Method for constructing nonionic surfactant-modified superhydrophobic materials in one step

Abstract

The application discloses a one-step method for constructing a nonionic surfactant modified super-hydrophobic material, which comprises the following steps: mixing a polyhydroxy silane, a polyol nonionic surfactant, an ethanol solution of a fluorine-containing nonionic surfactant, a layered silicate and an ethanol solution, adjusting to an acidic condition by using concentrated hydrochloric acid, and performing a heating and stirring reaction to obtain the super-hydrophobic material. The super-hydrophobic material prepared by the method has a 'budding structure', a water contact angle of more than 160 degrees, a rolling angle of 6.5 degrees at the lowest, and stable super-hydrophobic performance. In addition, the raw material is low in price and simple in synthesis process, and is suitable for industrial production, and can be better applied to the fields of agricultural film dust prevention, fabric stain prevention, corrosion protection and the like as a functional filling material.

Description

Technical Field

[0001] This invention belongs to the field of chemical materials technology, specifically relating to a one-step method for constructing superhydrophobic materials modified with nonionic surfactants. Background Technology

[0002] In recent years, the hydrophobic and self-cleaning phenomena exhibited by water droplets condensing on lotus leaves and carrying away dirt, water striders gliding on water, and butterflies fluttering in the rain have attracted widespread attention. With technological advancements, the surface design of various superhydrophobic materials has become a research hotspot. Researchers have constructed micro- and nano-rough structures and modified low-surface-energy groups on superhydrophobic materials to enable their widespread application in areas such as surface self-cleaning, biofouling prevention, oil-water separation, and corrosion protection. However, most current superhydrophobic materials face problems such as high cost, complex processes, and short lifespan, limiting their industrial production. Therefore, developing a low-cost, simple-to-process, and high-performance superhydrophobic material is of great significance.

[0003] Layered aluminosilicates are clay minerals with a layered structure composed of silicon-oxygen tetrahedra and aluminum-oxygen octahedra. They are inexpensive and widely available, but their small interlayer spacing, hydrophilicity and oleophobicity, and poor compatibility limit their application in superhydrophobic materials. However, by modifying layered aluminosilicates beforehand to increase their interlayer spacing, roughness, and surface energy, thus achieving a hydrophilic-to-hydrophobic transition, high-performance, low-cost superhydrophobic materials can be obtained.

[0004] Nonionic surfactants can adsorb onto the interlayer and surface of layered aluminosilicates through hydrogen bonds, covalent bonds, coordination bonds, and van der Waals forces, thereby expanding the interlayer spacing. Unlike the ion exchange mechanism of traditional cationic / anionic surfactants, the alkyl chains of nonionic surfactants, when introduced into the interlayer space, retain the ability of variable cations within that space to exchange with environmental cations, laying the foundation for enhancing the performance of superhydrophobic materials. White et al. used two nonionic surfactants to intercalate and modify montmorillonite, expanding the interlayer spacing of montmorillonite from 1.5 nm to 1.7 nm at room temperature. Simultaneously, the nonionic surfactant treatment retained more than 80% of the cation exchange capacity of montmorillonite, significantly improving the efficiency of heavy metal ion removal. However, there are few reports on the preparation of high-performance, low-cost, and simple superhydrophobic materials using two nonionic surfactants to modify montmorillonite. Summary of the Invention

[0005] The purpose of this invention is to provide a one-step method for constructing superhydrophobic materials modified with nonionic surfactants.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A one-step method for constructing superhydrophobic materials modified with nonionic surfactants involves mixing a polyhydroxysilane, a polyol nonionic surfactant, an ethanol solution of a fluorinated nonionic surfactant, a layered silicate, and an ethanol solution, adjusting the mixture to acidic conditions with concentrated hydrochloric acid, and heating and stirring the mixture to obtain the superhydrophobic material. The polyhydroxysilane is tetraethyl orthosilicate (TEOS) or methyl orthosilicate (TMOS); the layered silicate is montmorillonite, talc, or mica; the fluorinated nonionic surfactant is perfluoroalkyl ethanol polyoxyethylene ether (FX), fluorocarbon surfactant, or perfluoroalkyl polyether; the polyol nonionic surfactant is polyglycerol fatty acid ester (FL), glycerol monostearate, or sorbitan fatty acid ester.

