Light-operated reversible adhesive gel as well as preparation method and use method thereof

Abstract

The invention relates to light-operated reversible adhesive gel as well as a preparation method and a use method thereof. The light-operated reversible adhesive gel comprises gel and at least one metal element of iron, cobalt, cerium, zirconium and molybdenum, wherein the metal element has the highest valence state, and the mass percent of the metal element is 0.2-15%. The light-operated reversible adhesive gel disclosed by the invention can realize rapid, stable and repeated light-operated reversible adhesion under visible light-ultraviolet irradiation, is simple and convenient in preparation process and relatively low in cost, is beneficial to realizing large-scale production and application, and has a wide application prospect. Meanwhile, compared with the prior art that reversible pasting is achieved through direct heating, safety is higher, and compared with an infrared irradiation mode in the prior art, rapidness is higher.

Description

Technical Field

[0001] This invention relates to the field of light-controlled reversible smart adhesion technology, specifically to a light-controlled reversible adhesion gel and its preparation and application methods. Background Technology

[0002] Research on photosensitive reversible adhesive materials began with studies on photoresponsive molecules. Early on, it was discovered that certain organic molecules, such as azobenzene, undergo cis-trans isomerization under ultraviolet and visible light irradiation. This discovery sparked in-depth research into photoresponsive materials. From the late 20th to the early 21st century, with continuous exploration of molecular design and material synthesis technologies, photoresponsive materials gradually extended to macroscopic material applications, and photosensitive reversible adhesive materials entered the initial research and development stage.

[0003] The working principle of photosensitive reversible adhesive materials is mainly based on mechanisms such as photochromic reactions, photo-induced free radical reactions, and photoinduced molecular recombination. When exposed to ultraviolet light, the photoresponsive units undergo photochemical reactions, such as cis-trans isomerization and electron transfer, which lead to changes in the surface energy, intermolecular forces, or chemical bonding ability of the material, thereby enhancing or weakening the material's adhesive properties. Conversely, under visible light irradiation, the photoresponsive units return to their initial state, and the adhesive properties are reversed accordingly.

[0004] Photosensitive reversible adhesive materials can be used to develop novel reversible adhesive wound dressings, controlling the adhesion between the dressing and the wound using ultraviolet light to reduce pain and tissue damage during dressing changes. In tissue engineering, they can be used for reversible cell adhesion and release, improving the efficiency and effectiveness of cell culture. Photosensitive reversible adhesive materials can also serve as drug carriers, controlling drug release with ultraviolet light for precise drug delivery. In the sensor field, they can detect changes in adhesion properties to sense environmental changes, leading to the development of novel sensors. In the field of smart materials, their photoresponsiveness can be used to develop novel smart materials, enabling remote control of material properties. During the assembly, transfer, and repair of micro / nano devices, photosensitive reversible adhesive materials can be used to precisely grasp, move, and release micro / nano objects, improving operational accuracy and efficiency. Furthermore, the unique properties of photosensitive reversible adhesive materials can be used to design novel anti-counterfeiting labels and information encryption materials, enhancing anti-counterfeiting and information security levels. In the packaging of food, pharmaceuticals and other products, photosensitive reversible adhesive materials can be used to prepare smart packaging that can be repeatedly opened and sealed, extending the shelf life of products and improving packaging convenience.

[0005] Despite the broad application prospects of photosensitive reversible adhesive materials, current technologies still have some limitations. Existing photosensitive reversible adhesive materials often exhibit slow response speeds, making it difficult to achieve rapid adhesion and deadhesion switching. Under repeated ultraviolet-visible light irradiation, the photoresponse performance of the materials may gradually decline, affecting their long-term stability and reusability. The preparation process of some photosensitive reversible adhesive materials is quite cumbersome, requiring the use of rough substrates made from other materials or special preparation methods, making large-scale production and application difficult. Some photosensitive reversible adhesive materials require the use of special photoresponse units, adhesive groups, or complex preparation processes, resulting in high material costs and limiting their widespread application in certain fields. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art and provide a light-controlled reversible adhesive gel, its preparation method and application method.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A photosensitive reversible adhesive gel comprising a gel and at least one metallic element selected from iron, cobalt, cerium, zirconium and molybdenum in the highest valence state at a mass percentage of 0.2-15%.

