Reversibly adhesive double-network hydrogel adhesive and its preparation method and application

Abstract

This application discloses a reversibly adhesive double-network hydrogel adhesive, its preparation method, and application. The preparation method comprises: providing a sodium alginate solution and a monomer solution; wherein the monomer solution comprises at least one of an acrylamide monomer solution and an acrylic acid monomer solution; the sodium alginate solution is an aqueous sodium alginate solution, the acrylamide monomer solution is an aqueous acrylamide monomer solution, and the acrylic acid monomer solution is an aqueous acrylic acid monomer solution; and oxidizing the sodium alginate solution to form an oxidized sodium alginate solution using an initiator, and initiating crosslinking and copolymerization of the monomer solution and the oxidized sodium alginate solution to form a reversibly adhesive double-network hydrogel adhesive.

Description

[0001] This application is a divisional application based on the invention with application number 202110323759.3, application date March 26, 2021, applicant being Shandong University of Technology, and invention name being "Double network hydrogel adhesive, preparation method and application thereof". Technical Field

[0002] The present application belongs to the field of adhesive technology, and specifically relates to a reversibly adhesive double-network hydrogel adhesive and a preparation method and application thereof. Background Art

[0003] Adhesives are indispensable in daily life. However, traditional adhesives are difficult to remove after adhesion, and their adhesion is difficult to restore after the adhesion is removed. Summary of the Invention

[0004] To solve the above technical problems, the present application provides a reversibly adhesive double-network hydrogel adhesive and its preparation method and application.

[0005] In a first aspect, the present application provides a method for preparing a reversibly adhesive double-network hydrogel adhesive, comprising: providing a sodium alginate solution and a monomer solution; wherein the monomer solution comprises at least one of an acrylamide monomer solution and an acrylic acid monomer solution; the sodium alginate solution is an aqueous sodium alginate solution, the acrylamide monomer solution is an aqueous acrylamide monomer solution, and the acrylic acid monomer solution is an aqueous acrylic acid monomer solution; using an initiator to oxidize the sodium alginate solution to form an oxidized sodium alginate solution, and initiating cross-linking and copolymerization of the monomer solution and the oxidized sodium alginate solution to form a reversibly adhesive double-network hydrogel adhesive.

[0006] In an embodiment of the first aspect of the present application, the initiator is at least one of ammonium persulfate, sodium persulfate and potassium persulfate.

[0007] In any of the aforementioned embodiments of the first aspect of the present application, the acrylamide monomer solution includes at least one of an acrylamide solution, a dimethylacrylamide solution, a diethylacrylamide solution, and an N-isopropylacrylamide solution.

[0008] In any of the aforementioned embodiments of the first aspect of the present application, the acrylic monomer solution includes at least one of an acrylic acid solution, a methyl acrylate solution, an ethyl acrylate solution, a methyl methacrylate solution, and a methyl ethyl acrylate solution.

[0009] In any of the aforementioned embodiments of the first aspect of the present application, the mass ratio of the initiator, the sodium alginate solution, and the monomer solution is 1-20:1-5:5-30.

[0010] In any of the aforementioned embodiments of the first aspect of the present application, the step of using an initiator to oxidize the sodium alginate solution to form an oxidized sodium alginate solution, and initiating cross-linking and copolymerization of the monomer solution and the oxidized sodium alginate solution to form a reversibly adhesive double-network hydrogel adhesive comprises:

[0011] The initiator and the sodium alginate solution are mixed and reacted for 10 to 60 minutes at a constant temperature of 60 to 90° C., so that the initiator oxidizes the sodium alginate solution into an oxidized sodium alginate solution;

[0012] Under a constant temperature of 50-80°C, the oxidized sodium alginate solution and the monomer solution are allowed to stand for 1-5 minutes to cross-link and copolymerize to form a reversibly adhesive double-network hydrogel adhesive.

[0013] The second aspect of the present application provides a reversibly adhesive double-network hydrogel adhesive, which is prepared by the preparation method of the first aspect of the present application.

