Raspberry-shaped nano SiO2 / perfluoropolyether super-hydrophobic compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of super-hydrophobic materials, and relates to a raspberry-shaped nano SiO2 / perfluoropolyether super-hydrophobic compound applied to fluid drag reduction and a preparation method of the raspberry-shaped nano SiO2 / perfluoropolyether super-hydrophobic compound. The compound is prepared from the following raw materials: nano SiO2, a main monomer, an auxiliary monomer, a cross-linking agent, an initiator, an amino-containing silane coupling agent (based on the nano-compound), perfluoropolyether acyl fluoride (based on the nano-compound), a perfluoropolyether acrylate prepolymer (PFPE-EMA) and water, and the preparation method comprises the following steps: firstly, preparing a raspberry-shaped nano SiO2 / polymer compound, and then preparing the raspberry-shaped nano SiO2 / polymer compound. The preparation method comprises the following steps: preparing an aminated nano SiO2 / polymer compound (RB-NH2), finally preparing a raspberry-shaped nano SiO2 / perfluoropolyether compound (RB-PFPE), taking a perfluoropolyether acrylate prepolymer as a reactive macromolecule, carrying out a copolymerization reaction with a main monomer during a polymerization reaction period, and also taking the perfluoropolyether acrylate prepolymer as an auxiliary nucleation site, so as to realize the copolymerization reaction between the main monomer and the perfluoropolyether acrylate. A newly generated polymer is induced to gather on the surface of the nano SiO2 to form a raspberry-shaped structure, and the raspberry-shaped structure and the nano SiO2 have a synergistic effect, so that the stability of the Pickering emulsion is promoted.

Description

Technical field:

[0001] The invention belongs to the technical field of super-hydrophobic materials, and in particular relates to a raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite used for fluid drag reduction and a preparation method thereof. Background technology:

[0002] Perfluoropolyether is a type of perfluoropolymer that is liquid at room temperature. It has the characteristics of low surface energy, good thermal stability, excellent lubricity, good biocompatibility, high temperature resistance, oxidation resistance, corrosion resistance, and strong chemical stability. It is widely used in many fields such as aerospace, electronics, petrochemicals, machinery, and medicine.

[0003] Tiantian Gao et al. (polymer.2020.122732.) synthesized a series of polyisobornyl methacrylate-perfluoropolyether-polyisobornyl methacrylate (PIBOMA-PFPE-PIBOMA) triblock copolymers with fixed PFPE block length and different PIBOMA (polyisobornyl methacrylate) block lengths through atom transfer radical polymerization. There are micro-nanoscale particle structures on the surface, with a water contact angle (WCA) of 155° and a sliding angle of 4°. They have good self-cleaning properties and have potential application prospects in the field of superhydrophobic coatings.

[0004] Zhujun Lu et al. (RSC Adv., 2019, 9, 4765-4770) reacted 1H,1H,2H,2H-perfluorooctyl acrylate, methyl (meth)acrylate, n-butyl acrylate, hydroxypropyl acrylate, methacryloyloxypropyltrimethoxysilane and methacryloylisobutyl POSS through free radical solution polymerization to synthesize POSS-containing poly(perfluoropolyether) methacrylate (PFPEM) hybrid copolymer (PFPEM–POSS), which has a distinct micro-nano hierarchical structure and shows excellent hydrophobicity and wear resistance.

[0005] Fan Song et al. (RSC Adv., 2017, 7, 44239-44246) constructed a hierarchical superhydrophobic surface on the surface of magnesium alloy by a one-step method, and then immersed the superhydrophobic surface in perfluoropolyether to obtain a smooth liquid-infused porous surface (SLIPS). Compared with untreated magnesium alloy and the prepared superhydrophobic coating, the SLIPS coating has good corrosion resistance in 3.5wt% NaCl solution.

[0006] Chen Kun et al. (Synthetic Resins and Plastics, 2018, 35(1): 6-9) used silane coupling agent KH550 to modify perfluoropolyether to prepare perfluoropolyether siloxane, prepared SiO2 sol with a particle size of 200 nm by sol-gel method, then used KH550 to modify the surface of SiO2 sol, prepared SiO2 coating on the glass surface by immersion method, and modified the surface with perfluoropolyether siloxane to prepare a durable superhydrophobic coating composed of perfluoropolyether siloxane and SiO2.

