A method for encapsulating liquid metal microspheres

Abstract

The present invention belongs to the field of liquid metal encapsulation and relates to a method for encapsulating liquid metal microspheres. The method involves first preparing a hydrogel powder with self-gelling and adhesive properties and then preparing a solidified spherical liquid metal, followed by encapsulation of the spherical liquid metal. The method for preparing a liquid metal coating is simple and versatile, and the resulting coating exhibits good uniformity. Compared to conventional dipping processes, this method avoids the accumulation of highly fluid polymer liquids at the bottom under the influence of gravity during the curing process, thereby achieving a more uniform surface hydrogel coating.

Description

Technical Field

[0001] The invention belongs to the field of liquid metal packaging, in particular to a method for packaging liquid metal microspheres. Background Art

[0002] As an emerging material that can meet major national needs in aerospace, medical health, and electronic information, liquid metal (gallium-based or bismuth-based) has attracted widespread attention due to its low melting point, excellent electrical conductivity, thermal conductivity, fluidity, low toxicity, and near-zero saturated vapor pressure.

[0003] In particular, in the medical field, liquid metals, which are naturally high-density, can serve as new contrast agents in medical imaging examinations such as CT, MRI, and photoacoustic imaging to achieve efficient diagnosis and treatment. In addition, liquid metals can also generate heat under the action of external light, magnetic fields, or electric fields to achieve thermal ablation of tumors. At the same time, after being dispersed into micro-nanoparticles, liquid metals can be modified with anti-cancer drugs to achieve synergistic treatments including chemotherapy. Flexible or rigid-flexible medical implantable electrodes or wearable devices based on liquid metals as physiological signal sensors have also shined due to the active development of fields such as brain-computer interfaces and flexible electronics.

[0004] However, due to the presence of sticky surface oxides (gallium oxide and indium oxide, etc.) and high reactivity, liquid metals will adhere to or wet substrates including skin, glass and metal plates, making these liquid metals difficult to handle. In particular, liquid metals that enter the body by injection or swallowing often come into frictional contact with the surrounding environment, so that the liquid metal will inevitably remain on the surface of the tissue it passes through. This will undoubtedly cause great trouble for the subsequent recovery of liquid metals. Although liquid metals are considered to be non-cytotoxic, the role played by liquid metals remaining in the body in the metabolic process is still unclear, that is, there are still certain safety risks. In addition, the presence of metal foreign matter in the body will also have a certain degree of impact on daily life, such as unnecessary troubles during security checks. Therefore, it is necessary to appropriately and effectively package and protect the liquid metal to reduce the problem of liquid metal leakage.

[0005] Currently encapsulating macro blocks (volume greater than 1mm 3Liquid metal solutions primarily involve injecting or wetting the liquid metal into a mold and then encapsulating it with a polymer material (such as silicone) [Adv. Sci. 2022, 2105-289, Polymers 2021, 13, 2407]. Alternatively, bulk materials can be broken down into micron-sized particles through ultrasound or mechanical stirring, which can then be encapsulated with polymer materials for applications in flexible electronics and other fields [Nature Communications (2019) 10:1300]. However, these solutions all have challenges such as complex preparation processes, poor permeability of polymer materials like silicone, excessively thick encapsulation shells, and high costs.

[0006] Hydrogels have been widely used in the biomedical field as a material with high biocompatibility and similar mechanical properties to human tissue to reduce chemical stimulation and mechanical damage of implanted devices or wearable devices under long-term use. Compared with materials such as silica gel (such as polydimethylsiloxane PDMS), the material system coated with hydrogel has better permeability (including ions and aqueous solutions, etc.), thereby achieving a certain degree of interaction with the external environment. Therefore, the use of hydrogel to wrap bulk liquid metal has a wider application prospect. At present, some people have used objects to be soaked in hydrogel prepolymer solution to achieve the coating of hydrogel thin layer [Adv.Mater.2019,31,1807101, Adv.Mater.2019,1903062]. However, due to the weak mechanical properties of the hydrogel film obtained after dipping in the hydrogel prepolymer solution and the uneven shell caused by its surface sedimentation after a large amount of dipping in hydrogel, In addition, some researchers have used hydrogels to encapsulate liquid metal micro- and nanoparticles, but this approach has difficulty encapsulating high-density metal blocks due to poor mechanical properties [Adv. Funct. Mater. 2018, 28, 1804-197]. Therefore, it remains difficult to encapsulate a hydrogel shell with stable physical and chemical properties, relatively uniform thickness, and controllable thickness on the surface of a highly fluid macroscopic liquid metal block. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for encapsulating liquid metal microspheres to more conveniently and quickly prepare new liquid metal hydrogel capsules with excellent mechanical properties to ensure that the liquid metal does not easily leak during daily use or medical applications.

