A kind of (SiC) with lotus leaf effectPPreparation method of super-hydrophobic membrane layer
Technical Field
The invention relates to the technical field of preparation and surface modification of inorganic powder materials, in particular to a preparation method of a silicon carbide super-hydrophobic film layer with a lotus leaf effect.
Background
Because the contact area of the super-hydrophobic surface and water is limited, the chemical reaction and chemical bond combination of the super-hydrophobic surface and the water are inhibited, and the super-hydrophobic surface has the advantages of pollution resistance, self-cleaning, ice and snow prevention, oxidation resistance, corrosion resistance and the like. In nature, leaves of many plants and some parts of animals have super-hydrophobic properties, such as lotus leaves, dragonfly wings, mosquito compound eyes, and the like. The lotus leaf is a plant which is firstly discovered to have super-hydrophobicity, and researches show that the surfaces with the super-hydrophobic characteristic in the nature all have a micro-nano structure similar to the surfaces of the lotus leaf, and the micro-nano structure is called as' lotus leafLeaf effect ". The wettability of a solid surface is determined by its surface chemical composition and roughness, and lower surface free energy and suitable roughness are important factors for preparing a superhydrophobic surface. The lower the free energy of the material surface, the stronger the hydrophobic properties of the membrane. Common methods for preparing the superhydrophobic film layer include phase separation, sol-gel method, chemical deposition, electrodeposition method, laser etching method, and the like. In general, hydrophobic groups in organic modifiers are introduced into particles to make the particles hydrophobic due to organic long chains grafted on the surfaces of the particles, and metal oxides such as TiO are more studied2、Al2O3ZnO, etc. How to Li Red, etc. of the related documents silane coupling agent surface modified titanium dioxide particles have super-hydrophobic property [ J]Fine chemical industry, 2014; single spray displacement of a hot water-repeat and oil-water separation of hydrophilic organic polymers modification of hydrophilic nano-alumina [ J]Progress in Organic Coatings, 2018. Populus and the like, a preparation method of a ZnO/AAO composite film with hydrophobic/super-hydrophobic performance, wherein patent numbers CN111996516A and CN101932661A are used for grafting fluoroalkyl silane to the surface of inorganic particles to obtain hydrophobic and oleophobic inorganic particles. However, the above preparation methods mostly require the use of organic solvents, and have high preparation cost, no environmental protection, complex process, or high requirements for raw materials and equipment.
Silicon carbide particles [ abbreviated as (SiC)P]Has the advantages of high hardness, wear resistance, high temperature resistance and the like, but shows hydrophilicity, particularly, the silicon carbide micro powder has small granularity, large specific surface area and strong hydrophilicity, and is related to (SiC)PThe preparation method of the super-hydrophobic membrane has few reports. The silicon carbide particles have super-hydrophobicity by an environment-friendly and simple method, are combined with excellent performances such as wear resistance, corrosion resistance and the like, can be widely applied to the fields such as self-cleaning, anti-icing, anti-fogging and anti-fouling, and have important value in the fields of scientific research, production, life and the like.
Disclosure of Invention
The invention aims to provide (SiC) which is environment-friendly, has low requirements on raw materials and can keep hydrophobicity for a long timePSuper-hydrophobic film layerThe preparation method of (1).
Based on accumulated experimental and theoretical experience, industrial waste (SiC) produced by Raymond mill and supersonic jet milling in the production processPUsing chemical deposition method to treat the irregular shape waste (SiC)PCarrying out surface modification and simple post-treatment, spontaneously constructing a micro-nano structure to obtain (SiC) with lotus leaf effectPA super-hydrophobic membrane layer.
