Hydrogel microspheres, method for preparing hydrogel microspheres, and ice-repellent coating
By preparing hydrogel microspheres and applying them to anti-icing coatings, the problems of high cost, poor stability and transparency of existing anti-icing materials are solved, achieving efficient and environmentally friendly ice nucleation control, which is suitable for anti-icing of transportation vehicles, energy facilities and public infrastructure.
Patent Information
- Application Number
- CN202411096834.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2044-08-09
AI Technical Summary
Existing anti-icing materials are costly, have poor stability, and affect coating transparency and uniformity. Traditional de-icing methods are harmful to the environment, and uneven application of ice nucleating materials leads to inconsistent anti-icing performance.
A hydrogel microsphere preparation method was adopted. By controlling the flow rate ratio of the first monomer and the second monomer, the use of crosslinking agent and photoinitiator, hydrogel microspheres with a tight polymer network structure were formed. The hydrophilicity and large specific surface area of the microspheres were used to promote ice nucleation and prepare an anti-icing coating.
It enables rapid induction of ice nucleus formation at higher temperatures, increases the nucleation temperature, maintains material transparency and uniformity, avoids environmental pollution, and is suitable for anti-icing of vehicles, energy facilities, and public infrastructure.
Smart Images
Figure CN118791667B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of anti-icing, more particularly to a water gel microsphere for promoting ice nucleation, a preparation method of the water gel microsphere and an anti-icing coating. BACKGROUND
[0002] Ice and snow are common in our daily life, and the most common phenomenon in nature is that liquid water freezes into solid ice. In terms of ice crystal formation, nature also has its unique and ingenious method to control ice crystal formation, for example, there is a special family of proteins in the protein world. Two important branches of ice-binding proteins and nucleation proteins can affect ice crystal formation in completely opposite ways. The molecular weight of anti-icing protein is generally 3000-35000 Da, and it usually appears as a monomer protein molecule. It can be adsorbed on the surface of ice crystals, making the ice crystals curved, and according to the Kelvin effect, inhibiting the further growth of ice crystals. Anti-icing protein is one of the most efficient biological anti-icing agents at present, but the extraction of anti-icing protein from biological bodies is a very tedious and inefficient process. Although anti-icing protein can be artificially synthesized by gene expression method, its price is also very expensive. And most of the anti-icing proteins have poor stability and are easily inactivated, so they have not been widely used.
[0003] Nucleation protein, on the other hand, is much larger than anti-icing protein, with a molecular weight generally greater than 100000 Da, and often appears in the form of a multimer. Nucleation protein can promote ice nucleation, allowing ice to form at higher subzero temperatures.
[0004] In cold environments, ice and frost can cause serious problems to transportation vehicles (such as airplanes, cars), energy facilities (such as wind turbine blades, power transmission lines) and public infrastructure (such as bridges, roads), affecting their normal operation and safety. Traditional deicing methods, such as chemical deicing agents and mechanical deicing, can have adverse effects on the environment, so it is urgent to develop more environmentally friendly solutions. With the development of new materials and surface technology, it is possible to find materials that can effectively inhibit or control the ice nucleation process. The discovery and application of high-efficiency ice nucleation agents is a direct manifestation of this progress. By engineering the surface of materials, it is possible to precisely control their influence on ice nucleation and growth, thereby effectively inhibiting the adhesion and accumulation of ice.
[0005] However, the addition of some traditional ice nucleation materials can affect other properties of the coating, such as reducing transparency, which may not be desirable in some applications. Non-uniform application of traditional coatings can result in inconsistent anti-icing performance across different areas of the surface, affecting the overall effect. SUMMARY
[0006] In view of the above problems of the prior art, the technical scheme of the present application provides a hydrogel microsphere for promoting ice nucleation, a preparation method of the hydrogel microsphere and an anti-icing coating, which can solve at least part of the problems existing in the ice nucleation materials in the prior art.
[0007] In one aspect, the present application provides a preparation method of a hydrogel microsphere, comprising the following steps:
[0008] In the first solution preparation step, a first monomer having a dilenamide group and a second monomer having an oleic acid group are weighed separately and then dissolved in water, and then an appropriate amount of a crosslinking agent and a photoinitiator are sequentially added to obtain a first solution.
