Preparation method and application of supramolecular surfactant based on fluorine-fluorine interaction

Abstract

The invention relates to a preparation method and application of a supramolecular surfactant based on fluorine-fluorine interaction, and belongs to the technical fields of supramolecular coordination chemistry, surface modification engineering and hydrophobic coatings. According to the invention, perfluorooctanoic acid and high-molecular-weight polypropylene glycol are subjected to esterification reaction to prepare a flexible ligand PFOA-PPG-PFOA, the ligand can be bent, supramolecular micelles are formed under the help of zinc ions in a solvent by virtue of fluorine-fluorine interaction, and the supramolecular surfactant based on fluorine-fluorine interaction is self-assembled. The active agent can be applied to the field of hydrophobic coatings, and the coatings have the characteristics of lotus leaf-like structures and hydrophobic waxiness and have good hydrophobic performance.

Description

Technical Field

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

[0002] Due to the fact that droplets on the hydrophobic surface are difficult to stay, the surface has the characteristics of waterproof, anti-icing, anti-fogging, and self-cleaning. In the field of aerospace, the hydrophobic coating on the surface of the aircraft can effectively prevent the fuselage from icing, ensure flight performance, and avoid air crashes; in the field of transportation, the hydrophobic coating can prevent the glass from fogging, ensure clear vision, and ensure driving safety; in the field of electronics and electrical, the hydrophobic coating can prevent water accumulation on the circuit board and prevent short circuits or rusting of electronic components; in daily life, the hydrophobic coating can prevent the bottom of the pot from sticking. Therefore, the hydrophobic surface has a very broad application prospect.

[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 the characteristics of this surface micro-nano composite structure combined with biological wax that give lotus leaves unique hydrophobic properties, making it difficult for water droplets to stay on the surface of lotus leaves, and the droplets will carry away dust and debris on the surface during the rapid rolling process on its 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 the micro-nano structure of imitating lotus leaves, it is more difficult because the structural structure requires fine design.

[0004] Early research mainly focuses on chemical synthesis methods. Fluoride is insoluble in water and conventional organic solvents, and is soluble in organic fluoride 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 organic solvents, and is limited in application. Therefore, it is increasingly emerging to prepare green and environmentally friendly water-based super-hydrophobic coatings by replacing volatile organic solvents with water-based solvents. So far, some preparation methods have been explored, such as wet chemical processes of polymer-particle dispersions, electrochemical deposition methods, template methods, etching methods, sol-gel methods, and hydrothermal methods. However, how to coat the substrate surface with both a hydrophobic material with low surface energy and a 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: overcome the deficiencies of the prior art, utilize the non-covalent interaction of supramolecular chemistry, and prepare supramolecular micellar surfactants. First, perfluorooctanoic acid (PFOA) and high molecular weight polypropylene glycol (PPG) are used for esterification reaction to generate a triblock ester in the form of PFOA-PPG-PFOA. In the solvent, because the blocks at both ends have fluorine-fluorine interactions, and the perfluorinated chain segments have electron-withdrawing effects, the middle block is flexible and can be bent, so coordinated metal ions can be added as auxiliary adhesives to make PFOA-PPG-PFOA self-assemble into a supramolecular micellar structure. The structure is small in scale and good in dispersibility, and can be used as a surfactant. Because of the hydrophobicity of PPG, it can be applied in the field of hydrophobic coatings, and the coating has the characteristics of imitating lotus leaf structure and 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, the supramolecular surfactant comprising a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker and anhydrous ethanol;

[0008] The zinc chloride crosslinking agent and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and are dispersed in anhydrous ethanol;

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

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

[0011] In the first step, the 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 separatory funnel, and 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 into a three-necked flask, stir continuously and heat the three-necked flask to 110° C., and react for 5 hours;

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

[0019] Step 5: Pour out the solution after the reaction, add saturated sodium bicarbonate solution to the solution, and a precipitate is generated. Adjust the pH to 6.8-7.2, and then filter. Dry the filtrate 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, and 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 0.1 g:20 ml;

[0024] In the second step, zinc chloride is prepared into a 50 mmol / L anhydrous ethanol solution, and 5-10 ml is added dropwise into 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 5-10ml:20ml.

[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] The first step is to take 10-20 ml of supramolecular surfactant, dilute it with anhydrous ethanol, and slowly stir it to obtain a diluted surfactant solution.

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

[0030] In the second step, the substrate is 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 the present invention, perfluorooctanoic acid and high molecular weight polypropylene glycol are subjected to esterification reaction to prepare a flexible ligand PFOA-PPG-PFOA, which can be bent, and forms supramolecular micelles with the help of zinc ions in the solvent by relying on fluorine-fluorine interaction, and self-assembles into a supramolecular surfactant based on fluorine-fluorine interaction. The surfactant can be used in the field of hydrophobic coatings, and the coatings have the characteristics of imitating lotus leaf structure and hydrophobic wax, and have good 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 a SEM image of the lotus leaf structure on the substrate surface after surface modification by the active agent in Example 1;

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

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

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

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

[0042] Example 1

[0043] A supramolecular surfactant based on fluorine-fluorine interaction, the supramolecular surfactant 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) is placed in a beaker, and 30 ml of toluene is 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 is placed in a beaker, and 30 ml of toluene is added to completely dissolve it to obtain a toluene solution of perfluorooctanoic acid, which is 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 separatory funnel, and connected to the three-necked flask in the second step.

