Compositions, ionogel coatings, and methods of making and using the same

Abstract

The application provides a composition, an ionic gel coating and a preparation method and application thereof, wherein the composition contains fluorine-containing polyamide acid, an ionic liquid, a surfactant and an additive, and the mass ratio of the four is (20-60):(1.5-27):1:(40-60). The composition of the application locks the ionic liquid with low freezing point, non-volatility and chemical stability in the fluorine-containing polyimide with high and low temperature resistance and excellent mechanical properties, and couples the ionic liquid with the surfactant and the additive, so that the material as a whole has high hydrophobicity and transparency, and has multiple functions such as room temperature self-repairing and self-cleaning, and has high adhesion with the surface of a substrate such as stainless steel, and can greatly reduce the ice adhesion strength of the surface and improve the robustness of the low ice adhesion performance of the material in an extremely low temperature environment.

Description

Technical Field

[0001] This application relates to the field of functional materials technology, and in particular to a composition, an ion gel coating, a method for preparing the same, and its application. Background Technology

[0002] Ice formation has a very negative impact on industrial facilities, including transportation, telecommunications, and energy systems, often causing catastrophic safety problems and huge economic losses.

[0003] Current anti-icing / de-icing strategies mainly include two directions: active and passive. Active de-icing mainly includes active melting and de-icing achieved by using traditional chemical agents (ice melters), thermal (steam heating and electric melting), and mechanical force (mechanical vibration). However, this active de-icing strategy is often accompanied by high costs and complex system design, and many methods are considered to be environmentally unfriendly.

[0004] Building on this foundation, zero-energy passive anti-icing / de-icing materials and surfaces have received significant attention over the past decade. Various methods have been employed to construct materials and surfaces capable of repelling water droplets, inhibiting icing, and reducing ice adhesion, thereby preventing icing. These methods primarily include the following three approaches:

[0005] (1) Superhydrophobic structure or coating; In the process of freezing, supercooled droplets first wet the solid surface and then freeze rapidly into ice. In this case, the superhydrophobic surface can be called an ideal anti-icing surface: on the one hand, it can remove supercooled droplets by means of simple tilting of the surface and droplet bouncing away from the surface, reducing the probability of them nucleating on the surface; on the other hand, the heat transfer between the coating surface and the supercooled droplets is significantly suppressed, thereby reducing the freezing temperature and delaying the freezing time. However, most of the current superhydrophobic coatings are brittle, and due to the low adhesion of low surface energy materials, they are easily subjected to various mechanical damages such as peeling, wear, and dynamic impact. Moreover, the preparation process is generally more complicated and cannot meet the strict requirements of industrial applications. In addition, the defect of this interface is that it will form a high-energy solid-liquid interface. At low temperatures, this interface will promote the heterogeneous nucleation of ice, destroy the cavitation in the structure, and thus lead to higher ice adhesion strength. In addition, it has the defects of easy damage to the microstructure and insufficient stability.

[0006] (2) Hygroscopic polymers are used to prepare ice-repellent coatings and hydrogels that are highly hydrated. Their water-containing lubricating layers can significantly reduce the adhesion of ice, thereby inhibiting ice accumulation under wind. However, the preparation process of such coatings or gels is relatively complex and they are easily damaged in humid or other extreme climates.

[0007] (3) Smooth liquid-injected porous surfaces. Researchers have developed a series of smooth porous surfaces and waxy organic gels that incorporate lubricating oil, mimicking the smooth leaves of terrestrial plants such as pitcher plants. These materials can significantly reduce the adhesion of ice, allowing it to be easily separated by gravity or airflow. However, this approach faces challenges. On the one hand, the injected lubricating oil is extremely prone to migration, evaporation, or leakage, making the durability of the liquid-injected smooth surface a challenge. On the other hand, the high cost, susceptibility to damage due to mechanical wear or repeated icing / de-icing cycles, and the need for frequent maintenance and re-lubrication limit its practical application.

[0008] Therefore, developing low-interface toughness material surfaces that are low in preparation cost, simple in preparation process and coupled with multifunctional properties to improve their low-temperature environmental adaptability and long-term durability (e.g., the ability to retain low ice adhesion properties) is an urgent problem to be solved. Summary of the Invention

[0009] In view of this, one object of this application is to provide a composition for ion gel coatings that can lock ionic liquids with low freezing point, non-volatility and chemical stability into fluorinated polyimide with high and low temperature resistance and excellent mechanical properties through various forces such as hydrogen bonding and electrostatic interaction, and couple them with surfactants and additives, so that the material as a whole has high hydrophobicity and transparency, while also having multiple functions such as room temperature self-healing and self-cleaning, and has high adhesion to the surface of substrates (such as Al, GCr15, stainless steel, silicon wafers, glass sheets, etc.), which can greatly reduce the surface ice adhesion strength and improve the robustness of the material's low ice adhesion performance in extreme low temperature environments.

[0010] Another object of this application is to provide a method for preparing the composition.

[0011] Another object of this application is to provide an ion gel coating.

[0012] Another objective of this application is to provide a method for preparing an ion gel coating.

[0013] Another object of this application is to provide the use of an ion gel coating.

[0014] To achieve the above objectives, the first aspect of this application provides a composition comprising a fluorinated polyamic acid, an ionic liquid, a surfactant, and an additive.

[0015] In some embodiments, the mass ratio of the fluorinated polyamic acid, ionic liquid, surfactant and additive is (20-60):(1.5-27):1:(40-60).

[0016] In some embodiments, the fluorinated polyamic acid includes at least one of compounds having the structure shown in Formula 1, the structure shown in Formula 2, and the structure shown in Formula 3:

[0017]

[0018]

[0019] Where a, b, and c represent the number of repeating units in the compounds with the structures shown in Formula 1, Formula 2, and Formula 3, respectively.

[0020] In some embodiments, the number average molecular weight of the compounds with the structures shown in Formula 1, Formula 2, and Formula 3 is 20,000-30,000, including but not limited to 20,000, 22,500, 25,000, 27,500, or 30,000.

[0021] In some embodiments, the viscosity of the fluorinated polyamic acid is 0.1-2 Pa·s.

[0022] In some embodiments, the ionic liquid includes, but is not limited to, at least one of imidazole chloride, imidazole tetrafluoroborate, imidazole bis(trifluoromethanesulfonyl)imide, imidazole trifluoromethanesulfonate, imidazole acetate, imidazole hexafluorophosphate, etc., preferably 1-propyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide.

[0023] In some embodiments, the surfactant includes, but is not limited to, at least one of dodecyl dimethyl ammonium bromide, hexadecyl dimethyl ammonium bromide, 1-dodecyl-2,3-dimethylimidazolium bromide, etc., preferably dodecyl dimethyl ammonium bromide.

[0024] In some embodiments, the additive includes, but is not limited to, at least one of octavinyl-cage polysilsesquioxane, anilinepropyl-cage polysilsesquioxane, dodecylphenyl-cage polysilsesquioxane, etc., preferably anilinepropyl-cage polysilsesquioxane.

[0025] A second aspect of this application discloses a method for preparing a composition, comprising:

[0026] The fluorinated polyamic acid and the ionic liquid are first mixed to obtain a mixed solution;

[0027] The mixed solution, the surfactant, and the additive are mixed a second time to obtain the composition.

[0028] In some embodiments, the method for preparing the composition further includes the step of preparing the fluorinated polyamic acid; the method for preparing the fluorinated polyamic acid includes:

[0029] The fluorinated polyamic acid is obtained by reacting 2,2′-bis(trifluoromethyl)benzidine with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride in an organic solvent.

[0030] In some embodiments, both the first mixing and the second mixing methods include at least one of ultrasonic dispersion, stirring, and grinding.

[0031] A third aspect of this application discloses an ionogel coating comprising the composition described in this application or a composition prepared by the method described in this application; wherein the fluorinated polyamic acid in the composition is cured into a fluorinated polyimide.

