Liquid metal paper and preparation method thereof

Abstract

The invention discloses liquid metal paper and a preparation method thereof, and belongs to the technical field of liquid metal materials. The liquid metal paper is prepared from a liquid metal, a fluorescent material, an inorganic filler and a hydrophilic material, through the synergistic effect of the raw materials, the liquid metal paper not only has the performance of the original liquid metal, but also has good water solubility, fluorescence stability and biocompatibility, and the liquid metal paper can keep high fluorescence intensity for a long time, so that the liquid metal paper can be applied to the field of medical equipment. The method has a good application prospect in the field of liquid metal.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid metal materials, and in particular relates to liquid metal paper and a preparation method thereof. Background Art

[0002] Liquid metal is the common name for amorphous alloys. Matter is classified by state: gas, liquid, and solid. The gaseous state is disordered, while the solid is ordered. The liquid state lies somewhere in between—short-range order and long-range disorder. Amorphous alloys also share a similar microstructure to liquids, similar to the common glass we see today.

[0003] Liquid metal refers to metal that is liquid at room temperature. Liquid metal alloys possess a unique amorphous molecular structure, distinct from the crystalline structure of traditional metals and more similar to glass. Liquid metal's characteristics include a low melting point, exceptional plasticity, high flexibility, high yield strength, high hardness, excellent strength-to-weight ratio, ultra-high elastic limit, corrosion resistance, high wear resistance, and unique acoustic properties. Its greatest advantages lie in its high plasticity, strength, and hardness.

[0004] However, there are only a few metals that can remain liquid at or near room temperature. These include mercury, gallium and its alloys, alkali metal alloys, rubidium, cesium, and francium. Rubidium, cesium, and francium are radioactive, and alkali metal alloys are highly reactive, requiring extremely stringent environmental requirements for storage and use, making them difficult to use in daily life. Mercury is the most common liquid metal, but its low vapor pressure makes it easily volatile at room temperature. The resulting mercury vapor is highly toxic and can be harmful to the human body if used improperly. Gallium and its alloys, however, stand out among these liquid metals due to their safety, low toxicity, and stable properties, making them a popular choice for application.

[0005] Liquid metal has a wide range of applications. In existing technologies, combining liquid metal with fluorescent substances can be applied to flexible intelligent machines, fluorescent markings in organisms, flexible electronic circuit printing and other fields, greatly expanding color applications.

[0006] However, the combination stability of liquid metal and fluorescent material is poor, and the addition of fluorescent material may affect the original performance of liquid metal. The above problems have become the main obstacles to the development of liquid metal. Summary of the Invention

[0007] Based on the above technical background, the main purpose of the present invention is to provide a liquid metal paper and a preparation method thereof to overcome the shortcomings of the prior art.

[0008] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include: A first aspect of the present invention is to provide a liquid metal paper, wherein the liquid metal paper is made of liquid metal, a fluorescent material, an inorganic filler and a hydrophilic material.

[0009] The mass ratio of the liquid metal, fluorescent material, inorganic filler and hydrophilic material is (70-120): (8-15): 1: (5-12).

[0010] Preferably, the mass ratio of the liquid metal, fluorescent material, inorganic filler and hydrophilic material is 100:10:1:8.

[0011] The liquid metal is a low melting point metal or a low melting point alloy.

[0012] The low melting point metal is selected from one or more of gallium, indium, tin and bismuth.

[0013] The low melting point alloy is a binary, ternary or quaternary alloy, selected from one or more of zinc-based alloys, gallium-based alloys, indium-based alloys, tin-based alloys and bismuth-based alloys.

[0014] Preferably, the low melting point metal is gallium, indium or tin.

[0015] Preferably, the low melting point alloy is a gallium-based alloy or an indium-based alloy.

[0016] More preferably, the liquid metal is gallium, tin, gallium-indium alloy or gallium-indium-tin alloy.

[0017] The fluorescent material is selected from one or more of fluorescent powder, fluorescein, fluorescent probe, and carbon quantum dots.