[0007] Raspberry-like particles are a kind of composite material with a rough surface and a shape similar to that of a raspberry. They have a micro-nano multi-level structure and present unique properties based on the special hierarchical structure: large specific surface area and surface roughness, excellent physical and chemical properties, and high light scattering properties, which provide new possibilities for the efficient preparation of large-area super-hydrophobic surfaces. On the one hand, the micro-nano rough structure can be introduced into the surface of the material; on the other hand, the nano-rough structure of raspberry-like particles provides good conditions for further modification and modification, and low surface energy substances containing fluorine organic matter can be introduced into the surface of the material to give the material super-hydrophobicity. It has the corresponding characteristics of both polymers and inorganic components and has a wide range of applications in the field of super-hydrophobic coatings.

[0008] The preparation methods of raspberry-like particles include polymerization, heterogeneous coagulation and particle surface directed hydrolysis of inorganic substances. Among them, polymerization is the most commonly used method. Raspberry-like particles are obtained by polymerization reaction by adding monomers in the presence of pre-prepared nanoparticles. When the pre-body particles are polymer particles, the monomers are swollen as seeds, and the monomers added later undergo polymerization reaction. The polymers formed are incompatible with the seeds, and phase separation occurs to obtain raspberry-like particles; or the polymer particles directly serve as nucleation sites to induce the newly generated polymers to aggregate on their surfaces to form raspberry-like structures. When the pre-body particles are inorganic substances such as SiO2, the interaction between them and monomers or polymers (acid-base or electrostatic effects) is used to fix inorganic nanoparticles on the surface of the generated polymer particles to obtain raspberry-like particles. According to different polymerization systems, polymerization methods are mainly divided into emulsion polymerization, mini-emulsion polymerization, dispersion polymerization, soap-free emulsion polymerization and Pickering emulsion polymerization.

[0009] Pickering emulsion polymerization refers to the use of shearing between two incompatible liquids in the presence of solid nanoparticles to form an emulsion, and the solid particles are coated on the surface to form a raspberry-like morphology. The most commonly used solid particles include nanoparticles such as SiO2, TiO2, Fe3O4, ZrO2, and SnO2. The stabilization mechanism of Pickering emulsion is that it has a certain surface activity and can spontaneously gather at the oil-water interface and surround the droplets to form an adsorption film. There is no need to add surfactants as emulsifiers. It completely relies on Pickering emulsifiers (i.e. solid nanoparticles) to form a stable emulsion. The solid particles are coated on the polymer surface to form a raspberry-like morphology through acid-base or electrostatic effects, which has certain advantages over other polymerization methods.

[0010] Barthet et al. (Advanced Materials, 1999, 11(5): 408-410) explored the effect of basic auxiliary monomers on the morphology of the polymer product in Pickering emulsion polymerization. 4-vinylpyridine (4-VP) and 2-vinylpyridine (2-VP) were used as auxiliary monomers to react with diethylaminoethyl methacrylate (DEAEMA) respectively. It was found that the particle size distribution of the particles obtained by using 4-VP was narrower (150-170nm), and the adsorption amount of SiO2 was higher (about 37%). However, the use of 2-VP could not obtain the ideal morphology of the composite. Chen et al. (Macromolecules, 2004, 37(37): 9613-9) investigated the effect of the amount of SiO2 particles and 1-vinylpyridine (1-VID) auxiliary monomer added in Pickering emulsion polymerization on the morphology and particle size of PMMA / SiO2 raspberry-like composites. The Pickering emulsion method uses solid particles such as SiO2 to replace traditional emulsifiers. On the one hand, it can fully utilize the advantages of low toxicity, low foaming and low cost of inorganic particles. On the other hand, the polymerization process is simple and controllable, and the equipment requirements are low. Therefore, the use of Pickering emulsion polymerization to prepare raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composites and then construct superhydrophobic surfaces has significant application advantages and broad development prospects. Summary of the invention:

[0011] The purpose of the present invention is to overcome the shortcomings of the prior art, develop and design a raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composite with excellent corrosion resistance, aging resistance, chemical stability and mechanical stability and a preparation method thereof, so as to be applied to fluid drag reduction.

