Adhesion-controllable hydrogel, preparation method thereof, and magnetically driven adhesion method

Abstract

The present invention discloses an adhesion controllable hydrogel, a preparation method thereof and a magnetically driven adhesion method. The preparation method comprises: moving an AAPM magnetic gel solution containing a magnetic material onto a glass plate and making a glass plate polymerization mold; injecting a P(AAm‑co‑AAc) gel solution into the mold and obtaining a hydrogel film after thermal polymerization; swelling the film so that the magnetic gel part forms a dome-shaped protrusion, thereby preparing an adhesion controllable hydrogel with a bistable structure. The magnetic gel part of the hydrogel is used to adhere to an object, and the magnetic gel part is magnetically driven to make it jump and then the object is separated to achieve controllable adhesion. The adhesion controllable hydrogel of the present invention adopts a bistable structure, and utilizes magnetic materials and changes in the magnetic field to regulate the position or distribution of the magnetic part, thereby achieving precise control of the behavior of the hydrogel. The magnetic drive of the present invention has the advantages of non-contact, remote control and fast response speed, and can achieve controllable adhesion of the hydrogel.

Description

Technical Field

[0001] The present invention relates to a magnetically driven adhesion method of a hydrogel, and in particular to an adhesion-controllable hydrogel and a preparation method thereof, and a magnetically driven adhesion method. Background Art

[0002] Bistability refers to a system with two stable states, or energy minima. The difference between the energy maximum and minimum can be considered an energy barrier. The system can switch between these two stable states through a series of transitions, with the energy stored in the barrier being rapidly released. Bistability is a common phenomenon in nature and everyday life, such as in Venus flytraps and light switches. Numerous advances have been made and in-depth research has been conducted on bistable hydrogel structures. However, there remains a significant lack of research on hydrogels with controllable adhesion, or on hydrogels that combine bistable structures with controllable adhesion. Summary of the Invention

[0003] In order to solve the problems existing in the background technology, the present invention provides an adhesion-controlled hydrogel, a preparation method thereof, and a magnetically driven adhesion method.

[0004] The technical solution adopted in the present invention is:

[0005] 1. A method for preparing a hydrogel with controllable adhesion:

[0006] Step 1) acrylamide, acrylic acid, potassium persulfate, polyvinyl alcohol and magnetic material are added to deionized water and mixed uniformly to obtain an AAPM (Acrylamide-Acrylic acid-Polyvinyl alcohol-Magnetite) magnetic gel solution.

[0007] Step 2) acrylamide, acrylic acid, potassium persulfate and N,N-methylenebisacrylamide are uniformly mixed to obtain a P(AAm-co-AAc) (Acrylamide-Acrylic acid) gel solution.

[0008] Step 3) The AAPM magnetic gel solution is moved to one or more preset positions on one side of a glass plate, and another glass plate is covered on the AAPM magnetic gel solution. The edge gap between the two glass plates is sealed with silicone to form a glass plate polymerization mold.

[0009] Step 4) The P(AAm-co-AAc) gel solution is injected into the gap between the two glass plates inside the glass plate polymerization mold, and then thermally polymerized. After the polymerization is completed, the two glass plates and the silica gel are removed to obtain a hydrogel film.

[0010] Step 5) The hydrogel film is subjected to a swelling treatment. Due to the swelling mismatch between the two gels, the AAPM magnetic gel portion in the hydrogel film forms a dome-shaped protrusion. The protrusion can jump and fix at the upper and lower ends of the film plane, thereby preparing a bistable structure of adhesion-controlled hydrogel.

[0011] In the step 1), in the AAPM magnetic gel solution, the total concentration of acrylamide and acrylic acid is 4 to 7M, the concentration of acrylamide is 10 to 70 mol%, the content of polyvinyl alcohol is 16 wt%, the content of potassium persulfate is 0.5% to 1% of the total amount of acrylamide and acrylic acid, and the content of magnetic material is 10 to 14 wt%.

[0012] In the step 1), the magnetic material is ferrosoferric oxide nanoparticles.

[0013] In the step 2), the total concentration of acrylamide and acrylic acid in the P(AAm-co-AAc) gel solution is 4 to 7 M, the concentration of acrylamide is 10 to 50 mol%, and the contents of potassium persulfate and N,N-methylenebisacrylamide are both 0.5% to 1% of the total amount of acrylamide and acrylic acid.

