An electrospinning device

Abstract

The present invention relates to an electrospinning device, which includes: a spinning electrode disposed in a spinning solution box at a distance from the first surface of the substrate on the same side as the first surface of the substrate; a receiving electrode disposed at a distance from the second surface of the substrate on the same side as the second surface of the substrate, wherein the polarity of the receiving electrode is set to be opposite to the polarity of the spinning electrode, whereby during the spinning process, filaments are deposited on the first surface of the substrate through the electric field between the spinning electrode and the receiving electrode. Wherein, at a position upstream of the spinning electrode and the receiving electrode in the traveling direction of the substrate, the electrospinning device is provided with a pretreatment device, through which the first surface of the substrate will carry a charge opposite to the polarity of the spinning electrode before entering the electric field formed by the spinning electrode and the receiving electrode.

Description

Technical Field

[0001] The present invention relates to an electrospinning device. Background Art

[0002] Electrospinning is a process of drawing extremely fine (generally in the micron or nanometer size) fibers from a liquid using an electric charge. Electrospinning mainly involves applying a sufficiently high voltage to a liquid droplet, causing static electricity to form on the liquid droplet. The force between the charges cancels out the surface tension of the liquid, causing the droplet to elongate. When the voltage exceeds a threshold, the liquid will eject from the droplet, and the point of this outflow is the Taylor cone. Subsequently, under the action of an electric field and by appropriately adjusting the adhesive force between liquid molecules, a jet will be formed, thereby performing electrospinning. In 1934, Formhals disclosed an electrospinning method in US Patent US1975504. This method has simple equipment, convenient operation, and is applicable to a variety of polymer materials. It is currently the main method for continuously producing nanofibers. A typical electrospinning device mainly includes an injection pump, a high-voltage power supply, a spinneret, a collection device, etc. Among them, the injection pump is used to supply the spinning solution to ensure the continuity of the solution supply during the electrospinning process; the high-voltage power supply is used to connect the spinneret and the collection device. After starting the high-voltage power supply, a strong electric field will be generated between the spinneret and the collection device. When the power supply voltage continuously increases, the amount of charge carried by the droplet at the tip of the spinneret increases, the repulsion between the charges strengthens, the surface of the droplet will fluctuate and deform, and the polymer will form a Taylor cone at the end of the spinneret. When the voltage increases to the critical value, the liquid will overcome the surface tension and form a jet at the tip of the cone. After the jet undergoes stretching, solvent evaporation, and curing, finally, nanofiber-level solid fibers will be deposited on the collection device.

[0003] In the electrospinning method, the electrostatic field is a very important factor for production efficiency and product quality. Therefore, it is desirable to further optimize and improve the electrostatic field and other aspects related to the electrostatic field in the electrospinning method in order to continuously improve production efficiency or product quality. Summary of the Invention

[0004] The present invention discloses an electrospinning device for electrospinning on a substrate. The substrate includes a first surface and a second surface opposite to each other in a first direction, which is perpendicular to the traveling direction and the transverse direction of the substrate. The electrospinning device includes: a spinning electrode, which is disposed in a spinning solution box at a distance from the first surface of the substrate on the same side as the first surface of the substrate in the first direction; a receiving electrode, which is disposed at a distance from the second surface of the substrate on the same side as the second surface of the substrate in the first direction, wherein the polarity of the receiving electrode is set to be opposite to the polarity of the spinning electrode, so that filaments are deposited on the first surface of the substrate through the electric field between the spinning electrode and the receiving electrode during the spinning process. Wherein, at a position upstream of the spinning electrode and the receiving electrode in the traveling direction of the substrate, the electrospinning device is provided with a pretreatment device, through which the first surface of the substrate will carry a charge opposite to the polarity of the spinning electrode before entering the electric field formed by the spinning electrode and the receiving electrode.

[0005] According to one or more embodiments of the present invention, the pretreatment device is provided with an additional electrode, the polarity of the additional electrode is set to be opposite to the polarity of the spinning electrode, and the additional electrode is in contact with the substrate.

[0006] According to one or more embodiments of the present invention, the pretreatment device is provided with an auxiliary emission electrode and an auxiliary receiving electrode. The auxiliary emission electrode is disposed at a distance from the first surface of the substrate on the same side as the first surface of the substrate and the polarity is set to be the same as the polarity of the spinning electrode. The auxiliary receiving electrode is disposed at a distance from the second surface of the substrate on the same side as the second surface of the substrate and the polarity is set to be opposite to the polarity of the spinning electrode.

[0007] According to one or more embodiments of the present invention, the receiving electrode is formed such that in the first direction, the distance between the corresponding part of the receiving electrode at the end part in the transverse direction of the substrate and the corresponding part of the spinning electrode is greater than the distance between the corresponding part of the receiving electrode at the middle part in the transverse direction of the substrate and the corresponding part of the spinning electrode.