[0012] In order to achieve the above-mentioned object, the present invention relates to a raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite comprising the following raw materials in parts by weight: 2-8 parts of nano-SiO2, 5-15 parts of a main monomer, 0.5-2.5 parts of an auxiliary monomer, 0.1-0.2 parts of a cross-linking agent, 0.05-0.15 parts of an initiator, 5-10 parts of an amino-containing silane coupling agent (based on a nano-composite), 5-10 parts of perfluoropolyether acyl fluoride (based on a nano-composite), 0.1-1 parts of a perfluoropolyether acrylate prepolymer (PFPE-EMA), and the rest is water;

[0013] Among them, the particle size of nano-SiO2 is 30-90nm;

[0014] The main monomer is one of styrene (St), methacrylamide (MAm) or methyl methacrylate (MMA);

[0015] The auxiliary monomer is one or a combination of two of 1-vinylimidazole (1-VID), 2-vinylimidazole (2-VID), 3-vinylimidazole (3-VID), 2-vinylpyridine (2-VP), and 4-vinylpyridine (4-VP);

[0016] The crosslinking agent is one of ethylene glycol diacrylate (EDA), 1,4-butanediol diacrylate (BDA), and divinylbenzene (DVB);

[0017] The initiator is one of ammonium persulfate (APS), sodium persulfate (SPS) and potassium persulfate (KPS);

[0018] The amino-containing silane coupling agent is one of aminotriethoxysilane, 3-aminopropyltriethoxysilane (APTS), and n-butyl-3-aminopropyltrimethoxysilane;

[0019] Perfluoropolyether acyl fluoride is a commercially available product with a molecular weight of 500-2000, including products from Maclean, Wuhan Kemik Biopharmaceutical Technology Co., Ltd., and Shanghai Chuangsai Technology Co., Ltd.;

[0020] Perfluoropolyether acrylate prepolymer is a commercially available product with a molecular weight of 1000-5000, including products from Taicang Sinochem Environmental Protection Chemical Co., Ltd. and Wuhan Kemik Biopharmaceutical Technology Co., Ltd.

[0021] The specific process of the preparation method of a raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite disclosed by the present invention is as follows:

[0022] (I) Preparation of raspberry-like nano-SiO2 / polymer composites (RB)

[0023] First, a 250 ml four-necked flask with a reflux condenser was placed in a constant temperature oil bath, and the nano-SiO2 aqueous dispersion and deionized water were added to the four-necked flask, and the main monomer, auxiliary monomer, crosslinking agent and perfluoropolyether acrylate prepolymer were added, ultrasonically dispersed for 15 minutes, mechanically stirred for 20 minutes for pre-emulsification, nitrogen was introduced for protection, and the temperature was raised to 65°C;

[0024] Then, the initiator was dissolved in deionized water and added dropwise to the four-necked flask under constant stirring to react, and the temperature in the four-necked flask was maintained at 65° C. for more than 12 hours to ensure complete reaction;

[0025] Finally, the emulsion obtained by the reaction was washed with deionized water and centrifuged (1000 rpm, 10-15 min) for several times until the supernatant was clear, and the excess nano-SiO2 was removed to prepare a pure raspberry-like nano-SiO2 / polymer composite (RB);

[0026] (II) Preparation of raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE)

[0027] First, a 250 ml three-necked flask with a reflux condenser and a stirring magnet was placed in a constant temperature oil bath, ethanol was added to the three-necked flask, and then raspberry-shaped nano-SiO2 / copolymer composite (RB) was added, stirred, ammonia water was added, APTS (3-aminopropyltriethoxysilane) was added dropwise, nitrogen was introduced for protection, and the temperature was kept at 65°C for 12 hours, during which uniform magnetic stirring (stirring rate was 180-300 rpm) was maintained;

[0028] Then, the product was washed with anhydrous ethanol and centrifuged (1000 rpm, 5 min), and the washing and centrifugation operations were repeated 3 times to obtain an amino-modified nano-SiO2 / polymer composite (RB-NH2);

[0029] Finally, the amino-modified nano-SiO2 / polymer composite (RB-NH2) was dispersed in acetonitrile and transferred to a three-necked flask, and perfluoropolyether acyl fluoride was added dropwise. The mixture was ultrasonically dispersed for 30 minutes and reacted with magnetic stirring at room temperature for 15 hours to obtain a raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE).

[0030] The raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE) prepared by the invention is applied to fluid drag reduction and metal corrosion protection.

