Airflow-assisted electrostatic spraying equipment, preparation method and application

Abstract

The invention relates to the technical field of electrostatic spraying, and discloses airflow-assisted electrostatic spraying equipment, a preparation method and application, the airflow-assisted electrostatic spraying equipment comprises a material assembly used for conveying a liquid material, a coaxial needle and a triaxial displacement mechanism capable of moving in three axial directions, the material assembly is connected to an outer needle of the coaxial needle, and the airflow-assisted electrostatic spraying equipment further comprises an air source assembly, the gas source assembly is used for conveying pressure-adjustable high-pressure gas to the inner needle of the coaxial needle; a shell of the coaxial needle is connected to an electrostatic generator, and the coaxial needle is fixedly connected with a sliding block of the three-axis displacement mechanism through a needle head fixing support. Compared with electrostatic spraying without airflow assistance, the air source assembly is adopted for conveying high-pressure air, efficient and rapid spraying can be achieved, and the device is suitable for fine spraying of low-viscosity liquid and heterogeneous liquid; compared with static-free mechanical spraying, the sphericity degree of the obtained microspheres is obviously improved, the particle size is smaller and more uniform, and the fog pollution in the spraying process is reduced in a large area.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic spraying, and in particular to an airflow-assisted electrostatic spraying device, a preparation method and an application thereof. Background Art

[0002] The research on the principle of electrostatic spray technology began in the early 20th century. After the electrostatic sprayer was developed in the 1970s, it began to be used in the market. Its working principle is to establish a high-voltage electrostatic field between the nozzle and the receiving device. Under the action of the external high-voltage electrostatic field, the charged droplets will form an electrostatic field force inside the droplets. At the same time, the droplets are also affected by a surface tension opposite to the electric field force. As the electric field intensity gradually increases, the electric field force overcomes the surface tension, causing the charged droplets to burst unstably, forming micron- or nano-sized charged droplets. In industrial production, electrostatic spray technology is widely used in many fields, including agricultural plant protection, industrial spraying, biomedicine and other fields.

[0003] The existing electrostatic spray technology has a slow spray speed and is greatly affected by the stability of the charging effect, resulting in uneven droplet dispersion and unstable spraying. The application and promotion of electrostatic spray technology in the field of fuel cells is relatively difficult, so it is necessary to provide a more efficient electrostatic spray device.

[0004] The existing Chinese patent with publication number CN217094113U provides an electrostatic spray device, which includes: a housing including a liquid outlet and a liquid reservoir for storing a liquid medium; a nozzle structure located in the housing and connected to the liquid reservoir and the liquid outlet; an ultrasonic atomizer, etc. This technology greatly improves the adsorption effect of droplets on target objects to a certain extent, but there is a problem of low spray efficiency.

[0005] The existing Chinese patent with publication number CN108441972A discloses an airflow-assisted portable electrospinning device and its application. The device includes an insulating shell, a large-capacity secondary battery, a charging jack, a high-voltage wire, a high-voltage electrostatic generating unit, a high-voltage electrostatic generating switch, an airflow duct connector, an airflow duct, a syringe fixing bracket, a disposable syringe, a needle fixing bracket, a stainless steel needle, and an airflow directional cover. The device uses a large-capacity secondary battery as a power source, generates high-voltage static electricity through a high-voltage electrostatic generating unit, and connects to an external airflow generator through an airflow duct connector. The stainless steel needle is fixed on the same central axis as the airflow duct, and electrospinning is performed with the assistance of airflow. The device can achieve a spray effect through modification to a certain extent, but the device uses a battery as a power source, and there is a certain risk of environmental pollution when the discarded battery is discarded, and the device cannot achieve a uniform spraying effect because it is a handheld device. In the electrostatic spraying process, since the external electric field will apply the same charge to the small droplets, and there is a charge repulsion effect between the small droplets with the same charge, the spray droplets will be distributed disorderly at the receiving target position.