[0008] The technical solution adopted by the present invention to solve the technical problem is:

[0009] The first aspect of the present invention is to provide a method for encapsulating liquid metal microspheres, comprising the following steps:

[0010] Step 1, preparing a hydrogel powder with self-gelling properties and adhesion: mixing a polymerizable small molecule monomer A with a carboxyl group or a hydroxyl group, a polymerizable small molecule monomer B with a silanol group, a crosslinker, a photoinitiator, and deionized water in a volume ratio of 40-180:0.1-1:1-3:0.05-0.1:60-200, mechanically stirring and mixing, removing bubbles, and UV curing at room temperature for 3-5 hours; dialyzing to remove unpolymerized small molecules in the hydrogel; crushing, freeze-drying, and sieving to obtain a hydrogel powder with a particle size of 100 mesh to 400 mesh;

[0011] Prepare solidified spherical liquid metal, first pass the liquid metal through a mold to shape it into a sphere with a particle size of 1mm to 3cm, and then solidify it at a temperature of 10℃ to -30℃;

[0012] Step 2: Encapsulate spherical liquid metal: Control the ambient humidity below 40% and the temperature below the melting point of the liquid metal. Spray the atomized glycerol aqueous solution on the liquid metal balls and place them in a container covered with hydrogel powder. Shake the container to allow the metal balls inside to roll. After rolling until the powder completely covers the liquid metal balls, take out the liquid metal balls, then place them in a new plastic container and continue rolling to remove the dry powder that is pseudo-adhered to the surface. Finally, spray a small amount of glycerol aqueous solution to cover the surface of the metal balls to promote the redissolution of the gel dry powder attached to the surface to form a complete hydrogel film.

[0013] Furthermore, the polymerizable small molecule monomer A having a carboxyl group or a hydroxyl group is one or more of acrylic acid, 2-butenoic acid, and polyvinyl alcohol.

[0014] Furthermore, the polymerizable small molecule monomer B with silanol groups is one or both of [3-(methacryloyloxy)propyl]trimethoxysilane and vinyltrimethylsilane.

[0015] Furthermore, the cross-linking agent is one or both of N,N-methylenebisacrylamide and polyethylene glycol dimethacrylate.

[0016] Furthermore, the photoinitiator is one or more of benzophenone, α-ketoglutaric acid, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

[0017] Further preferably, the volume ratio of the polymerizable small molecule monomer A with carboxyl or hydroxyl groups, the polymerizable small molecule monomer B with silanol groups, the crosslinking agent, the photoinitiator, and deionized water is 60-100:0.1-0.2:1-3:0.05-0.1:150-200.

[0018] Furthermore, the liquid metal is a gallium-based or bismuth-based metal or alloy.

[0019] Furthermore, the volume percentage of the glycerol aqueous solution is 10 vol% to 50 vol%.

[0020] Furthermore, the dialyzed hydrogel is placed in liquid nitrogen. When the liquid nitrogen no longer boils, it is taken out of the liquid nitrogen and placed in a stirring crusher for crushing to obtain a white hydrogel powder. The powder is then placed in a freeze dryer and freeze-dried at -70°C, preferably at -70°C to -120°C.

[0021] The second aspect of the present invention provides liquid metal hydrogel capsules obtained by the above encapsulation method.

[0022] The third aspect of the present invention provides applications of the liquid metal hydrogel capsule in the fields of thermal management, interventional medicine, and soft robotics.

[0023] The advantages and positive effects of the present invention are:

[0024] 1. Compared with the currently commonly used polymethyl methacrylate and polydimethylsiloxane, the hydrogel thin layer used in the present invention has natural permeability to ions, small molecules and solvents.

[0025] 2. The novel liquid metal hydrogel capsule of the present invention can controllably adjust the shell thickness and inner core size by changing the number of rolling coatings and the spherical mold to adapt to different size environments, for example, it can be adjusted to a size suitable for human swallowing.