[0014] In step 3), before transfer, the AAPM magnetic gel solution is first vacuumed to remove all dissolved oxygen, and then the AAPM magnetic gel solution is moved to one or more preset positions on one side of a glass plate using a pipette; the two glass plates are arranged in parallel.

[0015] In the step 4), the thermal polymerization is carried out at 60°C.

[0016] In the step 5), the hydrogel film is immersed in deionized water for swelling treatment.

[0017] 2. A controllable adhesion hydrogel:

[0018] The adhesion-controlled hydrogel is prepared by the above-mentioned method.

[0019] 3. A magnetically driven adhesion method for controllable hydrogel adhesion:

[0020] The controllable adhesion hydrogel includes a P(AAm-co-AAc) gel part and an AAPM magnetic gel part. When performing magnetically driven adhesion of an object, it is first arranged horizontally and moved to directly above the object to be adhered, and then moved downward until the upwardly curved AAPM magnetic gel part in the controllable adhesion hydrogel adheres to the object. Then, the controllable adhesion hydrogel is controlled to move directly above the position to be placed. A magnet is used to magnetically drive and apply a magnetic field directly above the controllable adhesion hydrogel, so that the AAPM magnetic gel part in the controllable adhesion hydrogel jumps to bend downward. During the jumping process, the adhesion area between the object and the AAPM magnetic gel part gradually decreases until the adhesion force between the controllable adhesion hydrogel and the object disappears, and the object naturally falls off to the position to be placed.

[0021] When only a few preset positions in the AAPM magnetic gel part of the controllable adhesion hydrogel need to be selectively magnetically driven to adhere, it is first arranged horizontally and moved to the top of the object to be adhered, and then a magnet is used to magnetically drive and apply a magnetic field directly above each preset position in the AAPM magnetic gel part of the controllable adhesion hydrogel, so that each preset position in the AAPM magnetic gel part jumps to bend downward, and then moves downward until the upward-bending AAPM magnetic gel part of the controllable adhesion hydrogel adheres to the object, and then the controllable adhesion hydrogel is controlled to move to the top of the position to be placed, and a magnet is used to magnetically drive and apply a magnetic field directly above other positions in the AAPM magnetic gel part of the controllable adhesion hydrogel, so that all AAPM magnetic gel parts jump to bend downward, and finally the object falls off naturally to the position to be placed; a magnet is used to magnetically drive and apply a magnetic field directly below the controllable adhesion hydrogel, so that all AAPM magnetic gel parts jump to bend upward, so as to continue the next step of magnetically driven adhesion of the object, thereby achieving controllable adhesion.

[0022] The adhesion-controlled hydrogel utilizes the swelling mismatch between AAPM gel and P(AAm-co-AAc) gel to form a bistable structure. The ferroferric oxide nanoparticles in the AAPM gel enable the gel to jump under the influence of magnetic force. During the jumping process, the adhesion area gradually decreases until the adhesion force disappears, thereby achieving a controllable adhesion effect.

[0023] The beneficial effects of the present invention are:

[0024] The controllable adhesion hydrogel of the present invention employs a bistable structure and utilizes magnetic nanoparticles or magnetic field-responsive polymers to precisely control the hydrogel's behavior. By varying the intensity or direction of the magnetic field, the position or distribution of the magnetic components can be regulated. Compared to traditional triggering methods, the magnetic actuation of the present invention offers the advantages of non-contact, remote control, and rapid response, enabling controlled adhesion of the hydrogel. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a flow chart for preparing the controllable adhesion hydrogel of the present invention;

[0026] Figure 2 Schematic diagram of the controllable adhesion of a single AAPM gel of the present invention;

[0027] Figure 3 Graph showing changes in adhesion force during the adhesion process of Example 1 of the present invention;

[0028] Figure 4 This is a comparison diagram of adhesion forces at different preloads according to Example 1 of the present invention;

[0029] Figure 5 This is a graph comparing the adhesion of the AAPM gel of Example 1 of the present invention to paper, plastic, glass, and silicon wafers with different degrees of roughness;

[0030] Figure 6 This is an optical image of objects of different shapes adhered to the first embodiment of the present invention;

[0031] Figure 7 This is an example diagram of selective adhesion of the array AAPM gel according to Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] The specific embodiments of the present invention are as follows:

[0034] Example 1:

[0035] like Figure 1As shown, first, acrylamide, acrylic acid, potassium persulfate, polyvinyl alcohol and ferrous oxide nanoparticles are added to deionized water and mixed evenly to obtain an AAPM magnetic gel solution, wherein acrylamide and acrylic acid are used as total monomers, polyvinyl alcohol is responsible for thickening, and ferrous oxide nanoparticles give the gel magnetism so that it can respond to an externally applied magnetic field. The total concentration of acrylamide and acrylic acid is 5M, the concentration of acrylamide is 40mol%, the content of polyvinyl alcohol is 16wt%, the content of potassium persulfate is 0.5% of the total amount of acrylamide and acrylic acid, and the content of ferrous oxide nanoparticles is 12wt%; then, acrylamide, acrylic acid, potassium persulfate and N,N-methylenebisacrylamide are mixed evenly to obtain a P(AAm-co-AAc) gel solution. In order to simplify the preparation process, acrylamide and acrylic acid are also selected as the gel system of total monomers. The total concentration of acrylamide and acrylic acid is 5M, the concentration of acrylamide is 40mol%, and the contents of potassium persulfate and N,N-methylenebisacrylamide are both 5M and 40mol%. The AAPM magnetic gel solution was vacuumed to remove the dissolved oxygen inside, and then the AAPM magnetic gel solution was moved to nine positions of a 3×3 array on one side of a glass plate by a pipette, 20 μL was injected into each position, and another parallel glass plate was covered on the AAPM magnetic gel solution, and the edge gap between the two glass plates was sealed with 1 mm thick silicone to form a glass plate polymerization mold; the P(AAm-co-AAc) gel solution was injected into the gap between the two glass plates inside the glass plate polymerization mold, and then thermally polymerized at 60°C for 12 hours. After the polymerization was completed, the two glass plates and the silicone were removed to obtain a hydrogel film; the hydrogel film was immersed in deionized water for swelling treatment for 24 hours. Due to the swelling mismatch of the two gels, the AAPM magnetic gel part in the hydrogel film formed a dome-shaped protrusion, which could jump and be fixed at the upper and lower ends of the film plane, showing an obvious bistable structure, thereby preparing a bistable structure of adhesion controllable hydrogel.

[0036] like Figure 2As shown, when the controllable adhesion hydrogel is magnetically driven to adhere to an object, it is first arranged horizontally and fixed on a bracket, and then the bracket is horizontally fixed on an electric lifting platform and moved to the top of the object to be adhered, and the electric lifting platform is used to move downward until the upward-bent AAPM magnetic gel part of the controllable adhesion hydrogel contacts and adheres to the object, and then the lifting platform is raised to use the adhesion force of the AAPM magnetic gel to adhere to the object at a specific position, and then the controllable adhesion hydrogel is controlled to move to the top of the position to be placed, and a magnet is used to magnetically drive and apply a magnetic field above the controllable adhesion hydrogel, so that the AAPM magnetic gel part of the controllable adhesion hydrogel jumps to bend downward. During the jump, the adhesion area between the object and the AAPM magnetic gel part gradually decreases until the adhesion force between the controllable adhesion hydrogel and the object disappears, and the object naturally falls off to the position to be placed, achieving the effect of non-contact transfer printing, that is, realizing controllable adhesion of hydrogel. As shown Figure 3 As shown in the figure, the adhesion force changes of AAPM magnetic gel when it approaches an object, contacts an object, and jumps. It can be seen that the adhesion force of AAPM magnetic gel is about 8mN. Figure 4 As shown in Figure 1, the adhesion force of AAPM magnetic gel under different preload conditions is compared. It can be seen that the adhesion force of AAPM magnetic gel is higher when the preload pressure is 2mN or above. Figure 5 The figure shows the adhesion force of AAPM magnetic gel when it contacts paper, plastic, glass and silicon wafer with different surface roughness. It can be seen that the smoother the surface, the higher the adhesion force of AAPM magnetic gel. In the adhesion process of AAPM magnetic gel, there is no limit to the object to be adhered. As long as it is within the adhesion range of AAPM magnetic gel, controllable adhesion can be achieved, such as Figure 6 As shown, AAPM magnetic gel can be used to adhere objects of different shapes, including 0.024g petals, 0.027g contact lenses, 0.056g ceramic capacitors, 0.078g pencil leads, 0.097g round washers, and 0.128g glass.

