Self-floating vein bionic interface solar evaporator and preparation method and application thereof

Abstract

The application discloses a self-floating vein bionic interface solar evaporator and a preparation method and application thereof. The evaporator comprises a supporting framework material and a filling main body material, the main body material is filled in the supporting framework material, the upper layer is a bionic vein capillary structure, and the lower layer is a vertical capillary structure. The supporting framework material is a hydrophobic polyurethane foam with vertical pores, the main body material is a biomass hydrogel material, a photothermal material and a crosslinking agent, and the preparation method comprises the following steps: adding the main body material into a solvent to obtain a precursor solution; then, the precursor solution is injected into the pores of the polyurethane foam and the space at the upper part, directional freezing is carried out, the frozen product is taken out after all the freezing is completed, freeze-drying is carried out, then the product is soaked in a calcium ion solution, and finally, the self-floating vein bionic interface solar evaporator is obtained. The evaporator realizes the self-suspension function, forms the evaporator with the upper layer being the bionic vein capillary and the lower layer being the vertical structure capillary structure, and achieves the high evaporation rate.

Description

Technical Field

[0001] This invention relates to a solar evaporator, and more particularly to a self-floating leaf vein biomimetic interface solar evaporator, its preparation method, and its application. Background Technology

[0002] As a sustainable seawater desalination technology, interfacial solar evaporation technology has advantages such as low cost, strong off-grid capability, and zero carbon footprint, making it particularly suitable for remote areas. However, in practical seawater desalination applications, salt crystallization easily occurs on the evaporation surface, significantly reducing the evaporation rate and even damaging the device. Biomimetic vertical structures, due to their strong water supply capacity, salt resistance, and advantages in facilitating water vapor dissipation, have been widely used in interfacial solar evaporators. However, because the water transfer capacity of the internal micron-level capillaries is too strong, the water replenishment capacity of the evaporator surface far exceeds its water consumption capacity. Furthermore, the direct contact between the evaporator and the main water source inevitably leads to significant heat loss, and additional devices are required for levitation in practical applications, limiting its expanded applications. In addition, the evaporation rate needs further improvement. Summary of the Invention

[0003] Objectives of the Invention: The first objective of this invention is to provide a self-floating leaf vein biomimetic interface solar evaporator with a high evaporation rate; the second objective of this invention is to provide a method for preparing the self-floating leaf vein biomimetic interface solar evaporator; and the third objective of this invention is to provide applications of the self-floating leaf vein biomimetic interface solar evaporator.

[0004] Technical solution: The self-floating leaf vein biomimetic interface solar evaporator of the present invention includes a supporting skeleton material and a filling main material. The main material is filled in the supporting skeleton material. The upper layer is a biomimetic leaf vein-like capillary structure formed by upward main veins and horizontally growing secondary veins, and the lower layer is a vertical capillary structure. The supporting skeleton material is a hydrophobic polyurethane foam with vertical channels, and the main material is a biomass hydrogel material, a photothermal material, and a crosslinking agent.

[0005] The method for preparing the hydrophobic polyurethane foam with vertical channels involves using a punch to create vertical channels in the polyurethane foam, such as... Figure 1 As shown.

[0006] Polyurethane foam, with its low density, provides buoyancy support for evaporator suspension, and its extremely low thermal conductivity enables excellent thermal management of the evaporator. Hydrophobic polyurethane foam effectively insulates and provides buoyancy. Using polyurethane foam with uniformly distributed macroscopic channels, during directional freezing, vertical capillary structures are generated along the vertical channels of the polyurethane foam at the bottom layer, while upward-growing primary veins and horizontally growing secondary veins form an upward-growing primary vein and a biomimetic leaf vein-like capillary structure at the top layer.

[0007] The biomimetic leaf vein-like structure formed in the upper layer can rapidly transport water from the lower layer upwards while simultaneously diffusing it in all directions, allowing the slender pipes to supply water to an evaporation surface hundreds of times its own projected area. The number of vertical capillary tubes in the lower layer can be adjusted according to different conditions of the actual use scenario, thereby regulating the water transfer capacity. This ensures that the water supply to the upper layer is neither too insufficient, leading to salt crystallization on the evaporation surface, nor too excessive, resulting in severe heat loss.