[0031] Compared with the prior art, the present invention firstly prepares a raspberry-shaped nano-SiO2 / polymer composite (RB) by a Pickering emulsion method, then adds the raspberry-shaped nano-SiO2 / copolymer composite (RB) and APTS (3-aminopropyltriethoxysilane) into ethanol for reaction, washes the product, and centrifuges to obtain an amino-type nano-SiO2 / polymer composite (RB-NH2), and finally disperses the amino-type nano-SiO2 / polymer composite (RB-NH2) in acetonitrile, then drips perfluoropolyether acyl fluoride, ultrasonically disperses, and reacts by magnetic stirring at room temperature to obtain a raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE) with excellent corrosion resistance, aging resistance, chemical stability and mechanical stability, which is used for fluid drag reduction and metal corrosion protection, wherein the perfluoropolyether acrylate prepolymer, as a reactive macromolecule, can not only undergo copolymerization reaction with the main monomer during the polymerization reaction, but also serve as an auxiliary nucleation site to induce the newly generated polymer to aggregate on its surface to form a raspberry-shaped structure, synergistically enhance the synergy with the nano-SiO2, and promote the stability of the Pickering emulsion. Description of the drawings:

[0032] Figure 1 This is a SEM (scanning electron microscope) image of the raspberry-shaped nano-SiO2 / perfluoropolyether composite of the present invention; wherein Figures a, b and c are Comparative Example 2, Example 1 and Example 2 respectively, and Figure d is Comparative Example 1. Specific implementation method:

[0033] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings.

[0034] Embodiment 1:

[0035] The specific process engineering of the preparation method of a raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite involved in this embodiment is as follows:

[0036] (I) Preparation of raspberry-like nano-SiO2 / polymer composites (RB)

[0037] First, a 250 ml four-necked flask with a reflux condenser was placed in a constant temperature oil bath, 15 parts by mass of nano-SiO2 aqueous dispersion and 60 parts by mass of deionized water were added to the four-necked flask, and then 9.7 parts by mass of St, 1.5 parts by mass of 1-VID, 0.16 parts by mass of DVB and 0.25 parts by mass of perfluoropolyether acrylate prepolymer were added, ultrasonically dispersed for 15 minutes, mechanically stirred for 20 minutes for pre-emulsification, nitrogen was introduced into the reaction system for protection, and the temperature was raised to 65°C;

[0038] Then, 0.12 parts by weight of APS initiator was dissolved in 15 parts by weight of deionized water, and added dropwise into the four-necked flask under constant stirring, and the temperature in the four-necked flask was maintained at 65° C. for more than 12 hours to ensure complete reaction;

[0039] Finally, the obtained emulsion was washed with deionized water and separated by centrifugation (1000 rpm, 10-15 min) for several times until the supernatant was clear, and the excess nano-SiO2 was removed to prepare a pure raspberry-shaped nano-SiO2 / polymer composite (RB);

[0040] (II) Preparation of raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE)

[0041] First, a 250 ml three-necked flask with a reflux condenser and a stirring magnet was placed in a constant temperature oil bath, 120 parts by mass of ethanol was added to the three-necked flask, and then 10 parts by mass of raspberry-shaped nano-SiO2 / polymer composite (RB) was added, and stirred, 7.5 parts by mass of ammonia water was added, and 8 parts by mass of APTS (3-aminopropyltriethoxysilane) was added dropwise. Nitrogen was introduced into the three-necked flask, and the temperature was kept at 65°C for 12 hours, during which uniform magnetic stirring (stirring rate was 180-300 rpm) was maintained;

[0042] Then, the product was washed with anhydrous ethanol and centrifuged (1000 rpm, 5 min), and the washing and centrifugation operations were repeated 3 times to obtain an amino-modified nano-SiO2 / polymer composite (RB-NH2);

[0043] Finally, the amino-modified nano-SiO2 / polymer composite (RB-NH2) was dispersed in 120 parts by weight of acetonitrile and transferred to a three-necked flask, 8 parts by weight of perfluoropolyether acyl fluoride was added dropwise, ultrasonically dispersed for 30 minutes, and reacted with magnetic stirring at room temperature for 15 hours to obtain a raspberry-shaped nano-SiO2 / perfluoropolyether composite (RB-PFPE) dispersion.

[0044] The concentration of the SiO2 dispersion is 30 wt%, the pH value is 9, and the particle size of the SiO2 is 50 nm;

[0045] The molecular weight of perfluoropolyether acyl fluoride is 1000 and the purity is >98%;

[0046] The molecular weight of the perfluoropolyether acrylate prepolymer is 1500.

[0047] Embodiment 2:

[0048] The specific process of the method for preparing the raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composite involved in this embodiment is the same as that in Example 1, the difference is that when preparing the nano-SiO2 / copolymer raspberry-shaped composite (RB), the added amount of perfluoropolyether acrylate prepolymer is 0.5 parts by mass.