[0007] Furthermore, the ratio of the amount of the polyhydroxysilane, the polyol nonionic surfactant, the ethanol solution of the fluorinated nonionic surfactant, the layered silicate, and the ethanol solution is 3-5g: 4-6g: 5.3-8g: 3-5g: 35mL.

[0008] Furthermore, the concentration of the ethanol solution of the fluorinated nonionic surfactant is: 0.3 to 3 g of the fluorinated nonionic surfactant is added to 5 mL of 50% ethanol solution.

[0009] Furthermore, the volume fraction of the ethanol solution is 50%.

[0010] Furthermore, the concentrated hydrochloric acid has a mass fraction of 36%-38%, the acidic conditions are pH 5-7, and the stirring speed is 500-1000 r / min.

[0011] In this invention, a "one-pot method" is used to grow SiO2 nanoparticles in situ on the surface of layered silicate through hydrolysis and condensation, which together with the layered silicate sheets to construct a rough micro-nano structure. Hydrophobic and intercalation modifications of the layered silicate are carried out by using the hydrogen bonding between nonionic surfactants and the layered silicate, so that it has both good and stable hydrophobic properties, thus making it better applicable to the field of surface dust prevention.

[0012] In this invention, layered silicates with a rough structure and a large specific surface area are used as the matrix material during the reaction process. Polyhydroxysilanes are grown in situ on the surface of the material by chemical bonding through hydrolysis and condensation. Together with FX / FL modified layered silicate sheets, they form a rough micro-nano structure, which greatly improves the stability of the superhydrophobic material.

[0013] The superhydrophobic material prepared by this invention exhibits low surface energy. The low surface energy is primarily due to the presence of fluorocarbon chains and long alkyl chains. This invention utilizes nonionic surfactants to modify layered silicates. Polyol nonionic surfactants and fluorinated nonionic surfactants intercalate and graft onto the surface and interlayers of the layered silicates via hydrogen bonding. The long alkyl chains and fluorocarbon chains significantly enhance the hydrophobicity of the layered silicates, thus addressing the problem of their poor dispersion in polymer matrices. Simultaneously, the layered silicate sheets curl, forming a "bud-like" structure, effectively increasing the roughness of the layered silicates. This results in stable hydrophobic properties. Furthermore, the introduction of alkyl chains from the nonionic surfactants into the interlayer spaces allows for the exchange of variable cations within these spaces with environmental cations, laying the foundation for further enhancements to the superhydrophobic material's properties.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) This invention improves the hydrophobicity of layered silicates by modifying them with fluorinated nonionic surfactants and polyol nonionic surfactants, thus solving the problem of difficult dispersion of layered silicates in polymer matrices. Simultaneously, the layered silicate sheets curl up, forming a "bud-like" structure, effectively increasing the roughness of the layered silicates. The curled sheets provide more protrusion sites and microporous structures, reducing the contact area between water droplets and the material, thereby improving the hydrophobic effect. The water contact angle of the superhydrophobic material can reach over 160°, and the roll-off angle is as low as 6.5°. Furthermore, after the alkyl chains of the nonionic surfactant are introduced into the interlayer space, the variable cations within the space still have the ability to exchange with environmental cations, laying the foundation for the subsequent performance enhancement of the superhydrophobic material.

[0015] (2) The raw materials for the superhydrophobic materials prepared by this invention are widely available and inexpensive.

[0016] (3) The superhydrophobic material prepared by this invention has a simple synthesis process. A one-pot method is used, where the reaction is carried out under acidic conditions to prepare a superhydrophobic material with good and stable hydrophobic properties. This allows it to be better applied to industrial production. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope (SEM) image of the superhydrophobic material with micro / nano structure in Example 1.

[0018] Figure 2 This is a dynamic light scattering particle size distribution (DLS) map of the micro-nano structured superhydrophobic material in Example 1.

[0019] Figure 3 The X-ray diffraction (XRD) patterns are shown for montmorillonite and the superhydrophobic material with micro / nano structure in Example 1.