The invention relates to a (SiC) with lotus leaf effectPThe preparation method of the super-hydrophobic membrane layer is carried out according to the following steps:
step one, (SiC)PPretreatment
Carrying out oxidation etching treatment by using a resistance furnace at the temperature of 900-1500 ℃ for 2-4 hours; carrying out hydrophilic treatment for 15-30 minutes at room temperature in a mixed solution of HF, HCl and distilled water with the volume ratio of 1:1: 10-15; then in the range of 0.2-1.5mol · L-1 TiCl3、0.5-2.0 g · L-1 PdCl2Activating in HCl mixed solution for 20-40 min at room temperature;
step two, preparation of deposition solution
Sequentially adding 50-80 g.L of oxidant-110 to 20 g/L of an accelerator-115-30 g.L of revival complexing agent-11.5-3.5 mg.L of rare earth-120 to 30 g.L of a reducing agent-1And 0.1-1.0 mg.L of stabilizer-1After uniformly mixing, adjusting the pH value to 7.0-8.5;
step three, preparation of the super-hydrophobic film layer
After the pretreatment of the first Step (SiC)PPreparing slurry by using distilled water as a solvent; wherein, (SiC)PMass ratio to distilled water: 1: 10-15. Adding into the deposition solution after ultrasonic dispersion, mechanically stirring, heating to 30-50 deg.C, depositing for 1-3 hr under the condition that pH value of the solution is 7.0-8.5, filtering, cleaning, drying, standing for more than 12 months to obtain the (SiC) with lotus leaf effectPAnd (3) preparing the super-hydrophobic membrane layer.
Furthermore, the oxidant is nickel sulfate or nickel chloride, the accelerator is sodium molybdate, the reactivation complexing agent is boric acid and sodium pyrophosphate, the reducing agent is sodium hypophosphite, and the stabilizer is thiourea or lead nitrate.
Further, the deposition solution is prepared as follows:
adding 50-80 g.L of nickel sulfate in sequence-110-20 g.L of sodium molybdate-110 to 20 g.L of sodium pyrophosphate-1Boric acid 5-10 g.L-11.5-3.5 mg.L of rare earth-1Sodium hypophosphite 20-30 g.L-1And 0.1-1.0 mg.L stabilizer-1After mixing evenly, adjusting the pH value to 7.0-8.5 by ammonia water.
Further, the volume ratio of the slurry to the deposition solution in the third step is 1: 8 to 20.
Further, the standing in the third step is performed under normal temperature conditions.
The beneficial technical effects of the invention are embodied in the following aspects:
(1) the invention firstly discovers that after the silicon carbide particles subjected to the chemical deposition treatment are placed for a long time, the silicon carbide particles can form obvious hydrophobic performance, and can form a super-hydrophobic film layer when meeting water and can be kept for a long time.
(2) Used (SiC)PFor industrial production 1200#In the process of monocrystalline silicon, the waste materials generated by Raymond mill and supersonic speed airflow pulverization are utilized, and the method is favorable for resource reutilization. Meanwhile, the used silicon carbide is micron-sized and irregular in shape, and the method has low requirements on raw materials and a wide application range.
(3) The method adopts environment-friendly pre-treatment, chemical deposition and post-treatment methods, does not generate secondary pollution, and is beneficial to
And (5) environmental protection. In the preparation process, the hydrophobic effect can be controlled by adjusting the formula of the deposition solution, process parameters, post-treatment conditions and the like, the repeatability and controllability of the process are improved, and the process gradually develops to scale.
(4) After surface modification (SiC)PThe appearance and the property are greatly changed, and the appearance color is changed from grey white to grey black. After being placed for more than 12 months, the water is changed from hydrophilicity to super hydrophobicity, and a super-hydrophobic film layer is formed. The contact angle test result shows that the static waterThe contact angle is 150-160 degrees, the rolling angle is less than 10 degrees, and good super-hydrophobicity is shown.
(5) The method disclosed by the invention is environment-friendly, simple to operate, low in requirements on equipment and raw materials, less in influence of temperature on the hydrophobic membrane, good in hydrophobicity within the temperature range of 10-80 ℃, and convenient to popularize and use.
