Airflow-assisted electrostatic spinning device, nanofiber with bead chain structure prepared by adopting device and preparation method of nanofiber

Abstract

The invention relates to the field of electrostatic spinning, and discloses an airflow-assisted electrostatic spinning device, nanofiber with a bead chain structure prepared by adopting the device and a preparation method. The device comprises a conveying channel, an electrostatic spinning nozzle, an auxiliary airflow nozzle, an air inlet hole, an exhaust hole, a collecting buffer wheel and a collecting funnel. The electrostatic spinning nozzle is mounted at the upper end of the conveying channel; the auxiliary airflow nozzle and the air inlet are formed in the left side of the conveying channel; the exhaust hole and the collecting buffer wheel are arranged on the right side of the conveying channel; the collecting funnel is positioned below the collecting buffer wheel; the electrostatic spinning nozzle is connected with the anode of the high-voltage power supply and communicated with the liquid supply device; the collecting buffer wheel is connected with the negative electrode of the high-voltage power supply and is externally connected with a power device, so that the collecting buffer wheel can rotate. By adopting the technical scheme, the nanofiber with a bead chain structure can be prepared.

Description

Technical Field

[0001] This invention relates to the field of electrospinning, and particularly to an airflow-assisted electrospinning apparatus and nanofibers with a beaded chain structure prepared using the apparatus, as well as a preparation method thereof. Background Technology

[0002] Electrospinning is a typical technique for preparing ultrafine fibers using electrostatic force. It involves applying a high-voltage electrostatic field to a polymer solution or melt, causing droplets to form Taylor cones and generate jets. These jets undergo stretching, whipping, and unstable motion under the influence of the electric field, ultimately solidifying and depositing into nano- to micron-sized fibers. Fibers prepared by this method possess characteristics such as small diameter, large specific surface area, and high porosity, showing broad application prospects in various fields including biomedical materials, tissue engineering scaffolds, smart textiles, high-efficiency filtration media, and environmental protection.

[0003] However, traditional electrospinning processes still have several significant limitations. First, their production efficiency is low, making it difficult to meet the demands of large-scale industrial production. Second, for polymer systems with high viscosity or special rheological behavior, the stretching effect of the electric field on the jet is often insufficient, resulting in larger fiber diameters and non-uniform morphology. Furthermore, the jet is susceptible to environmental disturbances and charge repulsion during its movement, leading to poor trajectory stability and uneven fiber deposition distribution, thus limiting its application in certain high-performance materials.

[0004] To address these issues, researchers developed an airflow-assisted electrospinning process. This technology introduces an auxiliary airflow field into the traditional apparatus, achieving a "secondary stretching" of the jet through the synergistic effect of pneumatic shearing and electrostatic stretching. This significantly improves fiber fineness and uniformity, while also enhancing spinning efficiency and process stability. Although the introduction of airflow assistance optimizes the macroscopic morphology of the fiber to some extent, it still makes precise control of the fiber's microstructure difficult.

[0005] Especially in certain cutting-edge application fields, such as drug sustained-release systems, sensitive sensors, and biomimetic interface materials, functional nanofibers with special morphologies are often required. Such structures can further increase specific surface area, regulate release behavior, or enhance interfacial response performance. However, current electrospinning technology still lacks effective means to reliably, controllably, and mass-produce these nanofibers. Therefore, developing a highly efficient mass-production spinning technology capable of precisely controlling the microstructure of fibers and preparing beaded nanofibers has become a critical problem urgently needing to be solved in this field. Summary of the Invention

[0006] The main objective of this invention is to propose an airflow-assisted electrospinning device that can prepare nanofibers with a beaded chain structure, thereby meeting the application needs of different fields for nanofibers with special morphologies.