[0032] In some embodiments, the fluorinated polyimide comprises at least one of a compound having the structure shown in Formula 4, a compound having the structure shown in Formula 5, and a compound having the structure shown in Formula 6:

[0033]

[0034] Wherein, n, m, and k are the number of repeating units in the compounds with the structures shown in Formula 4, Formula 5, and Formula 6, respectively.

[0035] In some embodiments, the number-average molecular weights of the compounds with the structures shown in Formula 4, Formula 5, and Formula 6 are all between 10,000 and 30,000.

[0036] In some embodiments, the ionogel coating has a water contact angle of 111-121°.

[0037] The fourth aspect of this application discloses a method for preparing an ion gel coating, comprising:

[0038] The composition is dripped or coated onto the surface of a substrate and then dried to obtain the ionogel coating.

[0039] In some embodiments, the method for preparing the ionogel coating further includes a step of allowing the composition to naturally level before drying, when the composition is dropped onto the substrate surface.

[0040] In some embodiments, the method for preparing the ionogel coating further includes a step of surface sandblasting or abrasioning the substrate before the composition is dripped or coated onto the substrate surface.

[0041] In some embodiments, the substrate comprises a material suitable for surface sandblasting.

[0042] In some embodiments, the drying method includes gradient temperature drying under vacuum conditions.

[0043] In some embodiments, the fluorinated polyamic acid is cured into the fluorinated polyimide after drying.

[0044] The fifth aspect of this application relates to the use of the ionogel coating described in this application as an anti-icing surface, or the use of the ionogel coating prepared by the method described in this application as an anti-icing surface.

[0045] The composition described in this application can bring at least the following beneficial effects:

[0046] Ion gel coatings utilize various forces such as hydrogen bonding and electrostatic interactions to lock ionic liquids with low freezing points, non-volatility, and chemical stability into fluorinated polyimides that possess high and low temperature resistance and excellent mechanical properties. Coupled with surfactants and additives, the material exhibits high hydrophobicity and transparency, while also possessing multiple functions such as room temperature self-healing and self-cleaning. Furthermore, it demonstrates strong adhesion to substrates (such as Al, GCr15, stainless steel, silicon wafers, and glass sheets), significantly reducing surface ice adhesion strength and enhancing the robustness of the material's low-ice-adhesion performance in extreme low-temperature environments (e.g., below -60°C, preferably -80°C to -60°C).

[0047] Specifically, the mechanism by which the above-mentioned beneficial effects are achieved is as follows:

[0048] Due to the high electronegativity of fluorine atoms and low intermolecular interactions, hydrogen atoms on the imidazole cations in ionic liquids and the long-chain cations in surfactants such as dodecyl dimethyl ammonium bromide (DDAB) can form hydrogen bonds with fluorine atoms or imide groups on polyimide molecules. The cations and anions of ionic liquids can form strong ion-dipole interactions (electrostatic interactions) with polar groups (such as imide groups) in polyimides. Among these, surfactants such as DDAB interact primarily with ionic liquids through electrostatic interactions (DDAB is a quaternary ammonium salt with a positive charge, while ionic liquids contain negatively charged anions. The electrostatic attraction between positive and negative charges leads to strong electrostatic interactions between DDAB and the anions in the ionic liquid) and ion-dipole interactions. The surfactants DDAB and others interact with each other through various mechanisms, including ion-dipole interactions (the cationic portion of surfactants like DDAB can form ion-dipole interactions with imidazole cations and anions in ionic liquids, enhancing their compatibility) and hydrophobic interactions (surfactants like DDAB possess long-chain alkyl groups, exhibiting significant hydrophobicity. Imidazole cations and anions in ionic liquids also possess some hydrophobicity, particularly the fluorinated groups of the anions. The interaction between these hydrophobic groups helps to form hydrophobic interactions, thereby stabilizing the mixture). These interactions allow surfactants like DDAB to form a stable system in ionic liquids. Additives such as octavinyl-cage polysilsesquioxane (8-POSS) primarily impart excellent and durable hydrophobic properties to the composition through their concentrated siloxy groups on the surface.

[0049] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0050] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings.

[0051] in:

[0052] Figure 1 These are comparative photographs of the ion gel coatings prepared in Examples 4, 1, and 5, wherein:

[0053] a is a photograph of the ion gel coating prepared in Example 4.

[0054] b is a photograph of the ion gel coating prepared in Example 1.

[0055] c is a photograph of the ion gel coating prepared in Example 5.

[0056] Figure 2This is a comparison diagram of the interfacial hydrophobicity of the coatings prepared in Comparative Example 3 and Example 1, where:

[0057] The F_PAA-ILs coating is the coating prepared in Comparative Example 3 (left side);

[0058] The ion gel coating is the coating prepared in Example 1 (right side);

[0059] WCA stands for contact angle.

[0060] Figure 3a This is a schematic diagram of a self-made ice adhesion strength testing device.

[0061] Figure 3b This is a graph showing temperature changes during ice adhesion strength and long-term robustness testing.

[0062] Figure 4 This is a comparison chart showing the anti-ice adhesion strength of the substrates or coatings of Comparative Example 1, Comparative Example 2, and Example 1.

[0063] Figure 5 This is a comparison chart showing the anti-ice adhesion strength of the substrates or coatings of Comparative Examples 7, 8 and 2.

[0064] Figure 6 This is a comparison chart showing the anti-ice adhesion strength of the substrates or coatings of Comparative Examples 9, 10, and 3.

[0065] Figure 7 Comparative figure showing the robustness of the coatings prepared in Example 3 and Example 3 in terms of low ice adhesion performance.

[0066] Figure 8 The image shows the self-healing performance of the ion gel coating prepared in Example 1, wherein:

[0067] d is a magnification of 300x showing the state of the coating surface with scratches;

[0068] e is a diagram showing the repaired state of surface scratches after the coating has been placed at 25°C for 3 hours and magnified 300 times.

[0069] f is a magnification of 500x showing the state of the coating surface with scratches;

[0070] g is a diagram showing the repaired state of surface scratches after the coating has been placed at 25°C for 3 hours and magnified 500 times.

[0071] Figure 9 The image shows the self-cleaning performance of the ion gel coating prepared in Example 1, where:

[0072] h represents the initial state of hydrophilic dust on the coating surface;

[0073] i represents a diagram showing the state of water dripping onto a coating surface with hydrophilic dust.

[0074] j is a diagram showing the cleanliness of a coated surface with hydrophilic dust after water has been dripped on it for a period of time.

[0075] k represents the initial state of hydrophobic dust on the coating surface;

[0076] m is a diagram showing the state of water droplets falling on a coating surface with hydrophobic dust;

[0077] n is a diagram showing the cleanliness of a coated surface with hydrophobic dust after water has been dripped on it for a period of time.

[0078] Figure label:

[0079] 1-Ambient temperature control cabinet; 2-Sample; 3-Ice column model; 4-Stepper push rod; 5-Cooling platform; 6-Drive unit. Detailed Implementation

[0080] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0081] In this application, the disclosure of numerical ranges includes all values ​​throughout the range and the disclosure of further subdivisions of the range, including the endpoints and subranges given for these ranges.

[0082] Unless otherwise specified, all raw materials and equipment involved in this application are self-made through commercial means or known methods; and all methods involved are conventional methods unless otherwise specified.

[0083] <Composition>

[0084] The compositions of the embodiments of this application include fluorinated polyamic acid, ionic liquid, surfactant, and additives.

[0085] In some embodiments, the mass ratio of fluorinated polyamic acid, ionic liquid, surfactant, and additive is (20-60):(1.5-27):1:(40-60). In the embodiments of this application, when the mass ratio of fluorinated polyamic acid, ionic liquid, surfactant, and additive is within the above range, a hydrophobic state with the highest water contact angle can be achieved, while possessing high robustness and low ice adhesion strength; exceeding the above range may lead to a deterioration of the interfacial hydrophobic state and an increase in ice adhesion strength. For example, when the content of ionic liquid is too high, it may lead to the inability to solidify due to the high liquid component (ionic liquid), thus failing to form a usable and testable coating. When the content of ionic liquid is too low, the low liquid component (ionic liquid) may prevent the formation of a coating with low interfacial toughness, i.e., the ice adhesion strength will be significantly increased. When the content of surfactants such as DDAB is too high, the amphiphilic nature of DDAB and other substances leads to a decrease in the contact angle of the coating, failing to achieve a good hydrophobic state. When the content of additives such as 8-POSS is too high, although the interfacial hydrophobicity will be further improved, the ice adhesion strength of the coating will also increase further. When the content of surfactants such as DDAB is too low, the internal ionic liquid cannot be more uniformly distributed within the fluorinated polyamic acid matrix; when the content of additives such as 8-POSS is too low, the contact angle of the coating decreases, failing to achieve a good hydrophobic state.