[0014] In an embodiment of the second aspect of the present application, the reversibly adhesive double-network hydrogel adhesive has high adhesive strength.

[0015] In an embodiment of the second aspect of the present application, the reversibly adhesive double-network hydrogel adhesive has a three-dimensional mesh structure.

[0016] The third aspect of the present application provides an application of a reversibly adhesive double-network hydrogel adhesive. The reversibly adhesive double-network hydrogel adhesive is prepared by the preparation method of the first aspect of the present application, or is the reversibly adhesive double-network hydrogel adhesive provided by the second aspect of the present application.

[0017] In an embodiment of the third aspect of the present application, the reversibly adhesive double network hydrogel adhesive is coated on the surface of the substrate and dried so that the reversibly adhesive double network hydrogel adhesive adheres to the surface of the substrate; and / or

[0018] The reversibly adhered double-network hydrogel adhesive is debonded from the surface of the substrate by using a debonding agent, wherein the debonding agent is a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution.

[0019] In any of the aforementioned embodiments of the third aspect of the present application, after the step of debonding the reversibly adhesive double-network hydrogel adhesive from the substrate surface using a debonding agent, the step further includes: re-coating the debonded reversibly adhesive double-network hydrogel adhesive on the substrate surface, and drying the double-network hydrogel adhesive to restore its adhesiveness to the substrate surface.

[0020] In any of the aforementioned embodiments of the third aspect of the present application, the concentration of the sodium hydroxide aqueous solution is 0.01-100 mol / L; and / or the concentration of the potassium hydroxide aqueous solution is 0.01-100 mol / L.

[0021] According to the embodiments of the present application, the initiator plays the role of oxidation and initiation. The initiator is used to oxidize sodium alginate into oxidized sodium alginate. The degree of oxidation of sodium alginate is high, and the solubility of oxidized sodium alginate in water is significantly improved; and under the conditions of initiation by the initiator, the oxidized sodium alginate and acrylamide monomers or acrylic acid monomers are cross-linked and polymerized to form a reversibly adhesive double-network hydrogel adhesive.

[0022] Furthermore, the preparation process is simple, and the prepared reversibly adhesive double-network hydrogel adhesive does not contain formaldehyde, is biodegradable, and is green and environmentally friendly.

[0023] According to the embodiments of the present application, no cross-linking agent is added, and the cross-linking polymerization process avoids the reduction in viscosity caused by the introduction of the cross-linking agent. The prepared reversibly adhesive double-network hydrogel adhesive has excellent adhesion properties to a variety of substrates, can achieve reversible adhesion, and can be reused, and the adhesion and de-adhesion methods are simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0025] Figure 1 A scanning electron microscope image of a double-network hydrogel adhesive provided according to one embodiment of the present application;

[0026] Figure 2 This is a graph showing the adhesion results of a double-network hydrogel adhesive on different substrates provided according to one embodiment of the present application;

[0027] Figure 3 The figure is a comparison of the adhesion of the double-network hydrogel adhesive and 502 glue to different metals according to one embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the application purpose, technical solution and beneficial technical effects of this application clearer, the following describes this application in detail with reference to specific embodiments. It should be understood that the embodiments described in this specification are only for the purpose of explaining this application and are not intended to limit this application.

[0029] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and similarly, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0030] In the description of this article, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number themselves, and “a variety” in “one or more” means more than two.

[0031] The above disclosure of the present application is not intended to describe every disclosed embodiment or every implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided through a series of examples, which can be used in various combinations. In each example, the enumeration is intended only as a representative group and should not be construed as exhaustive.

[0032] The applicant has conducted extensive research on the adhesive properties of sodium alginate. This research has revealed that sodium alginate has poor solubility in water. However, it can be oxidized to alginate dialdehyde, which not only retains the original properties of sodium alginate (e.g., good biocompatibility) but also significantly improves its solubility in water. However, the degree of oxidation of sodium alginate is poor. For example, oxidation of sodium alginate with sodium periodate only achieves approximately 50% oxidation. Furthermore, the oxidized sodium alginate exhibits poor adhesive properties and does not exhibit reversible adhesion.

