A frost-inhibiting surface based on an array of absorbent gels, and a method of making and using the same

Abstract

The application provides a frost-inhibiting surface based on a hygroscopic gel dot array, a preparation method, a frost-inhibiting method and application, and belongs to the technical field of surface engineering and anti-icing and frost technology. The frost-inhibiting surface comprises a substrate, and the surface of the substrate has a background area and a hygroscopic gel dot array area; the hygroscopic gel dot array comprises a plurality of discrete hygroscopic gel units; compared with the background area, the hygroscopic gel dot array area can preferentially adsorb water vapor in the environment to form adsorbed water in the area of the hygroscopic gel unit; when the temperature decreases to below the freezing point, the hygroscopic gel dot array area containing the adsorbed water preferentially freezes compared with the background area, so that the hygroscopic gel unit area acts as a water vapor collection site, and a dry isolation area is formed between adjacent hygroscopic gel units. The application overcomes the defects in the prior art, such as uncontrolled spread of frost crystals caused by homogenization design of the surface, easy saturation failure of the hygroscopic coating, and complicated operation of the physical film pasting method which cannot serve continuously.

Description

Technical Field

[0001] This invention belongs to the field of surface engineering and anti-icing and anti-frost technology, specifically relating to an anti-frost surface based on a moisture-absorbing gel lattice, its preparation method, anti-frost method, and its application. Background Technology

[0002] Frosting is a common phenomenon in industrial fields such as refrigeration, air conditioning, and cold storage. The accumulation of frost on the surface of heat exchangers significantly increases thermal resistance, reduces heat exchange efficiency, leads to a substantial increase in energy consumption, and can even cause equipment shutdowns. Traditional defrosting methods, such as reverse circulation defrosting and hot gas bypass defrosting, have drawbacks such as high energy consumption, large temperature fluctuations, and incomplete defrosting.

[0003] In recent years, surface modification technology has become a research hotspot in the field of frost suppression. Superhydrophobic surfaces utilize micro-nano structures and low surface energy chemical modifications to allow condensed droplets to detach from the surface through self-jumping behavior before freezing. However, numerous studies have shown that superhydrophobic surfaces suffer from a "failure bottleneck" under low-temperature, high-humidity, and long-term operating conditions: once residual microdroplets freeze, they become "seeds" for frost crystals, leading to a rapid frost layer covering the entire surface. Another approach involves constructing hygroscopic regions on the surface, using hygroscopic materials to reduce local water vapor partial pressure and suppress frost formation. However, existing hygroscopic coatings are mostly continuous thin films, which lose their function after moisture saturation, and moisture absorption and expansion easily lead to coating cracking and peeling.

[0004] In addition, the existing technology of using physical film pre-icing to achieve defrosting relies on external film application, requires manual intervention for each use, and the function disappears after the ice droplets are exhausted, which cannot meet the defrosting requirements of long-term continuous operation of the equipment. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing an anti-frost surface based on a hygroscopic gel lattice, its preparation method, anti-frost method, and its application.

[0006] The present invention is as follows: A defrosting surface based on a hygroscopic gel lattice includes a substrate, the surface of which has a background region and a hygroscopic gel lattice region; the hygroscopic gel lattice region is provided with a hygroscopic gel lattice composed of hygroscopic gel, which is a water-absorbing polymer network material formed by cross-linking and curing of a hygroscopic polymer, a cross-linking agent and an initiator, and the hygroscopic gel lattice includes a plurality of discretely distributed hygroscopic gel units; compared with the background region, the hygroscopic gel lattice region has higher hygroscopicity and can preferentially adsorb water vapor in the environment, forming adsorbed moisture in the region of the hygroscopic gel unit; when the temperature drops below the freezing point, the hygroscopic gel lattice region containing adsorbed moisture freezes preferentially compared with the background region, making the hygroscopic gel unit region a local water vapor collection site, forming a dry isolation zone between adjacent hygroscopic gel units.