[0007] To achieve the above objectives, the present invention proposes an airflow-assisted electrospinning device, comprising a conveying channel, an electrospinning nozzle, an auxiliary airflow nozzle, an air inlet, an exhaust outlet, a collection buffer wheel, and a collection funnel; The electrospinning nozzle is installed at the upper end of the conveying channel; the auxiliary airflow nozzle and the air inlet are located on the left side of the conveying channel; the exhaust port and the collecting buffer wheel are located on the right side of the conveying channel; the collecting funnel is located below the collecting buffer wheel. The auxiliary airflow nozzle is connected to the air supply device; The electrostatic spinning nozzle is connected to the positive terminal of a high-voltage power supply and is in communication with the liquid supply device; The collecting buffer wheel is connected to the negative terminal of a high-voltage power supply and is powered by an external power device, enabling the collecting buffer wheel to rotate.

[0008] This invention employs the aforementioned technical solution, utilizing auxiliary airflow to avoid direct deposition of electrospun nanofibers, thus overcoming the drawback of nanofibers agglomerating and difficult to disperse. The conveying channel increases the flight time of the nanofibers in the air, promoting solvent evaporation. The inclusion of a collection buffer wheel facilitates alteration of the nanofibers' flight trajectory, aiding in charge release and allowing the suspended nanofibers to easily contract and form beaded structures.

[0009] Preferably, the distance between the electrospinning nozzle and the bottom of the conveying channel is adjustable, with an adjustment range of 5~30cm.

[0010] Preferably, the rotational speed of the collecting buffer wheel is adjustable, with an adjustment range of 5~30 r / min. More preferably, the rotational speed of the collecting buffer wheel is controlled to be 10~20 r / min.

[0011] Preferably, the number of electrospinning nozzles is multiple. Setting multiple sets of electrospinning nozzles facilitates the mass production of nanofibers.

[0012] Preferably, the angle between the auxiliary airflow nozzle and the electrospinning nozzle is 60-120 degrees. This technical solution can alter the trajectory of the nanofibers and enhance their transport capabilities.

[0013] Preferably, the number of auxiliary airflow nozzles is three.

[0014] Preferably, the auxiliary airflow nozzles are arranged in a triangular pattern along the circumference of the air inlet, located on both sides and below the air inlet. This technical solution increases airflow, enabling faster and more stable transport of the nanofibers.

[0015] Preferably, the collecting buffer wheel has several guide vanes evenly distributed on it. The guide vanes allow the collecting buffer wheel to rotate under the influence of airflow, which, combined with the motor's rotation, facilitates concentrated collection and improves preparation efficiency.

[0016] Preferably, the device further includes a collection pipe and a collection port; the collection funnel is connected to one end of the collection pipe; and the other end of the collection pipe is connected to the collection port.

[0017] On the other hand, the present invention also provides a method for preparing nanofibers using the above-mentioned airflow-assisted electrospinning device, comprising the following steps: S1. Prepare the electrospinning solution; S2. Pass the electrospinning solution into the electrospinning nozzle, turn on the high voltage power supply to set the spinning voltage, so that the electrospinning solution forms a jet at the nozzle and is ejected. S3. The auxiliary airflow is input from the auxiliary airflow nozzle through the air supply device; S4. Turn on the power device and set the speed of the collecting buffer wheel to collect the electrospun fibers at the collection port to obtain nanofibers with a beaded chain structure.

[0018] Preferably, in step S2, the spinning voltage is adjustable, with an adjustment range of 30~50kV; the liquid supply rate of the electrostatic spinning nozzle is adjustable, with an adjustment range of 10~100 mL / hr; and the spinning environment parameters are: temperature 10~40℃, humidity 20%~60%.

[0019] Preferably, in step S3, the pressure of the auxiliary airflow is 0.2~0.8 MPa and the flow rate is 20~100 L / min.

[0020] Preferably, the above preparation method further includes a step of vacuum drying the prepared nanofibers with beaded chain structure at a temperature of 60~100 ℃ and a drying time of 30~120 min.

[0021] By employing the above preparation method and precisely controlling various parameters, the microstructure of nanofibers can be regulated, thus producing high-quality nanofibers with beaded structures.

[0022] In another aspect, the present invention also provides a nanofiber with a beaded chain structure, which is prepared by the preparation method described above.