[0008] Smaller pore sizes and a denser pore distribution enable more uniform surface water transfer. Preferably, the projected area of ​​the lower water transfer pipe in the evaporator accounts for 0.12% to 4.41%. Excessive pore projected area leads to excessive water supply and greater heat loss, while insufficient pore projected area results in insufficient water supply and salt crystallization on the evaporator surface.

[0009] Preferably, the thickness of the polyurethane foam is 1 to 3 cm.

[0010] Preferably, the hydrogel material is one or more of sodium alginate (SA), chitosan, cellulose, polyvinyl alcohol (PVA), and polyacrylic acid. The hydrogel exhibits excellent water transfer properties, porous characteristics, and can reduce the enthalpy of vaporization of water. More preferably, the hydrogel material is sodium alginate and polyvinyl alcohol; the hydrogel formed by these two materials has abundant hydrophobic groups and constitutes the aerogel matrix, effectively transferring water and reducing the enthalpy of vaporization of water.

[0011] A crosslinking agent enables the hydrogel to form a stable structure. Preferably, the crosslinking agent is γ-glycidoxypropyltrimethoxysilane (KH560), glutaraldehyde, tannic acid, N,N'-methylenebisacrylamide (MBA), or genipin. More preferably, the crosslinking agent is KH560. KH560 can stabilize the size of the aerogel, ensuring good bonding of the device.

[0012] Photothermal materials can absorb light and generate heat, allowing water to evaporate. Preferably, the photothermal material is carbon nanotubes, copper oxide particles, graphene, MXene, carbon black, etc. More preferably, the photothermal material is MXene. MXene is a class of two-dimensional transition metal carbides, nitrides, and carbonitrides composed of alternating metal and carbonitride layers. Due to its advantages such as full solar spectrum absorption and high photothermal conversion efficiency, it has been widely used in the field of photothermal evaporation.

[0013] The preparation method of the self-floating leaf vein biomimetic interface solar evaporator of the present invention includes the following steps:

[0014] (1) A precursor solution was prepared by adding the main biomass hydrogel material, photothermal material and crosslinking agent into a solvent;

[0015] (2) Place the polyurethane foam at the bottom of the polytetrafluoroethylene mold with a copper base, inject the precursor solution prepared in step (1) into the pores and upper space of the polyurethane foam, place the bottom of the mold in liquid nitrogen to form a temperature gradient for directional freezing, take it out after it is completely frozen, freeze-dry it, then soak it in calcium ion solution, and wash it to obtain a self-floating leaf vein biomimetic interface solar evaporator.

[0016] During the directional freezing process, due to the good thermal conductivity of the copper plate, a temperature gradient is formed, and the bottom of the polyurethane foam generates a vertical capillary structure along the pores. After the pores are completely frozen, because the upper layer temperature is higher than the lower layer temperature and the liquid projection area is larger than the pores, an upward main vein and horizontally growing secondary veins are gradually formed, creating a biomimetic leaf vein-like capillary structure.

[0017] Preferably, in step (1), the precursor solution is prepared by: adding the hydrogel material, photothermal material and crosslinking agent into a solvent and dispersing them evenly, then mixing the hydrogel material solution and the photothermal material solution evenly, and finally adding the crosslinking agent and mixing them evenly.

[0018] Preferably, when the hydrogel material is sodium alginate and polyvinyl alcohol, and the crosslinking agent is γ-glycidoxypropyltrimethoxysilane, the preparation method of the precursor solution is as follows: sodium alginate powder is slowly added to deionized water and stirred to prepare a 3-9 wt% sodium alginate solution; polyvinyl alcohol particles are added to deionized water to swell, and then a conical flask is placed in an oil bath and heated and stirred to prepare a 1-3 wt% PVA solution; the photothermal material is added to water and dispersed evenly to obtain a 1-5 wt% photothermal material solution; 10 ml of SA solution, 10 ml of PVA solution and 20 ml of photothermal material solution are mixed and ultrasonically dispersed in an ice bath to ensure uniform dispersion of the photothermal material; then 0.8 g of γ-glycidoxypropyltrimethoxysilane (KH560) is added and magnetically stirred to obtain the precursor solution.