[0018] The phosphor is selected from one or more of aluminate phosphor, silicate phosphor and LuAG phosphor.

[0019] The fluorescein is selected from one or more of fluorescein isothiocyanate, tetramethylrhodamine isocyanate, tetraethylrhodamine, peridinin chlorophyll protein, and phycoerythrin.

[0020] The carbon quantum dots are selected from one or more biomass fluorescent carbon quantum dots.

[0021] Preferably, the carbon quantum dots are made from biological materials.

[0022] The biological material is selected from one or more of cyanobacteria, coconut branches, coconut leaves and water hyacinth.

[0023] Preferably, the biological material is cyanobacteria or coconut leaves.

[0024] Cyanobacteria, also known as blue-green algae or blue bacteria; most cyanobacteria have a gelatinous coat outside their cell walls, also known as slime algae. In some nutrient-rich water bodies, some cyanobacteria often multiply in large numbers in summer and form a layer of blue-green cyanobacterial blooms with a fishy smell on the water surface, which is called "water bloom". A large-scale cyanobacterial outbreak is called "green tide" (corresponding to the red tide that occurs in the ocean). Green tides cause water quality deterioration and can deplete oxygen in the water, resulting in the death of fish when severe. Even more seriously, some species of cyanobacteria can produce microcystin, and about 50% of green tides contain a large amount of microcystin, which is toxic to fish, humans and livestock.

[0025] Synthesizing carbon quantum dots from cyanobacteria and coconut leaves is not only beneficial to environmental protection, provides high added value for cyanobacteria and coconut leaves, but also helps to reduce the preparation cost of carbon quantum dots.

[0026] Carbon quantum dots (CQDs), also known as carbon dots or carbon nanodots, are a class of zero-dimensional carbon nanomaterials with remarkable fluorescence properties. They are composed of ultra-fine, dispersed, quasi-spherical carbon nanoparticles with a size below 10 nm. Carbon quantum dots have excellent optical properties, good water solubility, low toxicity, environmental friendliness, wide raw material sources, low cost, good biocompatibility and many other advantages.

[0027] Adding carbon quantum dots can improve the fluorescence properties and water solubility of water-soluble metal paper, and can also improve the biocompatibility of metal paper.

[0028] The hydrophilic material is selected from one or more of carboxymethyl chitosan, sodium hyaluronate, polyvinyl alcohol, polylactic acid, polyethylene glycol, and water-soluble dietary fiber.

[0029] Preferably, the hydrophilic material is one or more of carboxymethyl chitosan, sodium hyaluronate, and polylactic acid.

[0030] More preferably, the hydrophilic material is a mixture of carboxymethyl chitosan, sodium hyaluronate, and polylactic acid, wherein the mass ratio of carboxymethyl chitosan, sodium hyaluronate, and polylactic acid is (5-15):(5-15):20.

[0031] Preferably, the mass ratio of carboxymethyl chitosan, sodium hyaluronate, and polylactic acid is 10:10:20.

[0032] Dietary fiber belongs to natural substances, is non-toxic and harmless, has good water solubility and hydrophilicity, and can also improve the flexibility of the product, making the prepared metal have higher ductility and flexibility.

[0033] Carboxymethyl chitosan is a derivative of chitosan and is a natural substance obtained by reacting chitin with chloroacetic acid under alkaline conditions. Carboxymethyl chitosan is an amphoteric polyelectrolyte and has good water solubility.

[0034] The inorganic filler is selected from one or more of zinc oxide, tungsten oxide, gallium oxide and silicon oxide.

[0035] Preferably, the inorganic filler is tungsten oxide or zinc oxide.

[0036] The addition of inorganic fillers can provide skeleton support and improve the mechanical strength of the liquid metal paper. At the same time, it can enable the liquid metal paper to be used as 3D printing ink when it is in a liquid state.