[0008] According to one or more embodiments of the present invention, the outer peripheral dimension of the receiving electrode at the end part in the transverse direction of the substrate gradually increases towards the outer peripheral dimension of the receiving electrode at the middle part between the end parts.

[0009] According to one or more embodiments of the present invention, the receiving electrode is formed as a hollow closed body formed by a silk thread.

[0010] According to one or more embodiments of the present invention, in the traveling direction of the substrate, the distance between the corresponding part of the spinning electrode and the end portion of the receiving electrode located in the lateral direction of the substrate is greater than the distance between the corresponding part of the spinning electrode and the middle portion of the receiving electrode located in the lateral direction of the substrate.

[0011] According to one or more embodiments of the present invention, the receiving electrode is composed of a plurality of linear sub-electrodes, the plurality of linear sub-electrodes are spaced apart along the traveling direction of the substrate, and each of the plurality of linear sub-electrodes extends along the lateral direction of the substrate.

[0012] According to one or more embodiments of the present invention, one or more of the plurality of linear sub-electrodes are arranged in an arc shape or an inclined linear shape.

[0013] According to one or more embodiments of the present invention, when viewed along the lateral direction, the plurality of linear sub-electrodes are formed to be arranged in a staggered high-low manner, a periodic staggered high-low manner, or a circular arc-shaped high-low arrangement.

[0014] According to one or more embodiments of the present invention, when viewed along the first direction, the plurality of linear sub-electrodes are formed to be arranged symmetrically adjacent to each other, symmetrically centered, or crosswise.

[0015] According to one or more embodiments of the present invention, an auxiliary cover is provided above the receiving electrode in the first direction. When the shape or voltage of the receiving electrode can cause ionization, the auxiliary cover is arranged to blow air downward. When the shape or voltage of the receiving electrode is set so that no ionization occurs, the auxiliary cover is arranged to extract air upward.

[0016] The present invention also discloses a method for electrospinning using an electrospinning device according to any one of the above aspects, the method comprising:

[0017] forming an electrostatic field between the spinning electrode and the receiving electrode so that filaments can be emitted from the spinning electrode and deposited on the substrate;

[0018] making the first surface of the substrate carry a charge opposite to the polarity of the spinning electrode through the pretreatment device before the substrate enters the electrostatic field. Description of the Drawings

[0019] The present invention will be further described below in conjunction with the drawings and embodiments:

[0020] Figure 1 Schematic diagram of the first embodiment of the electrospinning device according to the present invention.

[0021] Figure 2 Schematic diagram of the second embodiment of the electrospinning device according to the present invention.

[0022] Figures 3 - 6 Cross-sectional views of different forms of the receiving electrode of the electrospinning device of the first embodiment and / or the second embodiment provided by the present invention respectively.

[0023] Figure 7 Schematic diagram of the third embodiment of the electrospinning device according to the present invention.

[0024] Figures 8a - 8c Side views of different forms of the receiving electrode of the third embodiment of the electrospinning device according to the present invention respectively.

[0025] Figures 9a - 9c Top views of different forms of the receiving electrode of the third embodiment of the electrospinning device according to the present invention respectively.

[0026] Figure 10 Cross-sectional view of the receiving electrode of the third embodiment of the electrospinning device according to the present invention.

[0027] Figures 11a - 11d Schematic diagrams of other forms of the receiving electrode of the third embodiment of the electrospinning device according to the present invention respectively.

[0028] Figures 12a - 12b Schematic diagrams of different forms of the auxiliary cover of the electrospinning device according to the present invention.

[0029] Figure 13 Schematic diagram of the auxiliary cover and the receiving electrode of the electrospinning device according to the present invention assembled together.

[0030] Figures 14a - 14b Electron microscope image of the nanofibers provided by the electrospinning device according to the present invention. Detailed implementation manners

[0031] The present disclosure will be described below with reference to the accompanying drawings, in which several embodiments of the present disclosure are shown. However, it should be understood that the present disclosure can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and fully explain the protection scope of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide more additional embodiments.

[0032] It should be understood that in all the drawings, the same reference numerals denote the same elements. In the drawings, for clarity, the dimensions of some features may be distorted.

[0033] It should be understood that the terminology in the specification is only used to describe specific embodiments and is not intended to limit the present disclosure. All terms used in the specification (including technical and scientific terms) have the meaning commonly understood by those of ordinary skill in the art unless otherwise defined. Well-known functions or structures may not be described in detail for the sake of brevity and / or clarity.