[0019] Preferably, in step (2), the calcium ion solution is a 1-5 wt% calcium chloride solution. During the soaking process in the calcium ion solution, sodium ions in sodium alginate exchange with calcium ions in the solution, and the hydrogel forms a more stable "eggshell" structure.

[0020] The self-floating leaf vein biomimetic interface solar evaporator described in this invention is used in seawater desalination or interface solar evaporation.

[0021] The seawater salt concentration is 0.8–10 wt%.

[0022] Invention Mechanism: The working mechanism of traditional vertical structure hydrogel evaporators is as follows: Figure 2As shown on the right, traditional vertical hydrogel evaporators have high thermal conductivity due to excessive water supply and lack of insulation, which reduces the thermal management capability of the evaporator, resulting in a lower evaporation rate. In addition, they lack self-suspension function and require an additional auxiliary suspension device in actual use.

[0023] In the self-floating leaf-vein biomimetic interface solar evaporator of this invention, a precursor solution is injected into polyurethane foam and directionally frozen, resulting in the formation of vertical capillary structures with strong water transfer capabilities in the lower layer of the polyurethane foam channels, while the upper layer forms leaf-vein-shaped capillary structures that can uniformly supply water laterally and longitudinally and have strong ion migration capabilities. The hydrophobic polyurethane foam provides buoyancy and has a self-suspension function. The lower vertical capillary structure ensures sufficient water supply to the upper layer, and the polyurethane foam minimizes heat conduction losses. The lower leaf-vein-shaped capillary structure ensures that an evaporation layer with a projected area tens or even hundreds of times larger than the lower channel can evaporate rapidly without salt crystallization hindering surface evaporation. The mechanism diagram is shown below. Figure 2 As shown on the left.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention uses porous hydrophobic polyurethane as the supporting skeleton material and fills it with aerogel material to form an evaporator with a biomimetic leaf vein-like capillary upper layer and a vertical capillary structure lower layer, thus achieving self-suspension function without the need for additional auxiliary suspension devices and achieving a high evaporation rate; (2) The evaporator of the present invention, through the adjustable water transfer structure constructed by the lower polyurethane foam, can prepare an evaporator with an appropriate number of pipes according to the salt concentration of the actual application scenario to prevent excessive capillary water supply and reduce heat conduction loss, ensuring maximum heat utilization; (3) The preparation method is simple, the raw materials used are economical and readily available, and it is feasible to invest in large-scale production in the future. Moreover, it can be self-suspended without the need for additional auxiliary suspension equipment, and the area occupied is small. It has good application prospects in solving the problem of future freshwater scarcity; (4) The evaporator invented by this method was applied to seawater desalination. In mid-to-late September in Nanjing, it was applied to 5wt% simulated seawater and worked continuously for fourteen days, maintaining a daily flow rate of 9.69-11.98 Lm. -2 Its freshwater production has broad application prospects in the field of seawater desalination, and is especially suitable for people in remote coastal areas. Attached Figure Description

[0025] Figure 1 The lower layer of the self-floating leaf vein biomimetic interface solar evaporator of the present invention is a polyurethane foam with different numbers of pores.

[0026] Figure 2 This is a schematic diagram illustrating the working mechanism of the self-floating leaf vein biomimetic interface solar evaporator of the present invention.

[0027] Figure 3This is a schematic diagram illustrating the fabrication process of the self-floating leaf vein biomimetic interface solar evaporator of the present invention;

[0028] Figure 4 The self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1;

[0029] Figure 5 This is a scanning electron microscope image of the lower hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention.

[0030] Figure 6 This is a scanning electron microscope image of the upper hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention.

[0031] Figure 7 The spectral absorption rate of the upper hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention in the 250-2500 nm wavelength range;

[0032] Figure 8 Raman spectroscopy results of free water and bound water in the hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention.

[0033] Figure 9 This is a diagram showing the salt removal effect of the lower layer after salt is added to the upper surface of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention.