[0037] A second aspect of the present invention is to provide a method for preparing the liquid metal paper, the method comprising the following steps: Step (1), grinding the inorganic filler into powder, then adding it to the liquid metal and mixing it, followed by vacuum treatment to obtain a liquid metal mixture; Step (2), adding the hydrophilic material to the solvent and stirring evenly to obtain a hydrophilic solution; Step (3), adding the liquid metal mixture into the hydrophilic solution and performing ultrasonic dispersion to obtain a liquid metal mixed solution; Step (4): under stirring conditions, adding the fluorescent material to the liquid metal mixed solution, then performing rotary evaporation, and finally adding it to a mold, drying, forming, and demoulding to obtain liquid metal paper.

[0038] In step (1), the inorganic filler is ground to a particle size of 10 to 100 nm, preferably to a particle size of 10 to 50 nm.

[0039] The mass ratio of the inorganic filler to the liquid metal is 1:(70-120).

[0040] Preferably, the mass ratio of the inorganic filler to the liquid metal is 1:100.

[0041] The mixing is performed by grinding, which can enable the liquid metal and the inorganic filler to form lattice penetration, thereby improving the strength of the metal paper.

[0042] The vacuum is evacuated to a vacuum degree of 10 to 50 kPa, and the vacuum treatment time is 50 to 150 seconds.

[0043] Preferably, the vacuum is evacuated to a vacuum degree of 20 kPa for 100 seconds. The vacuum treatment can extract the internal gas, allowing more gas to be precipitated from the inorganic filler and the liquid metal, thereby increasing the strength of the liquid metal paper.

[0044] In step (2), the solvent is preferably dichloromethane.

[0045] The stirring speed is 800-1200 rpm, and the stirring time is 5-20 min.

[0046] Preferably, the stirring speed is 1000 rpm and the stirring time is 10 min.

[0047] The mass concentration of the hydrophilic material in the hydrophilic solution is 30 - 70 mg / mL, and preferably the mass concentration is 60 mg / mL.

[0048] By adding the hydrophilic material, the present invention can effectively improve the water solubility of the liquid metal and also improve the dispersion uniformity of the fluorescent material and the liquid metal.

[0049] In step (3), the conditions for ultrasonic dispersion are: the power of ultrasonic dispersion is 100 - 300 W, and the time of ultrasonic dispersion is 10 - 30 min.

[0050] Preferably, the conditions for ultrasonic dispersion are: the power of ultrasonic dispersion is 200 W, and the time of ultrasonic dispersion is 20 min.

[0051] In step (4), the stirring speed is 300 - 700 rpm and the stirring time is 30 - 60 min.

[0052] Preferably, the stirring speed is 500 rpm and the stirring time is 45 min.

[0053] The conditions for rotary evaporation are: the temperature of rotary evaporation is 35 - 40 °C, and the time of rotary evaporation is 20 - 45 min.

[0054] Preferably, the conditions for rotary evaporation are: the temperature of rotary evaporation is 39 °C, and the time of rotary evaporation is 30 min. The rotary evaporation temperature and time of the present invention can completely remove the organic solvent.

[0055] The conditions for drying and forming are: under the conditions of a vacuum degree of 5 - 20 Pa and a temperature of 10 - 20 °C, drying and forming for 1 - 3 h.

[0056] Preferably, the conditions for drying and forming are: under the conditions of a vacuum degree of 10 Pa and a temperature of 15 °C, drying and forming for 2 h.

[0057] Performing drying and forming under vacuum conditions can avoid the presence of unexhausted bubbles in the liquid metal paper.

[0058] The present invention can adjust the thickness of the liquid metal paper by adjusting the thickness of the mold.

[0059] The fluorescent material is preferably carbon quantum dots.

[0060] According to a preferred embodiment of the present invention, the preparation method of the carbon quantum dots includes the following steps: S-1. Clean, dry, and pulverize the biological material to obtain a biological material powder; S-2. Add the biological material powder into the mixed solvent, stir evenly, and then carry out a hydrothermal reaction at high temperature to obtain a mixed solution. S-3. Filter the mixed solution to obtain the carbon quantum dot solution.