[0023] Compared to existing technologies, this invention offers at least the following advantages: This solution utilizes an auxiliary airflow device in conjunction with a collection buffer wheel, increasing the flight time of the nanofibers in the air, guiding their flight trajectory, releasing charge, and promoting solvent evaporation. This causes the suspended nanofibers to contract and form a beaded chain structure, contributing to the acquisition of high-quality nanofibers. Furthermore, by incorporating multiple sets of electrospinning nozzles, efficient mass production can be achieved. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the airflow-assisted electrospinning device in Example 1; Figure 2 Electron microscopy of the finished nanofibers obtained in Example 1 Figure 1 ; Figure 3 Electron microscopy of the finished nanofibers obtained in Example 1 Figure 2 Figure 4 Electron microscopy of the finished nanofibers obtained in Comparative Example 1 Figure 1 ; Figure 5 Electron microscopy of the finished nanofibers obtained in Comparative Example 1 Figure 2 .

[0026] In the attached diagram: 1-Conveying channel, 2-Electrostatic spinning nozzle, 3-Auxiliary airflow nozzle, 4-Air inlet, 5-Exhaust outlet, 6-Collection buffer wheel, 7-Collection funnel, 8-Guide vane, 9-Collection pipe, 10-Collection port.

[0027] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In addition, the term "comprising" and any variations thereof mean "at least comprising."

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0032] It should also be understood that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. The specific process parameters in the following embodiments are only one example within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below. Where specific conditions are not specified in the embodiments, they should be performed under conventional conditions or conditions recommended by the manufacturer. Furthermore, all raw materials mentioned below that are not described in detail are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0033] The electrospinning solution used in the following examples and comparative examples is a PVDF + graphite solution, with a PVDF concentration of 4 wt% and a graphite concentration of 5 wt‰. The solvent used to prepare the solution is DMF. It is understood that the solution input to the electrospinning nozzle can also be other polymer solutions suitable for electrospinning, such as PAN solution.

[0034] Example 1 As Figure 1 shown, this example provides an air-assisted electrospinning device, including a conveying channel 1, an electrospinning nozzle 2, an auxiliary air nozzle 3, an air inlet 4, an exhaust hole 5, a collection buffer wheel 6 and a collection funnel 7. The electrospinning nozzle 2 is installed at the upper end of the conveying channel 1, connected to the positive pole of the high-voltage power supply (not shown in the figure), and communicates with a liquid supply device (not shown in the figure). The distance between the electrospinning nozzle 2 and the bottom of the conveying channel 1 is adjustable, and the adjustment range is 5-30 cm. In this example, the distance between the electrospinning nozzle 2 and the bottom of the conveying channel 1 is adjusted to 25 cm; multiple groups of electrospinning nozzles 2 are provided to facilitate the batch production of nanofibers. In actual operation, the number of electrospinning nozzles 2 can be set according to the requirements of electrospinning production. The auxiliary air nozzle 3 and the air inlet 4 are arranged on the left side of the conveying channel 1. The auxiliary air nozzle 3 is connected to an air supply device (not shown in the figure). The included angle between the auxiliary air nozzle 3 and the electrospinning nozzle 2 is 60-120 degrees. The included angle between the auxiliary air nozzle 3 and the electrospinning nozzle 2 should not be too large. If it exceeds 120°, the ejected air flow will hinder the rapid forming spray of electrospun nanofibers and easily cause the nanofibers to float around, unable to form a stable movement trajectory; if the angle is too small, less than 60°, the ejected air flow will accelerate the movement and deposition of nanofibers towards the bottom, unable to reach the collection buffer wheel 6, greatly limiting the transmission of nanofibers. In this example, the included angle between the auxiliary air nozzle 3 and the electrospinning nozzle 2 is set at 90°. Multiple auxiliary air nozzles 3 can be set as needed. In this example, three auxiliary air nozzles 3 are provided, arranged in a "pin" shape along the circumference of the air inlet 4, located on the left and right sides and below the air inlet 4 respectively. This can increase the air flow rate and improve the nanofiber collection efficiency. The exhaust hole 5 and the collection buffer wheel 6 are arranged on the right side of the conveying channel 1. In this example, the exhaust hole 5 is located at the top of the right side of the conveying channel 1. According to actual needs, the exhaust hole 5 can also be arranged at other positions on the right side of the conveying channel 1. The collection buffer wheel 6 is connected to the negative pole of the high-voltage power supply and is externally connected to a power device. The power device can be components such as a motor, providing rotational power for the collection buffer wheel 6 to make it rotate. The rotational speed of the collection buffer wheel 6 is adjustable, and the adjustment range is 5-30 r / min. More preferably, the rotational speed of the collection buffer wheel is controlled to be 10-20 r / min. The rotation of the collection buffer wheel 6 plays a certain buffering role on the nanofibers, avoiding excessive deposition of nanofibers at the same position and facilitating the uniform collection of nanofibers. On the other hand, the rotating buffer wheel avoids the accumulation of charges carried by nanofibers at the same place, generating more charges and repelling the deposition of subsequent charged nanofibers, thus affecting the production and directional deposition of nanofibers. A number of wind guiding blades 8 are evenly distributed on the collection buffer wheel 6. This enables the collection buffer wheel to be assisted in rotating under the action of the air flow, improving production efficiency. The collection funnel 7 is located below the collection buffer wheel 6.