Drawings
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
FIG. 1 shows a comparative picture of "silicon carbide raw powder, modified silicon carbide and photograph thereof dissolved in water in substance after standing for 18 months" in example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, and the right picture (c) is modified silicon carbide after standing for 18 months;
FIG. 2 shows "raw powder of silicon carbide, modified silicon carbide and the results obtained after standing still for 18 months" in example 1
A physical photograph comparison; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, and the right picture (c) is modified silicon carbide after standing for 18 months;
FIG. 3 shows a comparative photograph of "silicon carbide raw powder, modified silicon carbide and their dispersion in water after standing for 18 months" of example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, and the right picture (c) is modified silicon carbide after standing for 18 months;
FIG. 4 shows "silicon carbide raw powder, modified silicon carbide and SEM image contrast map thereof after standing for 18 months" of example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, the right picture (c) is modified silicon carbide after standing for 18 months, and (d) is modified silicon carbide after 18 months of high power;
FIG. 5 shows a comparison graph of "raw powder of silicon carbide, modified silicon carbide and EDS thereof after standing for 18 months" of example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, the right picture (c) is modified silicon carbide after standing for 18 months, and the right picture (d) is a selected area of the picture (c);
FIG. 6 shows "silicon carbide raw powder, modified silicon carbide and XRD contrast thereof after standing for 18 months" of example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, and the right picture (c) is modified silicon carbide after standing for 18 months;
FIG. 7 is a graph showing a comparison of "silicon carbide raw powder, modified silicon carbide and contact angle thereof after standing for 18 months" of example 1; wherein, the left picture (a) is silicon carbide raw powder, the middle picture (b) is modified silicon carbide, and the right picture (c) is modified silicon carbide after standing for 18 months.
Detailed Description
In order to more clearly illustrate the present invention, the present invention will be further described with reference to the following examples and the accompanying drawings. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
Example 1
Step one, (SiC)PSurface pretreatment
Will (SiC)PPutting the mixture into a resistance furnace, heating the mixture to 1200 ℃, and preserving the heat for 2 hours to carry out oxidation etching treatment. Taking 5g of the sample after oxidation etching, adding the sample into 200ml of mixed solution of HF, HCl and distilled water in a volume ratio of 1:1:10, and carrying out hydrophilic treatment for 20 minutes at room temperature; then the hydrophilic treated (SiC)PAdding 1.0 mol.L to 200ml-1 TiCl3、1.5 g · L-1 PdCl2Activating for 30 minutes at room temperature in an HCl mixed solution;
step two, preparation of deposition solution
Weighing 60 g.L of nickel carbonate-115 g.L of sodium molybdate-1Sodium pyrophosphate 15 g.L-1Boric acid 8 g.L-12.4 mg. L of rare earth-124 g.L of sodium hypophosphite-10.3 mg.L stabilizer-1Dissolving in distilled water to prepare 1L solution, and adjusting pH to 7.5 with ammonia water;
step three, preparation of the super-hydrophobic film layer
After pretreatment (SiC)PPreparing slurry by using distilled water as a solvent; wherein, (SiC)PMass ratio to distilled water: 1:12. After ultrasonic dispersion, adding the slurry into chemical deposition liquid under the conditions of normal pressure and normal temperature, wherein the volume ratio of the slurry to the deposition liquid is 1: stirring at 40 deg.C and pH 7.5, depositing for 2 hr, filtering, washing and drying. Will prepare (SiC)PPackaging in bags, and standing for 18 months.
Test method
Observing the micro morphology of the hydrophobic membrane by using a VEGA3 XMU type scanning electron microscope, and analyzing the element composition of the membrane layer by using an energy spectrometer; qualitatively analyzing the phase of the hydrophobic membrane by using an Shimadzu XRD-6100X-ray diffractometer; the contact angle of the hydrophobic membrane is tested by adopting a JCY series contact angle measuring instrument, the contact angle measuring instrument uses a digital camera, the highest resolution is 1280 multiplied by 1024, the frame frequency is 15-45/second, and simultaneously a micro-sampling device is adopted for sampling, and the highest injection precision can reach 0.005 mu l.