[0061] In S-1, the washed biological material is dried at 50-70 °C for 30-90 min. Preferably, the washed biological material is dried at 60 °C for 60 min.

[0062] The biological material is crushed to less than 80 mesh. Preferably, the biological material is crushed to less than 60 mesh.

[0063] In S-2, the mixed solvent is obtained by mixing ethanol, glycerol and water in a volume ratio of (5-15):(25-35):(45-55).

[0064] Preferably, the mixed solvent is obtained by mixing ethanol, glycerol and water in a volume ratio of 10:30:50.

[0065] Add the biological material powder into the mixed solvent and stir at a stirring speed of 200-400 rpm for 10-30 min.

[0066] Preferably, stir at a stirring speed of 300 rpm for 20 min.

[0067] The conditions of the hydrothermal reaction at high temperature are: carry out the hydrothermal reaction at 150-200 °C for 12-20 h.

[0068] Preferably, the conditions of the hydrothermal reaction at high temperature are: carry out the hydrothermal reaction at 170 °C for 15 h.

[0069] In S-3, filter the mixed solution through a microporous membrane with a pore size of 0.2-0.25 μm. Preferably, filter through a microporous membrane with a pore size of 0.22 μm to obtain the carbon quantum dot solution.

[0070] The carbon quantum dots of the present invention are prepared with biological materials as the main raw materials, and the obtained carbon quantum dot solution has good fluorescence stability and biocompatibility.

[0071] The beneficial effects of the present invention: (1) The liquid metal paper of the present invention is prepared from liquid metal, fluorescent material, inorganic filler and hydrophilic material. The liquid metal paper not only has the excellent properties of the original liquid metal, but also endows it with strong fluorescence properties and fluorescence stability through the addition of fluorescent materials; in addition, the present invention further improves the water solubility and fluorescence stability of the liquid metal paper through the addition of hydrophilic materials. The mechanical strength of the liquid metal paper can be improved by adding inorganic materials.

[0072] (2) The fluorescent material of the present invention is preferably carbon quantum dots. The carbon quantum dots of the present invention are prepared from biological raw materials and have the advantages of low toxicity, environmental friendliness, wide raw material sources, and low cost. They not only have strong fluorescence intensity but also have high fluorescence stability, good biocompatibility, and good water solubility, which can endow the liquid metal paper with higher fluorescence stability and better water solubility.

[0073] (3) The hydrophilic material of the present invention has excellent hydrophilicity. The carboxymethyl chitosan, sodium hyaluronate, and water-soluble dietary fiber selected are all natural materials, which are environmentally friendly, non-toxic, and have high biocompatibility. The polylactic acid selected has biodegradability. Experiments have proved that the hydrophilic material selected in the present invention has an important influence on the fluorescence stability and water solubility of the liquid metal paper. The addition of the hydrophilic material can further improve the fluorescence stability and water solubility of the liquid metal paper.

[0074] (4) The inorganic filler of the present invention is the "skeleton material" of the liquid metal paper, which improves the mechanical strength of the liquid metal paper.

[0075] (5) The preparation method of the liquid metal paper of the present invention is simple, convenient for storage, and the raw materials used are widely sourced, natural and non-toxic, with the advantages of low cost and environmental friendliness. The liquid metal paper has broad application prospects. Specific Embodiments

[0076] The present invention will be described in detail below, and the features and advantages of the present invention will become clearer and more definite with these descriptions. Examples

[0077] The present invention will be further elaborated through specific examples below. These examples are only for illustrating the present invention and are not used to limit the scope of the present invention. The raw materials used in the examples of the present invention are all commercially available.

[0078] Example 1: After cleaning the blue-green algae, it was placed at 60 °C and dried for 60 min, and then crushed to less than 60 mesh to obtain a biological material powder.

[0079] Ethanol, glycerol, and water were mixed in a volume ratio of 10:30:50 to obtain a mixed solvent. The biological material powder was added to the mixed solvent and stirred at a stirring speed of 300 rpm for 20 min, and then subjected to a high-temperature hydrothermal reaction at 170 °C for 15 h to obtain a mixed solution.