[0033] Based on the above problems discovered by the applicant, the applicant conducted further research and found that cross-linking and polymerization of oxidized sodium alginate and acrylamide monomers or acrylic acid monomers can not only improve the adhesion performance, but also have the property of reversible adhesion.

[0034] Therefore, in a first aspect, the present application provides a method for preparing a double-network hydrogel adhesive, the method comprising: step S100 of providing a sodium alginate solution and a monomer solution and step S200 of preparing the double-network hydrogel adhesive.

[0035] In step S100 of providing a sodium alginate solution and a monomer solution, the sodium alginate solution may be an aqueous sodium alginate solution; wherein the monomer solution may include an acrylamide monomer and / or an acrylic acid monomer solution, and may be an aqueous acrylamide monomer or acrylic acid monomer solution.

[0036] The step S200 of preparing the double network hydrogel adhesive includes:

[0037] An initiator is used to oxidize sodium alginate to form an oxidized sodium alginate solution, and acrylamide monomers or acrylic acid monomers and the oxidized sodium alginate solution are initiated to crosslink and copolymerize to form a double-network hydrogel adhesive.

[0038] According to the embodiments of the present application, the initiator plays the role of oxidation and initiation. The initiator is used to oxidize sodium alginate into oxidized sodium alginate. The degree of oxidation of sodium alginate is high, and the solubility of oxidized sodium alginate in water is significantly improved. In addition, the sodium alginate is linear oxidized sodium alginate containing an aldehyde group. The linear oxidized sodium alginate containing an aldehyde group is coupled with an acrylamide monomer or an acrylic acid monomer. The free acrylamide monomer or acrylic acid monomer is around the couple. The initiator initiates free radical polymerization, which can quickly form a double-network hydrogel adhesive.

[0039] According to the embodiments of the present application, no cross-linking agent is added, and the cross-linking polymerization process avoids the reduction in viscosity caused by the introduction of the cross-linking agent. The prepared double-network hydrogel adhesive has excellent adhesion properties to a variety of substrates, can achieve reversible adhesion, and the adhesion and de-adhesion methods are simple.

[0040] In some embodiments, the acrylamide monomer solution may include at least one of acrylamide, dimethylacrylamide, diethylacrylamide, and N-isopropylacrylamide solutions. The acrylic acid monomer solution may include at least one of acrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, and methyl ethylacrylate solutions. For example, the monomer solution may be an acrylamide solution. For another example, the monomer solution may be a mixed solution of acrylic acid and dimethylacrylamide. For another example, the monomer solution may be a mixed solution of dimethylacrylamide, diethylacrylamide, and N-isopropylacrylamide, which forms the backbone of the gel network and provides adhesion groups after polymerization.

[0041] In some embodiments, the initiator is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate, which is used to thermally initiate the generation of free radicals, thereby initiating free radical polymerization of acrylamide monomers or acrylic acid monomers.

[0042] In some embodiments, the weight ratio of the initiator, the sodium alginate solution, and the monomer solution is 1-20:1-5:5-30.

[0043] In some embodiments, the initiator and the sodium alginate solution are mixed and reacted at a constant temperature of 60-90° C. for 10-60 minutes, so that the initiator oxidizes the sodium alginate solution into an oxidized sodium alginate solution;

[0044] Under a constant temperature of 50-80°C, the oxidized sodium alginate solution and the monomer solution are allowed to stand for 1-5 minutes to cross-link and form a double-network hydrogel adhesive.

[0045] The second aspect of the present application provides a double network hydrogel adhesive, which can be prepared based on the preparation method of the double network hydrogel adhesive provided in the first aspect of the present application.

[0046] The dual-network hydrogel adhesive provided in the embodiments of the present application exhibits high adhesion strength, with average adhesion strengths of 67 N to polytetrafluoroethylene, 420 N to vulcanized rubber, 1000 N to glass, and 3288 N to wood. Compared to commercially available 502 glue (cyanoacrylate glue / adhesive), the dual-network hydrogel adhesive exhibits stronger adhesion to metal. Furthermore, the dual-network hydrogel adhesive exhibits reversible adhesion, making it reusable.