[0034] The singular forms "a", "the", and "said" used in the specification include the plural forms unless clearly specified otherwise. The terms "comprising", "including", and "having" used in the specification mean the presence of the claimed features, but do not preclude the presence of one or more other features. The term "and / or" used in the specification includes any and all combinations of one or more of the related listed items. The phrases "between X and Y" and "between approximately X and Y" used in the specification should be interpreted as including X and Y. The phrase "between approximately X and Y" used in this specification means "between approximately X and approximately Y", and the phrase "from approximately X to Y" used in this specification means "from approximately X to approximately Y".

[0035] In the specification, when it is said that an element is "on", "attached" to, "connected" to, "coupled" to, or "in contact" with another element, etc., the element may be directly on, attached to, connected to, coupled to, or in contact with the other element, or there may be an intermediate element. In contrast, when it is said that an element is "directly" "on", "directly attached" to, "directly connected" to, "directly coupled" to, or "directly in contact" with another element, there will be no intermediate element. In the specification, when a feature is arranged "adjacent" to another feature, it may mean that a feature has a part overlapping with the adjacent feature or a part located above or below the adjacent feature.

[0036] In the specification, spatial relationship terms such as "above", "below", "left", "right", "front", "rear", "high", "low", etc. may describe the relationship between one feature and another feature in the drawings. It should be understood that the spatial relationship terms include different orientations of the device during use or operation in addition to the orientations shown in the drawings. For example, when the device in the drawing is inverted, a feature originally described as "below" other features may then be described as "above" the other features. The device may also be oriented in other ways (rotated 90 degrees or in other orientations), and the relative spatial relationships will be interpreted accordingly at this time.

[0037] Figure 1 FIG. is a schematic view of a first embodiment of an electrospinning device according to the present invention. The electrospinning device may be an electrospinning device using a roller electrospinning method, but the present disclosure is not limited thereto, and may be other types of electrospinning devices, such as a bubble electrospinning method, a coil winding spinning method, a spiral coil spinning method, etc.

[0038] As Figure 1 shown, the electrospinning device according to the present invention is used for electrospinning on a substrate 9, and the substrate 9 is conveyed in a traveling direction during the spinning process ( Figure 1 in the figure is the rightward direction), and the substrate 9 includes a first surface and a second surface opposite to each other in a first direction. In the present exemplary embodiment, the first direction is the vertical direction, the first surface is the lower surface, and the second surface is the upper surface.

[0039] In addition, the electrospinning device according to the present invention further includes a spinning electrode 6 and a receiving electrode 1, and the spinning electrode 6 and the receiving electrode 1 are disposed on both sides of the substrate, that is, the substrate 9 is located between the spinning electrode 6 and the receiving electrode 1. A spinning electric field is formed between the spinning electrode 6 and the receiving electrode 1. The spinning electrode 6 is located below the substrate 9 in the vertical direction (that is, on the same side as the lower surface of the substrate 9), and is disposed at a distance from the lower surface of the substrate 9. The spinning electrode 6 is immersed in the spinning solution box 7, and under the drive of a motor (not shown), the spinning electrode 6 can rotate continuously to drive the slurry at the bottom of the spinning solution box to the top of the spinning electrode 6. In the present exemplary embodiment, the spinning electrode 6 is in the form of a cylindrical metal roller, but it should be understood that it can also be arranged as, for example, a metal spiral coil, or a metal screw, or a series of metal balls. The receiving electrode 1 is located above the substrate 9 in the vertical direction (that is, on the same side as the upper surface of the substrate 9), and is disposed at a distance from the upper surface of the substrate 9. The shape and structure of the receiving electrode will be described in more detail later.

[0040] The spinning electrode 6 and the receiving electrode 1 are respectively connected to voltages with opposite polarities. In the present exemplary embodiment, the spinning electrode 6 is connected to a positive high-voltage power supply, and the receiving electrode 1 is connected to a negative high-voltage power supply 3. Different from the receiving electrode being grounded, connecting the spinning electrode to the positive high-voltage power supply 4 and the receiving electrode to the negative high-voltage power supply 3 in the present exemplary embodiment can effectively improve the spinning electric field and reduce the phenomenon of flying filaments during the spinning process. This is because when the receiving electrode is grounded, after the spinning electric field is established and before spinning, positive charges will be generated at the positive electrode, and negative charges will be generated on the lower surface of the substrate near the positive electrode side. When spinning starts, the solution at the top of the positive electrode is stretched into nanofibers towards the substrate under the action of the electric field force. The nanofibers carry positive charges and are attracted by the negative charges and fall on the substrate. When the spinning amount increases, the positive charges on the lower surface of the substrate increase. If the receiving electrode is grounded, negative charges cannot be immediately replenished to the lower surface of the substrate, and a positive electric field may be formed on the lower surface of the substrate. Subsequently, the positively charged charges are repelled by the positive electric field on the lower surface of the substrate, resulting in the phenomenon of flying filaments. However, in the present exemplary embodiment, when the receiving electrode is negative, the upper surface of the substrate near the receiving electrode is positively charged, continuously replenishing negative charges to the lower surface, thereby eliminating the flying filament phenomenon caused by electric field repulsion. The setting of the negative high-voltage value has a corresponding relationship with the amount of nanofibers generated. Compared with the traditional receiving electrode being grounded, the present invention can make the electric field more concentrated when the substrate receives nanofibers, the spinning process is stable, the flying filaments are reduced, and the spinning efficiency and quality are improved.