[0080] The mixed solution was filtered through a 0.22 μm microporous membrane to obtain a carbon quantum dot solution, and the mass concentration of the carbon quantum dot solution was 10 mg / mL.

[0081] After testing, the optimal excitation wavelength is 350nm. The carbon quantum dot solution has strong fluorescence emission in the range of 365-600nm, and the emission peak of the fluorescent carbon quantum dots is around 432nm.

[0082] Example 2: Coconut leaves were washed, dried at 50° C. for 90 min, and then crushed to less than 60 mesh to obtain biomaterial powder.

[0083] Ethanol, glycerol, and water were mixed in a volume ratio of 10:30:50 to obtain a mixed solvent. The biomaterial powder was added to the mixed solvent, stirred at a stirring speed of 200 rpm for 30 minutes, and then subjected to a high-temperature hydrothermal reaction at 180° C. for 13 hours to obtain a mixed solution.

[0084] The mixed solution was filtered through a 0.22 μm microporous filter membrane to obtain a carbon quantum dot solution. The mass concentration of the carbon quantum dot solution was 15 mg / mL.

[0085] After testing, the optimal excitation wavelength is 335nm. The carbon quantum dot solution has strong fluorescence emission in the range of 350-550nm, and the emission peak of the fluorescent carbon quantum dots is around 432nm.

[0086] Example 3: Metal gallium and indium were weighed in a mass ratio of 85:15, and then the indium was heated to 80°C. After the metal indium was dissolved, metal gallium was added, and the metal indium and metal gallium were mixed evenly at a stirring speed of 300 rpm to obtain liquid metal Ga85In15.

[0087] Liquid metal Ga85In15, fluorescent material (the carbon quantum dot solution described in Example 1), inorganic filler tungsten oxide, and hydrophilic material were weighed in a mass ratio of 100:10:1:8. The hydrophilic material was prepared by mixing carboxymethyl chitosan, sodium hyaluronate, and polylactic acid in a mass ratio of 10:10:20.

[0088] The tungsten oxide was ground into a particle size of 10 to 50 nm, and then added into the liquid metal for grinding and mixing. Subsequently, the mixture was vacuumed for 100 seconds at a vacuum degree of 20 kPa to obtain a liquid metal mixture.

[0089] The hydrophilic material was added to dichloromethane, and then stirred at a stirring speed of 1000 rpm for 10 minutes to obtain an aqueous solution. The mass concentration of the hydrophilic material in the aqueous solution was 60 mg / mL.

[0090] The liquid metal mixture is added to the hydrophilic solution and ultrasonically dispersed. The ultrasonic dispersion conditions are: the ultrasonic dispersion power is 200 W, and the ultrasonic dispersion time is 20 minutes to obtain a liquid metal mixed solution.

[0091] The fluorescent material was added to the liquid metal mixed solution at a stirring speed of 500 rpm, and the stirring time was 45 min. Subsequently, rotary evaporation was carried out at 39 °C for 30 min to completely remove the organic solvent. Finally, it was added to a mold and dried and formed for 2 h under the conditions of a vacuum degree of 10 Pa and a temperature of 15 °C. After demolding, the liquid metal paper was obtained.

[0092] Example 4: Gallium and indium were weighed according to a mass ratio of 75:25. Then, indium was heated to 85 °C. After the molten indium was dissolved, gallium was added, and indium and gallium were mixed evenly at a stirring speed of 300 rpm to obtain liquid metal Ga75In25.

[0093] Each raw material was weighed according to a mass ratio of liquid metal Ga75In25, fluorescent material (using the carbon quantum dot solution described in Example 1), inorganic filler tungsten oxide, and hydrophilic material of 70:8:1:5. The hydrophilic material was obtained by mixing carboxymethyl chitosan, sodium hyaluronate, and polylactic acid according to a mass ratio of 15:15:20.