[0006] There is a Chinese patent with publication number CN104225738. The patent technology discloses an airflow-guided directional in-situ hot melt electrostatic spraying device and its application. The device includes a control box, a liquid reservoir, a temperature control system, a pressurization system, an electric stirring system, a liquid inlet pipe, a spray gun handle, a nozzle, an airflow duct and a high-voltage wire. Under the action of airflow guidance, the device can realize the fixed-point, directional and in-situ precise spraying of liquid medicine and medical biomaterials directly at the target, but the structural integration of the device is not high and the volume is large. Summary of the invention

[0007] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide an airflow-assisted electrostatic spray device, a preparation method and an application, which can be applied in the field of fuel cells to evenly disperse the catalyst in the solution, and evenly spray the catalyst dispersion on the proton exchange membrane, carbon paper or carbon cloth through airflow-assisted electrostatic spraying, thereby efficiently completing the catalyst coating.

[0008] The present invention provides the following technical solutions:

[0009] In the first aspect, the present invention provides an airflow-assisted electrostatic spray device, which includes a material component for conveying liquid material, a coaxial needle and a three-axis displacement mechanism capable of three-axial movement, wherein the material component is connected to the outer needle of the coaxial needle, and further includes an air source component, wherein the air source component is used to convey adjustable high-pressure gas to the inner needle of the coaxial needle; the outer shell of the coaxial needle is connected to an electrostatic generator, and the coaxial needle is connected and fixed to a slider of the three-axis displacement mechanism via a needle fixing bracket.

[0010] According to some embodiments, the gas source assembly includes a high-pressure gas flow source, a gas chromatography drying tube, an adjustable pressure gauge, a catheter and a catheter connector connected in sequence, and the catheter connector is connected to the gas source input end of the coaxial needle.

[0011] According to some embodiments, the high-pressure gas flow source is selected from an air compressor or a high-pressure gas cylinder.

[0012] According to some embodiments, the material used to manufacture the catheter and the catheter connector is an insulating material.

[0013] According to some embodiments, the needle fixing bracket is an electrospinning nozzle bracket made of plastic material, and the needle fixing bracket is connected and fixed to the slider of the three-axis displacement mechanism through a screw.

[0014] According to some embodiments, the electrostatic generator is connected to the housing of the coaxial needle via a high voltage wire clamp.

[0015] According to some embodiments, the material assembly includes a material conveyor and a material reservoir, and the material conveyor is selected from a peristaltic pump or a micro-injection pump.

[0016] According to some embodiments, the coaxial needle is detachable or fixed, and is connected to the needle fixing bracket via a Luer connector.

[0017] In a second aspect, the present invention further provides a method for preparing the above-mentioned airflow-assisted electrostatic spray device, comprising the following steps:

[0018] S1: firstly connect the solution to the material conveyor through the catheter, and connect it to the outer needle of the coaxial needle;

[0019] S2: Then connecting the high-pressure airflow source to the inner needle of the coaxial needle through the catheter;

[0020] S3: connecting the electrostatic generator to the housing of the coaxial needle, and starting the electrostatic generator, the material conveyor and the high-pressure air flow source;

[0021] S4: adjusting the position of the coaxial needle through the three-axis displacement mechanism so that the front end is vertically directed to the collection end;

[0022] S5: adjusting the electrostatic voltage and the flow rate of the liquid material and adjusting the air pressure using an adjustable pressure gauge, so that the solution flows out from the inner needle of the coaxial needle, forms uniform small droplets under the action of the high-voltage electric field and the airflow, and falls on the collection end in a directional and stable manner;

[0023] S6: After spraying is completed, disconnect the electrostatic generator switch, disconnect the material conveyor switch, disconnect the high-pressure air flow source, and end the spraying.

[0024] In a third aspect, the present invention also provides the application of the above-mentioned airflow-assisted electrostatic spray device, wherein the airflow-assisted electrostatic spray device is applied in the preparation of microspheres, spray coatings or emulsions.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) Compared with electrostatic spraying without airflow assistance, the present invention uses an air source component to deliver high-pressure gas, which can spray efficiently and quickly, and is suitable for fine spraying of low-viscosity liquids and heterogeneous liquids.

[0027] (2) Compared with non-static mechanical spray, the sphericity of the obtained microspheres is significantly improved, the particle size is smaller and more uniform, and the fog pollution is greatly reduced during the spraying process.

[0028] (3) The equipment has a high degree of overall integration and can achieve long-term continuous spraying.

