Ion response type intelligent super-hydrophobic coating as well as preparation method and application thereof

Abstract

The invention discloses an ion response type intelligent super-hydrophobic coating as well as a preparation method and application thereof. The invention discloses an ion response type intelligent super-hydrophobic coating which is prepared from a film-forming binder, a low-surface-energy substance, a structure enhancer and an intelligent response unit, the intelligent response unit is a xanthine compound with metal ion coordination ability, the general formula of the compound is shown in the following formula I, and R1, R3 and R7 are the same or different and are independently hydrogen, C1-C6 alkyl or C1-C6 alkyl containing oxygen atoms. According to the invention, the reversible coordination chemical reaction between the intelligent response unit and the metal ions is utilized to realize the artificial, dynamic and reversible regulation and control of the surface energy of the coating, the static passive protection of the super-hydrophobic surface is upgraded to the dynamic active intelligent response, and the response speed and the wettability switching degree are obviously better. Formula I

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, in particular to an ion-responsive intelligent super-hydrophobic coating and a preparation method and application thereof. BACKGROUND

[0002] Super-hydrophobic coating, generally refers to a surface with a contact angle greater than 150° and a rolling angle less than 10° with water, due to its excellent water-repellent, ice-repellent, self-cleaning and anti-corrosion properties, it shows broad application prospects in industry, military and daily life. These properties mainly come from its micro-nano scale rough structure and low surface energy chemical composition.

[0003] However, the surface properties of the existing super-hydrophobic coating are mostly static. Once prepared, its super-hydrophobic characteristics remain unchanged. This static characteristic greatly limits its application in some frontier fields. For example: intelligent oil-water separation: static coating cannot realize selective and efficient separation of different types of oil stains according to the change of ion composition in water body. Environmental sensing and detection: it cannot convert the presence of specific chemicals (such as heavy metal ions) in the environment into intuitive and readable surface wettability change signals. Controllable micro-reactor and drug release: it lacks the "switch" ability triggered by environmental signals, and cannot realize precise control and release of substances. Advanced antifouling materials: in marine environment, static physical anti-adhesion may not be enough to cope with long-term biological fouling, and lacks active and responsive antifouling mechanism.

[0004] At present, researchers have developed intelligent surfaces that respond to light, heat, pH, electric field, etc. However, there is still no relevant report on super-hydrophobic coating that produces rapid, significant and reversible response to specific metal ions (such as Cu²⁺, Fe³⁺) commonly existing in the environment and having important detection significance. Such materials have urgent needs and great market potential in the fields of environmental remediation, industrial monitoring, biomedicine and intelligent equipment. SUMMARY

[0005] The present application solves the problem of static super-hydrophobic coating in the prior art, and provides an ion-responsive intelligent super-hydrophobic coating and a preparation method and application thereof. The ion-responsive intelligent super-hydrophobic coating proposed in the present application can respond to changes in the concentration of specific metal ions in the external environment, thereby realizing intelligent and reversible switching of surface wettability.

[0006] The first object of the present application is to provide an ion-responsive intelligent super-hydrophobic coating prepared from a film-forming binder, a low surface energy substance, a structure reinforcing agent and an intelligent response unit. The intelligent response unit is a xanthine compound with metal ion coordination ability, and the general formula of the compound is shown as formula I: ;

[0007] Among them, R1, R3 and R7 may be the same or different, and are independently hydrogen, C1-C6 alkyl or C1-C6 hydrocarbon groups containing oxygen atoms.

[0008] Preferably, the xanthine compound is selected from one or more of theophylline, theobromine, pentoxifylline, and propargyl theophylline, wherein the pentoxifylline and propargyl theophylline are compounds of general formula (I), and the substituents at the corresponding positions are C1-C6 hydrocarbon groups containing oxygen atoms.

[0009] Preferably, the metal ion is a divalent or trivalent metal ion.

[0010] More preferably, the metal ion is selected from one or more of Cu²⁺, Fe²⁺, and Fe³⁺.

[0011] Preferably, the ion-responsive smart superhydrophobic coating is prepared from the following components based on the total dry weight of the coating: 50-85 parts of film-forming binder; 5-30 parts of low surface energy material; 2-15 parts of smart response unit; and 5-20 parts of structural reinforcing agent.