[0020] Figure 4 The images show the infrared (FTIR) spectra of montmorillonite, FX, FL, and the micro / nano-structured superhydrophobic materials in Example 1.

[0021] Figure 5 This is a static water contact angle (WCA) test diagram of the micro-nano structured superhydrophobic material in Example 1.

[0022] Figure 6 This is a dynamic water contact angle (WSA) test diagram of the micro-nano structured superhydrophobic material in Example 1.

[0023] Figure 7 This is a static water contact angle (WCA) test diagram of the superhydrophobic material in Example 2.

[0024] Figure 8 The static water contact angle (WCA) test diagram of the hydrophobic material in Comparative Example 1 is shown.

[0025] Figure 9 The static water contact angle (WCA) test diagram of the hydrophobic material in Comparative Example 2 is shown.

[0026] Figure 10 The static water contact angle (WCA) test diagram of the hydrophobic material in Comparative Example 3 is shown. Detailed Implementation

[0027] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0029] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0030] In the following examples, fluorocarbon surfactant (model: TF-310; manufacturer: Jinan Guochen Taifu Chemical Co., Ltd.), perfluoroalkyl polyether (model: FN-6810; manufacturer: Haisen Chemical), glyceryl monostearate (CAS: 123-94-4; manufacturer: Yingxin Laboratory), and sorbitan fatty acid ester (CAS: 1338-41-6; manufacturer: Hebei Liqia Biotechnology Co., Ltd.) were used. Example 1

[0031] 4 g TEOS, 5.25 g FL, 5 g FX solution (0.75 g dissolved in 5 mL ethanol), 4 g MMT, and 35 mL ethanol solution were mixed, and concentrated hydrochloric acid was added to adjust the pH to 5. The mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. After the reaction was completed, the product was filtered, and the filter cake was collected and dried in an oven at 50 °C for 24 h. The product was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure.

[0032] like Figure 1 As shown, in-situ grown nano-SiO2 particles are uniformly dispersed on the "petal" surface of the MMT sheet. Due to the intercalation and grafting of FX / FL onto the MMT surface and between layers via hydrogen bonding, the sample exhibits a layered structure of MMT exfoliation. Simultaneously, the SiO2 particles and the curled MMT sheet increase the roughness of the nanocomposite material.

[0033] like Figure 2 As shown, the average particle size of the superhydrophobic material is around 1 μm. The composite material did not exhibit large agglomerations, possibly because the more extended MMT sheets controlled the contact between the agglomerates.

[0034] like Figure 3 As shown, the original unmodified MMT's d 001 The interlayer spacing of the crystal planes was 1.30 nm; after surface modification, the interlayer spacing increased to 2.1 nm. This is because some FX / FL entered the MMT interlayer, and in addition, FL has greater solubility in ethanol, which promoted the intercalation of FL into MMT, as well as the entry of small molecule ethanol into the MMT interlayer.

[0035] MMT, FX, FL, and the prepared layered silicate superhydrophobic material modified with nonionic surfactants were mixed with potassium bromide (mass ratio of potassium bromide to sample 100:1), ground and pressed into tablets, and measured using a Bruker ALPHA II Fourier transform infrared spectrometer with a scanning range of 4000-500 cm⁻¹. -1 .like Figure 4 As shown, in the FT-IR spectrum of the superhydrophobic material, 3627 cm⁻¹ -1 The absorption peak at 3438 cm⁻¹ is attributed to the stretching vibration of the OH bonds in the layered silicate octahedral framework. -1 The absorption peak at 1088 cm⁻¹ is due to the stretching vibration of the HOH bonds caused by the interlayer crystal water or adsorbed water in layered silicates; -1 and 1035 cm -1 A strong Si-O-Si symmetric stretching vibration peak exists at 2978-2899 cm⁻¹. -1 The characteristic peak of the alkyl chain appeared at 1736 cm⁻¹.-1 The C=O characteristic peak at 1207 cm⁻¹ proves the successful introduction of FL; -1 The presence of the CF characteristic peak at this point proves the successful introduction of FX. In conclusion, FL and FX have been successfully introduced into the MMT interlayer.