[0086] In some embodiments, the fluorinated polyamic acid includes at least one of the compounds having the structure shown in Formula 1, the structure shown in Formula 2, and the structure shown in Formula 3:

[0087]

[0088] Where a, b, and c represent the number of repeating units in the compounds with the structures shown in Formula 1, Formula 2, and Formula 3, respectively.

[0089] In some embodiments, the number average molecular weight of the compounds with the structures shown in Formula 1, Formula 2, and Formula 3 is 20,000-30,000, including but not limited to 20,000, 22,500, 25,000, 27,500, or 30,000.

[0090] It should be noted that the compounds with the structure shown in Formula 1 above correspond to the case of Example 1 below, the compounds with the structure shown in Formula 2 above correspond to the case of Example 2 below, and the compounds with the structure shown in Formula 3 above correspond to the cases of Example 3 and Example 10 below.

[0091] In some embodiments, the viscosity of the fluorinated polyamic acid is 0.1-2 Pa·s, including but not limited to 0.1 Pa·s, 0.5 Pa·s, 1 Pa·s, 1.5 Pa·s or 2 Pa·s.

[0092] In some embodiments, the fluorinated polyamic acid exists in the form of a fluorinated polyamic acid solution.

[0093] For example, the solid content of the fluorinated polyamic acid solution is 15-20 wt%, and the solvent includes, but is not limited to, at least one of dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP).

[0094] In some embodiments, the ionic liquid includes, but is not limited to, at least one of imidazole chloride, imidazole tetrafluoroborate, imidazole bis(trifluoromethanesulfonyl)imide, imidazole trifluoromethanesulfonate (CAS: 29727-06-8), imidazole acetate, and imidazole hexafluorophosphate.

[0095] For example, imidazole chloride salts include, but are not limited to, at least one of 1-ethyl-2,3-dimethylimidazolium chloride (CAS: 92507-97-6), 1-octyl-3-methylimidazolium chloride (CAS: 64697-40-1), 1-butyl-3-methylimidazolium chloride (CAS: 79917-90-1), 1-ethyl-3-methylimidazolium chloride (CAS: 65039-09-0), or 1-dodecyl-3-methylimidazolium chloride (CAS: 114569-84-5).

[0096] For example, imidazole tetrafluoroborate includes, but is not limited to, at least one of 1-propyl-3-methylimidazolium tetrafluoroborate (CAS: 244193-48-4), 1-butyl-3-methylimidazolium tetrafluoroborate (CAS: 174501-65-6), 1-ethyl-3-methylimidazolium tetrafluoroborate (CAS: 143314-16-3), 1-methylimidazolium tetrafluoroborate (CAS: 151200-14-5), or 1-octyl-3-methylimidazolium tetrafluoroborate (CAS: 244193-52-0).

[0097] For example, imidazole bis(trifluoromethanesulfonyl)imine salts include, but are not limited to, at least one of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-83-3), 1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-82-2), 1-octyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 862731-66-6), 1-propyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 216299-72-8), or 1-ethyl-2,3-dimethylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-90-2).

[0098] For example, imidazole acetate includes, but is not limited to, at least one of 1-ethyl-3-methylimidazolium acetate (CAS: 143314-17-4), 1-butyl-3-methylimidazolium acetate (CAS: 284049-75-8), 1-octyl-3-methylimidazolium acetate (CAS: 366491-21-6), 1-methylimidazolium acetate (CAS: 616-47-7), or 1-propyl-3-methylimidazolium acetate (CAS: 1005328-08-4).

[0099] For example, imidazole hexafluorophosphate includes, but is not limited to, at least one of 1-methylimidazolium hexafluorophosphate (CAS: 57367-08-5), 1-ethyl-3-methylimidazolium hexafluorophosphate (CAS: 155371-19-0), 1-propyl-3-methylimidazolium hexafluorophosphate (CAS: 216300-12-8), 1-butyl-3-methylimidazolium hexafluorophosphate (CAS: 174501-64-5), or 1-octyl-3-methylimidazolium hexafluorophosphate (CAS: 304680-36-2).

[0100] As a preferred example, the ionic liquid is 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]).

[0101] In some embodiments, the surfactant includes, but is not limited to, at least one of dodecyl dimethyl ammonium bromide, hexadecyl dimethyl ammonium bromide, 1-dodecyl-2,3-dimethylimidazolium bromide, etc.

[0102] As a preferred example, the surfactant is dodecyl dimethyl ammonium bromide.

[0103] In some embodiments, the additives include, but are not limited to, at least one of octavinyl-cage polysilsesquioxane (8-POSS), anilinepropyl cage polysilsesquioxane (N-POSS), and dodecylphenyl cage polysilsesquioxane (N12-POSS).

[0104] As a preferred example, the additive is aniline propyl cage-type polysilsesquioxane (N-POSS), more preferably aniline propyl cage-type polysilsesquioxane (N-POSS) with a particle size of 1-3 nm.

[0105] The compositions of the embodiments of this application can bring at least the following beneficial effects:

[0106] Ion gel coatings utilize various forces such as hydrogen bonding and electrostatic interactions to lock ionic liquids with low freezing points, non-volatility, and chemical stability into fluorinated polyimides that possess high and low temperature resistance and excellent mechanical properties. Coupled with surfactants and additives, the material exhibits high hydrophobicity and transparency, while also possessing multiple functions such as room temperature self-healing and self-cleaning. Furthermore, it demonstrates strong adhesion to substrates (such as Al, GCr15, stainless steel, silicon wafers, and glass sheets), significantly reducing surface ice adhesion strength and enhancing the robustness of the material's low-ice-adhesion performance in extreme low-temperature environments (e.g., below -60°C, preferably -80°C to -60°C).

[0107] <Preparation method of the composition>

[0108] The preparation method of the composition in the embodiments of this application can be used to prepare the composition in the embodiments of this application.

[0109] The preparation method of the composition in the embodiments of this application includes the following steps:

[0110] S101. Fluorinated polyamic acid and ionic liquid are mixed for the first time to obtain a mixed solution (F_PAA-ILs).

[0111] In some embodiments, the mixing mass ratio of fluorinated polyamic acid and ionic liquid is (20-60):(1.5-27), that is, the amount of ionic liquid used is 7.5-45 wt.% of fluorinated polyamic acid.

[0112] For example, the amount of ionic liquid used is 7.5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, or 45 wt.% of fluorinated polyamic acid.

[0113] In some embodiments, the fluorinated polyamic acid includes at least one of the compounds having the structure shown in Formula 1, the structure shown in Formula 2, and the structure shown in Formula 3:

[0114]

[0115] Where a, b, and c represent the number of repeating units in the compounds with the structures shown in Formula 1, Formula 2, and Formula 3, respectively.

[0116] In some embodiments, the number average molecular weight of the compounds with the structures shown in Formula 1, Formula 2, and Formula 3 is 20,000-30,000, including but not limited to 20,000, 22,500, 25,000, 27,500, or 30,000.

[0117] It should be noted that the compounds with the structure shown in Formula 1 above correspond to the case of Example 1 below, the compounds with the structure shown in Formula 2 above correspond to the case of Example 2 below, and the compounds with the structure shown in Formula 3 above correspond to the cases of Example 3 and Example 10 below.

[0118] In some embodiments, the viscosity of the fluorinated polyamic acid is 0.1-2 Pa·s, including but not limited to 0.1 Pa·s, 0.5 Pa·s, 1 Pa·s, 1.5 Pa·s or 2 Pa·s.