[0029] (4) The equipment has a wide range of applications, such as the preparation of microspheres, coatings and emulsions. For example, in the field of fuel cells, the catalyst dispersion is evenly sprayed on the proton exchange membrane, carbon paper or carbon cloth to efficiently complete the catalyst coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the airflow-assisted electrostatic spray equipment provided in Example 1 of the present invention.

[0031] Figure 2 This is a schematic diagram of the structure of the airflow-assisted electrostatic spray equipment provided in Example 2 of the present invention for preparing membrane electrodes.

[0032] Figure 3 A schematic diagram of the structure of graphene oxide aerogel microspheres prepared by the airflow-assisted electrostatic spray equipment provided in Example 3 of the present invention.

[0033] Figure 4 This is an electron scanning microscope image of the membrane electrode obtained in Example 5 of the present invention.

[0034] Figure 5 This is an electron scanning micrograph of graphene oxide aerogel microspheres obtained in Example 6 of the present invention.

[0035] Figure 6 This is an electron scanning microscope image of graphene oxide aerogel microspheres obtained in Comparative Example 1 of the present invention.

[0036] In the figure:

[0037] 1-high-pressure air flow source; 2-gas chromatography drying tube; 3-adjustable pressure gauge; 4-catheter; 5-catheter connector; 6-high-voltage wire; 7-electrostatic generator; 8-material conveyor; 9-material storage; 10-coaxial needle; 11-needle fixing bracket; 12-three-axis displacement mechanism; 12-1-lifting platform; 12-2-slide bar; 12-3-slide block; 12-4-laser displacement sensor; 13-air compressor; 14-proton exchange membrane; 15-peristaltic pump; 16-microinjection pump; 17-receiving bath; 18-super low-temperature circulation tank. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] Example 1

[0041] like Figure 1 The present embodiment provides an airflow-assisted electrostatic spray device, which includes an air source component, a material component, a coaxial needle 10 and a three-axis displacement mechanism 12. The air source component is used to convey high-pressure gas, and the material component is used to convey liquid material; the inner needle of the coaxial needle 10 conveys the air source, and the outer needle conveys the material. The air source input end of the coaxial needle 10 is connected to the air source component, and the material input end is connected to the material component. The coaxial needle 10 is connected to the electrostatic generator 7 through a high-voltage wire 7; the top needle part of the coaxial needle 10 is fixed to the three-axis displacement mechanism 12 through an insulating needle fixing bracket 11 and is movable.

[0042] The gas source component of this embodiment includes a high-pressure gas flow source 1, a gas chromatography drying tube 2, an adjustable pressure gauge 3, a catheter 4 and a catheter connector 5. The catheter connector 5 is installed at the gas source input end of the coaxial needle 10; the material component includes a material conveyor 8 and a material storage tank 9 connected to the material input end of the coaxial needle 10 through the catheter 5. The coaxial needle 10 is detachable for easy assembly.

[0043] The three-axis displacement mechanism 12 of this embodiment is a three-axis motion platform, which includes a frame, a slide bar 12-2, a slider 12-3, a lifting platform 12-1 (with heating), a laser displacement sensor 12-4, a servo drive mechanism and a control system. The slider 12-3 of the three-axis displacement mechanism 12 slides freely on the slide bar 12-2, and the slider 12-3 can move in two dimensions of the X axis and the Y axis. The lifting platform 12-1 can move in the Z axis direction, and the height between the coaxial needle tip and the receiver is adjusted by the linkage of the laser displacement sensor 12-4 and the servo drive mechanism. The three-axis displacement mechanism 12 is a prior art and will not be described here.

[0044] In this embodiment, the material is stored in the material storage device 8 and connected to the outer needle of the coaxial needle 10 through the material conveyor 9 and the conduit 4 for conveying the material. The high-pressure air flow source 1 is connected to the gas chromatography drying tube 2, the adjustable pressure gauge 3 and the inner needle of the coaxial needle 10 through the conduit 4. The high-pressure gas is purified and dried by the gas chromatography drying tube 2, and the pressure is adjusted by the adjustable pressure gauge 3. The electrostatic generator 7 is connected to the outer shell of the coaxial needle 10 through a high-voltage wire clamp; the coaxial needle 10 is fixed on the slider 12-3 of the three-axis displacement mechanism 12 through an insulating needle fixing bracket 11, and the needle fixing bracket 11 is a commonly used electrospinning nozzle bracket made of plastic material.