[0041] The electrospinning device according to the present invention further includes a pretreatment device, which makes the lower surface of the substrate carry charges with the opposite polarity to that of the spinning electrode before entering the spinning electric field formed by the spinning electrode and the receiving electrode. In the present exemplary embodiment, the pretreatment device is set as an auxiliary emission electrode 5, and the polarity of the auxiliary emission electrode 5 is opposite to that of the spinning electrode 6, that is, in this embodiment, the polarity of the auxiliary emission electrode 5 is negative. The auxiliary emission electrode 5 is in contact with the lower surface of the substrate, so that the substrate carries negative charges before entering the spinning electric field. Combined with the above-mentioned receiving electrode 1 being connected to the negative high-voltage power supply, it can further avoid the situation that the positive charges accumulated on the lower surface of the substrate gradually increase during the spinning process, and can continuously ensure that the lower surface of the substrate carries charges with the opposite polarity to that of the spinning electrode, ensuring the stable and smooth progress of the spinning process and improving the spinning efficiency and quality. The contact between the auxiliary emission electrode 5 and the substrate not only makes the lower surface of the substrate carry negative charges before entering the spinning electric field, but also can continuously provide negative charges for the substrate during the process of positive charges gradually accumulating on the lower surface of the substrate during the spinning process to offset the influence of the positive charges.

[0042] The electrospinning device according to the present invention further includes an automatic control system 11. In this exemplary embodiment, the automatic control system 11 is connected to the negative high-voltage power supply 3 and is used to adjust the voltage data of the negative high-voltage power supply 3. According to one or more embodiments of the present disclosure, the automatic control system controls the voltage of the negative high-voltage power supply such that the substrate is substantially neutral after passing through the spinning electric field. For example, in the case where the negative high-voltage power supply can generate tip discharge, the negative electrons generated by the breakdown of air deposited on the substrate in the downward direction are neutralized with the positive electrons of the spinning solution deposited on the substrate in the upward direction.

[0043] In addition, the automatic control system 11 can also be configured to be connected to the auxiliary emission electrode 5 and the positive high-voltage power supply 4 (not shown in this embodiment) and is used to adjust the voltages of the auxiliary emission electrode 5 and the positive high-voltage power supply 4 respectively. According to this embodiment, the automatic control system 11 can further optimize the voltage condition of the entire system, thereby optimizing the electric field.

[0044] During the spinning process, it is important to continuously ensure that the lower surface of the substrate has an appropriate number of negative charges for stable spinning. In this exemplary embodiment, the receiving electrode 1 is connected to the negative high-voltage power supply 3 and the auxiliary emission electrode 5 is brought into contact with the substrate to make the lower surface of the substrate have a stable number of negative charges. In addition, during the spinning process, although the higher the voltage of the negative high-voltage power supply, the better the spinning effect, it will also lead to higher requirements for the cost and stability of the equipment and the production cost, etc. And although it is beneficial for the lower surface of the substrate to have an appropriate number of negative charges during the spinning process, at the same time, it is desirable that when the spinning is completed, the substrate as a whole can be as neutral as possible for further subsequent processing. Therefore, it is preferably desired to uniformly control the polarities of the auxiliary emission electrode, the spinning electrode, and the receiving electrode, so that not only can it be ensured that the lower surface of the substrate has a stable number of negative charges during the spinning process, but also the substrate is as neutral as possible as a whole when the spinning is completed.