[0026] 3. The gel powder used in the present invention is a three-dimensional network formed by copolymerization and cross-linking of acrylic acid molecules obtained by long-term dialysis and freeze-drying and a small amount of [3-(methacryloyloxy)propyl]trimethoxysilane as monomers, which has good biocompatibility. The polymerized high-molecular polyacrylic acid has a large number of carboxyl groups, which can achieve healing between powders under the action of water redissolution and hydrogen bonding; and a small amount of [3-(methacryloyloxy)propyl]trimethoxysilane can not only provide Si-O-Si covalent cross-linking to improve the mechanical strength and stability of the re-dissolved hydrogel film, but also produce a cross-linking reaction with the metal surface with hydroxyl groups to improve the adhesion to the metal. Here, acrylic acid can be replaced by various polymerizable small molecule monomers with carboxyl groups or hydroxyl groups, such as 2-butenoic acid or polyvinyl alcohol, and [3-(methacryloyloxy)propyl]trimethoxysilane can also be replaced with other polymerizable small molecule monomers with silanol groups, such as vinyltrimethylsilane.

[0027] 4. The method for preparing liquid metal coating of the present invention is simple and universal, and the obtained coating has good uniformity. Compared with the previous dipping process, it can avoid the bottom accumulation of high-fluidity polymer liquid under the action of gravity during the curing process, thereby making the surface hydrogel coating have better uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flow chart is prepared for the method of the present invention;

[0029] Figure 2 This is a photo of the morphology of liquid metal hydrogel capsules during the preparation process;

[0030] Figure 3 is the amount of powder and coating thickness on the surface of the liquid metal hydrogel capsule under different rolling times, where a) is the amount of powder on the surface of the liquid metal sphere under different rolling times; b) is the shell thickness on the surface of the liquid metal sphere under different rolling times;

[0031] Figure 4 is the compression performance of liquid metal hydrogel capsules with different shell thicknesses;

[0032] Figure 5 This is a photo of the liquid metal hydrogel capsule prepared in Example 2;

[0033] Figure 6 This is a photo of the liquid metal hydrogel capsule prepared in Example 3;

[0034] Figure 7 The liquid metal spheres are obtained by the drop-dipping method and dipped in the hydrogel prepolymer solution;

[0035] Figure 8 After the liquid metal melts, the hydrogel cannot achieve long-term stable wrapping of the liquid metal with high deformability;

[0036] Figure 9 It is pAAc powder after soaking in water;

[0037] Figure 10 Photos of the preparation process of Comparative Example 3, where A shows the powder obtained by copolymerization with NIPAM instead of TMSPMA, coated on the solidified liquid metal spheres; B shows the hydrogel film and the separated liquid metal spheres that were easily torn off with the help of tweezers; C shows the hydrogel film and the separated liquid metal spheres that lost their mechanical properties after being soaked in water;

[0038] Figure 11 These are photos of the preparation process of Comparative Example 4, where A is the p(AAm-co-TMSPMA) hydrogel powder after immersion in water; B is the hydrogel layer stretched and adhered to the surface of the solidified liquid metal sphere. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the scope of protection of the present invention cannot be limited thereto.

[0040] Example 1

[0041] A method for encapsulating liquid metal microspheres comprises the following steps:

[0042] Step 1: Prepare hydrogel powder with self-gelling properties and adhesion.

[0043] ① Preparation of p(AAc-co-TMSPMA) hydrogel:

[0044] In a 500mL glass, slowly pour 160mL of deionized water, 80mL of acrylic acid, 2.1mL of 0.1mol / L N,N-methylenebisacrylamide, 60µL of 1mol / L α-ketoglutaric acid, and 120µL of [3-(methacryloyloxy)propyl]trimethoxysilane [TMSPMA]. The precursor solution is then thoroughly mixed and de-bubbled using mechanical stirring and waterbath sonication. A 50mL syringe is then used to load the precursor solution, and visible bubbles are removed using sonication. Finally, the syringes filled with the hydrogel prepolymer solution are transferred to plastic sealable bags, filled with nitrogen for protection, and placed in a 365nm UV curing chamber for approximately 3–5 hours.

[0045] ②p(AAc-co-TMSPMA) hydrogel dialysis:

[0046] The solidified hydrogel was removed from the needle tube and soaked in 1000 mL of deionized water. The dialysate was replaced every 24 hours. The unpolymerized acrylic acid monomers and other small molecules in the hydrogel could be removed by replacing the dialysate about 3 to 5 times.