[0119] In some embodiments, the ionic liquid includes, but is not limited to, at least one of imidazole chloride, imidazole tetrafluoroborate, imidazole bis(trifluoromethanesulfonyl)imide, imidazole trifluoromethanesulfonate (CAS: 29727-06-8), imidazole acetate, and imidazole hexafluorophosphate.

[0120] For example, imidazole chloride salts include, but are not limited to, at least one of 1-ethyl-2,3-dimethylimidazolium chloride (CAS: 92507-97-6), 1-octyl-3-methylimidazolium chloride (CAS: 64697-40-1), 1-butyl-3-methylimidazolium chloride (CAS: 79917-90-1), 1-ethyl-3-methylimidazolium chloride (CAS: 65039-09-0), or 1-dodecyl-3-methylimidazolium chloride (CAS: 114569-84-5).

[0121] For example, imidazole tetrafluoroborate includes, but is not limited to, at least one of 1-propyl-3-methylimidazolium tetrafluoroborate (CAS: 244193-48-4), 1-butyl-3-methylimidazolium tetrafluoroborate (CAS: 174501-65-6), 1-ethyl-3-methylimidazolium tetrafluoroborate (CAS: 143314-16-3), 1-methylimidazolium tetrafluoroborate (CAS: 151200-14-5), or 1-octyl-3-methylimidazolium tetrafluoroborate (CAS: 244193-52-0).

[0122] For example, imidazole bis(trifluoromethanesulfonyl)imine salts include, but are not limited to, at least one of 1-butyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-83-3), 1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-82-2), 1-octyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 862731-66-6), 1-propyl-3-methylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 216299-72-8), or 1-ethyl-2,3-dimethylimidazole bis(trifluoromethanesulfonyl)imine salt (CAS: 174899-90-2).

[0123] For example, imidazole acetate includes, but is not limited to, at least one of 1-ethyl-3-methylimidazolium acetate (CAS: 143314-17-4), 1-butyl-3-methylimidazolium acetate (CAS: 284049-75-8), 1-octyl-3-methylimidazolium acetate (CAS: 366491-21-6), 1-methylimidazolium acetate (CAS: 616-47-7), or 1-propyl-3-methylimidazolium acetate (CAS: 1005328-08-4).

[0124] For example, imidazole hexafluorophosphate includes, but is not limited to, at least one of 1-methylimidazolium hexafluorophosphate (CAS: 57367-08-5), 1-ethyl-3-methylimidazolium hexafluorophosphate (CAS: 155371-19-0), 1-propyl-3-methylimidazolium hexafluorophosphate (CAS: 216300-12-8), 1-butyl-3-methylimidazolium hexafluorophosphate (CAS: 174501-64-5), or 1-octyl-3-methylimidazolium hexafluorophosphate (CAS: 304680-36-2).

[0125] As a preferred example, the ionic liquid is 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]).

[0126] For example, the first mixing of fluorinated polyamic acid and ionic liquid includes, but is not limited to, at least one of stirring, ultrasonic dispersion, grinding, etc.

[0127] It should be noted that in the embodiments of this application, the fluorinated polyamic acid can be a commercially available product or can be self-made.

[0128] When fluorinated polyamic acid needs to be prepared in-house, the preparation method of the composition in this application embodiment further includes the step of preparing fluorinated polyamic acid.

[0129] For example, the preparation methods of fluorinated polyamic acid include, but are not limited to, the following two methods: Method 1 and Method 2.

[0130] [Method 1]

[0131] A method for preparing fluorinated polyamic acid includes the following steps:

[0132] 2,2′-bis(trifluoromethyl)benzidine (TFDB) and 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) were reacted in an organic solvent to obtain fluorinated polyamic acid (F-PAA).

[0133] In some embodiments, the mass ratio of 2,2′-bis(trifluoromethyl)benzidine to 4,4′-(hexafluoroisopropylidene)phthalic anhydride is (0.64-0.96):(0.56-0.84), including but not limited to 0.64:0.6, 0.64:0.7, 0.64:0.8, 0.96:0.7, 0.96:0.8, 0.8:0.7, or 0.8:0.84.

[0134] As an alternative example, the mass ratio of 2,2′-bis(trifluoromethyl)benzidine to 4,4′-(hexafluoroisopropylidene)diphthalic anhydride is 8:7.

[0135] In some embodiments, the amount of organic solvent used is generally 20-28 mL of organic solvent per gram of 2,2′-bis(trifluoromethyl)benzidine.

[0136] In some embodiments, the organic solvent includes, but is not limited to, at least one of dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP).

[0137] In some implementations, the reaction is carried out under stirred conditions, and the stirring speed is not limited.

[0138] In some embodiments, the reaction temperature is between -5°C and 0°C, including but not limited to -5°C, -4°C, -3°C, -2°C, -1°C, or 0°C.

[0139] In some implementations, the reaction time is 2-6 hours, including but not limited to 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours.

[0140] As an alternative example, the reaction temperature is -5°C and the reaction time is 4 hours.

[0141] As a preferred example, a method for preparing fluorinated polyamic acid includes the following steps:

[0142] (1) Add the above organic solvent to 2,2′-bis(trifluoromethyl)benzidine (TFDB) and stir until the solid powder is completely dissolved to obtain solution A.

[0143] (2) Add 4,4′-(hexafluoroisopropylidene) phthalic anhydride (6FDA) to solution A and stir continuously. When the solution begins to adhere and rise, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0144] In some implementations, the standard for observing the increase in solution adhesion in step (2) is a viscosity greater than Q Pa·s, where Q is 0.5-1.2, including but not limited to 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1 or 1.2.

[0145] As an alternative example, the standard for observing an increase in solution adhesion in step (2) is a viscosity greater than 0.5 Pa·s.

[0146] [Method Two]

[0147] In the embodiments of this application, the preparation method of fluorinated polyamic acid in Method 2 is basically the same as that in Method 1, except that: 4,4′-(hexafluoroisopropylidene) phthalic anhydride (6FDA) in Method 1 is replaced with biphenyltetraic dianhydride (BPDA), and 2,2′-bis(trifluoromethyl)benzidine (TFDB) in Method 1 is replaced with 4,4′-(trifluoromethyl)benzidinediamine (TFMB). At the same time, the order and ratio of addition of 4,4′-(trifluoromethyl)benzidinediamine (TFMB) and biphenyltetraic dianhydride (BPDA) are changed.

[0148] In some embodiments, the mass ratio of biphenyltetracarboxylic dianhydride (BPDA) to 4,4'-(trifluoromethyl)benzyldiamine (TFMB) is 1:(0.7-0.9), including but not limited to 1:0.7, 1:0.8 or 1:0.9, preferably 1:0.8.

[0149] For example, the preparation method of fluorinated polyamic acid in Method 2 includes the following steps:

[0150] 1) Add biphenyltetracarboxylic dianhydride (BPDA) to the organic solvent and stir continuously until the solid powder is completely dissolved to obtain solution B.

[0151] 2) Add 4,4'-(trifluoromethyl)benzidine (TFMB) to solution B and stir continuously. When the solution begins to adhere and rise, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0152] S102. The mixed solution obtained in step S101, surfactant, and additive are mixed a second time to obtain a composition.

[0153] In some embodiments, the mass ratio of fluorinated polyamic acid, ionic liquid, surfactant, and additive is (20-60):(1.5-27):1:(40-60).

[0154] In some embodiments, the mass ratio of fluorinated polyamic acid to surfactant is 20:1 to 60:1, including but not limited to 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1 or 60:1.

[0155] In some embodiments, the mass ratio of fluorinated polyamic acid to additives is 40:1 to 60:1, including but not limited to 40:1, 45:1, 50:1, 55:1 or 60:1.

[0156] In some embodiments, the surfactant includes, but is not limited to, at least one of dodecyl dimethyl ammonium bromide, hexadecyl dimethyl ammonium bromide, 1-dodecyl-2,3-dimethylimidazolium bromide, etc.