[0037] like Figure 7As shown, when only a few preset positions in the AAPM magnetic gel part of the controllable hydrogel need to be selectively magnetically driven to adhere, it is first arranged horizontally and moved to the top of the object to be adhered, and then a magnet is used to magnetically drive and apply a magnetic field to the array AAPM magnetic gel part of the controllable hydrogel adhesion directly above the non-target object, so that each preset position in the array AAPM magnetic gel part jumps to bend downward, realizing the transfer of a specific pattern, and then moves downward until the upward-bent array AAPM magnetic gel part in the controllable hydrogel adhesion adheres to the target object. , then control the adhesion controllable hydrogel to move to just above the position to be placed, and use a magnet to magnetically drive and apply a magnetic field just above the target object in the array AAPM magnetic gel part of the adhesion controllable hydrogel, so that the array AAPM magnetic gel part all jumps to bend downward, and finally the target object naturally falls off to the position to be placed; use a magnet to magnetically drive and apply a magnetic field just below the adhesion controllable hydrogel, so that the array AAPM magnetic gel part all jumps to bend upward, so as to continue the next step of magnetically driven adhesion of the object, thereby achieving the effect of controllable adhesion.

[0038] Example 2:

[0039] First, acrylamide, acrylic acid, potassium persulfate, polyvinyl alcohol and ferroferric oxide nanoparticles are added to deionized water and mixed evenly to obtain an AAPM magnetic gel solution, wherein acrylamide and acrylic acid serve as total monomers, polyvinyl alcohol is responsible for thickening, and ferroferric oxide nanoparticles give the gel magnetism, enabling it to respond to an externally applied magnetic field. The total concentration of acrylamide and acrylic acid is 6M, the concentration of acrylamide is 50mol%, the content of polyvinyl alcohol is 16wt%, the content of potassium persulfate is 0.5% of the total amount of acrylamide and acrylic acid, and the content of magnetic material is 13wt%; then, acrylamide, acrylic acid, potassium persulfate and N,N-methylenebisacrylamide are mixed evenly to obtain a P(AAm-co-AAc) gel solution. In order to simplify the preparation process, acrylamide and acrylic acid are also selected as the gel system of total monomers. The total concentration of acrylamide and acrylic acid is 6M, the concentration of acrylamide is 50mol%, and the contents of potassium persulfate and N,N-methylenebisacrylamide are both 60% of the total amount of acrylamide and acrylic acid. 0.5% of the mass; the AAPM magnetic gel solution was vacuumed to exhaust the dissolved oxygen inside, and then the AAPM magnetic gel solution was moved to four positions of a 2×2 array on one side of a glass plate by a pipette, 20 μL was injected into each position, and another parallel glass plate was covered on the AAPM magnetic gel solution, and 1 mm thick silicone was used to seal the edge gap between the two glass plates to form a glass plate polymerization mold; the P(AAm-co-AAc) gel solution was injected into the gap between the two glass plates inside the glass plate polymerization mold, and then thermally polymerized at 60°C for 12 hours. After the polymerization was completed, the two glass plates and silicone were removed to obtain a hydrogel film; the hydrogel film was immersed in deionized water for swelling treatment for 24 hours. Due to the swelling mismatch of the two gels, the AAPM magnetic gel part in the hydrogel film formed a dome-shaped protrusion, which could jump and fix at the upper and lower ends of the film plane, showing an obvious bistable structure, thereby preparing a bistable structure of adhesion controllable hydrogel.

[0040] The method of magnetic drive to achieve controllable adhesion of hydrogels proposed in the present invention controls the jumping of bistable structure hydrogels by applying a magnetic field, thereby achieving the effect of controllable adhesion. It has the characteristics of simple preparation, fast response speed, and non-contact response. It can have broad application prospects in flexible drive, flexible sensing, optical devices, biomedicine and other fields.

[0041] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The scope of protection of the present invention should not be regarded as limited to the specific forms described in the examples. The scope of protection of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the inventive concept.