[0049] Step 4: Take 0.15 g of p-toluenesulfonic acid, dissolve it in toluene and then add it dropwise into a three-necked flask. Stir continuously and heat the three-necked flask to 110° C. to react for 5 hours.

[0050] In the fifth step, the solution after the reaction is poured out, and a saturated sodium bicarbonate solution is added dropwise to the solution, at which time a precipitate is generated, and the pH is adjusted to 7, and then filtered. The filtrate is 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 is taken into a beaker, 20 ml of anhydrous ethanol is added, and the mixture is stirred continuously to dissolve the mixture, and the mixture is allowed to stand for 30 minutes to obtain an ethanol solution of PFOA-PPG-PFOA.

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

[0054] The third step is to stir slowly for 5 minutes and let 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] The first step is to take 10 ml of the prepared supramolecular surfactant, add 10 ml of anhydrous ethanol to dilute it, and slowly stir it 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. The contact angle test diagram of the substrate without hydrophobic treatment is shown in the figure below. 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 a SEM image of the lotus leaf structure on the substrate surface after the surface modification by the active agent in Example 1. Figure 5 The contact angle test of the substrate after the surface modification of the active agent in Example 1. 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, the supramolecular surfactant comprising a flexible ligand PFOA-PPG-PFOA, a zinc chloride crosslinker and anhydrous ethanol;

[0062] The zinc chloride crosslinking agent and the flexible ligand PFOA-PPG-PFOA self-assemble into micelles and are dispersed 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) is placed in a beaker, and 60 ml of toluene is 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 is placed in a beaker, and 30 ml of toluene is added to completely dissolve it to obtain a toluene solution of perfluorooctanoic acid, which is 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 separatory funnel, and connected to the three-necked flask in the second step.

[0067] Step 4: Take 0.15 g of p-toluenesulfonic acid, dissolve it in toluene and then add it dropwise into a three-necked flask. Stir continuously and heat the three-necked flask to 110° C. to react for 5 hours.

[0068] In the fifth step, the solution after the reaction is poured out, and a saturated sodium bicarbonate solution is added dropwise to the solution, at which time a precipitate is generated, and the pH is adjusted to 7, and then filtered. The filtrate is 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 is taken into a beaker, 20 ml of anhydrous ethanol is added, and the mixture is stirred continuously to dissolve the mixture, and the mixture is allowed to stand for 30 minutes to obtain an ethanol solution of PFOA-PPG-PFOA.

[0071] In the second step, zinc chloride is prepared into a 50 mmol / L anhydrous ethanol solution, and 5 ml is 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] The first step is to take 20 ml of the prepared supramolecular surfactant, add 20 ml of anhydrous ethanol to dilute it, and slowly stir it 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 a SEM image of the lotus leaf structure on the substrate surface after surface modification by the active agent in Example 2. Figure 7 This is the contact angle test of the substrate after the surface modification of 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 protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a supramolecular surfactant based on fluorine-fluorine interaction, characterized in that The steps are: The ethanol solution of PFOA-PPG-PFOA and the ethanol solution of zinc chloride are mixed and stirred to obtain a supramolecular surfactant based on fluorine-fluorine interaction; In the ethanol solution of PFOA-PPG-PFOA, the preparation method of PFOA-PPG-PFOA is as follows: The toluene solution of polypropylene glycol, the toluene solution of perfluorooctanoic acid and the toluene solution of p-toluenesulfonic acid are mixed and reacted. After the reaction is completed, a saturated sodium bicarbonate solution is added dropwise to produce a precipitate. The precipitate is filtered and the filtrate is dried in a vacuum oven at 85-95°C for 4.5-5.5h to obtain PFOA-PPG-PFOA.

2. The method for preparing a 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 polypropylene glycol is >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 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. The method for preparing a supramolecular surfactant based on fluorine-fluorine interaction according to claim 2, characterized in that: The pH of the filtrate is 6.8-7.2; The reaction temperature is 100-120°C and the reaction time is 4-5h.

4. The method for preparing a supramolecular surfactant based on fluorine-fluorine interaction according to claim 1, characterized in that: In the ethanol solution of PFOA-PPG-PFOA, the ratio of PFOA-PPG-PFOA to anhydrous ethanol is 0.1 g:20 ml; The concentration of the zinc chloride ethanol solution is 50mmol / L; The volume ratio of the zinc chloride ethanol solution to the PFOA-PPG-PFOA ethanol solution is 5-10ml:20ml.

5. Application of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coating, characterized in that The steps are: The substrate is immersed in a supramolecular surfactant solution based on fluorine-fluorine interaction, and after the immersion is completed, the substrate is taken out and dried to obtain a hydrophobic substrate modified by a supramolecular surfactant based on fluorine-fluorine interaction.

6. The use of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coating according to claim 5, characterized in that: The supramolecular surfactant solution refers to an ethanol solution of a supramolecular surfactant, and the volume ratio of the supramolecular surfactant solution to ethanol is 1:

1.

7. The use of a supramolecular surfactant based on fluorine-fluorine interaction in the field of hydrophobic coating according to claim 5, characterized in that: The immersion time is 0.5-1h.

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