[0047] ③ Preparation of p(AAc-co-TMSPMA) gel powder:

[0048] The dialyzed hydrogel is placed in liquid nitrogen. When the liquid nitrogen no longer boils, it is removed from the liquid nitrogen and crushed in a blender to produce a white hydrogel powder. Subsequently, the powder is placed in a freeze dryer and freeze-dried at approximately -70°C. After approximately 48 hours, the powder is removed to obtain the desired dry gel powder. Finally, the powder is passed through a sifter (100-400 mesh) to obtain a uniformly distributed dry gel powder, which is then placed in a drying cabinet for use.

[0049] Step 2: Prepare solidified spherical liquid metal.

[0050] A gallium- or bismuth-based metal or alloy (preferably pure gallium, gallium-indium alloy, bismuth-indium-tin alloy, bismuth-indium alloy, or gallium-indium-tin alloy) is accurately filled into a spherical silicone mold using a pipette. To ensure that the liquid metal is completely filled into the container environment, the mold can be gently dropped several times to allow the liquid metal to fully contact the silicone mold and reduce surface defects in the resulting solidified liquid metal sphere. Finally, the mold filled with liquid metal is placed in an ultra-low temperature freezer (-80°C). After about 1 hour, the solidified spherical liquid metal can be removed.

[0051] Step 3: Encapsulate the spherical liquid metal.

[0052] ① In order to prevent the gel dry powder from absorbing moisture in the environment and melting the liquid metal, the ambient humidity needs to be controlled below 40% and the temperature needs to be controlled below the melting point of the liquid metal before subsequent experimental preparation can be carried out.

[0053] ②First, take the same volume of p(AAc-co-TMSPMA) gel powder as that of the solidified liquid metal ball and place it in a plastic container. Then use a spray bottle to spray the atomized glycerol aqueous solution (V 甘油 :V 水 =1:4) spray the liquid metal spheres onto the powdered container. Shake the container to encourage the metal spheres to roll. After rolling for about 5 seconds, remove the spheres with adhered powder. Then, place the spheres into a new plastic container and continue rolling for about 10 seconds to remove any adhering powder. This helps to improve the uniformity of the subsequent hydrogel shell thickness. Finally, use a spray bottle to spray the glycerol solution onto the spheres to dissolve the adhered gel powder, ultimately forming a complete hydrogel film.

[0054] ③ In order to obtain liquid metal hydrogel capsules of different thicknesses, the small balls can be placed in a container covered with dry powder and the steps in ② can be repeated to obtain hydrogel capsules with controllable shell thickness.

[0055] Figure 2 This is a morphological photograph of the liquid metal hydrogel capsule prepared in Example 1. It can be seen from the figure that the surface of the liquid metal is completely covered by the hydrogel coating, and the coating can still maintain the wrapped state and appear transparent after swelling.

[0056] The method for measuring the amount of powder on the surface of the liquid metal ball is: measure the original mass m0 of the liquid metal ball, the total mass m1 after water spraying, the total mass m2 after powder coating, and the total mass m3 after water spraying respectively, and then subtract the total mass m2 after powder coating from the total mass m1 after water spraying to obtain the mass of powder used for roller coating.

[0057] The method for measuring the shell thickness on the surface of the liquid metal ball is as follows: use a vernier caliper to measure the diameter of three liquid metal hydrogel balls with the same number of roll coatings, subtract the diameter of the original liquid metal ball, divide it by 2, and take the average value to obtain the shell thickness on the surface of the liquid metal ball under different roll coating times.

[0058] Figure 3 a) is the amount of powder on the surface of the liquid metal ball under different roller coating times; b) is the shell thickness on the surface of the liquid metal ball under different roller coating times. Figure 3 It can be seen that the powder required for each roll coating is about 16 mg, and as the number of roll coatings increases, the thickness of the surface coating will also increase. The thickness increased by each roll coating layer is also similar, about 120 μm.

[0059] The compression performance of the liquid metal hydrogel capsule was determined by placing the liquid metal hydrogel pellet under an Instron tensile tester. The accessories and software were set to compression mode and then a compression test was performed at a compression speed of 10 mm / min. The force-working distance curve was obtained and converted into a force-strain curve.

[0060] Figure 4 The compression performance of liquid metal hydrogel capsules with different shell thicknesses is shown in Figure 2. Figure 4 It can be seen that after being coated with a hydrogel coating, the liquid metal can resist a certain compression, and as the coating becomes thicker, the pressure it can withstand also increases. These liquid metal hydrogel capsules only break when they reach a strain of about 80%.