[0034] Figure 10 A comparison of the thermal conductivity of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention with that of air, pure water, and a traditional vertical structure evaporator.

[0035] Figure 11 This is a hydrophilicity test diagram of the upper layer of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention.

[0036] Figure 12 The evaporation effect diagrams are shown for the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 of the present invention and the traditional vertical structure hydrogel evaporator prepared in Comparative Example 1.

[0037] Figure 13 The evaporation effect diagrams are shown for the self-floating leaf vein biomimetic interface solar evaporators prepared in Examples 1 and 2 of this invention.

[0038] Figure 14 The evaporation effect diagrams are shown for the self-floating leaf vein biomimetic interface solar evaporators prepared in Examples 1 and 3 of this invention.

[0039] Figure 15 A diagram of a device for collecting seawater for desalination applications;

[0040] Figure 16 The graph shows the freshwater production of the floating leaf vein biomimetic interface solar evaporator prepared in Example 1 after fourteen days of continuous operation. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the embodiments.

[0042] Example 1

[0043] The self-floating leaf vein biomimetic interface solar evaporator of the present invention is prepared by the following steps:

[0044] (1) Sodium alginate powder was slowly added to deionized water and stirred to prepare a 9 wt% sodium alginate (SA) solution. Polyvinyl alcohol (PVA) particles were dissolved in deionized water and swollen. Then, an Erlenmeyer flask was placed in an oil bath and heated to 80–100 °C with stirring to prepare a 3 wt% PVA solution. 0.2 g of Ti3C2T x Add to 19.8 ml and stir to prepare a 1 wt% MXene solution. Mix 10 ml of SA solution, 10 ml of PVA solution and 20 ml of photothermal material solution, and then sonicate in an ice bath to disperse the photothermal material evenly. Then add 0.8 g of γ-glycidoxypropyltrimethoxysilane (KH560) and stir magnetically to obtain the precursor solution.

[0045] (2) Figure 3 As shown, a porous polyurethane foam (1.7 cm thick, 0.07 cm pore diameter, and 0.866% of the projected area of ​​the lower pores) was placed in a polytetrafluoroethylene mold with a copper base. The precursor solution prepared in step (1) was injected into the pores and upper space of the polyurethane foam. The bottom of the mold was placed in liquid nitrogen to form a temperature gradient for directional freezing. After complete freezing, the mold was removed and freeze-dried. Then, it was immersed in a 2 wt% calcium ion solution for 30 min to obtain a self-floating leaf vein biomimetic interface solar evaporator (e.g., Figure 4 (As shown).

[0046] Example 2

[0047] Based on Example 1, the proportion of the projected area of ​​the lower layer of polyurethane foam was changed to 2.405%, while the other conditions remained unchanged, to obtain a self-floating leaf vein biomimetic interface solar evaporator.

[0048] Example 3

[0049] Based on Example 1, the thickness of the polyurethane foam was changed to 3 cm, while other conditions remained unchanged, to obtain a self-floating leaf vein biomimetic interface solar evaporator.

[0050] Comparative Example 1

[0051] The traditional vertical hydrogel evaporator is prepared by the following steps:

[0052] Based on Example 1, step (2) is as follows: inject the precursor solution prepared in step (1) into the mold, place the bottom of the mold in liquid nitrogen to form a temperature gradient for directional freezing, take it out after it is completely frozen, freeze-dry it, and then soak it in 2wt% calcium ion solution for 30 min to obtain a traditional vertical structure hydrogel evaporator.

[0053] Structural characterization

[0054] The upper and lower aerogel layers of the freeze-dried self-floating leaf vein biomimetic interface solar evaporator of Example 1 were characterized using scanning electron microscopy and high-power transmission electron microscopy. The results are as follows: Figure 5 and Figure 6 As shown.

[0055] Depend on Figure 5 It can be seen that the upper layer has upward-growing "main vein" structural channels (diameter ≈24.4-34.6μm) and "secondary vein" structural channels (diameter ≈21-32.3μm) growing at a 40° angle to the horizontal plane, forming biomimetic leaf vein-like capillaries, which is conducive to multidirectional water supply and ion migration. Figure 6 It can be seen that the lower layer has vertical capillary structures with strong capillary action, providing sufficient water supply to the upper layer (diameter ≈ 17.7–29.4 μm).