Test results
After surface modification (SiC)PThe appearance and the property of the material are greatly changed, the appearance color is changed from grey white to grey black, the material is mixed with water to form turbid liquid, the density of the turbid liquid is higher than that of the water, and the turbid liquid is settled at the bottom of a beaker after standing. The color remained grey-black after standing for 18 months, but when the particles were put into the water solution, the particles floated on the water surface and automatically dispersed to form a film [ FIG. 1 is a photograph of silicon carbide raw powder (a), modified silicon carbide (b) and water-soluble substance (c) after standing for 18 months](ii) a After magnetic rapid stirring and mixing, the mixture still had distinct layering with the aqueous solution as shown in FIG. 2 [ FIG. 2 is a photograph showing a comparison of the original powder of silicon carbide (a), the modified silicon carbide (b) and the actual photographs thereof after standing for 18 months (c) under magnetic stirring]. After the stirring is stopped, the particles spontaneously gather on the liquid surface again to form a hydrophobic film layer, as shown in fig. 3.
FIG. 4 is a SEM comparison of raw silicon carbide powder (a), modified silicon carbide powder (b) and its rest 18 months later (c), and it can be seen that the raw powder silicon carbide surface is smooth, and the deposits are crumbs generated in the crushing process and have different shapes; a new layer of substance is deposited on the surface of the modified silicon carbide, the coating is relatively flat, and the crushing is not obvious; after standing for 18 months, cellular micro-nano structures with different sizes are formed on the surface of the silicon carbide. FIG. 5 is a comparison of EDS of silicon carbide raw powder (a), modified silicon carbide (b) and its (c) after standing for 18 months. The observation shows that the EDS spectrum of the raw powder silicon carbide is mainly a Si peak, and the Ni peak content is zero; the EDS spectrum of the modified silicon carbide shows an obvious Ni peak; the EDS spectrum of the silicon carbide still shows obvious Ni peak after standing for 18 months.
FIG. 6 is a XRD comparison of silicon carbide raw powder (a), modified silicon carbide (b) and its (c) after standing for 18 months. As can be seen from FIG. 6, the raw powder silicon carbide isαSilicon carbide, XRD only observes silicon carbide phases; XRD of modified silicon carbide is 2θ=45 DEG has obvious Ni characteristic diffraction peak; XRD of silicon carbide after standing for 18 months is 2θAnd the diffraction peak of Ni is obvious when the angle is 45 degrees. Fig. 7 is a comparison of contact angle tests of silicon carbide raw powder (a), modified silicon carbide (b) and silicon carbide (c) after standing for 18 months, and the results show that the silicon carbide raw powder and the modified silicon carbide have no hydrophobicity, the static water contact angle of the silicon carbide after standing for 18 months is 156 degrees, the rolling angle is 5 degrees, good superhydrophobicity is shown, and the silicon carbide can be stored for more than 3 months.
Example 2
Step one, (SiC)PSurface pretreatment
Will (SiC)PPutting the mixture into a resistance furnace, heating the mixture to 1000 ℃, and preserving heat for 3 hours for oxidation etching treatment. Taking 7g of the sample after oxidation etching, adding the sample into 300ml of mixed solution of HF, HCl and distilled water in a volume ratio of 1:1:12, and carrying out hydrophilic treatment for 25 minutes at room temperature; then the hydrophilic treated (SiC)P300ml of 0.8 mol. L was added-1TiCl3、1.0 g·L- 1PdCl2Activating for 35 minutes at room temperature in an HCl mixed solution;
step two, preparation of deposition solution
Weighing 70 g.L of nickel carbonate-118 g.L of sodium molybdate-1Sodium pyrophosphate 16 g.L-1Boric acid 6 g.L-12.6 mg. L of rare earth-126 g.L of sodium hypophosphite-10.5 mg.L stabilizer-1Dissolving in distilled water to prepare 1L solution, and adjusting pH to 8.0 with ammonia water;
step three, preparation of the super-hydrophobic film layer
After pretreatment (SiC)PDistilled water as solventPreparing slurry; wherein, (SiC)PMass ratio to distilled water: 1:14. After ultrasonic dispersion, adding the slurry into chemical deposition liquid under the conditions of normal pressure and normal temperature, wherein the volume ratio of the slurry to the deposition liquid is 1: 15, stirring, reacting at 45 ℃ and pH value of 8.0, depositing for 2 hours, filtering, cleaning and drying. Will prepare (SiC)PPackaging in bags, and standing for 15 months.