[0009] In the second solution preparation step, a surfactant is added to an oily solvent to obtain a second solution.
[0010] In the mixing step, the first solution and the second solution are simultaneously released into a pipeline at different flow rates to obtain a mixed solution.
[0011] In the solidification step, the mixed solution is placed in a UV lamp box for solidification to obtain a hydrogel microsphere.
[0012] According to the technical scheme of the present application, the first monomer and the second monomer can be well polymerized under the promotion of the crosslinking agent and the action of the initiator, and the formed polymer has a polymer network structure that is interconnected and closely arranged. Further, the shearing force between the second solution (oily) and the first solution (aqueous) can effectively prepare microspheres of different sizes and uniform sizes. Such a structure can ensure the hydrophilicity of the material while obtaining a larger specific surface area.
[0013] Moreover, since ice is formed by the ordered arrangement of water molecules in a low-temperature environment, the polymerized network structure can provide an effective platform and template for the arrangement of water molecules. In addition, the excellent hydrophilicity and large specific surface area of the gel enable it to adsorb more water molecules, which provides a convenient basis condition for ice formation. The specific size combined with the unique physicochemical properties possessed by the surface of the gel particles enables the gel particles to play a great promoting role in the ice nucleation formation process, thereby effectively improving the temperature at which pure water freezes into ice.
[0014] Experiments have proved that the hydrogel microsphere provided by the present application can induce the rapid formation and growth of ice nuclei at an environmental temperature of-2℃. Compared with the existing ice nucleation materials, it has a higher nucleation temperature and good optical effect, and the size of the microsphere is uniform, which does not affect the uniformity of the material as a whole.
[0015] As a preferred technical scheme of the present application, in the mixing step, the flow rate ratio of the first solution to the second solution is 1:1-5:1.
[0016] According to the preferred technical scheme, by controlling the flow rate ratio of the first solution and the second solution, the particle size range of the prepared hydrogel microspheres can be controlled to be between 10 and 100 mu m, the small particle size hydrogel microspheres can have better optical properties, and can be better mixed with other materials, and can better maintain the smoothness and transparency of the material.
[0017] As a preferred technical scheme of the present application, in the second solution preparation step, the concentration of the surfactant in the oily solvent is 1-10wt%.
[0018] According to the preferred technical scheme, the surfactant can increase the shear force between the hydrogel precursor and the oily solvent, and promote the formation of uniform microspheres of the hydrogel precursor.
[0019] As a preferred technical scheme of the present application, the first monomer is methacrylamide; the second monomer is methacrylic acid.
[0020] According to the preferred technical scheme, methacrylamide and methacrylic acid can generate a more compact polymer network structure under the action of photo-initiated polymerization, increase the specific surface area of the hydrogel microspheres, and further promote ice nucleation.
[0021] As a preferred technical scheme of the present application, the crosslinking agent is selected from one or more combinations of dimethyl acrylamide, N,N'-methylene bisacrylamide and glutaraldehyde, and the initiator is selected from at least one of ammonium persulfate, potassium persulfate and sodium persulfate.
[0022] As a preferred technical scheme of the present application, the mass fraction of the first monomer, the second monomer, the crosslinking agent and the photo-initiator in the hydrogel microspheres is: the first monomer is 200-800 parts by mass; the second monomer is 200-800 parts by mass; the crosslinking agent is 30-50 parts by mass; the photo-initiator is 50-120 parts by mass.
[0023] According to the preferred technical scheme, by controlling the ratio of the first monomer and the second monomer, the first monomer and the second monomer in the hydrogel microspheres can form a hydrogel microsphere with a controllable size, a uniform polymer network structure with mutual connection and close arrangement under the action of the initiator and the promotion of the crosslinking agent, so that the hydrogel microsphere has excellent performance in promoting ice nucleation.
[0024] As a preferred technical scheme of the present application, in the first solution preparation step, further comprising:
[0025] Adjusting the PH of the first solution to be less than 7.