[0045] Therefore, the electrospinning device of the present invention is provided with an automatic control system 11, and the automatic control system 11 is connected to a charge amount detection device 8. The charge amount detection device 8 can detect the remaining charge amount on the surface of the substrate after the substrate has completed electrospinning, and adjust the voltage magnitudes of the auxiliary emission electrode, the spinning electrode, and the receiving electrode based on the detected charge amount. In addition, the automatic control system 11 can be connected to a detection device such as a high-speed camera. The detection device such as the high-speed camera can be used to detect and determine whether the phenomenon of filament flying occurs, and adjust the voltage magnitudes of the auxiliary emission electrode, the spinning electrode, and the receiving electrode based on whether the phenomenon of filament flying is detected. In the present exemplary embodiment, the adjustment of the voltage magnitudes of the auxiliary emission electrode, the spinning electrode, and the receiving electrode by the automatic control system is carried out within a predetermined range. The predetermined range is determined by the staff during the debugging process based on further detailed detection. For example, based on the detection of the electrospinning output, based on the SEM detection of the fibers produced by electrospinning, etc. Through this further detailed detection, an acceptable range for the voltage magnitudes of the auxiliary emission electrode, the spinning electrode, and the receiving electrode is preset in advance, and then the automatic detection system further dynamically adjusts the voltage magnitudes based on the detection during the production process.

[0046] Figure 2 FIG. is a schematic diagram of a second embodiment of the electrospinning device according to the present invention. The difference between this embodiment and the first embodiment lies in the structure of the pretreatment device. Other structures (such as the structures of the spinning electrode and the receiving electrode, etc.) are the same as those of the first embodiment. Hereinafter, components that are substantially the same as those in the first embodiment will be given the same reference numerals, and they have the same structures and effects as those in the first embodiment, so their descriptions will be omitted.

[0047] In the second embodiment, the pretreatment device further includes an auxiliary receiving electrode 10 in addition to the auxiliary emitting electrode 5. Different from the first embodiment, the auxiliary emitting electrode 5 does not contact the substrate, but forms a pretreatment electric field through the auxiliary emitting electrode 5 and the auxiliary receiving electrode 10. In this embodiment, the polarity of the auxiliary emitting electrode 5 is set to be the same as that of the spinning electrode 6, and the polarity of the auxiliary receiving electrode 10 is set to be the same as that of the receiving electrode 1, that is, the polarities of the spinning electric field and the pretreatment electric field are similar. Before entering the spinning electric field, the substrate first passes through the pretreatment electric field, so that the lower surface of the substrate will carry negative charges, and the upper surface of the substrate will carry positive charges. Subsequently, the substrate passes through the pretreatment electric field in this state. And because the lower surface of the substrate has been precharged with negative charges in advance, it will be more conducive to the spinning process and reduce the occurrence of flying fiber phenomenon. Therefore, similar effects to those of the first embodiment can be obtained. In this exemplary embodiment, the distance from the auxiliary emitting electrode 5 to the substrate can be set to 5 mm - 100 mm, and the distance from the auxiliary receiving electrode 10 to the substrate can be set to 5 mm - 100 mm. Through the formed high-voltage electric field, opposite-polarity charges are generated on the lower surface of the receiving substrate.

[0048] In addition, in this exemplary embodiment, since the auxiliary emitting electrode 5 does not contact the substrate, but induces charges in the lower surface of the substrate through the electrostatic field, the substrate itself is not given corresponding charges. When the shape of the receiving electrode is set to un-ionized air (which will be described in detail later), the substrate itself will only receive the positive charges carried by the spinning solution from the outside. Therefore, after the spinning is completed, the whole substrate will be positively polarized. At this time, a charge elimination device (such as an ion wind rod, etc.) can be set on the traveling path of the sheet between the charge amount detection device 8 and the receiving electrode 1.

[0049] It can also be conceived that in the second embodiment, not only a pretreatment electric field is formed between the auxiliary emitting electrode 5 and the auxiliary receiving electrode 10, but the shape and voltage of the auxiliary receiving electrode 10 are set such that air can be ionized, and the ionized negative ions will fly towards the substrate under the action of the electric field force, so that not only negative charges are induced on the lower surface of the substrate, but the whole substrate will also be negatively polarized. Through this setting, the distribution of negative charges on the lower surface of the substrate after the substrate enters the spinning electric field can be further improved, making it more conducive to the spinning process.

[0050] Figures 3 - 6 Respectively are cross-sectional views of different forms of receiving electrodes of the electrospinning device according to the first embodiment and / or the second embodiment provided by the present invention.

[0051] During the spinning process, the uniformity of the spinning electric field is crucial for the spinning process. Due to the edge effect of the spinning electrode, the electric field in the middle part is more uniform, while the electric field at both ends is stronger, affecting the overall electric field uniformity. In the present disclosure, the electric field is optimized by setting the shape of the receiving electrode and the relative position between the receiving electrode and the spinning electrode. Specifically, in the present disclosure, the shape of the receiving electrode is set such that the distance between the end portion of the receiving electrode and the corresponding portion of the spinning electrode is greater than the distance between the middle portion of the receiving electrode and the corresponding portion of the spinning electrode. As the distance increases, the intensity of the electric field will gradually weaken, thus increasing the uniformity of the overall electric field between the receiving electrode and the spinning electrode. That is, by increasing the distance between the end portion of the receiving electrode and the corresponding portion of the spinning electrode, the electric field intensity between the end portion of the receiving electrode and the corresponding portion of the spinning electrode is weakened. In the present disclosure, the above distance can be the distance in the advancing direction of the substrate or the vertical distance. It should be noted that the distance can also be the distance in other directions, as long as the electric field intensity formed between the end portion of the receiving electrode and the corresponding portion of the spinning electrode is weakened to be closer to the electric field intensity formed between the middle portion of the receiving electrode and the corresponding portion of the spinning electrode.