[0009] Specifically, if the mass percentage of the metal element is too low, the viscosity of the gel will easily decrease; if it is too high, the gel will be too hard and its extensibility will decrease. Specifically, it is preferably 2-5%, more preferably 2.2-5%, and even more preferably 5%.

[0010] Further, the monomer of the gel is at least one selected from acrylamide, acrylic acid, N-isopropylacrylamide, sodium acrylate, methyl methacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, styrene, dimethylammonium propanesulfonate propylmethacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, lauryl acrylate, vinylpyrrolidone, methacryloyloxyethyltrimethylammonium chloride, and furan acrylate.

[0011] Furthermore, the initiator of the gel is at least one selected from the following: ammonium persulfate and tetramethylethylenediamine, persulfate and ferrous salt, hydrogen peroxide and bisulfite, benzoyl peroxide and N,N-dimethylaniline, azobisisobutyronitrile and cobalt naphthenate, di-tert-butyl peroxide and sulfite, ammonium persulfate and bisulfite, potassium persulfate and ascorbic acid, and a combination of chlorate and ascorbic acid.

[0012] Specifically, the types and ratios of monomers and initiators in the gel can be selected by those skilled in the art according to actual conditions. As long as the gel has suitable adhesion strength, photo-controlled reversible adhesion can be achieved by adding the aforementioned metal elements. For example, when the monomers are acrylamide and acrylic acid, the molar ratio of the two can be 10:0.02-0.05:10, and the corresponding initiator can be a combination of ammonium persulfate and tetramethylethylenediamine, wherein the mass of the ammonium persulfate is 0.01-0.8 g / g relative to the total mass of acrylamide and acrylic acid, and the volume of the tetramethylethylenediamine is 0.1-3 μL / g relative to the total mass of acrylamide and acrylic acid.

[0013] Furthermore, the gel also includes viscosity enhancers and structural stabilizers, including at least one of phenols, starch, polypeptides, oligopeptides, and modified cellulose.

[0014] Furthermore, the viscosity enhancer and structural stabilizer constitute 0.3-18% of the gel by mass.

[0015] Furthermore, the gel also includes a stretching enhancer, including at least one of sodium tetraborate, sodium octaborate, sodium phenylborate, boric acid, trimethyl borate, triethyl borate, and boron-containing bioactive glass.

[0016] Furthermore, the stretching enhancer has a mass percentage of 0.5-10% in the gel.

[0017] Furthermore, the present invention also provides a method for preparing the above-mentioned light-controlled reversible adhesion gel, comprising:

[0018] The metal salt of the metal element is dissolved in water, the monomer and initiator of the gel are added, the mixture is stirred and poured into a mold, and then kept in an oven at 40-90℃ for 0.5-8 hours to prepare the light-controlled reversible adhesion gel.

[0019] When the gel includes a viscosity enhancer and a structural stabilizer, it is stirred together with the metal salt of the metal element and dissolved in water.

[0020] Wherein, when the gel also includes a stretching enhancer, the stretching enhancer is added after the metal salt of the metal element and the viscosity enhancer and structural stabilizer have dissolved in water, and the mixture is stirred and dissolved.

[0021] Specifically, when the gel includes a viscosity enhancer and structural stabilizer and a stretching enhancer, the viscosity enhancer and structural stabilizer and the metal salt of the metal element are stirred and dissolved in water at 40-100°C, and then the stretching enhancer is added and stirred and dissolved; after cooling, the monomer and initiator of the gel are added.

[0022] Furthermore, the present invention also provides a method for using the above-mentioned light-controlled reversible adhesive gel, wherein the gel adheres under visible light irradiation and de-adhedes under ultraviolet irradiation.

[0023] Furthermore, the duration of the ultraviolet irradiation is 3-30 s, and the wavelength of the ultraviolet irradiation is 200-400 nm.

[0024] Furthermore, the duration of visible light irradiation is 1-5 minutes, and the wavelength of visible light irradiation is 500-800 nm.

[0025] Beneficial effects:

[0026] 1. The metal element selected in this invention can connect with hydroxyl groups in the gel at its highest valence state, exhibiting high viscosity. When irradiated with ultraviolet light, the metal element can be reduced from its highest valence state to an intermediate valence state, rapidly breaking the connection with the hydroxyl groups and significantly reducing the viscosity of the gel, thus achieving deadhesion after short-term ultraviolet irradiation. Simultaneously, after visible light irradiation, it can return to its highest valence state and reconnect with the hydroxyl groups in the gel, restoring the gel's viscosity. This adhesion and deadhesion process can be repeated, exhibiting long-term stability and reusability.

