A supramolecular surfactant based on fluoro-fluoro interactions

Abstract

The present application relates to a kind of supramolecular surfactants based on fluorine-fluorine interaction, belong to supramolecular coordination chemistry, surface modification engineering and hydrophobic coating technical field.The esterification reaction of perfluorooctanoic acid and high molecular weight polypropylene glycol is carried out in the present application to prepare flexible ligand PFOA-PPG-PFOA, the ligand can be bent, form supramolecular micelles by fluorine-fluorine interaction with the help of zinc ion in solvent, and self-assemble into a kind of supramolecular surfactants based on fluorine-fluorine interaction.The active agent can be applied in the field of hydrophobic coating, coating has the characteristics of imitating lotus leaf structure and hydrophobic wax, and has good hydrophobic performance.

Description

Technical Field

[0001] The invention relates to a supramolecular surfactant based on fluorine-fluorine interaction, and belongs to the technical fields of supramolecular coordination chemistry, surface modification engineering and hydrophobic coating. Background Art

[0002] Because droplets are difficult to settle on hydrophobic surfaces, these surfaces possess properties such as water repellency, anti-icing, anti-fogging, and self-cleaning. In the aerospace field, hydrophobic coatings on aircraft surfaces effectively prevent icing on the fuselage, ensuring flight performance and preventing air crashes. In transportation, hydrophobic coatings prevent glass fogging, ensuring clear vision and driving safety. In the electrical and electronics field, hydrophobic coatings prevent water accumulation on circuit boards, preventing short circuits and rusting of electronic components. In everyday life, hydrophobic coatings can prevent the bottoms of pots from sticking. Therefore, hydrophobic surfaces have a wide range of applications.

[0003] Imitation of lotus leaf structure has always been the research direction of researchers of hydrophobic coatings. The surface of lotus leaves has a dense micro-protrusion structure with a height of about 5 microns. Further magnification and observation can reveal that a layer of nano-scale papillae is attached to the surface of the micro-protrusions, with a height of about 200 nanometers. In addition, lotus leaves secrete a layer of biological wax on their surface to resist external invasion. It is precisely this characteristic of the combination of surface micro-nano composite structure and biological wax that gives lotus leaves unique hydrophobic properties, making it difficult for water droplets to stay on the surface of lotus leaves. In the process of rapid rolling down the surface, the droplets will carry away dust and debris on the surface, achieving self-cleaning. At present, the ideas for preparing hydrophobic surfaces are mostly focused on the preparation and coating of biological wax, mainly through perfluorinated compounds or other low surface energy materials. From the perspective of imitating the micro-nano structure of lotus leaves, it is more difficult because the structural construction requires fine design.

[0004] Early research mainly focuses on chemical synthesis methods, and fluoride is soluble in organic fluoride solvents because it is insoluble in water and conventional organic solvents. Therefore, when the material is subjected to hydrophobic surface treatment, it is necessary to infiltrate fluorinated organic solvents. This treatment method is considered to be not green enough because of the toxicity of the organic solvent and is restricted in application. Therefore, the preparation of green and environment-friendly water-based super-hydrophobic coatings using aqueous solvents as substitutes for volatile organic solvents is increasingly emerging. So far, some preparation methods have been explored, such as the wet chemical process of polymer-particle dispersions, electrochemical deposition, template method, etching method, sol-gel method and hydrothermal method. However, how to coat the substrate surface with a hydrophobic material having low surface energy and to make this material have the microscopic hydrophobic structure of imitating lotus leaves is a major problem at present. Summary of the Invention

[0005] The technical solution of the present invention is to overcome the deficiencies of the prior art and prepare a supramolecular micellar surfactant by utilizing the non-covalent interaction of supramolecular chemistry. First, perfluorooctanoic acid (PFOA) and high molecular weight polypropylene glycol (PPG) are subjected to an esterification reaction to generate a triblock ester in the form of PFOA-PPG-PFOA. In the solvent, because the blocks at both ends have a fluorine-fluorine interaction and the perfluorinated chain segments have an electron-withdrawing effect, the middle block is flexible and can be bent, so a coordinated metal ion can be added as an auxiliary adhesive to allow PFOA-PPG-PFOA to self-assemble into a supramolecular micellar structure. This structure has a small scale and good dispersibility and can be used as a surfactant. Due to the hydrophobicity of PPG, it can be applied in the field of hydrophobic coatings. The coating has the characteristics of imitating a lotus leaf structure and a hydrophobic wax and has good hydrophobic properties.