[0026] According to the preferred technical scheme, it is more beneficial for the first monomer and the second monomer to emit photo-initiated polymerization reaction in an acidic environment, and to quickly and uniformly form a polymer network structure.
[0027] As a preferred technical solution of the present application, after the solidification step, further comprising:
[0028] The cleaning step is to immerse the hydrogel microspheres in water first, and then immerse the hydrogel microspheres in cyclohexane.
[0029] According to the preferred technical solution, on the one hand, repeated washing with water can wash away as much as possible the unreacted first monomer or second monomer; on the other hand, cyclohexane can replace the water in the hydrogel, which affects the anti-icing effect of the overall material.
[0030] The second aspect of the present application provides a hydrogel microsphere prepared by the method for preparing a hydrogel microsphere according to any one of the above technical solutions.
[0031] The third aspect of the present application provides an anti-icing coating, which comprises the hydrogel microsphere provided in the above technical solutions. BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 is a flowchart of the method for preparing a hydrogel microsphere provided by the embodiments of the present application. DETAILED DESCRIPTION
[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0034] The embodiments of the present application provide a method for preparing a hydrogel microsphere, which has a polymer network structure. The polymer network structure is formed by interpenetrating and crosslinking a first monomer and a second monomer. Specifically, a first monomer having an enamide group, a second monomer having an enoic acid group, a photoinitiator and a crosslinking agent are mixed in water, and then solidified by light (for example, solidified by irradiation of an ultraviolet lamp). The first monomer and the second monomer can be well polymerized under the promotion of the crosslinking agent and the action of the initiator, and the formed polymer has a polymer network structure with mutual connection and close arrangement.
[0035] In the present application, the specific selection of the first monomer and the second monomer is not limited, and a person skilled in the art can freely select an organic compound having an enamide group as the first monomer and an organic compound having an enoic acid group as the second monomer, and select a photoinitiator and a crosslinking agent based on the types of the first monomer and the second monomer to form a hydrogel having a polymer network, without exceeding the protection scope of the present application.
[0036] Preferably, the first monomer can be selected from methacrylamide, and the second monomer can be selected from methacrylic acid. The molecules of methacrylamide and methacrylic acid are small, and the steric hindrance is also small, which can generate a more compact polymer network structure under the action of photopolymerization, thereby improving the specific surface area of the hydrogel microspheres and further promoting ice nucleation.
[0037] Further preferably, based on the specific selection of the first monomer and the second monomer, the crosslinking agent can be selected from one or more combinations of dimethylacrylamide, N,N'-methylenebisacrylamide and glutaraldehyde, and the initiator can be selected from at least one of ammonium persulfate, potassium persulfate and sodium persulfate.
[0038] Preferably, the mass fractions of the first monomer, the second monomer, the crosslinking agent and the photoinitiator in the hydrogel microspheres can be as follows: the first monomer is 200-800 parts by mass; the second monomer is 200-800 parts by mass; the crosslinking agent is 30-50 parts by mass; and the photoinitiator is 50-120 parts by mass. Further, the mass ratio of the first monomer to the second monomer in the hydrogel is 1-9:1-9, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1, and the like. By controlling the ratio of the first monomer to the second monomer, the first monomer and the second monomer in the hydrogel microspheres can form a hydrogel microsphere having a uniform polymer network structure with a controllable size and a mutual connection and a compact arrangement under the action of the initiator and the promotion of the crosslinking agent, so that the hydrogel microspheres have excellent performance in promoting ice nucleation.
[0039] In particular, Figure 1 A flowchart of a preparation method of the hydrogel microspheres provided by the present embodiment is shown. In the present embodiment, the hydrogel microspheres are prepared by the preparation method shown in Figure 1
[0040] In the first solution preparation step S1, the first monomer having a dilenamide group and the second monomer having an enoic acid group are weighed and then dissolved in water, and then an appropriate amount of a crosslinking agent and a photoinitiator are added in sequence to obtain a first solution.
[0041] A second solution preparation step S2, adding a surfactant in an oily solvent to obtain a second solution.