[0094] Tungsten oxide was ground to a particle size of 10 - 50 nm, and then added to the liquid metal for grinding and mixing. Subsequently, vacuum treatment was carried out for 150 s under the condition of a vacuum degree of 10 kPa to obtain a liquid metal mixture.

[0095] The hydrophilic material was added to dichloromethane, and then stirred at a stirring speed of 800 rpm for 20 min to obtain a hydrophilic solution. The mass concentration of the hydrophilic material in the hydrophilic solution was 60 mg / mL.

[0096] The liquid metal mixture was added to the hydrophilic solution for ultrasonic dispersion. The conditions for ultrasonic dispersion were: the power of ultrasonic dispersion was 300 W, and the time of ultrasonic dispersion was 10 min to obtain a liquid metal mixed solution.

[0097] At a stirring speed of 700 rpm, the fluorescent material was added to the liquid metal mixed solution, and the stirring time was 30 min. Subsequently, rotary evaporation was carried out at 40 °C for 20 min to completely remove the organic solvent. Finally, it was added to a mold and dried and formed for 1 h under the conditions of a vacuum degree of 20 Pa and a temperature of 20 °C. After demolding, the liquid metal paper was obtained.

[0098] Example 5: Gallium and indium were weighed according to a mass ratio of 95:5. Then, indium was heated to 85 °C. After the molten indium was dissolved, gallium was added, and indium and gallium were mixed evenly at a stirring speed of 300 rpm to obtain liquid metal Ga95In5.

[0099] Liquid metal Ga95In5, fluorescent material (the carbon quantum dot solution described in Example 2), inorganic filler tungsten oxide, and hydrophilic material were weighed in a mass ratio of 120:15:1:12. The hydrophilic material was prepared by mixing carboxymethyl chitosan, sodium hyaluronate, and polylactic acid in a mass ratio of 5:5:20.

[0100] The tungsten oxide was ground into a particle size of 10 to 50 nm, and then added into the liquid metal for grinding and mixing. Subsequently, the mixture was vacuumed for 50 seconds at a vacuum degree of 50 kPa to obtain a liquid metal mixture.

[0101] The hydrophilic material was added to dichloromethane, followed by stirring at a stirring speed of 1200 rpm for 5 minutes to obtain an aqueous solution, wherein the mass concentration of the hydrophilic material in the aqueous solution was 60 mg / mL.

[0102] The liquid metal mixture is added to the hydrophilic solution and ultrasonically dispersed. The ultrasonic dispersion conditions are: the ultrasonic dispersion power is 100 W, and the ultrasonic dispersion time is 30 minutes to obtain a liquid metal mixed solution.

[0103] The fluorescent material was added to the liquid metal mixture at a stirring speed of 300 rpm for 60 minutes. The organic solvent was then completely removed by rotary evaporation at 35°C for 45 minutes. Finally, the mixture was added to a mold and dried for 3 hours under a vacuum of 5 Pa and a temperature of 10°C. After demolding, the liquid metal paper was obtained.

[0104] Example 6: Liquid metal Ga (gallium), fluorescent material (the carbon quantum dot solution described in Example 2), inorganic filler tungsten oxide, and hydrophilic material were weighed in a mass ratio of 100:10:1:8. The hydrophilic material was prepared by mixing carboxymethyl chitosan, sodium hyaluronate, and polylactic acid in a mass ratio of 10:10:20.

[0105] The tungsten oxide was ground into a particle size of 10 to 50 nm, and then added into the liquid metal for grinding and mixing. Subsequently, the mixture was vacuumed for 100 seconds at a vacuum degree of 20 kPa to obtain a liquid metal mixture.

[0106] The hydrophilic material was added to dichloromethane, and then stirred at a stirring speed of 1000 rpm for 10 minutes to obtain an aqueous solution. The mass concentration of the hydrophilic material in the aqueous solution was 60 mg / mL.

[0107] The liquid metal mixture is added to the hydrophilic solution and ultrasonically dispersed. The ultrasonic dispersion conditions are: the ultrasonic dispersion power is 200 W, and the ultrasonic dispersion time is 20 minutes to obtain a liquid metal mixed solution.