[0006] The technical solution of the present invention is:

[0007] A supramolecular surfactant based on fluorine-fluorine interaction, comprising a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker, and anhydrous ethanol;

[0008] The zinc chloride crosslinker and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and disperse in anhydrous ethanol;

[0009] The usage ratio of the flexible ligand PFOA-PPG-PFOA, the zinc chloride crosslinking agent, and anhydrous ethanol is 1 mmol: 1-3 mmol: 100 ml.

[0010] A method for preparing a flexible ligand PFOA-PPG-PFOA, comprising the following steps:

[0011] In the first step, polypropylene glycol is placed in a beaker, and toluene is added dropwise to completely dissolve the polypropylene glycol, thereby obtaining a toluene solution of the polypropylene glycol; the molecular weight of the polypropylene glycol is >1000 g / mol.

[0012] The ratio of polypropylene glycol to toluene is 0.01 mol:30-60 ml;

[0013] In the second step, perfluorooctanoic acid is placed in a beaker, and toluene is added to completely dissolve it to obtain a toluene solution of perfluorooctanoic acid, which is then transferred into a three-necked flask.

[0014] The ratio of perfluorooctanoic acid to toluene is 0.02 mol: 20-30 ml;

[0015] In the third step, the toluene solution of polypropylene glycol obtained in the first step is transferred into a constant pressure separating funnel, which is connected to the three-necked flask in the second step.

[0016] The volume ratio of the toluene solution of polypropylene glycol obtained in the first step to the toluene solution of perfluorooctanoic acid in the second step is 1:0.5-1;

[0017] Step 4: Take p-toluenesulfonic acid, dissolve it in toluene, and then add it dropwise to the three-necked flask. Stir continuously and heat the three-necked flask to 110° C. for 5 hours.

[0018] The ratio of toluenesulfonic acid to toluene is 0.15g:5ml;

[0019] In the fifth step, the reaction solution is poured out and saturated sodium bicarbonate solution is added dropwise to the solution, which produces a precipitate. The pH is adjusted to 6.8-7.2, and the solution is filtered. The filtrate is dried in a vacuum oven at 85-95°C for 4.5-5.5 hours to obtain a flexible ligand PFOA-PPG-PFOA.

[0020] The ratio of polypropylene glycol, perfluorooctanoic acid, and p-toluenesulfonic acid is 0.1 mol:0.2 mol:0.15 g.

[0021] A method for preparing a supramolecular surfactant based on fluorine-fluorine interaction, comprising the following steps:

[0022] In the first step, PFOA-PPG-PFOA is placed in a beaker, anhydrous ethanol is added, and the mixture is stirred continuously to dissolve the mixture. The mixture is allowed to stand for 30 minutes to obtain an ethanol solution of PFOA-PPG-PFOA.

[0023] The ratio of the flexible ligand PFOA-PPG-PFOA to anhydrous ethanol is 0.1g:20ml;

[0024] In the second step, zinc chloride is prepared into a 50 mmol / L anhydrous ethanol solution, and 5-10 ml is added dropwise to the ethanol solution of PFOA-PPG-PFOA obtained in the first step.

[0025] The volume ratio of the anhydrous ethanol solution of zinc chloride to the ethanol solution of PFOA-PPG-PFOA in the first step is 5-10 ml:20 ml.

[0026] The third step is to slowly stir for 5-10 minutes and stand for 30-40 minutes to obtain a supramolecular surfactant based on fluorine-fluorine interaction.

[0027] An application of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coatings comprises the following steps:

[0028] In the first step, 10 to 20 ml of supramolecular surfactant is taken, diluted with anhydrous ethanol, and slowly stirred to obtain a diluted surfactant solution.

[0029] The volume ratio of the surfactant to the anhydrous ethanol in the first step is 1:1.

[0030] In the second step, the substrate was immersed in the surfactant solution diluted in the first step and stirred slowly for 1 hour.

[0031] In the third step, the modified substrate is taken out and placed in an oven to dry the excess solvent, thereby obtaining a hydrophobic substrate modified by a supramolecular surfactant based on fluorine-fluorine interaction.

[0032] Beneficial effects

[0033] In this invention, perfluorooctanoic acid (PFOA) and high-molecular-weight polypropylene glycol (PPG) undergo an esterification reaction to prepare a flexible ligand, PFOA-PPG-PFOA. This ligand is capable of bending and, through fluorine-fluorine interactions, forms supramolecular micelles with the aid of zinc ions in the solvent. These micelles then self-assemble into a supramolecular surfactant based on fluorine-fluorine interactions. This surfactant can be applied in hydrophobic coatings, resulting in coatings with lotus leaf-like structures and hydrophobic waxy properties, exhibiting excellent hydrophobic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the self-assembly of supramolecular micellar surfactants;