[0042] A mixing step S3, simultaneously releasing the first solution and the second solution into the pipe at different flow rates to obtain a mixed solution.
[0043] A solidification step S4, solidifying the mixed solution in a UV light box to obtain hydrogel microspheres.
[0044] By controlling the flow rates of the second solution and the first solution, different sizes and uniform sizes of microspheres can be effectively prepared by using the shearing force between the second solution (oily) and the first solution (aqueous).
[0045] In addition, since ice is formed by the ordered arrangement of water molecules in a low-temperature environment, the aggregated network structure can provide an effective platform and template for the arrangement of water molecules. In addition, the excellent hydrophilicity and large specific surface area of the gel enable it to adsorb more water molecules, which provides a convenient basis for ice formation. The specific size combined with the unique physicochemical properties of the surface enables the gel particles to play a great role in the ice nucleus formation process, thereby effectively improving the temperature at which pure water freezes into ice.
[0046] Experiments have proved that the hydrogel microspheres provided by the present application can induce the rapid formation and growth of ice nuclei at an environmental temperature of-2℃. Compared with existing ice nucleation materials, it has a higher nucleation temperature and good optical effect. The size of the microspheres is uniform, and it will not affect the uniformity of the material as a whole.
[0047] Preferably, in the mixing step S3, the flow rate ratio of the first solution and the second solution is 1:1-5:1. By controlling the flow rate ratio of the first solution and the second solution, the particle size range of the prepared hydrogel microspheres can be controlled to be between 10 μm-100 μm. Small particle size hydrogel microspheres can have better optical properties and can better mix with other materials, and can better maintain the smoothness and transparency of the material. Further, in the mixing step S3, the second solution can be injected into the inside of the pipe using a syringe, and after the second solution fills the bottom of the pipe, the flow rate of the second solution is maintained for continuous injection, and then the first solution is continuously injected into the pipe at a certain flow rate, to obtain a solution containing hydrogel microspheres.
[0048] The surfactant can be freely selected according to requirements, and preferably can be selected from Span 80 (sorbitan oleate) and / or Tween 80 (polysorbate-80). Span 80 and Tween 80 are widely used in various industries due to their respective emulsifying properties and stability. The selection and combined use of the two surfactants can effectively solve the problems of emulsification, solubilization and stability, and meet different industrial requirements.
[0049] Further preferably, in the second solution preparation step S2, the concentration of the surfactant in the oily solvent is 1-10 wt%.
[0050] Preferably, in the first solution preparation step S1, further comprising: adjusting the pH of the first solution to be less than 7. Specifically, the pH adjuster is selected from at least one of hydrochloric acid, sulfuric acid and phytic acid, which is not limited herein. In an acidic environment, the first monomer and the second monomer are more conducive to photoinitiated polymerization, and the polymer network structure is formed quickly and uniformly.
[0051] Further preferably, after the curing step S4, further comprising:
[0052] The washing step S5 first immerses the hydrogel microspheres in water, and then immerses the hydrogel microspheres in cyclohexane. On the one hand, repeated washing with water can wash away as much unreacted first monomer or second monomer as possible; on the other hand, cyclohexane can replace the water in the hydrogel, which affects the ice prevention effect of the overall material.
[0053] The following experiments further demonstrate the ice prevention performance of the ice prevention coating provided by the embodiment.
[0054] 1. Material preparation
[0055] First, the first solution preparation step S1 is performed, 5 ml of methacrylic acid (second monomer) is slowly dissolved in 10 ml of ultrapure water, after forming a uniform temperature solution, 5 g of methacrylamide is weighed and added to the solution and ultrasonicated for 30 minutes, then 100 mg of crosslinking agent (BISNN, methylene bisacrylamide) is added and ultrasonicated for 10 minutes, and after complete dissolution, it is used as solution A. 100 mg of photoinitiator (UV-2959, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone) is completely dissolved in 10 ml of ultrapure water as solution B. Solution B is slowly added to solution A, and constant stirring is required throughout the process. After the solution is stable, the first solution is obtained.