[0035] In operation, the liquid supply device is connected to the electrospinning nozzle 2 to supply the electrospinning solution, and the positive terminal of the electrostatic high-voltage power supply provides a strong electric field to the electrospinning nozzle 2. The negative voltage provided by the negative terminal of the electrostatic high-voltage power supply at the collecting buffer wheel 6 plays an auxiliary guiding role in the transmission of nanofibers. The air supply device injects airflow from the auxiliary airflow nozzle 3. The electrospinning solution is conveyed to the nozzle of the electrospinning nozzle 2, where it is stretched into a Taylor cone under the action of the electrostatic high-voltage electric field, and a jet is formed from the tip of the Taylor cone. After solvent evaporation and solidification, nanofibers are obtained. The obtained nanofibers move towards the bottom of the conveying channel 1 under the action of the electric field. At this time, the nanofibers in the air are in a free motion state. The auxiliary airflow input from the auxiliary airflow nozzle 3 can carry the free-moving solid nanofibers to continue to be conveyed towards the collecting buffer wheel 6. After the flight trajectory of the nanofibers is changed by the collecting buffer wheel 6, it is more conducive to the contraction of nanofibers to form a beaded chain structure and deposit them at the collecting funnel 7. In this embodiment, a collecting pipe 9 and a collecting port 10 are also included. The collecting funnel 7 is connected to one end of the collecting pipe 9, and the other end of the collecting pipe 9 is connected to the collecting port 10. The nanofibers deposited at the collecting funnel 7 move toward the collecting pipe 9 and are finally collected at the collecting port 10. The auxiliary airflow is discharged from the exhaust port 5.

[0036] The method for preparing nanofibers with a beaded chain structure using the above-mentioned apparatus includes the following steps: S1. Prepare a spinning solution with a PVDF concentration of 4 wt% and a graphite concentration of 5 wt‰, using DMF as the solvent; S2. Pass the spinning solution into the electrostatic spinning nozzle, turn on the high-voltage power supply and set the spinning voltage to 35 kV, so that the electrostatic spinning solution forms a jet at the nozzle and is ejected. Adjust the supply rate to 6 mL / hr. Control the spinning environment parameters as follows: temperature 28℃, humidity 50%. S3. The auxiliary airflow is input from the auxiliary airflow nozzle through the air supply device; the pressure of the auxiliary airflow is 0.4 MPa and the flow rate is 60 L / min; S4. Turn on the power device and set the speed of the collecting buffer wheel 6 to 15 r / min; collect the electrospun fibers at the collection port to obtain nanofibers with a beaded chain structure.

[0037] The collected nanofibers with beaded chain structures were vacuum dried at a temperature of 70 °C for 60 min to obtain the final nanofibers.