[0012] Further preferably, the ion-responsive smart superhydrophobic coating is prepared from the following components by mass: 65 parts film-forming binder; 13 parts low surface energy material; 9 parts smart response unit; and 13 parts structural reinforcing agent.

[0013] Preferably, the film-forming adhesive is selected from one or more of epoxy resin, acrylic resin, polyurethane and fluorocarbon resin.

[0014] Preferably, the low surface energy material is selected from fluorinated silanes, fluorinated acrylates, and silane coupling agents.

[0015] Further preferably, the low surface energy material is selected from one or more of perfluorooctyltrichlorosilane and heptadecafluorodecyltrimethoxysilane.

[0016] Preferably, the structural reinforcing agent is a nano-sized inorganic particle, which is selected from one or more of hydrophobic nano-silica, nano-zinc oxide, and nano-titanium dioxide.

[0017] A second objective of this invention is to provide a method for preparing the aforementioned ion-responsive smart superhydrophobic coating, comprising the following steps:

[0018] a. Dissolve the film-forming binder in a solvent to form a homogeneous solution;

[0019] b. Add the low surface energy material, the smart response unit and the structure enhancer sequentially to the solution in step a, and perform ultrasonic dispersion or mechanical stirring to form a uniform coating slurry;

[0020] c. Apply the coating slurry obtained in step b to the surface of the substrate, and after curing, form an ion-responsive smart superhydrophobic coating with a thickness of 0.1-200 μm. The curing temperature is 20℃-120℃ and the curing time is 0.2-48 hours.

[0021] Preferably, the mass fraction of the film-forming binder in the homogeneous solution described in step a is 15%-20%.

[0022] Further preferably, the mass fraction of the film-forming binder in the homogeneous solution described in step a is 18.75%.

[0023] A third objective of this invention is to provide a method for using the aforementioned ion-responsive smart superhydrophobic coating, comprising the following steps (e.g. Figure 1 As shown, the intelligent response unit, taking theophylline as an example: the coating is in an initial superhydrophobic state, and the coating is brought into contact with a triggering liquid containing target metal ions coordinated with the intelligent response unit, so that the surface wettability of the coating changes from a superhydrophobic state to a hydrophilic state; after completing the required function, the coating, which is now in a hydrophilic state, is brought into contact with a complexing agent solution to remove the target metal ions coordinated with the intelligent response unit, thereby restoring the coating to a superhydrophobic state; the complexing agent is selected from one or more of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, ethylenediamine, oxalic acid, citric acid, aminotriacetic acid, and salicylic acid.

[0024] This invention also protects the application of the ion-responsive smart superhydrophobic coating in the preparation of smart oil-water separation devices, metal ion sensors, anti-counterfeiting labels, or marine biofouling prevention equipment.

[0025] Compared with the prior art, the present invention has the following advantages: The present invention introduces xanthine compounds (especially theophylline) as smart response units into the superhydrophobic coating system for the first time, and creatively develops a new type of ion-responsive smart surface, filling a technological gap.

[0026] Intelligence and dynamism: This invention utilizes the intelligent response unit and the reversible coordination chemical reaction of metal ions to achieve artificial, dynamic and reversible control of the coating surface energy, upgrading the superhydrophobic surface from static passive protection to dynamic active intelligent response, exhibiting significantly better response speed and wettability switching degree.

[0027] Excellent reversibility: The response process is completely reversible, and the coating can be restored to a superhydrophobic state by simple chemical elution (such as EDTA solution). It has a long cycle life and practical application value.

[0028] With broad application prospects, this invention has opened up several new application areas such as intelligent separation, chemical sensing, and advanced antifouling, and has high added value. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the response mechanism of the ion-responsive smart superhydrophobic coating proposed in this invention.

[0030] Figure 2 These are comparative photographs of the water contact angle of the coating prepared in Example 1 before and after responding to Cu²⁺ solution, where a is the water contact angle photograph of the coating in the initial state, and b is the water contact angle photograph after immersion in Cu²⁺ solution and drying.