[0056] Then, the second solution preparation step S2 is performed, 1 ml of surfactant Span 80 (sorbitan oleate) and Tween 80 (polysorbate-80) is added dropwise to 100 ml of mineral oil, and the whole process requires 80°C oil bath heating and constant stirring, until a uniform transparent second solution is formed.
[0057] Then, a mixing step S3 is performed, 3 ml of the first solution is taken from the first syringe and placed in the first syringe pump, 5 ml of the second solution is taken from the second syringe and placed in the second syringe pump, after the instruments are connected, the flow rates of the first syringe pump and the second main device are set to 1:2 respectively, and the shear stress between the two is used to form hydrogel microspheres of a certain size.
[0058] Next, a curing step S4 is performed, the collected microspheres are irradiated under a UV lamp for 20 min to initiate polymerization, and hydrogel microspheres are obtained.
[0059] Finally, a cleaning step S5 is performed, after polymerization, the hydrogel microspheres are cleaned and soaked with deionized water and cyclohexane respectively, the soaking time is 6 h, and the unaggregated monomers and other impurities are removed, and clean hydrogel microspheres are obtained.
[0060] Preferably, the obtained hydrogel microspheres can also be freeze-dried for 12 h, and then ground to obtain microsphere powder.
[0061] 2. Material characterization
[0062] In-situ ice nucleation test of hydrogel microspheres
[0063] The hydrogel microspheres with a mass fraction of 10% are dispersed in ultrapure water, 0.2 μl of the solution is taken by a microsyringe and dropped on a silicon wafer to form a small droplet, the above operation is repeated until 20 small droplets are formed, the silicon wafer is placed in a cooling table, the cooling rate is controlled by a program, and the freezing temperature of the droplets is observed and recorded in-situ, which is the ice nucleation temperature. Through the test, the nucleation temperature of the above-mentioned ice nucleation agent is -2.5℃. Experiments show that the hydrogel microspheres provided by the embodiment can induce the rapid formation and growth of ice nuclei at an ambient temperature of -2℃, and compared with existing ice nucleation materials, the hydrogel microspheres have a higher nucleation temperature.
[0064] In some other embodiments of the present application, an anti-icing coating is also provided, which comprises the hydrogel microspheres provided in any of the above embodiments.
[0065] So far, the technical solutions of the present application have been described in conjunction with the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.
Claims
1. An icephobic coating, characterized in that, The hydrogel microspheres include a preparation method comprising the following steps: A first solution preparation step, in which a first monomer having an enamide group and a second monomer having an enoic acid group are weighed and dissolved in water respectively, and then an appropriate amount of a crosslinking agent and a photoinitiator are sequentially added to obtain the first solution; A second solution preparation step, in which a surfactant is added to an oily solvent to obtain the second solution; A mixing step, in which the first solution and the second solution are simultaneously released into a pipeline at different flow rates to obtain a mixed solution; A curing step, in which the mixed solution is cured in a UV lamp box to obtain the hydrogel microspheres; In the mixing step, the flow rate ratio of the first solution to the second solution is 1:1-5:1; The mass fraction of the first monomer, the second monomer, the crosslinking agent and the photoinitiator in the hydrogel microspheres is: The first monomer is 200-800 mass parts; The second monomer is 200-800 mass parts; The crosslinking agent is 30-50 mass parts; The photoinitiator is 50-120 mass parts; The first monomer is methacrylamide; and the second monomer is methacrylic acid.
2. The anti-ice coating of claim 1, wherein, In the second solution preparation step, the concentration of the surfactant in the oily solvent is 1-10 wt%.
3. The anti-ice coating of claim 1, wherein, The crosslinking agent is selected from one or more combinations of N,N'-methylene bisacrylamide and glutaraldehyde, and the initiator is selected from at least one of ammonium persulfate, potassium persulfate and sodium persulfate.
4. The anti-ice coating of claim 1, wherein, In the first solution preparation step, further comprising: Adjusting the pH of the first solution to be less than 7.
5. The anti-ice coating of claim 1, wherein, After the curing step, further comprising: A washing step, in which the hydrogel microspheres are first soaked in water, and then soaked in cyclohexane.