[0056] Performance testing

[0057] 1. The hydrogel on the upper layer of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 was characterized using a spectrophotometer, and the results are as follows: Figure 7 As shown.

[0058] Depend on Figure 7 It can be seen that the upper hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 has a weighted spectral absorption rate of up to 97.8%, which can achieve more efficient energy utilization and increase the evaporation rate.

[0059] 2. The hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 was characterized using Raman spectroscopy, and the results are as follows: Figure 8 As shown.

[0060] Depend on Figure 8 It is known that hydrogels contain intermediate water and free water. The intermediate water can reduce the enthalpy of evaporation and increase the evaporation rate.

[0061] 3. The salt reflux generated after adding 1g of sodium chloride to the upper layer of the hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 was photographed. The results are as follows: Figure 9 As shown.

[0062] Depend on Figure 9 It can be seen that clear salt flow is visible beneath the hydrogel, indicating that this structural design has strong salt resistance and ion migration properties.

[0063] 4. Laser thermal conductivity testing was used to characterize the thermal conductivity of the lower layer of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 and the traditional vertical structure hydrogel evaporator. The results are as follows: Figure 10 As shown.

[0064] Depend on Figure 10 It is known that, compared with pure water and traditional vertical structure hydrogel evaporators, the self-floating leaf vein biomimetic interface solar evaporator has extremely low thermal conductivity, is close to that of air, and has excellent thermal insulation performance.

[0065] 5. The wettability of the upper hydrogel of the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 was characterized using a surface tension meter. The results are as follows: Figure 11 As shown.

[0066] Depend on Figure 11 It can be seen that the rapid water penetration when droplets come into contact with the upper surface of the hydrogel of the self-floating leaf vein biomimetic interface solar evaporator indicates that it has excellent hydrophilicity.

[0067] 6. Evaporation rate test

[0068] The evaporation rate evaluation involved in this invention employs a top-illuminated (Perfect Light) system (using a 300W xenon lamp as the light source, equipped with a 400nm filter). Mass changes in the evaporation system are monitored by an electronic balance (LIANGPING-FA2004) with an accuracy of 0.0001g. Wind deflectors are placed on all four sides of the testing device to eliminate the influence of pressure fluctuations and air convection in the testing environment.

[0069] The evaporation effects of the self-floating leaf vein biomimetic interface solar evaporator prepared in Examples 1-3 and the traditional vertical structure hydrogel evaporator prepared in Comparative Example 1 are as follows: Figures 12-14 As shown.

[0070] Depend on Figure 12 As can be seen, the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 1 exhibits excellent visible seawater evaporation performance at 1.0 kW m³ / s. -2 In sunlight and a 5wt% NaCl solution, a concentration of 2.323 kg m can be achieved in just 20 minutes. -2 h -1 The stable evaporation rate is achieved with an energy utilization rate of 93.71%. In contrast, traditional vertical hydrogel evaporators achieve a similar efficiency of 1.0 kW / m³. -2Under sunlight and in a 5wt% NaCl solution, a stable concentration of 1.776 kg m³ was reached after 50 minutes. -2 h -1 The evaporation rate is low, and the energy utilization rate is only 75.7%. The self-floating leaf vein biomimetic interface solar evaporator is significantly improved compared with the traditional vertical structure hydrogel evaporator.

[0071] Depend on Figure 13 As can be seen, the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 2 exhibits excellent visible seawater evaporation performance at 1kW m³ / s. -2 In sunlight and a 10wt% NaCl solution, a concentration of 2.254 kg m can be achieved in just 20 minutes. - 2 h -1 The stable evaporation rate has an energy utilization rate of 90.9%. This demonstrates that increasing the projected area enhances mass and heat transfer, but reduces the evaporation rate.