[0036] The static and dynamic water contact angles of the prepared nonionic surfactant-modified layered silicate superhydrophobic material were tested. First, double-sided tape was fixed to one side of a glass slide. One g of the superhydrophobic material was spread onto the tape, and excess sample was blown away using a syringe. The contact angle was then measured using deionized water. When using a droplet shape analyzer (DSA30S) to test the contact angle, the droplet volume was 10 μL. Tests were performed at three different locations on the sample surface, and the average value was taken as the test value. Figure 5 The material exhibits superhydrophobic properties, with a static water contact angle of 161.4°. Figure 6 The test results show that the superhydrophobic material has a roll-off angle as low as 6.5°. The test results indicate that the excellent hydrophobic properties of the superhydrophobic material are due to the "bud-like" microstructure of the superhydrophobic material and the unique porous micro-nano layered structure composed of SiO2 nanoparticles on the MMT sheets, as well as the hydrophobic modification of the long alkyl chain of FL and the polyfluorocarbon chain of FX. Example 2

[0037] 3.5 g TMOS, 4.25 g glyceryl monostearate, 5.1 g FX solution (0.85 g dissolved in 5 mL ethanol), 3.7 g mica, and 35 mL ethanol solution were mixed. Concentrated hydrochloric acid was added to adjust the pH to 6, and the mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 600 r / min. After the reaction, the product was filtered, and the filter cake was dried in a 50 °C oven for 24 h. The mixture was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure.

[0038] The static water contact angle of the prepared nonionic surfactant-modified layered silicate superhydrophobic material was tested. First, double-sided tape was fixed to one side of a glass slide. One g of the superhydrophobic material was spread onto the tape, and excess sample was blown away using a syringe. The contact angle was then measured using deionized water. When testing the contact angle using a droplet shape analyzer (DSA30S), the droplet volume was 10 μL. Tests were performed at three different locations on the sample surface, and the average value was taken as the test value. Figure 7 The material exhibits superhydrophobic properties, with a static water contact angle of 156.6°. Example 3

[0039] 4 g TEOS, 5.25 g FL, 5.1 g fluorocarbon surfactant solution (0.85 g dissolved in 5 mL ethanol), 4 g talc, and 35 mL ethanol solution were mixed. Concentrated hydrochloric acid was added to adjust the pH to 7, and the mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 600 r / min. After the reaction, the product was filtered, and the filter cake was collected and dried in an oven at 50 °C for 24 h. The mixture was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure. Example 4

[0040] 3.5 g TEOS, 4.25 g glyceryl monostearate, 5.1 g perfluoroalkyl polyether solution (0.85 g dissolved in 5 mL ethanol), 3.7 g mica, and 35 mL ethanol solution were mixed. Concentrated hydrochloric acid was added to adjust the pH to 7, and the mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 600 r / min. After the reaction, the product was filtered, and the filter cake was dried in a 50 °C oven for 24 h. The mixture was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure. Example 5

[0041] 4.5 g TEOS, 5.25 g sorbitan fatty acid ester, 4.81 g perfluoroalkyl polyether solution (0.56 g dissolved in 5 mL ethanol), 4 g MMT, and 35 mL ethanol solution were mixed. Concentrated hydrochloric acid was added to adjust the pH to 7, and the mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. After the reaction, the product was filtered, and the filter cake was dried in a 50 °C oven for 24 h. The mixture was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure. Example 6

[0042] 4.5 g TEOS, 5.25 g sorbitan fatty acid ester, 4.81 g FX solution (0.56 g dissolved in 5 mL ethanol), 4 g talc, and 35 mL ethanol solution were mixed. Concentrated hydrochloric acid was added to adjust the pH to 6, and the mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. After the reaction, the product was filtered, and the filter cake was collected and dried in a 50 °C oven for 24 h. The mixture was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure.

[0043] Comparative Example 1 The difference between this embodiment and Embodiment 1 is that FL is not added.

[0044] 4 g TEOS, 5 g FX solution (0.75 g dissolved in 5 mL ethanol), 4 g MMT, and 35 mL ethanol solution were mixed, and concentrated hydrochloric acid was added to adjust the pH to 5. The mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. After the reaction was completed, the product was filtered, and the filter cake was collected and dried in an oven at 50 °C for 24 h. The product was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure.