[0031] Figure 3 These are comparative photographs of the water contact angle of the coating prepared in Example 2 before and after responding to the Fe³⁺ solution, where a is the water contact angle photograph of the coating in the initial state, and b is the water contact angle photograph after immersion in the Fe³⁺ solution and drying.

[0032] Figure 4 The coating prepared in Example 3 responds to Cu 2 Comparison of water contact angle photographs before and after solution treatment, where a is the water contact angle photograph of the initial state of the coating, and b is the water contact angle photograph after immersion in Cu. 2 Photograph of the water contact angle after the solution has been dried.

[0033] Figure 5 These are comparative photographs of the water contact angle of the coating prepared in Comparative Example 1 before and after responding to Cu²⁺ solution, where a is the water contact angle of the coating in its initial state, and b is the water contact angle after immersion in Cu²⁺ solution and drying. Detailed Implementation

[0034] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0035] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental materials and reagents used herein are commercially available products conventionally available in this technical field.

[0036] Example 1: Preparation of Cu²⁺-responsive superhydrophobic coating based on theophylline

[0037] Dissolve 1.5 g of epoxy resin in 6.5 g of N,N-dimethylformamide (DMF) and stir magnetically until completely dissolved. Then, add 0.3 g of heptadecafluorodecyltrimethoxysilane, 0.2 g of theophylline powder, and 0.3 g of nano-SiO2 to the solution sequentially. Ultrasonically disperse the mixture for 1 hour, then uniformly coat it onto a clean glass substrate using a spray method. Cure the coating in an 80°C oven for 2 hours to form a 50 μm thick intelligent superhydrophobic coating.

[0038] Performance testing and effect verification:

[0039] Test results: The measured water contact angle of the coating was 158°, exhibiting excellent superhydrophobic properties. Figure 2 As shown in (a), the coating was immersed in a 0.01 mol / L CuSO4 aqueous solution for approximately 30 seconds. The coating was then removed from the solution, the surface was rinsed with deionized water, and dried. A drop of water was placed on the dry surface, and it was observed that the water droplet spread rapidly, with the water contact angle dropping below 10°. Figure 2 As shown in (b).

[0040] Reversibility test: The responded coating was immersed in a 0.05 mol / L EDTA aqueous solution for 5 minutes, then rinsed with deionized water and dried at room temperature. The water contact angle was measured again and returned to 155°. This cycle was repeated multiple times, and the coating could still be restored to the superhydrophobic state, demonstrating its good reversibility.

[0041] Example 2: Fe³⁺ responsive coating based on theobromine

[0042] Referring to Example 1, theophylline was replaced with an equal amount of theobromine, and the response test solution was changed to a 0.01 mol / L FeCl3 solution.

[0043] Test results: The initial water contact angle of the coating was 154°, as shown below. Figure 3 As shown in (a), after contacting the FeCl3 solution for 30 seconds, the coating was removed from the solution, the surface was rinsed with deionized water, and the coating surface was dried. A drop of water was then placed on the dry surface, and it was observed that the water droplet spread across the surface, with the water contact angle measured to decrease to 20°. Figure 3 As shown in (b), the superhydrophobic state was successfully restored using EDTA solution. This demonstrates that the technical solution of this invention is applicable to other xanthine compounds besides theophylline.

[0044] Example 3

[0045] Referring to Example 1, the theophylline was replaced with 0.1 g theophylline and 0.1 g theobromine.

[0046] Test results: The measured water contact angle of the coating was 159°, exhibiting excellent superhydrophobic properties. Figure 4 As shown in (a), the coating was immersed in a 0.01 mol / L CuSO4 aqueous solution for approximately 30 seconds. The coating was then removed from the solution, the surface was rinsed with deionized water, and dried. A drop of water was placed on the dry surface, and it was observed that the water droplet spread rapidly, with the water contact angle dropping below 10°. Figure 4 As shown in (b).

[0047] Comparative Example 1: (excluding the intelligent response unit)

[0048] The preparation method is exactly the same as in Example 1, but without the addition of theophylline.