[0072] Depend on Figure 14 As can be seen, the self-floating leaf vein biomimetic interface solar evaporator prepared in Example 3 exhibits excellent visible seawater evaporation performance at 1kWm³. -2 In sunlight and a 5wt% NaCl solution, a concentration of 2.334 kg m can be achieved in just 20 minutes. -2 h -1 The stable evaporation rate and energy utilization rate are 94.44%. Therefore, increasing the thickness of the polyurethane foam by 13mm has little impact on the evaporation rate. Thus, from a cost-saving perspective, an insulation layer thickness of 17mm is sufficient to achieve excellent thermal insulation performance.

[0073] 7. Seawater desalination applications

[0074] Method: such as Figure 15 As shown, the evaporator of this invention is applied to seawater desalination, and a seawater desalination system is formed by combining a self-suspended freshwater collection canopy and a collection tank. The seawater desalination system of the self-floating leaf vein biomimetic interface solar evaporator and freshwater collection device prepared in Example 1 was placed in 5wt% simulated seawater in Nanjing in mid-to-late September for freshwater collection testing. The test period was from 8:00 AM to 5:00 PM, requiring only daily evening freshwater measurement without additional operation. The test results are as follows... Figure 16 As shown.

[0075] No salt crystals formed on the evaporator surface during the 14-day test, indicating that the evaporator design has good stability and can continuously and stably produce fresh water. Its self-suspension characteristics and salt resistance reduce the required maintenance costs. It operated continuously for 14 days, maintaining a daily flow rate of 9.69–11.98 Lm. -2 Freshwater production ( Figure 16 ).

Claims

1. A self-floating leaf vein biomimetic interface solar evaporator, characterized in that, It includes a supporting skeleton material and a filling body material. The body material is filled in the supporting skeleton material. The upper layer is a biomimetic leaf vein-like capillary structure formed by upward-growing main veins and horizontally growing secondary veins, and the lower layer is a vertical capillary structure. The supporting skeleton material is a hydrophobic polyurethane foam with vertical channels, and the body material is a biomass hydrogel material, a photothermal material, and a crosslinking agent.

2. The self-floating leaf vein biomimetic interface solar evaporator according to claim 1, characterized in that, The projected area of ​​the lower water transmission pipe of the evaporator accounts for 0.12% to 4.41%.

3. The self-floating leaf vein biomimetic interface solar evaporator according to claim 1, characterized in that, The hydrogel is one or more of sodium alginate, chitosan, cellulose, polyvinyl alcohol, and polyacrylic acid.

4. The self-floating leaf vein biomimetic interface solar evaporator according to claim 1, characterized in that, The crosslinking agent is one or more of γ-glycidoxypropyltrimethoxysilane, glutaraldehyde, tannic acid, N,N'-methylenebisacrylamide, or genipin.

5. The self-floating leaf vein biomimetic interface solar evaporator according to claim 1, characterized in that, The photothermal material is one or more of carbon nanotubes, copper oxide particles, graphene, or MXene.

6. A method for preparing a self-floating leaf vein biomimetic interface solar evaporator according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) A precursor solution was prepared by adding the main biomass hydrogel material, photothermal material and crosslinking agent into a solvent; (2) Place the polyurethane foam at the bottom of the polytetrafluoroethylene mold with a copper base, inject the precursor solution prepared in step (1) into the pores and upper space of the polyurethane foam, place the bottom of the mold in liquid nitrogen to form a temperature gradient for directional freezing, take it out after it is completely frozen, freeze-dry it, then soak it in calcium ion solution, and wash it to obtain a self-floating leaf vein biomimetic interface solar evaporator.

7. The method for preparing a self-floating leaf vein biomimetic interface solar evaporator according to claim 6, characterized in that, In step (1), the precursor solution is prepared by adding the hydrogel material, photothermal material and crosslinking agent into the solvent and dispersing them evenly, then mixing the hydrogel material solution and the photothermal material solution evenly, and finally adding the crosslinking agent and mixing them evenly.

8. The method for preparing a self-floating leaf vein biomimetic interface solar evaporator according to claim 6, characterized in that, In step (2), the calcium ion solution is a 1-5 wt% calcium chloride solution.

9. The application of the self-floating leaf vein biomimetic interface solar evaporator according to any one of claims 1 to 5 in seawater desalination or interface solar evaporation.

10. The application according to claim 9, characterized in that, The seawater salt concentration is 0.8–10 wt%.

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