[0049] Embodiment 3:

[0050] The specific process of the method for preparing the raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composite involved in this embodiment is the same as that in Example 1, except that when preparing the nano-SiO2 / copolymer raspberry-shaped composite (RB), the amount of perfluoropolyether acrylate prepolymer added is 0.75 parts by mass.

[0051] Comparative Example 1:

[0052] The specific process of the method for preparing the raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composite involved in this embodiment is the same as that in Example 1, except that 1-VID and perfluoropolyether acrylate prepolymer are not added when preparing the nano-SiO2 / copolymer raspberry-shaped composite (RB).

[0053] Comparative Example 2:

[0054] The specific process of the method for preparing the raspberry-shaped nano-SiO2 / perfluoropolyether superhydrophobic composite involved in this embodiment is the same as that in Example 1, the difference is that no perfluoropolyether acrylate prepolymer is added when preparing the nano-SiO2 / copolymer raspberry-shaped composite (RB).

[0055] The main raw materials of Comparative Examples 1-2 and Examples 1-3 are summarized in Table 1:

[0056] <![CDATA[Dispersion of SiO2]]> St DVB PFPE-EMA 1-VID <![CDATA[H2O]]> Comparative Example 1 15 9.7 0.16 0 0 75 Comparative Example 2 15 9.7 0.16 0 1.5 75 Example 1 15 9.7 0.16 0.25 1.5 75 Example 2 15 9.7 0.16 0.5 1.5 75 Example 3 15 9.7 0.16 0.75 1.5 75

[0057] The raspberry-like nano-SiO2 / perfluoropolyether composites prepared in Comparative Example 1-2 and Example 1-2 were observed by scanning electron microscopy. Figure 1 As shown, it can be seen that in the presence of the main monomer St and the auxiliary monomer 1-VID, the particles of the raspberry-shaped nano-SiO2 / perfluoropolyether complex all have a raspberry-shaped microstructure, and the particle size is uniform, with a particle size of about 100-120nm; while in the absence of the auxiliary monomer 1-VID, the particle surface of the raspberry-shaped nano-SiO2 / perfluoropolyether complex is relatively smooth, and the raspberry-like structure is not obvious.

[0058] The water drop contact angle and rolling angle of the raspberry-shaped nano-SiO2 / perfluoropolyether composite coating synthesized in Comparative Examples 1-2 and Examples 1-3 were measured respectively, and the results are shown in Table 2:

[0059] Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Contact Angle 140° 150° 153° 156° 158° Roll Angle 15° 9° 7° 6° 4°

[0060] It can be seen that in the absence of auxiliary monomers, the raspberry-shaped nano-SiO2 / perfluoropolyether composite coating synthesized in Comparative Example 1 is close to super-hydrophobicity, with a water drop contact angle of 140° and a rolling angle of 15°, but it still does not achieve the super-hydrophobic effect; in the presence of auxiliary monomers and the absence of perfluoropolyether acrylate prepolymer, the raspberry-shaped nano-SiO2 / perfluoropolyether copolymer composite coating synthesized in Comparative Example 2 has super-hydrophobicity, with a water drop contact angle of 150° and a rolling angle of 9°; the reaction body Under the condition that 2.5% of perfluoropolyether acrylate prepolymer based on the total amount of reactive monomers is pre-existed in the system, the superhydrophobicity of the raspberry-shaped nano-SiO2 / perfluoropolyether composite coating synthesized in Example 1 is further improved, the water droplet contact angle increases to 153°, and the rolling angle continues to decrease to 7°; when the amount of perfluoropolyether acrylate polymer increases to 7.5%, the water droplet contact angle of the raspberry-shaped nano-SiO2 / perfluoropolyether composite coating synthesized in Example 3 increases to 158°, and the rolling angle decreases to 4°.

[0061] Take 10 parts of the raspberry-shaped nano-SiO2 / perfluoropolyether composites prepared in Comparative Examples 1-2 and Examples 1-3, place them in 100-120 parts by mass of anhydrous ethanol for ultrasonic dispersion for 30 minutes, and coat them on 120 μm white corundum sandblasted aluminum alloy (2A12) samples, and heat and dry them in a constant temperature drying oven at 80 ° C to form a film; according to the method disclosed in the literature (Y. Liu, J. Liu, Y. Tian, ​​H. Zhang, R. Wang, B. Zhang, H. Zhang, Q. Zhang, Robust organic-Inorganic composite films with multifunctional properties of superhydrophobicity, self-healing, and drag reduction, Ind. Eng. Chem. Res. 58 (2019) 4468-4478.), the drag reduction rate of the samples at a water flow rate of 0.1-4.5 m / s was tested respectively, and the results are shown in Table 3:

[0062]

[0063]

[0064] It can be seen that the drag reduction rate of the coating with added perfluoropolyether acrylate polymer is higher than that of the coating without added perfluoropolyether acrylate polymer; when the flow rate is 0.5-0.1m / s, the drag reduction rate reaches more than 16-20%; when the flow rate is less than 1m / s, the drag reduction rate reaches more than 10%, and the drag reduction rate increases as the flow rate slows down.

Claims

1. A raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite, characterized in that: The raw materials include: nano-SiO2, main monomer, auxiliary monomer, cross-linking agent, initiator, amino-containing silane coupling agent, perfluoropolyether acyl fluoride, perfluoropolyether acrylate prepolymer and water; The main monomer is one of styrene, methacrylamide or methyl methacrylate; The auxiliary monomer is one or a combination of two of 1-vinylimidazole, 2-vinylimidazole, 3-vinylimidazole, 2-vinylpyridine and 4-vinylpyridine.

2. The raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite according to claim 1, characterized in that: The raw materials are as follows: 2-8 parts of nano-SiO2, 5-15 parts of main monomer, 0.5-2.5 parts of auxiliary monomer, 0.1-0.2 parts of crosslinking agent, 0.05-0.15 parts of initiator, 5-10 parts of amino-containing silane coupling agent, 5-10 parts of perfluoropolyether acyl fluoride, 0.1-1 parts of perfluoropolyether acrylate prepolymer, and the rest is water.

3. A raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite according to claim 1 or 2, characterized in that: The particle size of nano-SiO2 is 30-90nm; The molecular weight of perfluoropolyether acyl fluoride is 500-2000; The molecular weight of the perfluoropolyether acrylate prepolymer is 1000-5000.

4. A raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite according to claim 1 or 2, characterized in that: The crosslinking agent is one of ethylene glycol diacrylate, 1,4-butanediol diacrylate, and divinylbenzene; The initiator is one of ammonium persulfate, sodium persulfate and potassium persulfate; The amino-containing silane coupling agent is one of aminotriethoxysilane, 3-aminopropyltriethoxysilane and n-butyl-3-aminopropyltrimethoxysilane.

5. The raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite according to claim 4, characterized in that: Used in fluid drag reduction and metal corrosion protection.

6. A raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite and its preparation method, characterized in that: The process is: (I) Preparation of raspberry-like nano-SiO2 / polymer composites First, a four-necked flask with a reflux condenser is placed in a constant temperature oil bath, nano-SiO2 aqueous dispersion and deionized water are added to the four-necked flask, and then the main monomer, auxiliary monomer, cross-linking agent and perfluoropolyether acrylate prepolymer are added, ultrasonic dispersion, mechanical stirring pre-emulsification, and nitrogen protection is introduced; Then, the initiator was dissolved in deionized water and added dropwise to the four-necked flask under constant stirring; Finally, the emulsion obtained by the reaction was washed with deionized water and centrifuged to remove excess nano-SiO2, thereby preparing a pure raspberry-like nano-SiO2 / polymer composite. (II) Preparation of raspberry-like nano-SiO2 / perfluoropolyether composites First, a three-necked flask with a reflux condenser and a stirring magnet was placed in a constant temperature oil bath, ethanol was added to the three-necked flask, and then raspberry-shaped nano-SiO2 / copolymer composite was added, stirred, ammonia water was added, APTS was added dropwise, nitrogen protection was introduced, and stirring was performed at a constant speed; Then, the product is washed, centrifuged, and the washing and centrifugation are repeated to obtain an amino-modified nano-SiO2 / polymer composite; Finally, the amino-modified nano-SiO2 / polymer composite was dispersed in acetonitrile and transferred into a three-necked flask, and perfluoropolyether acyl fluoride was added dropwise, ultrasonically dispersed, and reacted by magnetic stirring at room temperature to obtain a raspberry-shaped nano-SiO2 / perfluoropolyether composite.

7. The method for preparing a raspberry-shaped nano-SiO2 / perfluoropolyether super-hydrophobic composite according to claim 5, characterized in that: The prepared raspberry-shaped nano-SiO2 / perfluoropolyether composites are used in fluid drag reduction and metal corrosion protection.

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