[0007] Preferably, the hygroscopic polymer is selected from at least one of sodium polyacrylate, polyacrylamide, sodium alginate, polyvinyl alcohol, and polyethylene glycol.

[0008] Preferably, the hygroscopic gel unit is a regular or irregular closed geometric shape; specifically, it can be any one or a combination of circles, squares, ellipses, strips or other polygons; the equivalent diameter of the hygroscopic gel unit is 50 μm to 5 mm; the spacing between adjacent hygroscopic gel units is 100 μm to 20 mm.

[0009] Preferably, the substrate is a metallic material selected from copper, aluminum, stainless steel, titanium, or their alloys.

[0010] Preferably, the substrate is a non-metallic material selected from glass, ceramics, and plastics, and the substrate has undergone surface pretreatment to enhance the adhesion of the moisture-absorbing gel.

[0011] A method for preparing an anti-frost surface based on a hygroscopic gel lattice, specifically including the following steps: S1. Dispersing a hygroscopic polymer in a liquid medium, adding a crosslinking agent and an initiator, mixing evenly to obtain a gel precursor liquid; S2. A mask with a predetermined aperture pattern is installed on the substrate surface; S3. Apply the gel precursor solution to the substrate surface with the mask, so that the gel precursor solution fills the substrate surface corresponding to the mask cutout area; S4. Crosslink and solidify the gel precursor to form a gel lattice; S5. Remove the mask to form a lattice of hygroscopic gel on the substrate surface.

[0012] Preferably, in step S3, the application method is any one of spraying, scraping, dripping, spin coating, or dispensing.

[0013] Preferably, in step S2, the mask is any one of a stainless steel mask, a polyimide mask, a silicone rubber mask, or a polyester mask; A defrosting method involves placing the defrosting surface based on a hygroscopic gel lattice in a low-temperature, high-humidity environment. Utilizing the preferential hygroscopic and preferential freezing characteristics of the hygroscopic gel lattice, after freezing, it continuously adsorbs water molecules from adjacent areas by reducing the partial pressure of local water vapor in the surrounding area, forming a dry isolation zone between the hygroscopic gel units, thereby inhibiting the formation and spread of frost crystals on the substrate surface.

[0014] An application of a frost-resistant surface based on a moisture-absorbing gel lattice, for use in heat exchangers, heat pumps, refrigeration equipment, outdoor units of air conditioners, refrigeration equipment, or cold surface protection structures.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent anti-frost performance: This invention constructs discrete hygroscopic gel lattices on the substrate surface, utilizing the higher hygroscopicity of the gel lattice region compared to the background region, so that water vapor in the environment is preferentially adsorbed and enriched at the gel lattice. Under low temperature conditions, the adsorbed water in the gel lattice freezes before the background region. The frozen gel lattice forms and maintains a dry isolation zone between adjacent units, thereby effectively inhibiting the nucleation and spread of frost crystals in the background region.

[0016] 2. Significantly Improved Heat Exchange Performance: This invention effectively inhibits the formation and accumulation of frost on the heat exchange surface, avoiding the decrease in heat exchange efficiency caused by the thermal resistance of frost. The anti-frost surface maintains a high heat transfer coefficient during long-term operation, and its performance remains stable and does not degrade, which helps reduce the energy consumption of the refrigeration system.

[0017] 3. Simple preparation process and low cost: This invention only requires three steps to complete the preparation: gel modulation, mask application and curing. It does not require complex micro-nano processing equipment such as photolithography and etching, nor does it require low surface energy chemical modification required for superhydrophobic surfaces. The mask can be reused. The process is simple and low cost, making it suitable for large-area industrial production.

[0018] 4. Wide range of applications: This invention has no special requirements for the substrate material. It is suitable for metal substrates such as copper, aluminum, stainless steel, titanium and their alloys, as well as non-metal substrates such as glass, ceramics and plastics. It can be widely used in various heat exchangers, heat pumps, refrigeration equipment, outdoor air conditioning units, refrigeration equipment and cold surface protection structures.