[0108] At a stirring speed of 500 rpm, the fluorescent material was added to the liquid metal mixed solution, and the stirring time was 45 min. Subsequently, rotary evaporation was carried out at 39 °C for 30 min to completely remove the organic solvent. Finally, it was added to a mold and dried and formed at a vacuum degree of 10 Pa and a temperature of 15 °C for 3 h. After demolding, the liquid metal paper was obtained.

[0109] Example 7: Gallium and indium were weighed according to a mass ratio of 65:35. Then indium was heated to 80 °C. After the indium metal was dissolved, gallium metal was added, and indium metal and gallium metal were mixed evenly at a stirring speed of 300 rpm to obtain liquid metal Ga65In35.

[0110] Each raw material was weighed according to a mass ratio of liquid metal Ga65In35, fluorescent material (using the carbon quantum dot solution described in Example 1), inorganic filler tungsten oxide, and hydrophilic material of 100:12:1:8. The hydrophilic material was obtained by mixing carboxymethyl chitosan, sodium hyaluronate, and polylactic acid according to a mass ratio of 7:10:20.

[0111] Tungsten oxide was ground to a particle size of 10 - 50 nm, then added to the liquid metal for grinding and mixing, and then vacuum treatment was carried out for 100 s under a vacuum degree of 20 kPa to obtain a liquid metal mixture.

[0112] The hydrophilic material was added to dichloromethane, and then stirred at a stirring speed of 1000 rpm for 10 min to obtain a hydrophilic solution, and the mass concentration of the hydrophilic material in the hydrophilic solution was 60 mg / mL.

[0113] The liquid metal mixture was added to the hydrophilic solution for ultrasonic dispersion. The conditions for ultrasonic dispersion were: the power of ultrasonic dispersion was 300 W, and the time of ultrasonic dispersion was 20 min to obtain a liquid metal mixed solution.

[0114] At a stirring speed of 500 rpm, the fluorescent material was added to the liquid metal mixed solution, and the stirring time was 45 min. Subsequently, rotary evaporation was carried out at 39 °C for 30 min to completely remove the organic solvent. Finally, it was added to a mold and dried and formed at a vacuum degree of 10 Pa and a temperature of 15 °C for 1 h. After demolding, the liquid metal paper was obtained.

[0115] Comparative example: Comparative example 1: The liquid metal paper was prepared in a manner similar to that of Example 3, except that: the hydrophilic material was not added.

[0116] Comparative example 2: The liquid metal paper was prepared in a manner similar to that of Example 3, except that: the inorganic filler was not added.

[0117] Experimental example: Experimental Example 1: Performance Test The water solubility test and fluorescence stability test were respectively carried out on the liquid metal papers prepared in Examples 3 - 7 and Comparative Example 1. The test results are shown in Table 1.

[0118] The water solubility test includes: placing the liquid metal paper in water at a temperature of 30 °C and observing whether there is sedimentation.

[0119] Fluorescence stability test: The liquid metal paper was stored in the dark at a low temperature of 5 °C, and fluorescence tests were carried out every day starting from the 20th day.

[0120] Table 1

[0121] As can be seen from Table 1, the liquid metal papers prepared in Examples 3 - 7 had no sedimentation after being stored for 51 hours and still had strong fluorescence after 40 days. It shows that the liquid metal paper described in the present invention has good water solubility and fluorescence stability.

[0122] Compared with Example 3, in Comparative Example 1, no hydrophilic material was added, the sedimentation property of Comparative Example 1 decreased, and the fluorescence stability also decreased, indicating that the hydrophilic material described in the present invention has a great influence on water solubility and fluorescence stability, and the addition of the water-soluble material can improve the water solubility and fluorescence stability of the liquid metal paper.

[0123] Compared with Example 3, in Comparative Example 2, no inorganic filler was added, the sedimentation property of Comparative Example 2 decreased slightly, and the fluorescence stability also decreased, indicating that the addition of the inorganic filler described in the present invention helps to improve the water solubility and fluorescence stability of the liquid metal paper.