[0052] Figure 3 The receiving electrode of the first embodiment and / or the second embodiment shown is a shuttle-shaped structure. The longitudinal direction of the shuttle-shaped structure is parallel to the transverse direction of the substrate, that is, perpendicular to the advancing direction of the substrate. In addition, the length in the longitudinal direction of the shuttle-shaped structure is substantially the same as the width in the transverse direction of the substrate. The shuttle-shaped structure is formed such that the outer peripheral dimension gradually increases from the two end portions of the receiving electrode in the longitudinal direction towards the middle portion of the receiving electrode in the longitudinal direction. In the present exemplary embodiment, the maximum outer diameter of the shuttle-shaped structure (that is, the outer peripheral dimension at the middle portion of the receiving electrode in the longitudinal direction) can be set to 10 - 60 mm, the minimum outer diameter (that is, the outer peripheral dimensions at the two end portions of the receiving electrode in the longitudinal direction) can be set to 3 mm - 10 mm, and the length can be set to 300 mm - 2000 mm.

[0053] Figure 4 The receiving electrode of the first embodiment and / or the second embodiment in another structure is shown. Compared with Figure 3The difference of the spindle-shaped structure therein is that the middle part in the longitudinal direction is set to be cylindrical, while the end part in the longitudinal direction is set to be frustum-conical. In this exemplary embodiment, the maximum outer diameter received (i.e., the outer diameter of the cylinder) can be set to 10 - 60 mm, the minimum outer diameter (i.e., the outer peripheral dimension of the end part of the frustum-conical shape located on the outer side in the longitudinal direction) can be set to 3 mm - 10 mm, and the length can be set to 300 - 2000 mm.

[0054] It can be seen that Figure 3 and Figure 4 the spindle-shaped structures of both have the outer peripheral dimension at the end part along the longitudinal direction set to be smaller than that at the middle part. The advantage lies in that it can further optimize the electric field, making the spinning process more uniform and stable. As shown above, this is because when the outer peripheral dimension at the end part of the receiving electrode is reduced, in the vertical direction, the electric field intensity formed between the end part of the receiving electrode and the corresponding part of the spinning electrode can be weakened to be closer to the electric field intensity formed between the middle part of the receiving electrode and the corresponding part of the spinning electrode.

[0055] Figure 5 To show the receiving electrode of the first embodiment and / or the second embodiment in yet another structure. Figure 5 The receiving electrode therein can be set to be a closed body formed by wires, that is, it is hollow inside. The closed body can be generally rectangular or generally spindle-shaped or other shapes. Figure 5 The spindle-shaped closed body therein can be regarded as composed of four sides, that is, two symmetric long sides and two symmetric short sides. The extending direction of the long side of the spindle-shaped closed body (also called the longitudinal direction) is parallel to the transverse direction of the substrate, that is, perpendicular to the traveling direction of the substrate.

[0056] In this exemplary embodiment, the closed body is not formed into a planar shape located in the same plane, that is, the long side and the short side are not located in the same plane, but the long side is set to be similar to an arc or curved such that when the receiving electrode is located above the substrate, the distance between the short side and the second surface of the substrate in the vertical direction is greater than the distance between the middle part of the long side in the longitudinal direction and the second surface of the substrate. That is, the closed body is formed into a shape with both ends upturned and the middle part sunken. By upturning both ends, the distance between both ends and the second surface of the substrate is increased, which can also play a role in weakening the electric field at the end part of the receiving electrode. Therefore, it can obtain the same effect as Figure 3 and Figure 4The effects are substantially the same as those of the embodiments. In this exemplary embodiment, the maximum width of the spindle-shaped enclosure (the distance between the centers of the long sides along the traveling direction of the sheet) can be set to 10 - 60 mm, the minimum width (i.e., the length of the short side) can be set to 3 - 10 mm, the wire diameter can be set to 0.2 mm - 5 mm, the length (i.e., the distance between the short sides along the longitudinal direction) can be set to 300 mm - 2000 mm, and the minimum distance between the receiving electrode and the substrate can be set to 0 - 100 mm.