[0019] 5. High design flexibility: By adjusting the single-point size, dot spacing and arrangement of the moisture-absorbing gel matrix, it can be optimized for different temperature and humidity conditions and supercooling conditions, flexibly adapting to diverse application scenarios and achieving the best anti-frost effect.

[0020] 6. Good long-term stability: The moisture-absorbing gel lattice has good water retention and structural stability. It maintains structural integrity after multiple freeze-thaw cycles, and its moisture absorption performance does not decrease significantly. It does not require frequent maintenance or replacement and meets the anti-frost requirements for long-term continuous operation of equipment. Attached Figure Description

[0021] Figure 1 : A schematic diagram of the process for preparing an anti-frost surface based on a hygroscopic gel lattice in this invention.

[0022] Figure 2 : A schematic diagram of the anti-frost principle of the anti-frost surface based on the hygroscopic gel lattice in this invention.

[0023] Figure 3 Comparison of frosting effects in this invention.

[0024] Figure 4 Comparison of frosting effects under extreme high humidity conditions in this invention.

[0025] Figure 5 Comparison of heat transfer performance between the smooth metal surface and the anti-frost surface based on the hygroscopic gel lattice in this invention. Detailed Implementation

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] like Figure 1 As shown, a method for preparing an anti-frost surface based on a hygroscopic gel lattice includes the following steps: S1. Dispersing a hygroscopic polymer in a liquid medium, adding a crosslinking agent and an initiator, mixing evenly to obtain a gel precursor liquid; S2. A mask with a predetermined aperture pattern is installed on the substrate surface; S3. Apply the gel precursor solution to the substrate surface with the mask, so that the gel precursor solution fills the substrate surface corresponding to the mask cutout area; S4. Crosslink and solidify the gel precursor to form a gel lattice; S5. Remove the mask to form a lattice of hygroscopic gel on the substrate surface.

[0029] The anti-frost principle of this invention is as follows: 1. Hygroscopic and condensation characteristics of the hygroscopic gel lattice: The hygroscopic gel has strong hydrophilicity and a porous network structure, and has a higher adsorption capacity for water vapor than ordinary surfaces. In the initial stage of condensation, water vapor in the environment preferentially adsorbs, dissolves, or condenses at the gel lattice, making the gel lattice a sink for water vapor and actively capturing surrounding water molecules. The water in the gel lattice exists in the form of bound water and free water, and its saturated vapor pressure is lower than that of pure water, further enhancing the driving force of hygroscopic absorption. 2. Preferential freezing and evaporation effect of the gel lattice: When the temperature drops below the freezing point, the freezing behavior of a large amount of water in the gel lattice differs from its intrinsic freezing point due to the freezing point reduction effect of hygroscopic salts or polymer chains. This invention has found that at low temperatures, it preferentially freezes (relative to the background region), and the frozen gel lattice acts as a stable ice core, continuously adsorbing surrounding water molecules because its surface water vapor partial pressure is lower than that of the surrounding supercooled water droplets or supersaturated vapor environment. This mechanism leads to a significant decrease in the local water vapor partial pressure in adjacent regions of the gel lattice, making it impossible to meet the thermodynamic conditions for new droplet nucleation or frost crystal growth, thus forming a stable dry zone between the gel lattice points. (See attached image) Figure 2 As shown: (a) discrete droplets are regularly arranged on the substrate surface; (b) the droplets absorb moisture and grow, with condensed microdroplets appearing around them; (c) the droplets preferentially freeze and then evaporate the surrounding condensed microdroplet clusters; (d) in a high humidity environment, frost crystals grow on the top of the frozen droplets, but the background area remains frost-free. In the early stage of condensation, the adsorption probability of water molecules on the surface is positively correlated with the local surface energy. Therefore, the highly wettable lattice region becomes a gathering site for water vapor, preferentially undergoing nucleation and growth. Due to the extremely strong hydrophobicity of the background region, the small droplets condensed on it are in a high surface energy state. Once they merge with adjacent droplets, they release excess surface energy and detach from the surface in a jumping manner. These jumping droplets are highly likely to be captured and absorbed by droplets in the more wettable lattice region during their flight or when they fall back onto the surface. This positive feedback mechanism ultimately leads to all condensed droplets self-assembling into the preset lattice region, forming a macroscopically ordered discrete distribution.