[0124] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A liquid metal paper, characterized in that: The liquid metal paper is prepared from liquid metal, fluorescent material, inorganic filler and hydrophilic material; The mass ratio of the liquid metal, fluorescent material, inorganic filler and hydrophilic material is (70-120):(8-15):1:(5-12).

2. The liquid metal paper according to claim 1, wherein The mass ratio of the liquid metal, fluorescent material, inorganic filler and hydrophilic material is 100:10:1:

8.

3. The liquid metal paper according to claim 1, wherein The liquid metal is a low melting point metal or a low melting point alloy; The low melting point metal is selected from one or more of gallium, indium, tin, and bismuth; The low melting point alloy is selected from one or more of zinc-based alloy, gallium-based alloy, indium-based alloy, tin-based alloy, and bismuth-based alloy.

4. The liquid metal paper according to claim 1, wherein The fluorescent material is selected from one or more of phosphor powder, fluorescein, fluorescent probe, and carbon quantum dots; and / or, The hydrophilic material is selected from one or more of carboxymethyl chitosan, sodium hyaluronate, polyvinyl alcohol, polylactic acid, polyethylene glycol, and water-soluble dietary fiber; and / or, The inorganic filler is selected from one or more of zinc oxide, tungsten oxide, gallium oxide, and silicon oxide.

5. The liquid metal paper according to claim 4, wherein The phosphor powder is selected from one or more of aluminate phosphor powder, silicate phosphor powder, and LuAG phosphor powder; and / or, The fluorescein is selected from one or more of fluorescein isothiocyanate, tetramethyl rhodamine isothiocyanate, tetraethyl rhodamine, peridinin chlorophyll protein, and phycoerythrin; and / or, The carbon quantum dots are selected from one or more of biomass fluorescent carbon quantum dots.

6. A method for preparing the liquid metal paper according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: Step (1), grinding the inorganic filler into a powder, then adding it to the liquid metal for mixing, and then performing vacuum treatment to obtain a liquid metal mixture; Step (2), adding the hydrophilic material to a solvent and stirring evenly to obtain a hydrophilic solution; Step (3), adding the liquid metal mixture to the hydrophilic solution and performing ultrasonic dispersion to obtain a liquid metal mixed solution; Step (4), adding the fluorescent material to the liquid metal mixed solution under stirring conditions, then performing rotary evaporation, and finally adding it to a mold, followed by drying and forming, and demolding to obtain the liquid metal paper.

7. The preparation method according to claim 6, characterized in that In step (1), The inorganic filler is ground to a particle size of 10-100 nm, The mixing is carried out by grinding and mixing, and the vacuum is pumped to a vacuum degree of 10-50 kPa.

8. The preparation method according to claim 6, characterized in that, In step (2), The stirring speed is 800-1200 rpm, and the stirring time is 5-20 min; In step (3), the conditions for ultrasonic dispersion are: the power of ultrasonic dispersion is 100-300 W, and the time of ultrasonic dispersion is 10-30 min.

9. The preparation method according to claim 6, characterized in that, In step (3), The stirring speed is 300-700 rpm, and the stirring time is 30-60 min; and / or, The conditions for rotary evaporation are: the temperature of rotary evaporation is 35-40 °C, and the time of rotary evaporation is 20-45 min; and / or, The conditions for drying and forming are as follows: drying and forming for 1 - 3 h under the conditions of a vacuum degree of 5 - 20 Pa and a temperature of 10 - 20 °C.

10. The preparation method according to claim 6, wherein In step (3), the preparation method of the carbon quantum dots includes the following steps: S-1. Cleaning, drying, and pulverizing the biological material to obtain a biological material powder; S-2. Adding the biological material powder into a mixed solvent, stirring evenly, and then performing a high-temperature hydrothermal reaction to obtain a mixed solution; S-3. Filtering the mixed solution to obtain a carbon quantum dot solution.

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