Test method
Observing the micro morphology of the hydrophobic membrane by using a VEGA3 XMU type scanning electron microscope, and analyzing the element composition of the membrane layer by using an energy spectrometer; qualitatively analyzing the phase of the hydrophobic membrane by using an Shimadzu XRD-6100X-ray diffractometer; the contact angle of the hydrophobic membrane is tested by adopting a JCY series contact angle measuring instrument, the contact angle measuring instrument uses a digital camera, the highest resolution is 1280 multiplied by 1024, the frame frequency is 15-45/second, and simultaneously a micro-sampling device is adopted for sampling, and the highest injection precision can reach 0.005 mu l.
Test results
After surface modification (SiC)PThe appearance and the property are greatly changed, the appearance color is changed from grey white to grey black, the grey black is mixed with water to form turbid liquid, the density is higher than that of the water, and the turbid liquid is settled at the bottom of a beaker after standing. After being placed for 15 months, the color is still grey black, but when the water-based organic silicon gel is placed in the water solution, the particles float on the water surface and automatically disperse to form a film, the film forming effect is the same as that shown in figure 1, and after the magnetic force is rapidly stirred and mixed, the particles still have obvious layering with the water solution, and the layering effect is the same as that shown in figure 2. After stirring is stopped, the particles spontaneously gather on the liquid surface again to form a hydrophobic membrane layer, and the same hydrophobic membrane layer effect as that of the figure 3 is shown. The contrast observation of the silicon carbide raw powder, the modified silicon carbide and SEM of the silicon carbide raw powder and the modified silicon carbide after standing for 15 months shows that the silicon carbide surface of the raw powder is smooth, the sediment is crushed powder generated in the crushing process, and the shapes of the sediment are different; a new layer of substance is deposited on the surface of the modified silicon carbide, the coating is relatively flat, and the crushing is not obvious; after standing for 15 months, cellular micro-nano structures with different sizes are formed on the surface of the silicon carbide. The comparison of the silicon carbide raw powder, the modified silicon carbide and the EDS (ethylene diamine tetraacetic acid) after the silicon carbide raw powder and the modified silicon carbide are kept still for 15 months shows that the silicon carbide raw powder mainly shows a Si peak and has no Ni peak; the EDS spectrum of the modified silicon carbide shows an obvious Ni peak; EDS spectra of silicon carbide after 15 months of standingA significant Ni peak still appears. The comparison of XRD (X-ray diffraction) of the silicon carbide raw powder, the modified silicon carbide and the silicon carbide after standing for 15 months shows that the silicon carbide raw powder is silicon carbideαSilicon carbide, only the silicon carbide diffraction peaks are observed; modified silicon carbide is in 2θ=45 DEG has obvious Ni characteristic diffraction peak; of silicon carbide after 15 months of standing at 2θAnd the diffraction peak of Ni is obvious when the angle is 45 degrees. Contact angle tests show that the silicon carbide raw powder and the modified silicon carbide have no hydrophobicity, the static water contact angle of the modified silicon carbide is 152 degrees and the rolling angle is 8 degrees after the silicon carbide raw powder and the modified silicon carbide are kept for 15 months, the silicon carbide is good in super-hydrophobicity, and the silicon carbide can be stored for more than 3 months.
The above embodiments are only exemplary of the invention, and it should be noted that any simple variation, modification or other equivalent replacement by those skilled in the art without inventive work falls within the scope of the present invention without departing from the core of the present invention.