[0030] To enable those skilled in the art to better understand the present application, the present application is clearly and specifically described, and the following embodiments are provided: Example 1: A frosting surface based on polyacrylamide gel lattice and its preparation method (aluminum substrate), comprising the following: Preparation of S1 gel precursor solution: Dissolve 8g of polyacrylamide and 0.4g of N,N'-methylenebisacrylamide in 100mL of deionized water and stir until completely dissolved. Add 0.15g of ammonium persulfate (APS) and 50μL of tetramethylethylenediamine (TEMED), and stir until homogeneous to obtain the gel precursor solution.

[0031] S2 substrate pretreatment: Select a 3cm×3cm aluminum alloy sheet, and after alkaline degreasing, acid pickling and neutralization, rinsing with deionized water, and then drying with nitrogen.

[0032] S3 Mask Loading and Coating: A polyimide (PI) mask with a square hole array (single hole size 0.3mm×0.3mm, spacing 2mm) is attached to the surface of the pretreated aluminum sheet. The gel precursor solution is scraped onto the mask surface using a doctor blade to fill the hollow area.

[0033] S4 Gel Curing: Place the coated aluminum sheet in a 50℃ oven and cure for 3 hours.

[0034] S5 Mask Removal: Peel off the PI mask to form a discrete polyacrylamide gel lattice on the aluminum sheet surface.

[0035] Example 2: An anti-frost surface (copper substrate) based on sodium polyacrylate gel lattice, comprising the following: Preparation of S1 gel precursor solution: Add 5g of sodium polyacrylate (PAAS, molecular weight approximately 5×10⁻⁶) to the solution. 6 Dissolve in 100 mL of deionized water and stir until completely dissolved. Add 0.5 g of N,N'-methylenebisacrylamide (MBA) as a crosslinking agent and 0.1 g of ammonium persulfate (APS) as an initiator, stir well to obtain a gel precursor solution.

[0036] S2 substrate pretreatment: Select a 3cm×3cm copper sheet, and ultrasonically clean it for 10 minutes each in acetone, ethanol and deionized water, and then dry it with nitrogen.

[0037] S3 Mask Loading: A stainless steel perforated plate mask is tightly bonded to the surface of the pretreated copper sheet. The mask aperture array consists of round holes with a diameter of 0.5 mm and a hole spacing of 3 mm, arranged in a periodic square pattern.

[0038] S4 Spray Coating: The gel precursor solution prepared in S1 is loaded into the spray device and sprayed evenly onto the surface of the copper sheet with the mask attached, ensuring that the gel solution fully fills the perforated area of ​​the mask.

[0039] S5 Gel Curing: The sprayed copper sheet is placed in a 60℃ oven and heated for 2 hours to cure the gel precursor to crosslink and form a stable three-dimensional network structure.

[0040] S6 Mask Removal: After the gel has fully cured, carefully peel off the stainless steel mask to form a discrete sodium polyacrylate gel lattice on the copper sheet surface.

[0041] Example 3: An anti-frost surface (stainless steel substrate) based on sodium alginate / polyvinyl alcohol composite gel lattice, comprising the following: Preparation of S1 gel precursor solution: Mix 3g sodium alginate and 2g polyvinyl alcohol (PVA, molecular weight approximately 8×10⁻⁶). 4 Dissolve the substance in 100 mL of deionized water and heat at 90 °C with stirring until completely dissolved. After cooling to room temperature, add 0.3 g of CaCl2 as a crosslinking agent and stir until homogeneous to obtain a gel precursor solution.

[0042] S2 substrate pretreatment: Select a 3cm×3cm 304 stainless steel sheet, ultrasonically clean it with acetone, rinse it with deionized water, and then dry it with nitrogen.