[0027] 2. The photo-controlled reversible adhesive gel of the present invention is safer than the direct heating method used in the prior art to achieve reversible adhesion, and is also faster than the infrared irradiation method (which is essentially a form of infrared heat generation) used in the prior art.

[0028] 3. The photo-controlled reversible adhesive gel of the present invention has a simple and convenient preparation process and low cost, which is conducive to large-scale production and application and has broad application prospects. Attached Figure Description

[0029] Figure 1 The results show the changes in adhesion strength in Examples 1-5 and Comparative Example 1 of this invention;

[0030] Figure 2 The results show the changes in adhesion strength in Examples 6-10 and Comparative Example 2 of this invention;

[0031] Figure 3 This is the result of the cyclic adhesion strength change in Example 1 of the present invention. Detailed Implementation

[0032] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0033] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0034] Example 1:

[0035] (1) Preparation of hydrogel precursor solution

[0036] Weigh 2g of tannic acid and 0.3g of CoCl3·6H2O and add them to 30g of deionized water. Stir at 90℃ for 10 min until all solutes are completely dissolved, confirming that no solids remain in the solution. Weigh 0.3g of sodium tetraborate and add it to a beaker, continuing to stir until dissolved.

[0037] (2) Preparation of hydrogels

[0038] After cooling the solution, add 4.5 g acrylamide, 6 g acrylic acid solution, 0.3 g ammonium persulfate and 10 μL tetramethylethylenediamine (TEMED), stir for 5 min, and then quickly pour into the prepared mold. Place in a 90 ℃ oven for 1 h to prepare the hydrogel with a cobalt content of 2.2 wt% as described in Example 1.

[0039] Example 2:

[0040] The only difference between Example 2 and Example 1 is that FeCl3 was used instead of CoCl3·6H2O in Example 1 to prepare the hydrogel with an iron content of 2.2 wt%.

[0041] Example 3:

[0042] The only difference between Example 3 and Example 1 is that CeCl3 was used instead of CoCl3·6H2O in Example 1 to prepare the hydrogel with a 2.2 wt% cerium content.

[0043] Example 4:

[0044] The only difference from Example 1 is that ammonium molybdate was used instead of CoCl3·6H2O in Example 1 to prepare the hydrogel with a molybdenum content of 2.2 wt% in Example 4.

[0045] Example 5:

[0046] The only difference from Example 1 is that ZrCl3 was used instead of CoCl3·6H2O in Example 1 to prepare the hydrogel with a zirconium content of 2.2 wt% in Example 5.

[0047] Example 6:

[0048] The only difference from Example 1 is that the amount of CoCl3·6H2O is increased to prepare the hydrogel with a 5wt% cobalt content as in Example 6.

[0049] Example 7:

[0050] The only difference from Example 2 is that the amount of FeCl3 is increased to prepare the hydrogel with a 5 wt% iron content as in Example 7.

[0051] Example 8:

[0052] The only difference from Example 3 is that the amount of CeCl3 is increased to prepare the hydrogel with a 5 wt% cerium content of Example 8.

[0053] Example 9:

[0054] The only difference from Example 4 is that the amount of ammonium molybdate is increased to prepare the hydrogel with a molybdenum content of 5 wt% as in Example 9.

[0055] Example 10:

[0056] The only difference from Example 5 is that the amount of ZrCl3 is increased to prepare the hydrogel with a 5 wt% zirconium content of Example 10.

[0057] Comparative Example 1:

[0058] The only difference from Example 1 is that AlCl3 was used instead of CoCl3·6H2O in Example 1 to prepare a hydrogel with an aluminum content of 2.2 wt% as in Comparative Example 1.

[0059] Comparative Example 2:

[0060] The only difference between this example and Comparative Example 1 is that the amount of AlCl3 was increased to prepare a hydrogel with a 5 wt% aluminum content, as in Comparative Example 2.

