in that, This material has the following properties: Solid adhesion: It is a solid glassy state in a dry state and can stably adhere to various substrate surfaces; Water-triggered lubrication: It partially dissolves upon contact with water, forming a liquid lubricating layer at the friction interface, which significantly reduces the coefficient of friction; Self-healing: After the water evaporates, the material can return to a solid glassy state and achieve structural self-healing.

2. The material according to claim 1, characterized in that, The material is formed by evaporation-induced self-assembly of metal ions and chiral organic ligands, wherein the metal ions are selected from at least one of zinc, cadmium, europium, and terbium, and the organic ligands are L-histidine or D-histidine.

3. The material according to claim 1, characterized in that, The material also contains two-dimensional material MXene; in a dry solid state, MXene is encapsulated in a glass matrix; upon contact with water, as the glass matrix dissolves, MXene is exposed at the interface, synergistically achieving liquid lubrication with a low coefficient of friction.

4. The material according to claim 3, characterized in that, The MXene content is 0.01–1.5 wt%, and its sheet thickness is 1–5 nm.

5. The material according to claim 1, characterized in that, After coating it onto the substrate surface and adding water to form a liquid lubricating layer, the coefficient of friction when rubbing against stainless steel is reduced to below 0.1, preferably below 0.

06.

6. A method for preparing the material according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Dissolve metal salts and histidine ligands in water, evaporate at room temperature to induce self-assembly, and form metal-organic hybrid glasses; S2: Grind the obtained glass material into powder, dissolve it in water, and use it as a coating precursor; S3: Optionally, the MXene dispersion is mixed with the precursor to obtain a composite slurry; S4: The precursor or slurry is coated onto the substrate surface and dried to form a solid coating.

7. A use of the material as described in any one of claims 1–5, characterized in that, The coating is used to prepare a "lubricating on demand" functional coating. Specifically, when lubrication is needed, water is added to the coating surface to trigger liquid lubrication; after lubrication is completed, the water evaporates, the coating returns to a solid state and self-heals; this coating is suitable for precision machinery, medical devices, microelectromechanical systems or moving parts that require intermittent lubrication.

8. A lubrication method, characterized in that, The method, using the material as a lubricating functional layer as described in any one of claims 1–5, comprises: In its dry state, this material provides basic protection as a solid coating; When it is necessary to reduce friction, water or an aqueous solution is applied to the coating surface to trigger the formation of a liquid lubricating film. After the lubrication process is completed, the water supply is stopped, and the coating returns to a solid state and achieves self-repair as the moisture evaporates.

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