[0043] S3 Mask Loading and Dispensing: A silicone rubber mask with an array of circular holes (0.8 mm in diameter and 4 mm in spacing) is bonded to a stainless steel surface. A micro-dispensing machine is used to precisely dispense the gel precursor solution into each hole.

[0044] S4 Gel Curing: Place the stainless steel sheet after dispensing at room temperature and let it cure for 6 hours to allow sodium alginate and Ca²⁺ to fully crosslink and form a gel.

[0045] S5 Mask Removal: Peel off the silicone rubber mask to form a discrete composite gel lattice on the stainless steel surface.

[0046] Comparative Example 1: Smooth metal surface (untreated): An aluminum alloy sheet of the same specifications as in Example 1 was selected, ultrasonically cleaned with acetone, ethanol and deionized water and then dried with nitrogen. No surface treatment was performed.

[0047] Anti-frost performance test: The samples prepared in Example 1 and Comparative Example 1 were placed in a constant temperature and humidity chamber. The ambient temperature inside the chamber was set to 5℃, the surface temperature was controlled to -6℃ by a semiconductor cooling chip, and the relative humidity was set to 30% (corresponding to a supersaturation of S~1.2). The samples were placed horizontally, and the surface frosting process was continuously observed using a high-resolution camera. The test results are as follows: 1. As Figure 3 As shown, comparative example (smooth aluminum alloy sheet): as attached Figure 3 As shown in (a), approximately 5 minutes after the start of the test, sporadic condensation droplets appeared on the surface; at 10 minutes, the droplets densely covered the surface and began to freeze; at 20 minutes, the surface was completely covered with frost crystals, and the frost layer thickness continued to increase. The heat transfer efficiency decreased from an initial ~500 W / m²·K to ~200 W / m²·K at 20 minutes. Example 1 (Sodium polyacrylate gel lattice): as attached Figure 3 As shown in (b), during the initial stage of condensation, water vapor preferentially adsorbs at the gel lattice sites and forms droplets; after about 5 minutes, the droplets in the gel lattice preferentially freeze; subsequently, it was observed that the microdroplets around the gel lattice gradually disappeared (evaporated), and the gaps between the gel lattice remained clear and frost-free; throughout the entire 60-minute observation period, except for the slow growth of the gel lattice itself due to continuous moisture absorption, the background area remained frost-free. The heat transfer efficiency remained stable at ~1480 W / m²·K.

[0048] Extreme high humidity condition test: The sample from Example 1 was tested under different supersaturation conditions. The ambient temperature was maintained at 5°C, and the surface temperature at -6°C. The supersaturation S was adjusted to 1.2, 1.8, and 2.4 by adjusting the relative humidity. The test results are attached. Figure 4 As shown: the anti-frost boundary under extreme high humidity conditions: as the supersaturation S (defined as the ratio of ambient vapor partial pressure to surface saturated vapor pressure) increases, the anti-frost effect of the gel lattice exhibits a gradient change: when S ~ 1.2, the gaps between gel lattice points are completely frost-free, and the anti-frost effect is excellent; when S ~ 1.8, a very small number of frozen microdroplets that were not removed appear in the gaps between gel lattice points, but they do not develop into a continuous frost layer; when S ~ 2.4, obvious frost crystals appear in the gaps between gel lattice points, but the frost layer coverage is still significantly lower than that of the control sample on a smooth metal surface (coverage reduced by about 60%). This result indicates that the present invention has excellent anti-frost effects under normal and moderate humidity conditions.

[0049] Heat transfer performance test: The sample from Example 1 and the smooth copper sheet control sample were placed in a wind tunnel testing system to test the heat transfer coefficient under natural convection and forced convection (wind speed 2 m / s) conditions, respectively. (See attached...) Figure 5 As shown: 1. Natural convection: The heat transfer efficiency of a smooth surface is ~450 W / m²·K and continues to decrease with increasing frost thickness; the gel array is stable at ~1480 W / m²·K, approximately 3 times that of the smooth surface. 2. Forced convection (wind speed 2 m / s): The heat transfer efficiency of a smooth surface is ~700 W / m²·K and continues to decrease; the gel array is stable at ~2000 W / m²·K, approximately 2.8 times that of the smooth surface.