[0035] Figure 2 This is a cryo-TEM image of supramolecular micelles;

[0036] Figure 3 This is the contact angle test diagram of the substrate without hydrophobic treatment;

[0037] Figure 4 This is an SEM image of the lotus leaf structure on the substrate surface after surface modification with the active agent in Example 1;

[0038] Figure 5 This is the contact angle test of the substrate after surface modification with the active agent in Example 1;

[0039] Figure 6 This is an SEM image of the lotus leaf structure on the substrate surface after surface modification with the active agent in Example 2;

[0040] Figure 7 This is the contact angle test of the substrate after surface modification with the active agent in Example 2. DETAILED DESCRIPTION

[0041] The present invention will be further described below by way of examples, but the examples do not limit the scope of protection of the present invention.

[0042] Example 1

[0043] A supramolecular surfactant based on fluorine-fluorine interaction, comprising a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker and anhydrous ethanol; Figure 1 As shown;

[0044] The zinc chloride crosslinker and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and disperse in anhydrous ethanol; Figure 2 As shown;

[0045] A method for preparing a flexible ligand PFOA-PPG-PFOA, comprising the following steps:

[0046] In the first step, 0.01 mol of polypropylene glycol (1000 g / mol) was placed in a beaker, and 30 ml of toluene was added dropwise to completely dissolve the polypropylene glycol to obtain a toluene solution of the polypropylene glycol.

[0047] In the second step, 0.02 mol of perfluorooctanoic acid was placed in a beaker, and 30 ml of toluene was added to completely dissolve it to obtain a toluene solution of perfluorooctanoic acid, which was then transferred into a three-necked flask.

[0048] In the third step, the toluene solution of polypropylene glycol obtained in the first step is transferred into a constant pressure separating funnel, which is connected to the three-necked flask in the second step.

[0049] In the fourth step, 0.15 g of p-toluenesulfonic acid was dissolved in toluene and then added dropwise to the three-necked flask. The flask was stirred continuously and heated to 110° C. for 5 hours.

[0050] In the fifth step, the reaction solution was poured out and saturated sodium bicarbonate solution was added dropwise to the solution, which produced a precipitate. The pH was adjusted to 7 and the solution was filtered. The filtrate was dried in a vacuum oven at 90°C for 5 hours to obtain a flexible ligand PFOA-PPG-PFOA.

[0051] A method for preparing a supramolecular surfactant based on fluorine-fluorine interaction, comprising the following steps:

[0052] In the first step, 0.1 g of PFOA-PPG-PFOA was placed in a beaker, 20 ml of anhydrous ethanol was added, and the mixture was stirred continuously to dissolve the mixture. The mixture was allowed to stand for 30 minutes to obtain an ethanol solution of PFOA-PPG-PFOA.

[0053] In the second step, zinc chloride was prepared into a 50 mmol / L anhydrous ethanol solution, and 5 ml was added dropwise into the ethanol solution of PFOA-PPG-PFOA.

[0054] The third step is to slowly stir for 5 minutes and let it stand for 30 minutes to obtain a supramolecular surfactant based on fluorine-fluorine interaction.

[0055] An application of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coatings comprises the following steps:

[0056] In the first step, 10 ml of the prepared supramolecular surfactant is taken, diluted with 10 ml of anhydrous ethanol, and slowly stirred to obtain a diluted surfactant solution.

[0057] In the second step, the substrate is immersed in the surfactant solution diluted in the first step and stirred slowly for 1 hour. Figure 3 As shown;

[0058] In the third step, the modified substrate is taken out and placed in an oven to dry the excess solvent, thereby obtaining a hydrophobic substrate modified by a supramolecular surfactant based on fluorine-fluorine interaction.

[0059] Figure 4 This is an SEM image of the lotus leaf structure on the substrate surface after surface modification with the active agent in Example 1. Figure 5 The contact angle test of the substrate after surface modification by the active agent in Example 1 is shown in FIG. Figure 4 It can be seen that the coating has a lotus leaf-like structure. Figure 5 It can be seen that the contact angle of Example 1 is 132.6°, which has good hydrophobicity.

[0060] Example 2

[0061] A supramolecular surfactant based on fluorine-fluorine interaction, comprising a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker, and anhydrous ethanol;

[0062] The zinc chloride crosslinker and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and disperse in anhydrous ethanol;

[0063] A method for preparing a flexible ligand PFOA-PPG-PFOA, comprising the following steps:

[0064] In the first step, 0.01 mol of polypropylene glycol (4000 g / mol) was placed in a beaker, and 60 ml of toluene was added dropwise to completely dissolve the polypropylene glycol to obtain a toluene solution of the polypropylene glycol.