[0045] When this embodiment is used, the dispersed slurry is first loaded into the material storage container 8, the material conveyor 9 is connected to the material storage container 8 and the outer needle of the coaxial needle 10 through the conduit 4, and then the high-pressure airflow source 1 is connected to the inner needle of the coaxial needle 10 through the conduit 4, the electrostatic generator 7 and the coaxial needle 10 are connected with the high-voltage wire 6, and the coaxial needle 10 is fixed on the slider 12-3 of the three-axis displacement mechanism 12 with the needle fixing bracket 11, and then the distance between the top of the needle position of the coaxial needle 10 and the receiving end is adjusted by the three-axis displacement mechanism 12, the material conveyor 9 and the electrostatic generator 7 are turned on, so that the high-pressure airflow flows out from the inner needle of the coaxial needle 10, and the material flows out from the outer needle, and the applied air pressure, high-voltage electrostatic voltage and liquid material flow rate are adjusted. Under the action of the high-voltage electric field and airflow, the liquid material is atomized and dispersed into uniform small droplets, and sprayed in a directionally and stably, the electrostatic generator 7 and the material conveyor 9 are disconnected, and the high-pressure airflow source 1 is disconnected, and the spraying ends.

[0046] Example 2

[0047] like Figure 2This embodiment is based on the airflow-assisted electrostatic spraying equipment provided in Example 1 to prepare a membrane electrode, wherein the material conveyor 9 is a peristaltic pump 15. The high-pressure airflow source 1 is an air compressor 13. The high-pressure air generated by the air compressor 13 is purified and dehydrated by the gas chromatography drying tube 2, and then adjusted by the adjustable pressure gauge 3 to provide a stable high-pressure airflow. The proton exchange membrane 14 is located directly below the coaxial needle 10, receives the atomized spherical droplets, and forms a uniform liquid film on its surface. At the same time, the heating function of the lifting platform 12-1 is used to quickly evaporate the solvent in the catalyst dispersion, so that the catalyst is evenly spread on the proton exchange membrane 14.

[0048] An adjustable pressure gauge 3 is arranged between the conduit 4 and the gas chromatography drying tube 2. The conduit 4 and the conduit connector 5 are made of insulating materials to avoid interference with the high-voltage electrostatic field and improve the safety of the electrostatic spinning device.

[0049] The needle of the stainless steel coaxial needle 10 is a detachable coaxial needle, which can be conveniently matched with inner and outer needles of different calibers according to different experimental requirements.

[0050] The peristaltic pump 15 regulates the atomization effect of the liquid material by adjusting the liquid material delivery flow rate.

[0051] The high-pressure air flow source 1 is adjusted through the adjustable pressure gauge 3 to adjust the pressure and control the atomization effect of the liquid material.

[0052] The high-voltage electrostatic generator 7 adjusts the atomization effect of the liquid material by applying different voltages.

[0053] Example 3

[0054] like Figure 3 This embodiment is based on the airflow-assisted electrostatic spraying device provided in Example 1 to prepare graphene oxide aerogel microspheres, wherein the material component is a microinjection pump 16. The super low temperature circulation tank 18 and the receiving bath 17 are located directly below the coaxial needle 10. The super low temperature circulation tank 18 is used to maintain the low temperature state of the receiving bath, and the receiving bath 17 is used to receive the atomized spherical droplets, and quickly freeze the atomized droplets to form ice microspheres, fixing the droplet shape.

[0055] Example 4

[0056] This embodiment provides a method for preparing the above-mentioned airflow-assisted electrostatic spray device, the purpose of which is to prepare an electrostatic spray, comprising the following steps:

[0057] 1. First, connect the solution to the material conveyor 9 through the catheter 4, and connect it to the outer needle of the coaxial needle 10;

[0058] 2. Then connect the high pressure air flow source 1 to the inner needle of the coaxial needle 10 through the catheter 4;

[0059] 3. Use a high-voltage electrostatic clamp to connect the electrostatic generator 7 to the housing of the coaxial needle 10, and start the electrostatic generator 7, the material conveyor 9 and the high-pressure air flow source 1;

[0060] 4. Use the three-axis displacement mechanism 12 to adjust the position of the coaxial needle 10 so that the front end points vertically toward the collection end;

[0061] 5. Adjust the electrostatic voltage and the flow rate of the liquid material and use the adjustable barometer 3 to adjust the air pressure so that the solution flows out from the inner needle of the coaxial needle 10, forms uniform small droplets under the action of the high-voltage electric field and airflow, and falls on the collection end in a directional and stable manner;

[0062] 6. After spraying is completed, turn off the switch of the electrostatic generator 7, turn off the switch of the material conveyor 9, and turn off the high-pressure air flow source 1 to end the spraying.