[0050] The above tests demonstrate that, while providing excellent anti-frost performance, the present invention can significantly improve the long-term heat exchange efficiency of the heat exchanger and reduce defrosting energy consumption.

[0051] Compared with the prior art, the beneficial effects of this application are as follows: 1. Excellent anti-frost performance: This invention constructs discrete hygroscopic gel lattices on the substrate surface, utilizing the higher hygroscopicity of the gel lattice region compared to the background region, causing water vapor to preferentially adsorb and accumulate at the gel lattice. Under low-temperature conditions, the adsorbed water in the gel lattice freezes before the background region. The frozen gel lattice acts as local vapor pressure regulation sites, forming and maintaining a dry isolation zone between adjacent gel lattices, thereby inhibiting the formation and spread of frost crystals on the substrate surface. Experiments show that under conditions of surface temperature -6℃, ambient temperature 5℃, and relative humidity 30%, a smooth metal surface is completely covered with frost crystals within 20 minutes, while the gel lattice surface of this invention remains frost-free throughout the entire 60-minute observation period.

[0052] 2. Significantly Improved Heat Transfer Performance: This invention effectively suppresses the formation of frost on the heat transfer surface, avoiding the decrease in heat transfer efficiency caused by the thermal resistance of frost. Under natural convection conditions, the heat transfer efficiency of a smooth metal surface is approximately 450 W / m²·K and decreases continuously with increasing frost thickness, while the gel lattice surface of this invention remains stable at approximately 1480 W / m²·K. Under forced convection conditions (wind speed 2 m / s), the heat transfer efficiency of a smooth surface is approximately 700 W / m²·K and decreases continuously, while the gel lattice surface of this invention remains stable at approximately 2000 W / m²·K. The heat transfer efficiency is improved by approximately 2 to 3 times, and this improvement does not decrease over long-term operation.

[0053] The fabrication process is simple and low-cost: This invention requires only three steps to complete the fabrication: gel modulation, mask application, and curing. The mask is reusable, eliminating the need for complex micro / nano fabrication equipment such as photolithography and etching, as well as the need for low surface energy chemical modification required for superhydrophobic surfaces, making it suitable for large-area industrial production.

[0054] 4. Wide range of applications: The substrate material of this invention is not limited. It is suitable for metal substrates such as copper, aluminum, stainless steel, titanium and their alloys, as well as non-metal substrates such as glass, ceramics and plastics (after appropriate surface treatment). It can be widely used in various heat exchangers, heat pumps, refrigeration equipment, outdoor air conditioning units, refrigeration equipment and cold surface protection structures.

[0055] 5. High design flexibility: By adjusting the single-point size (50μm~5mm), dot spacing (100μm~20mm), and arrangement of the moisture-absorbing gel matrix, the design can be optimized for different temperature and humidity conditions and supercooling conditions to achieve the best anti-frost effect.

[0056] 6. Excellent long-term stability: The moisture-absorbing gel lattice has good water retention and elasticity. Its structure remains intact after multiple freeze-thaw cycles, and its moisture absorption performance shows no significant decline. It requires no frequent maintenance or replacement, meeting the defrosting requirements for long-term continuous operation of equipment. The specific embodiments described herein are merely illustrative examples illustrating the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or substitute them with similar methods, without departing from the spirit of the invention or exceeding its defined scope. Although the invention has been detailed and described in the accompanying drawings and foregoing description, such descriptions are considered illustrative or exemplary rather than restrictive. It should be understood that changes and modifications can be made by those skilled in the art within the scope of the following claims.