[0157] As a preferred example, the surfactant is dodecyl dimethyl ammonium bromide.

[0158] In some embodiments, the additive includes at least one of octavinyl-cage polysilsesquioxane (8-POSS, also known as octavinylsilylsilsesquioxane (CAS: 69655-76-1)), anilinepropyl cage polysilsesquioxane (N-POSS, also known as anilinepropyl cage polysilsesquioxane (CAS: 1708993-28-5)), and dodecylphenyl cage polysilsesquioxane (N12-POSS, CAS: 18923-59-6).

[0159] As a preferred example, the additive is aniline propyl cage-type polysilsesquioxane (N-POSS), more preferably aniline propyl cage-type polysilsesquioxane (N-POSS) with a particle size of 1-3 nm.

[0160] In some embodiments, the second mixing method includes, but is not limited to, at least one of ultrasonic dispersion, stirring, grinding, etc.

[0161] As an alternative example, the second mixing method is ultrasonic dispersion.

[0162] In some implementations, the ultrasonic dispersion time is 2-4 hours, including but not limited to 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours.

[0163] In some embodiments, the frequency of ultrasonic dispersion is 20-30 kHz, including but not limited to 20 kHz, 22.5 kHz, 25 kHz, 27.5 kHz or 30 kHz.

[0164] As an optional example, step S102 above is: adding surfactant and additive sequentially to the mixed solution obtained in step S101, and ultrasonically dispersing to obtain a colloidal liquid, i.e., a composition.

[0165] <Ion gel coating>

[0166] The ionogel coating of the embodiments of this application includes the composition of the embodiments of this application, or the composition prepared by the preparation method of the composition of the embodiments of this application; the fluorinated polyamic acid in the composition is cured into fluorinated polyimide.

[0167] In some embodiments, the fluorinated polyimide includes at least one of the compounds having the structure shown in Formula 4, the structure shown in Formula 5, and the structure shown in Formula 6:

[0168]

[0169] Wherein, n, m, and k are the number of repeating units in the compounds with the structures shown in Formula 4, Formula 5, and Formula 6, respectively.

[0170] In some embodiments, the number average molecular weights of the compounds with the structures shown in Formula 4, Formula 5, and Formula 6 are all between 10,000 and 30,000, including but not limited to 10,000, 15,000, 20,000, 25,000, or 30,000.

[0171] It should be noted that, in the embodiments of this application, the compound with the structure shown in Formula 4 is the product of the compound with the structure shown in Formula 1 after curing, the compound with the structure shown in Formula 5 is the product of the compound with the structure shown in Formula 2 after curing, and the compound with the structure shown in Formula 6 is the product of the compound with the structure shown in Formula 3 after curing.

[0172] In some embodiments, the contact angle of the ionogel coating with water is 111-121°, including but not limited to 111°, 112°, 113°, 114°, 115°, 117°, 119° or 121°.

[0173] In some embodiments, the transparency of the ionogel coating is 80-95%, including but not limited to 80%, 82.5%, 85%, 87.5%, 90%, 92.5%, or 95%.

[0174] It should be noted that in the embodiments of this application, the ionogel coating cannot be cured and formed if there is no fluorinated polyamic acid.

[0175] The ionogel coating of this application combines the low-temperature stability of fluorinated polyimide and ionic liquid, giving the coating a lubricating effect, low freezing point, and low interfacial toughness. This allows for a significant reduction in surface ice adhesion strength and the maintenance of durable low ice adhesion performance even in extreme low-temperature environments (e.g., below -60°C, preferably -80°C to -60°C). Furthermore, the coating possesses multifunctional properties such as high transparency, room-temperature self-healing, and self-cleaning, which further enhances the environmental adaptability of the ionogel coating.

[0176] <Preparation Method of Ion Gel Coating>

[0177] The method for preparing the ionogel coating of this application embodiment can be used to prepare the ionogel coating of this application embodiment.

[0178] The method for preparing the ion gel coating according to the embodiments of this application includes the following steps:

[0179] The composition is dripped or coated onto the surface of a substrate and then dried to obtain an ionogel coating.

[0180] It should be noted that the above-mentioned compositions are compositions of the embodiments of this application, or compositions prepared by the preparation method of the compositions of the embodiments of this application.

[0181] In some embodiments, the method for preparing an ionogel coating further includes a step of allowing the composition to flow naturally before drying when the composition is dropped onto a substrate surface.

[0182] In some embodiments, the substrate comprises a material suitable for surface sandblasting.

[0183] For example, the substrate includes, but is not limited to, at least one of fiberglass sheets, Al sheets, GCr15, 304 stainless steel, silicon wafers, etc.

[0184] As a preferred example, fiberglass sheets are used as the substrate.

[0185] In some embodiments, the method for preparing the ion gel coating of this application further includes a step of surface sandblasting or abrasioning the substrate before the composition is dripped or coated onto the substrate surface.

[0186] In the embodiments of this application, surface sandblasting or grinding of the substrate can ensure that the surface roughness of the substrate is on the order of 1-3 μm, which improves the adhesion of the coating to the substrate, but has little impact on the properties of the coating surface itself.

[0187] In some implementations, the drying method includes gradient temperature drying under vacuum conditions.

[0188] As an alternative example, the drying method is gradient temperature drying under vacuum conditions.

[0189] For example, the gradient temperature drying under the above vacuum conditions includes: in a vacuum drying oven, controlling the vacuum degree to be less than 0.06 MPa, maintaining a constant temperature of 40-50℃ for 0.3-0.8 h, then maintaining a constant temperature of 70-90℃ for 0.8-1.2 h, then maintaining a constant temperature of 110-130℃ for 0.8-1.2 h, then maintaining a constant temperature of 140-160℃ for 0.8-1.2 h, and finally maintaining a constant temperature of 170-190℃ for 0.8-1.2 h.

[0190] In the embodiments of this application, the drying method adopts gradient heating drying under vacuum conditions, which can ensure the smooth progress of the dehydration condensation process of fluorinated polyamic acid and the solvent evaporation process, and ensure that the surface of the obtained coating is smooth and free of bubbles.

[0191] In some embodiments, the fluorinated polyamic acid is cured into the above-mentioned fluorinated polyimide after drying.

[0192] The method for preparing the ion gel coating in this application mainly locks the ion liquid in fluorinated polyimide through various forces such as hydrogen bonding and electrostatic interaction, and couples it with it through various surfactants and additives. This enables the controllable preparation of a hydrophobic ion gel coating with high adhesion on the surface of commonly used substrates (such as Al, GCr15, stainless steel, silicon wafers, glass sheets, etc.). The coating has multifunctional properties such as high transparency, room temperature self-healing, and self-cleaning. It can significantly reduce the ice adhesion strength of the surface and improve the robustness of the coating's low ice adhesion performance in extreme low temperature environments (e.g., below -60°C, preferably -80°C to -60°C).

[0193] <Applications of Iongel Coatings>

[0194] The ion gel coating prepared by the method of preparing the ion gel coating in the embodiments of this application can be used as an anti-icing surface for industrial facilities including but not limited to transportation systems, telecommunications systems, and energy systems.

[0195] For example, the aforementioned anti-icing surfaces include, but are not limited to, aircraft wings, ship decks, wind turbine blades, vehicle windows, windshields, and winter roads.

[0196] The following non-limiting embodiments further illustrate certain features of the present technology.

[0197] I. Examples and Comparative Examples

[0198] Example 1

[0199] (Composition preparation method)

[0200] The preparation method of the composition in this embodiment includes the following steps:

[0201] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0202] (2) Add 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) at a mass ratio of 20 wt.% of F_PAA to the F_PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F_PAA-ILs mixed solution.

[0203] (3) Add DDAB to the F_PAA-ILs solution obtained in step (2) at a mass ratio of F_PAA to surfactant dodecyl dimethyl ammonium bromide (DDAB) of 40:1. Further add aniline propyl cage-type polysilsesquioxane (N-POSS) to the resulting solution at a mass ratio of F_PAA to additive N-POSS of 40:1. Sonicate for 3 hours to disperse it evenly into a colloidal liquid. The frequency of the sonication treatment is 20 kHz. A mixed solution of F_PAA-ILs containing surfactant and additive is obtained, which is the composition of this embodiment.