[0063] Example 5

[0064] This embodiment is based on the airflow-assisted electrostatic spraying device provided in Example 2 to prepare a membrane electrode, and the preparation process is as follows:

[0065] 40 mg of platinum carbon catalyst was weighed and mixed with ionized water, isopropanol and 5 wt % Nafion 117 solution, and ultrasonicated in an ice water bath for 2 hours to uniformly disperse the catalyst to obtain a uniform catalyst dispersion. Use a suitable glass bottle as a catalyst dispersion storage tank, connect the dispersion storage tank, peristaltic pump 15 and the outer needle of the coaxial needle, then connect the air compressor 13, gas chromatography drying tube 2, adjustable pressure gauge 3 and the inner needle of the coaxial needle, then connect the high-voltage electrostatic generator 7, use the three-axis displacement mechanism 12 and the laser displacement sensor 12-4 to adjust the distance between the front end of the coaxial needle 10 and the proton exchange membrane 14 to 4 cm, turn on the air compressor 13, peristaltic pump 15 and high-voltage electrostatic generator 7, and set the air pressure to 0.35MPa, the electrostatic voltage to 15KV, and the liquid flow rate to 0.2mL / min. The catalyst dispersion is sprayed out from the outer needle of the coaxial needle, and uniform droplets are formed under the action of the high-voltage electric field and airflow, and are deposited on the proton exchange membrane in a directionally and uniform manner. After the spraying is completed, the high-voltage electrostatic generator 7 switch is disconnected, the peristaltic pump 15 is turned off, the high-pressure airflow is disconnected, and the spraying is completed. Figure 4 This is a scanning electron microscope image of the obtained membrane electrode.

[0066] Example 6

[0067] This embodiment is based on the airflow-assisted electrostatic spraying equipment provided in Example 3 to prepare graphene oxide aerogel microspheres, and the preparation process is as follows:

[0068] The graphite oxide dispersion is loaded into a syringe, and a coaxial needle 10 with an outer diameter of 19G and an inner diameter of 27G is installed on the syringe. The syringe is then loaded onto a micro-injection pump 16. The center position of the coaxial needle 10 is adjusted by a three-axis displacement mechanism 12, and the height between the coaxial needle 10 and the liquid surface of the receiving bath 17 is controlled to be 10 cm. The receiving bath is a low-melting-point non-polar solution. A beaker containing a low-melting-point oily solution is placed in a super-low-temperature circulation tank 18 to maintain the low-temperature state of the receiving bath 17. A pressure of 0.3 MPa and a high voltage of 15 kV are applied. Electrostatics, a micro-syringe controls the graphene oxide dispersion to perform airflow-assisted electrostatic spraying at a flow rate of 0.5 mL / min. The graphene oxide dispersion forms small droplets with uniform particle size under the dual effects of airflow and high-voltage static electricity. The small droplets fall into a low-melting-point oily solvent to form an oil-in-water emulsion, and quickly form ice microspheres under a low-temperature environment. The ice microspheres and the low-melting-point non-polar solution are separated by a sieve, and then the ice microspheres are freeze-dried at -50°C and 30 Pa for 60 hours to obtain graphene oxide aerogel microspheres, such as Figure 5 .