[0047] A third aspect of the present application provides an application of a double-network hydrogel adhesive, wherein the double-network hydrogel adhesive is applied to a substrate surface for adhesion or debonding. The double-network hydrogel adhesive can be prepared using the method for preparing the double-network hydrogel adhesive provided in the first aspect of the present application, or can be prepared using the method for preparing the double-network hydrogel adhesive provided in the second aspect of the present application.

[0048] The substrate may be a metal substrate, a wood substrate or an organic polymer substrate, and the specific material of the substrate is not limited here. Before the step of adhering the substrate, the substrate may be pretreated to remove impurities on the surface of the substrate.

[0049] In some embodiments, the double network hydrogel adhesive is applied to the surface of the substrate, adhered and dried, so that the double network hydrogel adhesive is applied to the surface of the substrate and adhered;

[0050] The double-network hydrogel adhesive is applied to the substrate surface. In the presence of solvent wettability, the double-network hydrogel adheres to the substrate surface. It can then be dried naturally by air drying. As the double-network hydrogel adhesive loses its solvent water during drying, its outer surface loses its wettability to the external substrate surface, losing its stickiness and becoming incapable of adhering to new substrates. Therefore, the already adhered substrate can be stored for a long time.

[0051] After spraying water on the outer surface of the double-network hydrogel adhesive, the outer surface of the double-network hydrogel adhesive can regain wettability, thereby restoring adhesion to the external substrate.

[0052] In some embodiments, a debonding agent may be used to debond the double-network hydrogel adhesive from the substrate surface. The debonding agent is an aqueous sodium hydroxide solution and / or an aqueous potassium hydroxide solution.

[0053] The double-network hydrogel adhesive has reversible adhesion properties. The swelling of the double-network hydrogel adhesive is accelerated by a debonder, so that the density of the adhesive group is reduced and the adhesion is released. After re-adhesion, the adhesive can be further naturally air-dried. The air-drying process restores the swelling of the double-network hydrogel adhesive and the density of the adhesive group, so that the adhesive property is restored again.

[0054] As an example, the debonding agent can be an aqueous sodium hydroxide solution and / or an aqueous potassium hydroxide solution. For example, the concentration of the sodium hydroxide solution is 0.01 to 100 mol / L; the concentration of the potassium hydroxide solution is 0.01 to 100 mol / L. These concentrations of sodium hydroxide or potassium hydroxide solution have better swelling properties and a better debonding effect.

[0055] According to the embodiments of the present application, the double-network hydrogel adhesive is easy to use and can be applied to the surface of a substrate. The double-network hydrogel can be debonded from the surface of the substrate using a debonding agent. The double-network hydrogel loses moisture and its viscosity disappears, allowing it to be stored for a long time. Spraying solvent water on the double-network hydrogel adhesive can restore its viscosity.

[0056] Example

[0057] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further processing, and all instruments used in the examples are commercially available.

[0058] Example 1

[0059] In this embodiment, a double-network hydrogel adhesive is prepared using sodium alginate, ammonium persulfate, acrylamide, and ultrapure water as raw materials, specifically comprising the following steps:

[0060] (1) Preparation of oxidized sodium alginate: Accurately weigh 0.3 g of sodium alginate and 0.6 g of ammonium persulfate, mix them, add 4.1 g of ultrapure water, and stir at 70 °C for 25 min. The sodium alginate is oxidized by the oxidation of persulfate to form sodium alginate dialdehyde, thereby obtaining an oxidized sodium alginate solution.

[0061] (2) Preparation of double network hydrogel adhesive: Accurately weigh 1.5 g of acrylamide and dissolve it in 3.5 g of ultrapure water to prepare an acrylamide aqueous solution. The acrylamide aqueous solution is mixed with the oxidized sodium alginate aqueous solution prepared in step (1). The linear oxidized sodium alginate containing aldehyde groups is coupled with acrylamide monomers. The free acrylamide monomers are around the conjugates. Free radical polymerization is initiated by ammonium persulfate at 70 °C for 1 min to form a double network hydrogel adhesive.