[0061] Performance testing:

[0062] The hydrogels obtained in Examples 1-9 and Comparative Examples 1-2 were subjected to adhesion strength tests on wood-based substrates. The test results are as follows: Figure 1-3As shown. Specifically, the visible light test used a 500-800nm ​​xenon lamp, and the ultraviolet (UV) test used a 365nm UV lamp. The results show that the hydrogels of Examples 1-9 exhibited significant differences in adhesion strength under both visible light irradiation (2 min) and UV irradiation (5 s), enabling them to adhere and de-adhere. With increasing metal element content, the adhesion after UV irradiation further decreased, further widening the adhesion strength difference and facilitating de-adhesion. In contrast, the hydrogels in Comparative Examples 1-2, lacking an intermediate valence state for aluminum, could not achieve a significant difference in adhesion strength, thus failing to achieve photocontrolled reversible adhesion. Furthermore, as... Figure 3 As shown, the adhesion performance of the hydrogel in Example 1 decreased significantly after 5 seconds of UV light irradiation. However, the adhesion performance recovered after 2 minutes of irradiation with visible light instead of UV light. The hydrogel maintained its performance after 70 cycles, achieving long-term stability and reusability.

[0063] The embodiments of the present invention have been described in detail above. The description of the embodiments above is only for the purpose of helping to understand the method and core idea of ​​the present invention, and is not intended to limit the scope of implementation of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the patent claims of the present invention should be included in the patent application scope of the present invention. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A light-controlled reversible adhesion gel, characterized in that, It contains a gel and at least one metallic element selected from iron, cobalt, cerium, zirconium and molybdenum in 0.2-15% by mass of the highest valence state.

2. The light-controlled reversible adhesion gel according to claim 1, characterized in that, The monomer of the gel is at least one selected from acrylamide, acrylic acid, N-isopropylacrylamide, sodium acrylate, methyl methacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, styrene, dimethylammonium propanesulfonate propyl methacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, lauryl acrylate, vinylpyrrolidone, methacryloyloxyethyltrimethylammonium chloride, and furan acrylate.

3. The light-controlled reversible adhesion gel according to claim 2, characterized in that, The initiator of the gel is at least one of the following: ammonium persulfate and tetramethylethylenediamine, persulfate and ferrous salt, hydrogen peroxide and bisulfite, benzoyl peroxide and N,N-dimethylaniline, azobisisobutyronitrile and cobalt naphthenate, di-tert-butyl peroxide and sulfite, ammonium persulfate and bisulfite, potassium persulfate and ascorbic acid, chlorate and ascorbic acid.

4. The light-controlled reversible adhesion gel according to claim 1, characterized in that, The gel also includes viscosity enhancers and structural stabilizers, including at least one of phenols, starch, polypeptides, oligopeptides, and modified cellulose.

5. The light-controlled reversible adhesion gel according to claim 4, characterized in that, The viscosity enhancer and structural stabilizer constitute 0.3-18% of the gel by mass.

6. The photosensitive reversible adhesion gel according to claim 1, characterized in that, The gel also includes a stretching enhancer, comprising at least one of sodium tetraborate, sodium octaborate, sodium phenylborate, boric acid, trimethyl borate, triethyl borate, and boron-containing bioactive glass.

7. The light-controlled reversible adhesion gel according to claim 6, characterized in that, The stretching enhancer has a mass percentage of 0.5-10% in the gel.

8. A method for preparing the photocontrolled reversible adhesive gel according to any one of claims 1-7, characterized in that, include: The metal salt of the metal element is dissolved in water, the monomer and initiator of the gel are added, the mixture is stirred and poured into a mold, and then kept in an oven at 40-90℃ for 0.5-8 hours to prepare the light-controlled reversible adhesion gel. When the gel includes a viscosity enhancer and a structural stabilizer, it is stirred together with the metal salt of the metal element and dissolved in water. Wherein, when the gel also includes a stretching enhancer, the stretching enhancer is added after the metal salt of the metal element and the viscosity enhancer and structural stabilizer have dissolved in water, and the mixture is stirred and dissolved.

9. A method of using the photosensitive reversible adhesive gel according to any one of claims 1-7, characterized in that, The gel adheres under visible light irradiation and de-adhedes under ultraviolet irradiation.

10. The method of use according to claim 9, characterized in that, The duration of the ultraviolet irradiation is 3-30 s, and the wavelength of the ultraviolet irradiation is 200-400 nm.

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