[0057] Figure 6 Shows the receiving electrode of the first embodiment and / or the second embodiment in yet another structure. Figure 6 Insulators are provided at both ends of the receiving electrode. The insulators are arranged in a roughly cap shape and are arranged to cover both ends of the receiving electrode. In this exemplary embodiment, when the width of the substrate changes, by changing the length of the insulators covering both ends of the receiving electrode, the length of the electric field generated by the receiving electrode can be changed, so as to match the width of the substrate. In addition, by providing the insulators, the existence of the edge effect can also be weakened, that is, the more uniform spinning electric field between the middle part of the receiving electrode and the corresponding part of the spinning electrode is retained, and the stronger spinning electric field between the end part of the receiving electrode and the corresponding part of the spinning electrode is shielded.

[0058] It should be understood that in the first embodiment and / or the second embodiment, the number of receiving electrodes can be set to multiple as needed as Figure 1 shown, and the spacing between the receiving electrodes can also be appropriately changed as needed. In addition, not only the number of receiving electrodes can be set, but multiple electrospinning devices can also be used in series as needed, for example, series-connected from one stage to five stages. That is, after the substrate passes through one electrospinning device, it continues to travel through one or more electrospinning devices.

[0059] Figure 7 Is a schematic diagram of the third embodiment of the electrospinning device according to the present invention. The difference between this embodiment and the second embodiment lies in the structure of the receiving electrode. Other structures are the same as those of the second embodiment. Hereinafter, components that are substantially the same as those of the second embodiment will be given the same reference numerals, and their structures and effects are the same as those of the second embodiment, so their descriptions will be omitted.

[0060] Different from the receiving electrode arranged as a single block in the first embodiment and / or the second embodiment, the receiving electrode in this exemplary embodiment is composed of multiple independent wires, and its shape and structure will be described in detail as follows.

[0061] Figures 8a - 8c Are respectively side views of receiving electrodes in different forms of the third embodiment of the electrospinning device according to the present invention. AsFigure 8a As shown, when the receiving electrode is composed of multiple independent wire materials, the arrangement of the multiple wire materials can be arranged in a high-low sequence. The distance from the lower row of receiving electrodes to the substrate is 0 - 50 mm, and the distance between two rows of receiving electrodes is 5 - 50 mm. As Figure 8b shown, the arrangement of the multiple wire materials can also be set to be arranged in a periodic high-low staggered pattern with respect to the distance from the substrate. The distance from the lower row of receiving electrodes to the substrate is 0 - 50 mm, the distance between two rows of receiving electrodes is 5 - 50 mm, and the number of high-low period intervals is 1 - 5. In addition, as Figure 8c shown, the arrangement of the multiple wire materials can also be set to be arranged in a circular arc high-low pattern, and the distance from the lowest position to the receiving substrate is 0 - 50 mm. By forming the receiving electrode in a high-low arrangement, for example, one or more electrodes can be set to contact the substrate, so that the substrate can also continuously carry negative charges, which can offset the positive charges carried by the spinning solution flying towards the lower surface of the substrate, and avoid the generation of flying filaments caused by the accumulation of positive charges on the lower surface.

[0062] Figures 9a - 9c are respectively top views of different forms of receiving electrodes of the third embodiment of the electrospinning device according to the present invention. As previously described for the shape of the receiving electrode of the second embodiment, in order to weaken the electric field strength formed between the corresponding parts of the end portion of the receiving electrode and the spinning electrode to be closer to the electric field strength formed between the corresponding parts of the middle portion of the receiving electrode and the spinning electrode, the distance between the corresponding parts of the end portion of the receiving electrode and the spinning electrode is greater than the distance between the corresponding parts of the middle portion of the receiving electrode and the spinning electrode. In the foregoing Figures 3 - 5 embodiment, the distance is the distance in the vertical direction, while in Figures 9a - 9c the embodiment, the distance is set to be the distance in the traveling direction of the substrate. That is, in Figures 9a - 9b , a single wire material is set to be a curved arc shape, so that in the traveling direction of the substrate, the distance between the corresponding parts of the end portion of the receiving electrode and the spinning electrode is greater than the distance between the corresponding parts of the middle portion of the receiving electrode and the spinning electrode. While in Figure 9c , although a single wire material is set to be straight, it is inclined in the traveling direction of the substrate, and also makes the distance between the corresponding parts of the end portion of the receiving electrode and the spinning electrode greater than the distance between the corresponding parts of the middle portion of the receiving electrode and the spinning electrode in the traveling direction of the substrate.

[0063] As Figures 9a - 9c shown, in the top view, the arrangement of the multiple wire materials can be respectively set to be adjacent symmetric arrangement, centered symmetric arrangement, cross arrangement, etc.