[0045] Comparative Example 2 The difference between this embodiment and Embodiment 1 is that FX is not included.

[0046] 4 g TEOS, 5.25 g FL, 4 g MMT, and 35 mL of ethanol solution were mixed, and concentrated hydrochloric acid was added to adjust the pH to 5. The mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. After the reaction was completed, the product was filtered, and the filter cake was dried in an oven at 50 °C for 24 h. The product was then ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with a micro / nano structure.

[0047] Comparative Example 3 The difference between this embodiment and Embodiment 1 is that a "two-step method" is used.

[0048] (1) First, 4 g TEOS, 5.25 g FL, 5 g FX solution (0.75 g dissolved in 5 mL ethanol) and 35 mL ethanol solution were mixed, and concentrated hydrochloric acid was added to adjust the pH to 5. The mixture was stirred at 60 °C for 3 h at a mechanical stirring speed of 500 r / min. Nano-SiO2 modified by fluorinated nonionic surfactant and polyol nonionic surfactant was generated.

[0049] (2) Next, add 4 g MMT to the solution and stir at 60 °C for 10 h with a mechanical stirring speed of 500 r / min.

[0050] (3) Finally, after the reaction was completed, the product was filtered and the filter cake was dried in an oven at 50 °C for 24 h. Then, it was ground and passed through a 100-mesh sieve to obtain a nonionic surfactant-modified layered silicate superhydrophobic material with micro-nano structure.

[0051] like Figure 8 As shown, if only the fluorinated nonionic surfactant FX is used to modify layered silicates, the final material prepared will have a water contact angle of approximately 116°; Figure 9As shown, if only polyol nonionic surfactant FL is used to modify layered silicates, the final material has a water contact angle of approximately 149.5°. However, the material modified with both fluorinated nonionic surfactant FX and polyol nonionic surfactant FL has a water contact angle as high as approximately 161.4° (e.g., ...). Figure 5 As shown in the figure, the hydrophobicity is greatly improved. Therefore, it is evident that modifying layered silicates with dual nonionic surfactants can improve the hydrophobicity of the material.

[0052] like Figure 10 As shown, if a two-step method is used to synthesize the material, the nano-SiO2 nanospheres are first modified with fluorinated nonionic surfactant FX and polyol nonionic surfactant FL, and then reacted with layered silicates. The resulting material has a water contact angle of approximately 143.4°. However, if a one-step method is used to synthesize the material, constructing the nano-SiO2 nanospheres through in-situ growth, the water contact angle reaches as high as approximately 161.4° (e.g., ...). Figure 5 As shown in the figure, the hydrophobicity is greatly improved. Therefore, it is evident that the "one-step" synthesis method not only improves the hydrophobicity of the material but also simplifies the preparation process, facilitating industrial production.

[0053] Therefore, it can be seen that the one-step method for constructing superhydrophobic materials modified with nonionic surfactants has a wide range of raw material sources, low prices, and good hydrophobic properties, making it better suited for industrial production.

Claims

1. A method for constructing nonionic surfactant-modified superhydrophobic materials in one step, characterized in that, The superhydrophobic material is prepared by mixing tetraethyl or methyl orthosilicate, a polyol nonionic surfactant, an ethanol solution of a fluorinated nonionic surfactant, a layered silicate, and an ethanol solution, adjusting the pH to 5-7 with concentrated hydrochloric acid, and heating and stirring the mixture. The layered silicate is montmorillonite, talc, or mica; the fluorinated nonionic surfactant is perfluoroalkyl ethanol polyoxyethylene ether; the polyol nonionic surfactant is polyglycerol fatty acid ester, glycerol monostearate, or sorbitan fatty acid ester. The ratio of the amount of tetraethyl or ... The concentration of the ethanol solution of the fluorinated nonionic surfactant is: 0.3 to 3 g of the fluorinated nonionic surfactant is added to 5 mL of 50% ethanol solution.

2. The method according to claim 1, characterized in that, The volume fraction of the ethanol solution is 50%.

3. The method according to claim 1, characterized in that, The concentrated hydrochloric acid has a mass fraction of 36%-38%, and the stirring speed is 500-1000 r / min.

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