[0062] Figure 1 It shows that the double-network hydrogel adhesive prepared in the example has a typical three-dimensional mesh structure of hydrogel.

[0063] Example 2

[0064] This embodiment uses sodium alginate, potassium persulfate, acrylic acid and ultrapure water as raw materials to prepare a double-network hydrogel adhesive, which specifically includes the following steps:

[0065] (1) Preparation of oxidized sodium alginate: Accurately weigh 0.3 g of sodium alginate and 0.6 g of potassium persulfate, mix them, add 4.1 g of ultrapure water, and stir at 70 °C for 25 min. The sodium alginate is oxidized by the oxidation of persulfate to form sodium alginate dialdehyde, thereby obtaining an oxidized sodium alginate solution.

[0066] (2) Preparation of a double network hydrogel adhesive: Accurately weigh 1.5 g of acrylic acid and dissolve it in 3.5 g of ultrapure water to prepare an acrylic acid aqueous solution. The acrylic acid aqueous solution is mixed with the oxidized sodium alginate aqueous solution prepared in step (1). The linear oxidized sodium alginate containing aldehyde groups is coupled with the acrylic acid monomer. The free acrylic acid monomer is around the conjugate. Free radical polymerization is initiated by potassium persulfate at 70°C for 1 minute to form a double network hydrogel adhesive.

[0067] Example 3

[0068] This embodiment uses sodium alginate, sodium persulfate, dimethylacrylamide and ultrapure water as raw materials to prepare a double network hydrogel adhesive, which specifically includes the following steps:

[0069] (1) Preparation of oxidized sodium alginate: Accurately weigh 0.3 g of sodium alginate and 0.6 g of sodium persulfate, mix them, add 4.1 g of ultrapure water, and stir at 70 °C for 25 min. The sodium alginate is oxidized by the oxidation of persulfate to form sodium alginate dialdehyde, thereby obtaining an oxidized sodium alginate solution.

[0070] (2) Preparation of double network hydrogel adhesive: Accurately weigh 1.5 g of dimethylacrylamide and dissolve it in 3.5 g of ultrapure water to prepare a dimethylacrylamide aqueous solution. The dimethylacrylamide aqueous solution is mixed with the oxidized sodium alginate aqueous solution prepared in step (1). The linear oxidized sodium alginate containing aldehyde groups is coupled with the dimethylacrylamide monomer. The free dimethylacrylamide monomer is around the conjugate. Free radical polymerization is initiated by sodium persulfate at 70 °C for 1 min to form a double network hydrogel adhesive.

[0071] Adhesion test 1

[0072] The double-network hydrogel adhesive prepared in Example 1 is used to adhere different substrates to obtain its adhesion to different substrates, specifically comprising the following steps:

[0073] (1) Cut different substrates: polytetrafluoroethylene, vulcanized rubber, glass, wood, and metal into rectangular sheets with a length of 7.5 cm and a width of 2.5 cm for later use.

[0074] (2) The double network hydrogel adhesive of Example 1 was coated on one end surface of each of the above substrates, and the coating area was a square with a side length of 2.5 cm.

[0075] (3) Take another piece of the same substrate and adhere one end of it to the substrate coated with the double network hydrogel adhesive to form a substrate pair, and obtain substrate pairs of polytetrafluoroethylene, vulcanized rubber, glass, wood, and metal respectively, and let them air-dry naturally.

[0076] (4) After air drying, the substrate was tested on a tensile testing machine to obtain the adhesion of the double network hydrogel adhesive to different substrates. The average value of the measured results is as follows: Figure 2 As shown, the average adhesion strength for polytetrafluoroethylene is 67 N, the average adhesion strength for vulcanized rubber is 420 N, the average adhesion strength for glass is 1000 N, and the average adhesion strength for wood is 3288 N.