[0204] (Preparation method of ionogel coating)

[0205] The method for preparing the ion gel coating in this embodiment includes the following steps:

[0206] Step 1: Select a fiberglass sheet with dimensions of 1.5cm×1.5cm×1mm as the substrate, and perform a frosting treatment on the surface of the substrate to give the surface a roughness of about 3μm.

[0207] Step 2: Drop 0.5g of the composition of this embodiment onto the surface of the substrate treated with sanding in Step 1, allowing it to level naturally. Then place it in a vacuum drying oven with gradient temperature: control the vacuum degree at 0.03MPa, maintain the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the ionogel coating of this embodiment (e.g., Figure 2 (As shown).

[0208] Example 2

[0209] (Composition preparation method)

[0210] The preparation method of the composition in this embodiment includes the following steps:

[0211] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 30mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 300r / min at -3℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0212] (2) Add 30 wt.% of 1-propyl-3-methylimidazolium tetrafluoroborate to the F-PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F-PAA-ILs mixed solution.

[0213] (3) C12MMImBr was added to the F_PAA-ILs solution obtained in step (2) at a mass ratio of 20:1 for F_PAA to surfactant 1-dodecyl-2,3-dimethylimidazolium bromide (C12MMImBr). 8-POSS was then added to the resulting solution at a mass ratio of 60:1 for F_PAA to additive octavinyl-cage polysilsesquioxane (8-POSS). The solution was then sonicated for 2 hours to disperse it evenly into a colloidal liquid. The sonication frequency was 20 kHz. This yielded a mixed solution of F_PAA-ILs containing surfactant and additive, which is the composition of this embodiment.

[0214] (Preparation method of ionogel coating)

[0215] The method for preparing the ion gel coating in this embodiment includes the following steps:

[0216] Step 1: Select a mirror Al sheet with dimensions of 1.5cm×1.5cm×1mm as the substrate, and perform a sanding treatment on the surface of the substrate to give the surface a roughness of about 5μm.

[0217] Step 2: Drop 0.6g of the composition of this embodiment onto the surface of the substrate after the sanding treatment in Step 1, allowing it to flow naturally and then place it in a vacuum drying oven with gradient temperature: control the vacuum degree to 0.04MPa, maintain the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the ion gel coating of this embodiment.

[0218] Example 3

[0219] (Composition preparation method)

[0220] The preparation method of the composition in this embodiment includes the following steps:

[0221] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir at 0℃ until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 400r / min for 3h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0222] (2) Add 45 wt.% of the ionic liquid 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) to the F_PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F_PAA-ILs mixed solution.

[0223] (3) Add DDAB to the F_PAA-ILs solution obtained in step (2) at a mass ratio of F_PAA to surfactant dodecyl dimethyl ammonium bromide (DDAB) of 40:1. Further add dodecylphenyl cage-type polysilsesquioxane (N12-POSS) to the resulting solution at a mass ratio of F_PAA to additive N12-POSS of 40:1. Sonicate for 4 hours to disperse it evenly into a colloidal liquid. The frequency of the sonication treatment is 20 kHz. A mixed solution of F_PAA-ILs containing surfactant and additive is obtained, which is the composition of this embodiment.

[0224] (Preparation method of ionogel coating)

[0225] The method for preparing the ion gel coating in this embodiment includes the following steps:

[0226] Step 1: Select a silicon wafer with dimensions of 1.5cm×1.5cm×1mm as the substrate, and perform a sandblasting treatment on the surface of the substrate to give the surface a roughness of about 2μm.

[0227] Step 2: Drop 0.7g of the composition of this embodiment onto the surface of the substrate after the sanding treatment in Step 1, allowing it to flow naturally and then place it in a vacuum drying oven with gradient temperature: control the vacuum degree at 0.05MPa, maintain the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the ion gel coating of this embodiment (as shown in Figure 3).

[0228] Example 4 (Lower limit of ionic liquid dosage, other details are the same as in Example 1)

[0229] This embodiment is basically the same as embodiment 1, except that:

[0230] In step (2), the amount of 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) added is 7.5% of the mass of F-PAA.

[0231] The ion gel coating of this embodiment was prepared as follows: Figure 1 As shown.

[0232] Example 5 (Upper limit of ionic liquid dosage, other details are the same as in Example 1)

[0233] This embodiment is basically the same as embodiment 1, except that:

[0234] In step (2), the amount of 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) added is 45% of the mass of F_PAA.

[0235] The ion gel coating obtained in this embodiment is shown in Figure 3.

[0236] Example 6 (lower limit of surfactant dosage, other details are the same as in Example 1)

[0237] This embodiment is basically the same as embodiment 1, except that:

[0238] In step (3), DDAB is added to the F_PAA-ILs solution obtained in step (2) at a mass ratio of 20:1 between F_PAA and the surfactant dodecyl dimethyl ammonium bromide (DDAB).

[0239] Example 7 (Upper limit of surfactant dosage, other details are the same as in Example 1)

[0240] This embodiment is basically the same as embodiment 1, except that:

[0241] In step (3), DDAB is added to the F_PAA-ILs solution obtained in step (2) at a mass ratio of 60:1 between F_PAA and the surfactant dodecyl dimethyl ammonium bromide (DDAB).

[0242] Example 8 (Intermediate Additive Dosage)

[0243] This embodiment is basically the same as embodiment 1, except that:

[0244] In step (3), aniline propyl cage-type polysilsesquioxane (N-POSS) is further added to the obtained solution at a mass ratio of F_PAA to additive N-POSS of 50:1.

[0245] Example 9 (Upper Limit of Additive Usage)

[0246] This embodiment is basically the same as embodiment 1, except that:

[0247] In step (3), aniline propyl cage-type polysilsesquioxane (N-POSS) is further added to the obtained solution at a mass ratio of F_PAA to additive N-POSS of 60:1.

[0248] Example 10 (The fluorinated polyamic acid differs from Example 1, but is otherwise the same as Example 1)

[0249] This embodiment is basically the same as embodiment 1, except that:

[0250] Step (1) is as follows: Weigh 1.0g of biphenyltetracarboxylic dianhydride (BPDA) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.8g of 4,4'-(trifluoromethyl)benzidine (TFMB) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0251] Comparative Example 1

[0252] This comparative example is the fiberglass sheet with dimensions of 1.5cm × 1.5cm × 1mm without frosting treatment, as described in Example 1.

[0253] Comparative Example 2 (The coating of Example 1 does not contain ionic liquids, surfactants, or additives)

[0254] The preparation method of the coating in this comparative example includes the following steps:

[0255] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0256] (2) Select a fiberglass sheet with a size of 1.5cm×1.5cm×1mm as the substrate and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 3μm.

[0257] (3) Drop 0.5g of F_PAA obtained in step (1) onto the surface of the substrate after sanding in step (2) and let it flow naturally. Then place it in a vacuum drying oven with gradient temperature: control the vacuum degree to 0.03MPa, keep the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the coating of this comparative example (fiberglass sheet-F_PAA coating).

[0258] Comparative Example 3 (The coating of Example 1 does not contain surfactants or additives)

[0259] The preparation method of the coating in this comparative example includes the following steps:

[0260] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0261] (2) Add 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) at a mass ratio of 20 wt.% of F_PAA to the F_PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F_PAA-ILs mixed solution.

[0262] (3) Select a fiberglass sheet with a size of 1.5cm×1.5cm×1mm as the substrate and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 3μm.

[0263] (4) Drop 0.5g of the F_PAA-ILs mixed solution obtained in step (2) onto the surface of the substrate after the sanding treatment in step (3) and let it flow naturally. Then place it in a vacuum drying oven with gradient temperature: control the vacuum degree to 0.03MPa, keep the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the coating (F_PAA-ILs coating) of this comparative example.