[0061] Example 2

[0062] The difference from Example 1 is that acrylic acid is replaced by 2-butenoic acid. The obtained liquid metal hydrogel capsule is as follows Figure 5 shown.

[0063] Example 3

[0064] The difference from Example 1 is that [3-(methacryloyloxy)propyl]trimethoxysilane is replaced by vinyltrimethylsilane. The obtained liquid metal hydrogel capsule is as follows Figure 6 shown.

[0065] Comparative Example 1

[0066] A method for encapsulating liquid metal microspheres comprises the following steps:

[0067] Step 1: prepare hydrogel prepolymer solution.

[0068] Slowly pour deionized water, acrylic acid, 1 mol / L α-ketoglutaric acid, and [3-(methacryloyloxy)propyl]trimethoxysilane into a 500 mL glass. Then, thoroughly mix the precursor solution with mechanical stirring and water bath sonication to remove air bubbles. Finally, place the treated prepolymer solution in a nitrogen-filled glove box for use.

[0069] Step 2: Prepare solidified spherical liquid metal in the same manner as in Example 1.

[0070] Step three: encapsulate the spherical liquid metal.

[0071] In a nitrogen-filled glove box, the hydrogel prepolymer prepared in step 1 is placed in a UV curing chamber and cured to a semi-fluid state to increase its adhesion to the liquid metal spheres and reduce gel sedimentation. The cured liquid metal spheres are then dipped into the semi-fluid hydrogel, held for about 30 seconds, and quickly removed and placed in a UV curing chamber for further final curing. To prevent the liquid metal from melting under UV light, a refrigeration unit or ice cubes are placed underneath. After waiting for 1 hour, the prepolymer is removed to obtain a liquid metal hydrogel capsule with a thin layer of hydrogel.

[0072] Compared with Example 1, the liquid metal hydrogel capsule obtained by this method always has less gel at some contact points, and due to gravity, there is always more gel at the bottom, such as Figure 7 As shown in Figure 2, this will lead to uneven gel layer on the liquid metal ball. In addition, after the liquid metal is melted, the external gel layer is too thin and has poor mechanical properties, making it impossible to achieve stable wrapping of the liquid metal. Figure 8 shown.

[0073] Comparative Example 2

[0074] A method for encapsulating liquid metal microspheres comprises the following steps:

[0075] Step 1: Preparation of hydrogel powder

[0076] ① Preparation of pAAc hydrogel:

[0077] Deionized water, a large amount of acrylic acid, a small amount of N,N-methylenebisacrylamide, and α-ketoglutaric acid were slowly poured into a 500 mL glass. The precursor solution was then thoroughly mixed and debubbled using mechanical stirring and water bath sonication. The precursor solution was then loaded into 50 mL syringes and ultrasonically removed to remove any visible bubbles. Finally, the syringes filled with the hydrogel prepolymer solution were transferred to plastic sealable bags, filled with nitrogen for protection, and placed in a 365 nm UV curing chamber for approximately 24 hours.

[0078] ② Dialysis:

[0079] The solidified hydrogel was removed from the needle tube and soaked in 1000 mL of deionized water. The dialysate was replaced every 24 hours. The unpolymerized acrylic acid monomers and other small molecules in the hydrogel could be removed by replacing the dialysate about 3 to 5 times.

[0080] ③ Preparation of gel dry powder:

[0081] The dialyzed hydrogel is placed in liquid nitrogen. When the liquid nitrogen no longer boils, it is removed from the liquid nitrogen and crushed in a blender to produce a white hydrogel powder. This powder is then placed in a freeze dryer for freeze drying. After approximately 48 hours, the powder is removed to obtain the desired dry gel powder. Finally, the powder is passed through a sifter (100-400 mesh) to obtain a uniformly distributed dry gel powder, which is then placed in a drying cabinet for use.

[0082] Step 2: Prepare solidified spherical liquid metal in the same manner as in Example 1.

[0083] Step three: encapsulating the spherical liquid metal, the method is the same as that in Example 1.

[0084] Compared with Example 1, without the covalent crosslinking effect of [3-(methacryloyloxy)propyl]trimethoxysilane [TMSPMA], the mechanical properties of the hydrogel shell will be sharply reduced during the acid or water soaking process, and even the powder will be scattered and cannot be formed. Therefore, it is not suitable for preparing stable target liquid metal hydrogel capsules. Figure 9 The figure shows the pAAc powder after soaking in water. It can be seen from the figure that the prepared coating cannot maintain good integrity in water and the coating cracks.