[0077] For vulcanized rubber, glass, and wood, the substrates were destroyed before the maximum adhesion force was measured, and the adhesion strength exceeded the strength of the substrate itself, further proving that the hydrogel adhesive has high adhesion strength.

[0078] Adhesion comparison test 1

[0079] The same metal sheet as in step (1) of the adhesion test experiment 1 was obtained, and cyanoacrylate glue / adhesive (502 glue) was used to coat one end surface of the metal sheet into a square with a side length of 2.5 cm. The metal pair adhered with 502 glue was obtained by step (3) of the adhesion test experiment 1. After the metal pair was naturally air-dried, it was tested on a tensile testing machine to obtain the adhesion of 502 glue to the metal. The adhesion was compared with the double network hydrogel adhesive prepared in Example 1. The average value of the measured results is shown as follows: Figure 3 The results show that the double network hydrogel adhesive prepared in Example 1 has stronger adhesion to metal than the commercially available 502 adhesive.

[0080] Adhesion test 2

[0081] The double network hydrogel adhesive of Example 1 is applied to the surface of cement bricks and allowed to dry. The adhesiveness disappears and the bricks can be stored for a long time. The adhesiveness is restored after spraying water. The process specifically comprises the following steps:

[0082] (1) The double network hydrogel adhesive in Example 1 was evenly coated on one end surface of two cement bricks of the same specifications: 8 cm in length, 4 cm in width, and 4 cm in height, that is, coated on a square surface with a side length of 4 cm. The adhesive was allowed to air dry naturally. The outer surface of the double network hydrogel adhesive lost its wettability due to the absence of solvent, and the viscosity disappeared.

[0083] (2) After the cement bricks are stored for one month, water is sprayed on the surface of the double network hydrogel adhesive. After the double network hydrogel adhesive is completely wetted, the surfaces of the two cement bricks coated with the double network hydrogel adhesive are bonded to each other to obtain a cement brick pair. After the double network hydrogel adhesive is naturally air-dried again, the flexural strength of the cement brick pair is tested. The obtained flexural strength can reach 2.28 MPa, realizing the recovery of the gel viscosity.

[0084] The average flexural strength of cement bricks adhered by the adhesion method of adhesion test 1 was 3.03 MPa, and there was no significant difference between the two.

[0085] Adhesion test 3

[0086] The double-network hydrogel adhesive of Example 1 is applied to the surface of paper and allowed to dry. The adhesiveness disappears and the paper can be stored for a long time. The adhesiveness is restored after spraying water and the paper can be used for instant adhesive stickers. The steps are as follows:

[0087] (1) Cut paper into different specifications as required, apply the double network hydrogel adhesive prepared in Example 1 evenly on the surface of the paper, and let it air dry naturally. The stickiness on the outer surface of the double network hydrogel adhesive disappears.

[0088] (2) After the paper is stored for one month, a small amount of water is sprayed on the surface of the double network hydrogel adhesive. It only needs to moisten the outer surface of the double network hydrogel adhesive to restore the stickiness and allow the paper to be attached to the desired position, achieving instant adhesion.

[0089] De-adhesion test

[0090] Using sodium hydroxide as a debonding agent, the air-dried nickel metal pair in Adhesion Test 1 was used to remove the adhesion by adding the debonding agent and then restore the adhesion through a simple air-drying process. The specific steps include the following:

[0091] (1) Preparation of sodium hydroxide solution: Weigh 0.4 g of sodium hydroxide solid and dissolve it in water to prepare a 0.1 mol / L sodium hydroxide solution.

[0092] (2) De-adhesion: Drill a hole at one end of the metal pair, hang a 5 kg weight, and lift the weight vertically. Use a 10 mL syringe to intermittently inject sodium hydroxide solution into the effective adhesion area of ​​the metal pair. This will cause the weight to fall, separating the two metal pieces and achieving de-adhesion.

[0093] (3) Restoring adhesion: The two metal sheets coated with the double network hydrogel adhesive are overlapped on one side to make them adhere to each other. After the double network hydrogel adhesive is naturally air-dried again, the nickel sheet can be used to lift the weight again to restore the adhesion.