[0038] Comparative Example 1 This comparative example uses the same apparatus and preparation method as Example 1, the only difference being that the collection buffer wheel 6 of Comparative Example 1 is kept in a stationary state.

[0039] like Figure 2 and Figure 3 As shown, the nanofibers prepared in Example 1 are three-dimensionally full and have a beaded chain structure, which can form a good coating effect. Figure 4 and Figure 5 As shown, the nanofibers prepared in Comparative Example 1 have a long fiber structure, and some areas are bonded together into blocks, resulting in poor fiber morphology.

[0040] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An airflow-assisted electrospinning device, characterized in that, It includes a transfer channel (1), an electrospinning nozzle (2), an auxiliary air flow nozzle (3), an air inlet hole (4), an exhaust hole (5), a collection buffer wheel (6) and a collection funnel (7); The electrospinning nozzle (2) is installed at the upper end of the transfer channel (1); the auxiliary air flow nozzle (3) and the air inlet hole (4) are arranged on the left side of the transfer channel (1); the exhaust hole (5) and the collection buffer wheel (6) are arranged on the right side of the transfer channel (1); the collection funnel (7) is located below the collection buffer wheel (6); The auxiliary air flow nozzle (3) is connected to a gas supply device; The electrospinning nozzle (2) is connected to the positive pole of a high-voltage power supply and is communicated with a liquid supply device; The collection buffer wheel (6) is connected to the negative pole of the high-voltage power supply and is externally connected to a power device, so that the collection buffer wheel (6) can rotate.

2. The airflow-assisted electrospinning device as described in claim 1, characterized in that, The rotation speed of the collection buffer wheel (6) is adjustable, and the adjustment range is 5 - 30 r / min.

3. The airflow-assisted electrospinning device as described in claim 1, characterized in that, The included angle between the auxiliary air flow nozzle (3) and the electrospinning nozzle (2) is 60 - 120 degrees.

4. The airflow-assisted electrospinning device as described in claim 1, characterized in that, The number of the auxiliary air flow nozzles (3) is three; the auxiliary air flow nozzles (3) are arranged in a "pin" shape along the circumferential direction of the air inlet hole (4), and are respectively located on both sides and below the air inlet hole (4).

5. The airflow-assisted electrospinning device as described in claim 1, characterized in that, A number of wind guiding blades (8) are evenly distributed on the collection buffer wheel (6).

6. The airflow-assisted electrospinning device as described in claim 1, characterized in that, It further includes a collection pipe (9) and a collection port (10); the collection funnel (7) is connected to one end of the collection pipe (9); the other end of the collection pipe (9) is connected to the collection port (10).

7. A method for preparing nanofibers using the airflow-assisted electrospinning apparatus as described in any one of claims 1 to 6, characterized in that, It includes the following steps: S1. Prepare an electrospinning solution; S2. Feed the electrospinning solution into the electrospinning nozzle (2), turn on the high-voltage power supply and set the spinning voltage, so that the electrospinning solution forms a jet at the nozzle and sprays out; S3. Make the auxiliary air flow input from the auxiliary air flow nozzle (3) through the gas supply device; S4. Turn on the power device and set the rotation speed of the collection buffer wheel (6), and collect electrospun fibers at the collection port (10) to obtain nanofibers with a bead-chain structure.

8. The preparation method according to claim 7, characterized in that, In step S2, the spinning voltage is adjustable, and the adjustment range is 30 - 50 kV; the liquid supply rate of the electrospinning nozzle (2) is adjustable, and the adjustment range is 10 - 100 mL / hr; the spinning environment parameters are: temperature 10 - 40 °C, humidity 20% - 60%; In step S3, the pressure of the auxiliary air flow is 0.2 - 0.8 MPa, and the flow rate is 20 - 100 L / min.

9. The preparation method according to claim 7, characterized in that, It further includes the step of vacuum drying the prepared nanofibers with a bead-chain structure, the drying temperature is 60 - 100 °C, and the drying time is 30 - 120 min.

10. A nanofiber with a beaded chain structure, characterized in that, It is prepared by using the preparation method described in any one of claims 7 - 9.

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