[0065] In the second step, 0.02 mol of perfluorooctanoic acid was placed in a beaker, and 30 ml of toluene was added to completely dissolve it to obtain a toluene solution of perfluorooctanoic acid, which was then transferred into a three-necked flask.

[0066] In the third step, the toluene solution of polypropylene glycol obtained in the first step is transferred into a constant pressure separating funnel, which is connected to the three-necked flask in the second step.

[0067] In the fourth step, 0.15 g of p-toluenesulfonic acid was dissolved in toluene and then added dropwise to the three-necked flask. The flask was stirred continuously and heated to 110° C. for 5 hours.

[0068] In the fifth step, the reaction solution was poured out and saturated sodium bicarbonate solution was added dropwise to the solution, which produced a precipitate. The pH was adjusted to 7 and the solution was filtered. The filtrate was dried in a vacuum oven at 90°C for 5 hours to obtain a flexible ligand PFOA-PPG-PFOA.

[0069] A method for preparing a supramolecular surfactant based on fluorine-fluorine interaction, comprising the following steps:

[0070] In the first step, 0.1 g of PFOA-PPG-PFOA was placed in a beaker, 20 ml of anhydrous ethanol was added, and the mixture was stirred continuously to dissolve the mixture. The mixture was allowed to stand for 30 minutes to obtain an ethanol solution of PFOA-PPG-PFOA.

[0071] In the second step, zinc chloride was prepared into a 50 mmol / L anhydrous ethanol solution, and 5 ml was added dropwise into the ethanol solution of PFOA-PPG-PFOA.

[0072] In the third step, the mixture was stirred slowly for 5 minutes and allowed to stand for 30 minutes to obtain a supramolecular surfactant based on fluorine-fluorine interaction.

[0073] An application of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coatings comprises the following steps:

[0074] In the first step, 20 ml of the prepared supramolecular surfactant is taken, diluted with 20 ml of anhydrous ethanol, and slowly stirred to obtain a diluted surfactant solution.

[0075] In the second step, the substrate is immersed in the surfactant solution diluted in the first step and stirred slowly for one hour.

[0076] In the third step, the modified substrate is taken out and placed in an oven to dry the excess solvent, thereby obtaining a hydrophobic substrate modified by a supramolecular surfactant based on fluorine-fluorine interaction.

[0077] Figure 6 This is an SEM image of the lotus leaf structure on the substrate surface after surface modification with the active agent in Example 2. Figure 7 This is the contact angle test of the substrate after surface modification by the surfactant in Example 2. Figure 6 It can be seen that the coating has a lotus leaf-like structure. Figure 7 It can be seen that the contact angle of Example 1 is 124.0°, which has good hydrophobicity.

[0078] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A supramolecular surfactant based on fluorine-fluorine interaction, characterized in that: The supramolecular surfactant comprises a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker and anhydrous ethanol; The zinc chloride crosslinker and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and disperse in anhydrous ethanol; The ratio of the flexible ligand PFOA-PPG-PFOA, zinc chloride crosslinker, and anhydrous ethanol is 1 mmol: 1-3 mmol: 100 ml; The preparation method of the flexible ligand PFOA-PPG-PFOA is: A toluene solution of polypropylene glycol, a toluene solution of perfluorooctanoic acid and a toluene solution of p-toluenesulfonic acid were mixed and reacted. After the reaction, a saturated sodium bicarbonate solution was added dropwise to produce a precipitate. The precipitate was filtered and the filtrate was dried in a vacuum oven at 85-95°C for 4.5-5.5h to obtain a flexible ligand PFOA-PPG-PFOA.

2. The supramolecular surfactant based on fluorine-fluorine interaction according to claim 1, characterized in that: In the toluene solution of polypropylene glycol, the ratio of polypropylene glycol to toluene is 0.01 mol:30-60 ml; the molecular weight of the polypropylene glycol is greater than 1000 g / mol; In the toluene solution of perfluorooctanoic acid, the ratio of perfluorooctanoic acid to toluene is 0.02 mol: 20-30 ml; In the toluene solution of p-toluenesulfonic acid, the ratio of p-toluenesulfonic acid to toluene is 0.15 g:5 ml; The ratio of the polypropylene glycol, perfluorooctanoic acid and p-toluenesulfonic acid is 0.1 mol:0.2 mol:0.15 g.

3. A supramolecular surfactant based on fluorine-fluorine interaction according to claim 1 or 2, characterized in that: The pH of the filtrate is 6.8-7.

2.

4. The supramolecular surfactant based on fluorine-fluorine interaction according to claim 1, characterized in that: The reaction temperature is 100-120°C and the reaction time is 4-5h.

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