[0085] Comparative Example 3

[0086] The difference from Example 1 is that [3-(methacryloyloxy)propyl]trimethoxysilane [TMSPMA] is replaced by N-isopropylacrylamide. Figure 10 As shown in Figure A, the presence of acrylic acid ensures that the powder forms a complete film on the metal ball after absorbing water and redissolving, but the loss of the polymer chain of TMSPMA copolymer makes it impossible to achieve strong adhesion on the metal ball ( Figure 10 B in the figure), and the stability and mechanical properties in aqueous solution ( Figure 10 (as shown in C in the figure).

[0087] Comparative Example 4

[0088] The difference from Example 1 is that acrylic acid is replaced by acrylamide. Figure 11As shown in Figure A, the prepared p(AAm-co-TMSPMA) powder cannot be redissolved into a gel after adding glycerol aqueous solution without sufficient hydrogen bonding provided by a large number of carboxyl groups, and most of the powders do not adhere to each other. Figure 11 As shown in Figure B, the presence of TMSPMA can provide a certain viscosity to coat the powder on the surface of the liquid metal sphere, but the resulting hydrogel layer is not strong in integrity and tends to appear as a wire-like rather than a complete stretched film.

[0089] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of the present invention.

Claims

1. A method for encapsulating liquid metal microspheres, characterized in that: The steps include: Step 1, preparing a hydrogel powder with self-gelling properties and adhesion: mixing a polymerizable small molecule monomer A with a carboxyl group or a hydroxyl group, a polymerizable small molecule monomer B with a silanol group, a crosslinker, a photoinitiator, and deionized water in a volume ratio of 40-180:0.1-1:1-3:0.05-0.1:60-200, mechanically stirring and mixing, removing bubbles, and UV curing at room temperature for 3-5 hours; dialyzing to remove unpolymerized monomers with carboxyl groups or hydroxyl groups and other uncrosslinked chemical substances in the hydrogel; crushing, freeze-drying, and sieving to obtain a hydrogel powder with a particle size of 100 mesh to 400 mesh; Prepare solidified spherical liquid metal, first pass the liquid metal through a mold to shape it into a sphere with a particle size of 1mm~3cm, and then solidify it at a temperature of 10℃~-30℃; Step 2: Encapsulate spherical liquid metal: Control the ambient humidity below 40% and the temperature below the melting point of the liquid metal. Spray the atomized glycerol aqueous solution on the liquid metal balls and place them in a container covered with hydrogel powder. Shake the container to allow the metal balls inside to roll. After rolling until the powder completely covers the liquid metal balls, take out the liquid metal balls, then place them in a new plastic container and continue rolling to remove the pseudo-adherent dry powder on the surface; finally, spray a small amount of glycerol aqueous solution to cover the surface of the metal balls to promote the redissolution of the gel dry powder attached to the surface to form a complete hydrogel film.

2. The packaging method according to claim 1, wherein: The polymerizable small molecule monomer A with a carboxyl group or a hydroxyl group is one or more of acrylic acid, 2-butenoic acid, and polyvinyl alcohol.

3. The packaging method according to claim 1, wherein: The polymerizable small molecule monomer B with silanol group is one or both of [3-(methacryloyloxy)propyl]trimethoxysilane and vinyltrimethylsilane.

4. The packaging method according to claim 1, wherein: The cross-linking agent is one or both of N,N-methylenebisacrylamide and polyethylene glycol dimethacrylate.

5. The packaging method according to claim 1, wherein: The photoinitiator is one or more of benzophenone, α-ketoglutaric acid, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone.

6. The packaging method according to claim 1, wherein: The liquid metal is a gallium-based or bismuth-based metal or alloy.

7. The packaging method according to claim 1, wherein: The dialyzed hydrogel is placed in liquid nitrogen. When the liquid nitrogen no longer boils, it is taken out of the liquid nitrogen and placed in a stirring crusher for crushing to obtain white hydrogel powder. The powder is then placed in a freeze dryer and freeze-dried at -70°C.

8. A liquid metal hydrogel capsule, characterized in that: Obtained according to the encapsulation method according to any one of claims 1 to 7.

9. Use of the liquid metal hydrogel capsule according to claim 8 in the fields of thermal management, interventional medicine, and soft robotics.

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