[0094] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing a reversibly adhesive double-network hydrogel adhesive, characterized in that: The preparation method comprises: Providing a sodium alginate solution and a monomer solution; wherein the monomer solution comprises at least one of an acrylamide monomer solution and an acrylic acid monomer solution; the sodium alginate solution is an aqueous sodium alginate solution, the acrylamide monomer solution is an aqueous acrylamide monomer solution, and the acrylic acid monomer solution is an aqueous acrylic acid monomer solution; The sodium alginate solution is oxidized by an initiator to form an oxidized sodium alginate solution, and the monomer solution and the oxidized sodium alginate solution are cross-linked and copolymerized to form a reversibly adhesive double-network hydrogel adhesive, and no cross-linking agent is added during the cross-linking and copolymerization process. The initiator is at least one of ammonium persulfate, sodium persulfate, and potassium persulfate. The mass ratio of the initiator, the sodium alginate solution and the monomer solution is 1-20:1-5:5-30.

2. The method for preparing the reversibly adhesive double-network hydrogel adhesive according to claim 1, wherein: The acrylamide monomer solution includes at least one of an acrylamide solution, a dimethylacrylamide solution, a diethylacrylamide solution and an N-isopropylacrylamide solution.

3. The method for preparing the reversibly adhesive double-network hydrogel adhesive according to claim 1, wherein: The acrylic monomer solution includes at least one of an acrylic acid solution, a methyl acrylate solution, an ethyl acrylate solution, a methyl methacrylate solution, and a methyl ethacrylate solution.

4. The method for preparing the reversibly adhesive double-network hydrogel adhesive according to claim 1, wherein: The step of using an initiator to oxidize the sodium alginate solution to form an oxidized sodium alginate solution, and initiating cross-linking and copolymerization of the monomer solution and the oxidized sodium alginate solution to form a reversibly adhesive double-network hydrogel adhesive comprises: The initiator and the sodium alginate solution are mixed and reacted for 10 to 60 minutes at a constant temperature of 60 to 90° C., so that the initiator oxidizes the sodium alginate solution into the oxidized sodium alginate solution; Under a constant temperature of 50-80° C., the oxidized sodium alginate solution and the monomer solution are allowed to stand for 1-5 minutes to cross-link and copolymerize to form the double-network hydrogel adhesive.

5. A reversibly adhesive double-network hydrogel adhesive, characterized in that: The reversibly adhesive double-network hydrogel adhesive is prepared by the preparation method according to any one of claims 1 to 4.

6. The reversibly adhesive double-network hydrogel adhesive according to claim 5, characterized in that The reversibly adhesive double-network hydrogel adhesive has a three-dimensional mesh structure.

7. A use of a double network hydrogel adhesive prepared by the method for preparing a reversibly adhesive double network hydrogel adhesive according to any one of claims 1 to 4 or a reversibly adhesive double network hydrogel adhesive according to claim 5 or 6, characterized in that: The reversibly adhesive double-network hydrogel adhesive is applied to a substrate surface for adhesion or debonding.

8. The use according to claim 7, characterized in that Applying the reversibly adhesive double-network hydrogel adhesive to a substrate surface, adhering and drying the adhesive so that the reversibly adhesive double-network hydrogel adhesive adheres to the substrate surface; and / or The double network hydrogel adhesive is debonded from the surface of the substrate by using a debonding agent, wherein the debonding agent is a sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution.

9. The use according to claim 8, characterized in that After the step of debonding the reversibly adhesive double-network hydrogel adhesive from the substrate surface using a debonding agent, the method further includes: re-coating the debonded reversibly adhesive double-network hydrogel adhesive on the substrate surface, and drying the double-network hydrogel adhesive to restore its adhesiveness to the substrate surface.

10. The use according to claim 8, characterized in that The concentration of the sodium hydroxide aqueous solution is 0.01-100 mol / L; and / or the concentration of the potassium hydroxide aqueous solution is 0.01-100 mol / L.

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