[0264] Comparative Example 4 (The coating of Example 1 does not contain additives)

[0265] The preparation method of the coating in this comparative example includes the following steps:

[0266] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0267] (2) Add 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) at a mass ratio of 20 wt.% of F_PAA to the F_PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F_PAA-ILs mixed solution.

[0268] (3) Add DDAB to the F_PAA-ILs solution obtained in step (2) at a mass ratio of 40:1 for F_PAA to surfactant dodecyl dimethyl ammonium bromide (DDAB), and sonicate for 3 hours to disperse it evenly into a colloidal liquid. The sonication frequency is 20 kHz to obtain a mixed solution of F_PAA-ILs containing surfactant.

[0269] (4) Select a fiberglass sheet with dimensions of 1.5cm×1.5cm×1mm as the substrate and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 3μm.

[0270] (5) Drop 0.5g of the F_PAA-ILs mixed solution containing surfactant obtained in step (3) onto the surface of the substrate after the sanding treatment in step (4), let it flow naturally, and then put it into a vacuum drying oven with gradient temperature: control the vacuum degree to 0.03MPa, keep the temperature at 50℃ for 0.5h, at 80℃ for 1h, at 120℃ for 1h, at 150℃ for 1h, and at 180℃ for 1h to obtain the coating of this comparative example (F_PAA-ILs coating containing surfactant).

[0271] Comparative Example 5 (The coating of Example 1 does not contain surfactants)

[0272] The preparation method of the coating in this comparative example includes the following steps:

[0273] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 200r / min at -5℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0274] (2) Add 1-propyl-3-methylimidazolium di(trifluoromethylsulfonyl)imide ([C3mim][NTf2]) at a mass ratio of 20 wt.% of F_PAA to the F_PAA obtained in step (1), and stir at 100 r / min for 15 min until the solution is completely mixed to obtain the F_PAA-ILs mixed solution.

[0275] (3) Add aniline propyl cage-type polysilsesquioxane (N-POSS) to the F_PAA-ILs solution obtained in step (2) at a mass ratio of F_PAA to additive N-POSS of 40:1, and sonicate for 3 hours to disperse it evenly into a colloidal liquid. The sonication frequency is 20 kHz to obtain a mixed solution of F_PAA-ILs containing additive.

[0276] (4) Select a fiberglass sheet with dimensions of 1.5cm×1.5cm×1mm as the substrate and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 3μm.

[0277] (5) Drop 0.5g of the F_PAA-ILs mixed solution containing additives obtained in step (3) onto the surface of the substrate after the sanding treatment in step (4), let it flow naturally, and then put it into a vacuum drying oven with gradient temperature: control the vacuum degree to 0.03MPa, keep the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the coating of this comparative example (F_PAA-ILs coating containing surfactant).

[0278] Comparative Example 7

[0279] This comparative example is a mirror Al sheet with dimensions of 1.5cm × 1.5cm × 1mm that has only undergone frosting treatment in Example 2, referred to as the Al sheet.

[0280] Comparative Example 8 (The coating of Example 2 does not contain ionic liquids, surfactants, or additives)

[0281] The preparation method of the coating in this comparative example includes the following steps:

[0282] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 30mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 300r / min at -3℃ for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0283] (2) Select a mirror Al sheet with a size of 1.5cm×1.5cm×1mm as the substrate, and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 5μm.

[0284] (3) Drop 0.6g of F_PAA obtained in step (1) onto the surface of the substrate after sanding in step (2) and let it flow naturally. Then place it in a vacuum drying oven with gradient temperature: control the vacuum degree to 0.04MPa, keep the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the coating (Al sheet-F_PAA) of this comparative example.

[0285] Comparative Example 9

[0286] This comparative example is a silicon wafer with dimensions of 1.5cm × 1.5cm × 1mm that has only undergone sanding treatment in Example 3.

[0287] Comparative Example 10 (The coating of Example 3 does not contain ionic liquids, surfactants, or additives)

[0288] The preparation method of the coating in this comparative example includes the following steps:

[0289] (1) Weigh 0.8g of 2,2′-bis(trifluoromethyl)benzidine (TFDB) and add it to a three-necked beaker. Then add 20mL of dimethylacetamide (DMAc) and stir until the solid powder is completely dissolved. Then add 0.7g of 4,4′-(hexafluoroisopropylidene)phthalic anhydride (6FDA) and stir continuously at 0℃ and 400r / min for 4h. When the viscosity of the solution starts to rise to 0.5Pa·s, stop stirring to obtain a viscous solution of fluorinated polyamic acid (F_PAA).

[0290] (2) Select a silicon wafer with a size of 1.5cm×1.5cm×1mm as the substrate and perform a sanding treatment on the surface of the substrate to give the surface of the substrate a roughness of about 2μm.

[0291] (3) Drop 0.7g of F_PAA obtained in step (1) onto the surface of the substrate after the sanding treatment in step (2), let it flow naturally, and then put it into a vacuum drying oven with gradient temperature: control the vacuum degree to 0.05MPa, keep the temperature at 50℃ for 0.5h, 80℃ for 1h, 120℃ for 1h, 150℃ for 1h, and 180℃ for 1h to obtain the coating of this comparative example (silicon wafer-F_PAA coating).

[0292] II. Performance Testing

[0293] 1. Testing Method

[0294] (1) Contact angle test

[0295] The contact angles of the coatings or substrates of each embodiment or comparative example (comparative examples 1, 7, and 9 are substrates, and all embodiments and other comparative examples are coatings) were measured using a contact angle measuring instrument.

[0296] (2) Ice adhesion strength

[0297] Adopting such Figure 3a The homemade ice adhesion strength test device shown is used to test the ice adhesion strength.

[0298] like Figure 3aAs shown, a self-made ice adhesion strength testing device includes an ambient temperature control cabinet 1, an icing column model 3, a stepper rod 4, and a force sensor. An ambient temperature controller is installed on the ambient temperature control cabinet 1, and a cooling platform 5 is located at the bottom of the cabinet. A cooling platform temperature controller for controlling the temperature of the cooling platform is also installed at the bottom of the cabinet 1. The icing column model 3 is a tubular structure (inner diameter 1cm, height 5mm). One end of the force sensor can contact the icing column model 3, and the other end is connected to the stepper rod 4, which is the piston rod of the drive unit 6. The drive unit 6 is mounted on the cooling platform 5 and can be a pneumatic cylinder, an electric cylinder, or a hydraulic cylinder.

[0299] During the test, the cooling platform temperature was controlled at -25℃, and the ambient temperature control cabinet temperature was set at -10℃. Sample 2 was placed on the upper surface of the cooling platform 5 inside the ambient temperature control cabinet. The icy ice column model 3 was placed on the upper surface of the sample away from the cooling platform 5, with the axis of the icy ice column model 3 perpendicular to the upper surface of the sample 2 away from the cooling platform 5. 1ml of water was added to the icy ice column model; after 10 minutes of cooling and freezing, the stepper rod carrying the force sensor was adjusted to the cut surface of the icy ice column model, with the center of the rod head 1-2mm from the cut surface and the height 1mm from the upper surface of the sample.

[0300] To begin the test, the stepper and force sensor are controlled to move at a speed of 0.2 mm / s until the ice column undergoes interfacial shearing and fracture. The stepper is then stopped, and the obtained force data is analyzed and calculated. The ice adhesion strength data is obtained by dividing the peak value of the instantaneous force at the moment of fracture by the ice area of ​​the ice column (the area of ​​a circle with a diameter of 1 cm).

[0301] Sample 2 may be a coating or substrate of each embodiment or comparative example (comparative examples 1, 7, and 9 are substrates, and all embodiments and other comparative examples are coatings) sample.

[0302] (3) Long-term robustness test

[0303] Adopting such Figure 3a The self-made extreme low temperature ice adhesion strength testing device shown was used to conduct long-term robustness tests on the coatings or substrates of each embodiment or comparative example (comparative examples 1, 7, and 9 are substrates, and all embodiments and other comparative examples are coatings). The specific test method is as follows: using the above test steps for ice adhesion strength, the ice adhesion strength of the coatings placed for different number of days is tested, and the change of the ice adhesion strength of the coatings over time is observed.