Claims

1. A defrosting surface based on a hygroscopic gel lattice, characterized in that, The system includes a substrate, the surface of which has a background region and a hygroscopic gel lattice region. The hygroscopic gel lattice region is composed of hygroscopic gel, which is a water-absorbing polymer network material formed by cross-linking and curing of a hygroscopic polymer, a cross-linking agent, and an initiator. The hygroscopic gel lattice includes several discretely distributed hygroscopic gel units. Compared to the background region, the hygroscopic gel lattice region can preferentially adsorb water vapor from the environment, forming adsorbed moisture in the hygroscopic gel unit region. When the temperature drops below the freezing point, the hygroscopic gel lattice region containing adsorbed moisture freezes preferentially compared to the background region, making the hygroscopic gel unit region a local water vapor collection site, forming a dry isolation zone between adjacent hygroscopic gel units.

2. The anti-frost surface based on a hygroscopic gel lattice as described in claim 1, characterized in that, The hygroscopic polymer is selected from at least one of sodium polyacrylate, polyacrylamide, sodium alginate, polyvinyl alcohol, and polyethylene glycol.

3. The anti-frost surface based on a hygroscopic gel lattice as described in claim 1, characterized in that, The hygroscopic gel unit is a regular or irregular closed geometric shape; the equivalent diameter of the hygroscopic gel unit is 50 μm to 5 mm; the spacing between adjacent hygroscopic gel units is 100 μm to 20 mm.

4. The anti-frost surface based on a hygroscopic gel lattice as described in claim 1, characterized in that, The substrate is a metallic material, selected from at least one of copper, aluminum, stainless steel, and titanium.

5. The anti-frost surface based on a hygroscopic gel lattice as described in claim 1, characterized in that, The substrate is a non-metallic material, selected from any one of glass, ceramic, or plastic. The substrate has undergone surface pretreatment to enhance the adhesion of the moisture-absorbing gel.

6. A method for preparing an anti-frost surface based on a hygroscopic gel lattice, used to prepare the anti-frost surface based on a hygroscopic gel lattice as described in any one of claims 1-5, characterized in that, Specifically, the following steps are included: S1. Disperse the hygroscopic polymer in a liquid medium, add a crosslinking agent and an initiator, mix thoroughly to obtain a gel precursor liquid; S2. A mask with a predetermined aperture pattern is installed on the substrate surface; S3. Apply the gel precursor solution to the substrate surface with the mask, so that the gel precursor solution fills the substrate surface corresponding to the mask cutout area; S4. Crosslink and solidify the gel precursor to form a gel lattice; S5. Remove the mask to form a lattice of hygroscopic gel on the substrate surface.

7. The method for preparing an anti-frost surface based on a hygroscopic gel lattice as described in claim 6, characterized in that, In step S3, the application method is any one of spraying, scraping, dripping, spin coating, or dispensing.

8. The method for preparing an anti-frost surface based on a hygroscopic gel lattice as described in claim 6, characterized in that, In step S2, the mask is any one of stainless steel mask, polyimide mask, silicone rubber mask or polyester mask.

9. A method for suppressing frost, characterized in that, The anti-frost surface based on the hygroscopic gel lattice as described in any one of claims 1-5 is placed in a low-temperature and high-humidity environment. By utilizing the preferential hygroscopic and preferential freezing characteristics of the hygroscopic gel lattice, after freezing, it continuously adsorbs water molecules in adjacent areas by reducing the partial pressure of local water vapor in the surrounding area, forming a dry isolation zone between adjacent hygroscopic gel units, thereby inhibiting the formation and spread of frost crystals on the substrate surface.

10. An application of an anti-frost surface based on a hygroscopic gel lattice, wherein the anti-frost surface based on the hygroscopic gel lattice is any one of the anti-frost surfaces based on a hygroscopic gel lattice as described in claims 1-5, characterized in that, Anti-frost surfaces based on hygroscopic gel lattices are used in heat exchangers, heat pumps, refrigeration equipment, outdoor air conditioning units, refrigeration equipment, or cold surface protection structures.

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