[0049] Test results: The initial water contact angle was 155°. After immersion in CuSO4 solution, the water contact angle remained above 150°, showing no response. Figure 5 As shown, (a) is a contact angle photograph of the initial state, and (b) is a contact angle photograph of the sample after immersion in CuSO4 solution and drying. This comparison demonstrates that theophylline is a key and essential component for generating ionic responsiveness.

[0050] Example 4

[0051] Similar to Example 1, except that the ion-responsive smart superhydrophobic coating is prepared from the following components by mass: 50 parts film-forming binder; 15 parts low surface energy material; 15 parts smart responsive unit; and 20 parts structural reinforcing agent. In the preparation method of the superhydrophobic coating, the mass fraction of the film-forming binder in the homogeneous solution is 15%, the curing temperature is 20°C, and the curing time is 48 hours.

[0052] Example 5

[0053] Similar to Example 1, except that the ion-responsive smart superhydrophobic coating is prepared from the following components by mass: 85 parts film-forming binder; 5 parts low surface energy material; 5 parts smart responsive unit; and 5 parts structural reinforcing agent. In the preparation method of the superhydrophobic coating, the mass fraction of the film-forming binder in the homogeneous solution is 20%, the curing temperature is 120°C, and the curing time is 0.2 hours.

[0054] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An ion-responsive smart superhydrophobic coating, characterized in that, It is prepared from a film-forming binder, a low surface energy material, a structural reinforcing agent, and a smart response unit; the smart response unit is a xanthine compound with metal ion coordination ability, and the general formula of the compound is shown in Formula I below: ； Among them, R1, R3 and R7 may be the same or different, and are independently hydrogen, C1-C6 alkyl, or C1-C6 hydrocarbon group containing oxygen atoms.

2. The ion-responsive smart superhydrophobic coating according to claim 1, characterized in that, The xanthine compounds mentioned are selected from one or more of theophylline, theobromine, pentoxifylline, and propargyl theophylline.

3. The ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The metal ions mentioned are divalent or trivalent metal ions.

4. The ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The coating is prepared from the following components based on the total dry weight parts: 50-85 parts by mass of film-forming binder; 5-30 parts by mass of low surface energy material; 2-15 parts by mass of smart response unit; and 5-20 parts by mass of structural reinforcing agent.

5. The ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The film-forming adhesive is selected from one or more of epoxy resin, acrylic resin, polyurethane and fluorocarbon resin.

6. The ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The low surface energy material is selected from fluorinated silanes, fluorinated acrylates, and silane coupling agents.

7. The ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The structural reinforcing agent is a nano-sized inorganic particle, which is selected from one or more of hydrophobic nano-silica, nano-zinc oxide, and nano-titanium dioxide.

8. The method for preparing the ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, Includes the following steps: a. Dissolve the film-forming binder in a solvent to form a homogeneous solution; b. Add the low surface energy material, the smart response unit and the structure enhancer sequentially to the solution in step a, and perform ultrasonic dispersion or mechanical stirring to form a uniform coating slurry; c. Apply the coating slurry obtained in step b to the surface of the substrate, and after curing, form an ion-responsive smart superhydrophobic coating with a thickness of 0.1-200 μm. The curing temperature is 20℃-120℃ and the curing time is 0.2-48 hours.

9. The method of using the ion-responsive smart superhydrophobic coating according to claim 1 or 2, characterized in that, The process includes the following steps: the coating is initially in a superhydrophobic state, and the coating is brought into contact with a triggering liquid containing target metal ions coordinated with the smart response unit, so that the surface wettability of the coating changes from a superhydrophobic state to a hydrophilic state; after the desired function is completed, the coating, which is now in a hydrophilic state, is brought into contact with a complexing agent solution to remove the target metal ions coordinated with the smart response unit, thereby restoring the coating to a superhydrophobic state; the complexing agent is selected from one or more of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, ethylenediamine, oxalic acid, citric acid, aminotriacetic acid, and salicylic acid.

10. The application of the ion-responsive smart superhydrophobic coating according to claim 1 or 2 in the preparation of smart oil-water separation devices, metal ion sensors, anti-counterfeiting labels or marine anti-biofouling equipment.

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