[0304] (4) Self-healing test

[0305] The coatings or substrates prepared with 0.3 mm deep scratches in each example or comparative example (Comparative Examples 1, 7, and 9 were substrates, and all examples and other comparative examples were coatings) were observed at 300x and 500x magnification after being placed at room temperature (25°C) for 3 hours to evaluate their room temperature self-healing properties. Specifically, if the scratch healed after 3 hours, the coating or substrate exhibited room temperature self-healing properties; if the scratch remained essentially unchanged, the coating or substrate did not possess room temperature self-healing properties.

[0306] (5) Self-cleaning ability test

[0307] Hydrophilic and hydrophobic quartz sand were placed on the coatings or substrates of each embodiment or comparative example (comparative examples 1, 7, and 9 were substrates, and all embodiments and other comparative examples were coatings) to simulate hydrophilic and hydrophobic dust, respectively. Water was then dropped onto the coatings or substrates containing the hydrophilic and hydrophobic quartz sand, and the water was observed using a camera to determine whether it could slide off. Based on whether it could slide off, the coating or substrate was judged to have self-cleaning ability. Specifically, if the water could easily slide off and the quartz sand on the surface of the coating or substrate could be easily washed away by the water, the coating or substrate was judged to have self-cleaning ability; if the water could not slide off, the coating or substrate was judged not to have self-cleaning ability.

[0308] 2. Test Results

[0309] The performance test results of the coatings or substrates of each embodiment or comparative example (comparative examples 1, 7, and 9 are substrates, and all embodiments and other comparative examples are coatings) are shown in Table 1. Figure 2 , Figure 4-9 As shown.

[0310] Table 1. Performance test results of coatings or substrates in each embodiment or comparative example.

[0311]

[0312]

[0313] According to Table 1, Figure 2 , Figure 4-9 :

[0314] Comparing Examples 1-10 and Comparative Examples 1-10, it can be seen that the ionogel coating of this application has better hydrophobicity, transparency, long-term robustness, self-healing properties, and self-cleaning ability compared to the coatings or substrates of the comparative examples, and also has lower ice adhesion strength. Wherein:

[0315] Comparing Comparative Examples 1, 2, and 1, it can be seen that the ice adhesion strength of the ion gel coating prepared in Example 1 is reduced by more than 99.3% compared to the test conducted on the unfrosted fiberglass sheet under the same cooling conditions; at the same time, compared to the fiberglass sheet-F_PAA coating without ionic liquid, surfactant, and additives, the ice adhesion strength of the ion gel coating prepared in Example 1 is reduced by approximately 94.3%.

[0316] Comparing Comparative Examples 7, 8, and 2, it can be seen that the ice adhesion strength of the ion gel coating prepared in Example 2 is reduced by more than 98.5% compared to the ice adhesion strength of the coating directly applied to the frosted mirror Al sheet under the same cooling conditions. At the same time, compared to the Al sheet-F_PAA coating without ionic liquid, surfactant, and additives, the ice adhesion strength of the ion gel coating prepared in Example 2 is reduced by approximately 94.1%.

[0317] Comparing Comparative Examples 9, 10, and 3, it can be seen that the ice adhesion strength of the ion gel coating prepared in Example 3 is reduced by more than 98.2% compared to the ice adhesion strength of the coating directly applied to the frosted silicon wafer under the same cooling conditions. At the same time, compared to the silicon wafer-F_PAA coating without ionic liquid, surfactant, and additives, the ice adhesion strength of the ion gel coating prepared in Example 3 is reduced by approximately 93.9%.

[0318] Comparing Comparative Example 3 and Example 1, it can be seen that, compared with the cases without surfactant and with surfactant, the contact angle of the ionogel coating of this application is increased by about 42%, and the hydrophobicity is greatly improved. At the same time, the ice adhesion strength at extreme low temperature for 21 days is 13.6 kPa, which is about 46% lower than the 25.3 kPa of Comparative Example 3. This shows that the ionogel coating of this application can maintain low ice adhesion performance for 21 days and has higher long-term robustness.

[0319] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0320] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0321] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A composition, characterized in that, This includes fluorinated polyamic acids, ionic liquids, surfactants, and additives; The mass ratio of the fluorinated polyamic acid, ionic liquid, surfactant and additive is (20-60):(1.5-27):1:(40-60). The ionic liquid includes at least one of imidazole chloride, imidazole tetrafluoroborate, imidazole bis(trifluoromethanesulfonyl)imide, imidazole trifluoromethanesulfonate, imidazole acetate, and imidazole hexafluorophosphate. The surfactant includes at least one of dodecyl dimethyl ammonium bromide, hexadecyl dimethyl ammonium bromide, and 1-dodecyl-2,3-dimethylimidazolium bromide. The additive includes at least one of octavinyl-cage polysilsesquioxane, anilinepropyl-cage polysilsesquioxane, and dodecylphenyl-cage polysilsesquioxane.

2. The composition according to claim 1, characterized in that, The fluorinated polyamic acid includes at least one of the compounds having the structure shown in Formula 1, the structure shown in Formula 2, and the structure shown in Formula 3: Formula 1; Formula 2; Formula 3; Wherein, a, b, and c are the number of repeating units in the compounds with the structure shown in Formula 1, Formula 2, and Formula 3, respectively, and / or, the number-average molecular weight of the compounds with the structure shown in Formula 1, Formula 2, and Formula 3 is 20,000-30,000. And / or, the viscosity of the fluorinated polyamic acid is 0.1-2 Pa·s.

3. A method for preparing the composition according to claim 1 or 2, characterized in that, include: The fluorinated polyamic acid and the ionic liquid are first mixed to obtain a mixed solution; The mixed solution, the surfactant, and the additive are mixed a second time to obtain the composition.

4. The preparation method according to claim 3, characterized in that, The method for preparing the composition further includes the step of preparing the fluorinated polyamic acid; the method for preparing the fluorinated polyamic acid includes: 2,2′-bis(trifluoromethyl)benzidine was reacted with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride in an organic solvent to obtain the fluorinated polyamic acid; And / or, both the first mixing and the second mixing methods include at least one of ultrasonic dispersion, stirring, and grinding.

5. An ionogel coating, characterized in that, The composition includes the composition as described in claim 1 or 2 or the composition prepared by the preparation method as described in claim 3 or 4; wherein the fluorinated polyamic acid in the composition is cured into a fluorinated polyimide.

6. The ionogel coating according to claim 5, characterized in that, The fluorinated polyimide includes at least one of the compounds having the structure shown in Formula 4, the structure shown in Formula 5, and the structure shown in Formula 6: Equation 4; Formula 5; Formula 6; Wherein, n, m, and k are the number of repeating units in the compounds with the structures shown in Formula 4, Formula 5, and Formula 6, respectively, and / or, the number-average molecular weights of the compounds with the structures shown in Formula 4, Formula 5, and Formula 6 are all between 10,000 and 30,000.

7. The ionogel coating according to claim 5, characterized in that, The contact angle of the ionogel coating with water is 111-121°.

8. A method for preparing an ion gel coating as described in any one of claims 5 to 7, characterized in that, include: The composition is dripped or coated onto the surface of a substrate and then dried to obtain the ionogel coating.

9. The preparation method according to claim 8, characterized in that, When the composition is dropped onto a substrate surface, the method for preparing the ionogel coating further includes a step of allowing the composition to naturally level before drying; and / or, The method for preparing the ion gel coating further includes a step of surface sandblasting or abrasioning the substrate before dripping or coating the composition onto the substrate surface; and / or, The substrate includes a material suitable for surface sandblasting treatment; And / or, The drying method includes gradient temperature drying under vacuum conditions; and / or, After drying, the fluorinated polyamic acid is cured into the fluorinated polyimide.

10. Use of the ionogel coating according to any one of claims 5 to 7 as an anti-icing surface, or use of the ionogel coating prepared by the preparation method according to claim 8 or 9 as an anti-icing surface.

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