Claims

1. A method for preparing an adhesion-controlled hydrogel, characterized in that: include: Step 1) adding acrylamide, acrylic acid, potassium persulfate, polyvinyl alcohol, and magnetic material into deionized water and mixing them uniformly to obtain an AAPM magnetic gel solution; Step 2) mixing acrylamide, acrylic acid, potassium persulfate, and N,N-methylenebisacrylamide to obtain a P(AAm-co-AAc) gel solution; Step 3) moving the AAPM magnetic gel solution to one or more predetermined locations on one side of a glass plate, and then covering it with another glass plate, and sealing the edge gap between the two glass plates with silicone to form a glass plate polymerization mold; Step 4) injecting the P(AAm-co-AAc) gel solution into the gap between the two glass plates in the glass plate polymerization mold, followed by thermal polymerization. After the polymerization is complete, the two glass plates and the silica gel are removed to obtain a hydrogel film; Step 5) The hydrogel film is subjected to a swelling treatment so that the AAPM magnetic gel portion in the hydrogel film forms a dome-shaped protrusion, thereby preparing a bistable adhesion controllable hydrogel.

2. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In the step 1), in the AAPM magnetic gel solution, the total concentration of acrylamide and acrylic acid is 4-7M, the concentration of acrylamide is 10-70 mol%, the content of polyvinyl alcohol is 16 wt%, the content of potassium persulfate is 0.5%-1% of the total amount of acrylamide and acrylic acid, and the content of magnetic material is 10-14 wt%.

3. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In the step 1), the magnetic material is ferrosoferric oxide nanoparticles.

4. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In the step 2), in the P(AAm-co-AAc) gel solution, the total concentration of acrylamide and acrylic acid is 4 to 7 M, the concentration of acrylamide is 10 to 50 mol%, and the contents of potassium persulfate and N,N-methylenebisacrylamide are both 0.5% to 1% of the total amount of acrylamide and acrylic acid.

5. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In step 3), before transfer, the AAPM magnetic gel solution is first vacuumed, and then the AAPM magnetic gel solution is moved to one or more preset positions on one side of a glass plate using a pipette; the two glass plates are arranged in parallel.

6. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In the step 4), the thermal polymerization is carried out at 60°C.

7. The method for preparing the adhesion-controlled hydrogel according to claim 1, wherein: In the step 5), the hydrogel film is immersed in deionized water for swelling treatment.

8. An adhesion-controlled hydrogel, characterized in that: The adhesion-controlled hydrogel is prepared by the method according to any one of claims 1-7.

9. A magnetically driven adhesion method for a controllable adhesion hydrogel prepared by the method according to any one of claims 1 to 7, characterized in that: include: The controllable adhesion hydrogel includes a P(AAm-co-AAc) gel portion and an AAPM magnetic gel portion. When magnetically driven adhesion of an object is performed, it is first arranged horizontally and moved to directly above the object to be adhered, and then moved downward until the upwardly curved AAPM magnetic gel portion in the controllable adhesion hydrogel adheres to the object. The controllable adhesion hydrogel is then controlled to move directly above the position to be placed, and magnetic drive is performed directly above the controllable adhesion hydrogel to apply a magnetic field, so that the AAPM magnetic gel portion in the controllable adhesion hydrogel jumps to bend downward. During the jumping process, the adhesion area between the object and the AAPM magnetic gel portion gradually decreases until the adhesion force between the controllable adhesion hydrogel and the object disappears, and the object naturally falls off to the position to be placed. When only a few preset positions in the AAPM magnetic gel part of the controllable adhesion hydrogel need to be selectively magnetically driven to adhere, it is first arranged horizontally and moved to the top of the object to be adhered, and then magnetic driving and applying a magnetic field are performed directly above each preset position in the AAPM magnetic gel part of the controllable adhesion hydrogel, so that each preset position in the AAPM magnetic gel part jumps to bend downward, and then moves downward until the upward-bending AAPM magnetic gel part of the controllable adhesion hydrogel adheres to the object, and then the controllable adhesion hydrogel is controlled to move to the top of the position to be placed, and magnetic driving and applying a magnetic field are performed directly above other positions in the AAPM magnetic gel part of the controllable adhesion hydrogel, so that all AAPM magnetic gel parts jump to bend downward, and finally the object falls off naturally to the position to be placed; magnetic driving and applying a magnetic field are performed directly below the controllable adhesion hydrogel, so that all AAPM magnetic gel parts jump to bend upward, so as to continue the next step of magnetically driven adhesion of the object, thereby achieving controllable adhesion.

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