[0069] Comparative Example 1

[0070] The graphite oxide dispersion is loaded into a syringe, and a coaxial needle 10 with an outer diameter of 19G and an inner diameter of 27G is installed on the syringe. The syringe is loaded onto a micro-injection pump 16, and the needle center position of the coaxial needle 10 is adjusted by a three-axis displacement mechanism 12 to control the height between the needle center and the liquid level of the receiving bath 17 to be 10 cm. The receiving bath 17 is a low-melting-point non-polar solution, and a beaker containing a low-melting-point oily solution is placed in a super-low-temperature circulation tank 18 to maintain the low-temperature state of the receiving bath. The micro-injector controls the graphene oxide dispersion to be electrostatically sprayed with an airflow at a flow rate of 0.2 mL / min with a high-voltage static electricity of 15 kV. The graphene oxide dispersion forms small droplets under the action of high-voltage static electricity. The small droplets fall into the low-melting-point oily solvent to form an oil-in-water emulsion, and quickly form ice microspheres under a low-temperature environment. The ice microspheres and the low-melting-point non-polar solution are separated by a sieve, and then the ice microspheres are freeze-dried for 60 hours at -50°C and 30 Pa to obtain graphene oxide aerogel microspheres, such as Figure 6 .

[0071] The spraying speed of Comparative Example 1 is slower than that of Example 6, and the prepared graphene oxide aerogel microspheres have a larger particle size and a worse sphericity.

[0072] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An airflow-assisted electrostatic spray device, comprising a material assembly for conveying liquid material, a coaxial needle, and a triaxial displacement mechanism for triaxial movement, wherein the material assembly is connected to an outer needle of the coaxial needle, characterized in that: It also includes an air source component, which is used to deliver adjustable high-pressure gas to the inner needle of the coaxial needle; the outer shell of the coaxial needle is connected to the electrostatic generator, and the coaxial needle is connected and fixed to the slider of the three-axis displacement mechanism through a needle fixing bracket.

2. The airflow-assisted electrostatic spray device according to claim 1, characterized in that: The gas source assembly comprises a high-pressure gas flow source, a gas chromatography drying tube, an adjustable pressure gauge, a catheter and a catheter connector which are connected in sequence, and the catheter connector is connected to the gas source input end of the coaxial needle.

3. The airflow-assisted electrostatic spray device according to claim 2, characterized in that: The high-pressure air flow source is selected from an air compressor or a high-pressure gas cylinder.

4. The airflow-assisted electrostatic spray device according to claim 2, characterized in that: The material used to make the catheter and the catheter connector is insulating material.

5. The airflow-assisted electrostatic spray device according to claim 1, characterized in that: The needle fixing bracket is an electrospinning nozzle bracket made of plastic material, and the needle fixing bracket is connected and fixed to the slider of the three-axis displacement mechanism through a screw rod.

6. The airflow-assisted electrostatic spray device according to claim 1, characterized in that: The electrostatic generator is connected to the outer shell of the coaxial needle through a high-voltage wire clamp.

7. The airflow-assisted electrostatic spray device according to claim 1, characterized in that: The material assembly comprises a material conveyor and a material storage device, and the material conveyor is selected from a peristaltic pump or a micro-injection pump.

8. The airflow-assisted electrostatic spray device according to claim 1, characterized in that: The coaxial needle is detachable or fixed, and is connected to the needle fixing bracket via a Luer connector.

9. A method for preparing the airflow-assisted electrostatic spray device according to claim 2, characterized in that: The following steps are involved: S1: firstly connect the solution to the material conveyor through the catheter, and connect it to the outer needle of the coaxial needle; S2: Then connecting the high-pressure airflow source to the inner needle of the coaxial needle through the catheter; S3: connecting the electrostatic generator to the housing of the coaxial needle, and starting the electrostatic generator, the material conveyor and the high-pressure air flow source; S4: adjusting the position of the coaxial needle through the three-axis displacement mechanism so that the front end is vertically directed to the collection end; S5: adjusting the electrostatic voltage and the flow rate of the liquid material and adjusting the air pressure using an adjustable pressure gauge, so that the solution flows out from the inner needle of the coaxial needle, forms uniform small droplets under the action of the high-voltage electric field and the airflow, and falls on the collection end in a directional and stable manner; S6: After spraying is completed, disconnect the electrostatic generator switch, disconnect the material conveyor switch, disconnect the high-pressure air flow source, and end the spraying.

10. Use of the airflow-assisted electrostatic spray device according to any one of claims 1 to 8, characterized in that: The airflow-assisted electrostatic spraying device is used in the preparation of microspheres, spray coatings or emulsions.

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