[0064] In this embodiment, the number of spinning electrodes can be set to one or more. For example, the number of spinning electrodes can be set to be the same asFigures 9a - 9c corresponds to the number of receiving electrodes shown in. By Figures 9a - 9c the structure in, the electric field can also be improved.

[0065] Figure 10 is a cross-sectional view of the receiving electrode of the third embodiment of the electrospinning device according to the present invention. It can be seen that the cross-sectional view of the wire material constituting the receiving electrode in the third embodiment is not only circular (i.e., formed by a cylindrical wire material), but can also be set to a rectangle, V-shaped, triangular, etc. In the case of a circle, the diameter range of the wire material can be set to 0.2 - 5 mm. In the case of a rectangle, the size of the wire material can be set to a width of 3 - 50 mm and a thickness of 0.2 - 5 mm. In the case of a V-shape, the size of the wire material can be set to a width of 10 - 50 mm, a thickness of 5 mm - 30 mm, and a groove depth of 3 - 40 mm. In the case of a triangle, the size of the wire material can be set to a width of 10 - 50 mm and a thickness of 2 - 30 mm.

[0066] In the present disclosure, by setting the shape of the receiving electrode and the positional relationship between the receiving electrode and the spinning electrode, the electric field can be improved. In Figures 3 - 6 , Figures 8a - 8c , Figures 9a - 9c , different receiving electrodes are respectively described. It should be understood that the different forms of the above receiving electrodes can be arbitrarily combined with each other. For example, Figures 8a - 8c the receiving electrode in is not only capable of being set as a linear electrode, but it can also be replaced with Figures 3 - 5 the receiving electrode shown in, such as a shuttle-shaped electrode. For example, Figures 9a - 9c the receiving electrode in can also be replaced with Figures 3 - 5 the receiving electrode shown in, such as a shuttle-shaped electrode. In this case, not only in the traveling direction of the substrate but also in the vertical direction, the electric field strength formed between the corresponding parts of the receiving electrode and the spinning electrode at the end portion of the receiving electrode is weakened to be closer to the electric field strength formed between the corresponding parts of the receiving electrode and the spinning electrode at the middle portion of the receiving electrode.

[0067] In the above embodiments, by setting the shape of the receiving electrode and the positional relationship between the receiving electrode and the spinning electrode, the electric field can be improved. In the case where the receiving electrode is set as multiple electrodes, the present disclosure is not limited thereto, and the electric field can be further optimized by independently controlling the voltages of the multiple electrodes. Specifically, the multiple electrodes are not set to the same voltage, but an additional controller is provided between the negative high-voltage power supply and the receiving electrode (the additional controller can also be omitted and controlled by an automatic control system), so that the additional controller can independently control the voltages of the multiple electrodes.

[0068] In addition, in Figure 7In the third embodiment, multiple independent wires are fixed by a fixing member (in this exemplary embodiment) located above them. Further modifications can be made to this structure, that is, multiple independent wires are integrally arranged, as shown in FIGS. 11a - 11d. Figures 11a - 11d They are respectively schematic diagrams of other forms of the receiving electrode according to the third embodiment of the electrospinning device of the present invention. Figures 11a - 11d In [the figure], the long side direction of the receiving electrode is the traveling direction of the substrate. In the third embodiment, the receiving electrode forms an integral block, and multiple protrusions are formed at the lower end of the integral block, and the multiple protrusions serve as single wires in the foregoing embodiments.

[0069] Figure 11a In [the figure], the receiving electrode is set as a whole, and a serrated structure is provided at the lower end of the integral receiving electrode, and a single serrated structure can be regarded as a single wire. Figure 11a The bottom serrations shown in [the figure] are triangular. Figure 11b The bottom serrations shown in [the figure] are trapezoidal with a groove in the middle. The bottom serrations shown in FIG. 11c are arc-shaped. In Figures 11a - 11c the embodiment of [the figure], the tooth height can be set to 1 mm - 40 mm. In addition, Figure 11d at the lower end of the integral receiving electrode in [the figure], it can be set with a needle tip, the needle diameter can be set to 0.5 - 5 mm, the height can be set to 5 - 30 mm, and the spacing can be set to 5 mm - 30 mm.

[0070] In Figures 11a - 11d the embodiment of [the figure], the structure at the lower end of the integral receiving electrode is uniformly symmetrically arranged, with the same height and evenly arranged. However, it should be understood that the structure at the lower end of the integral receiving electrode can also be non-uniformly symmetrically arranged.

[0071] Figures 11a - 11d In [the figure], multiple protrusions are formed at the lower end of the receiving electrode, and the protrusions serve as wires. In this embodiment, the multiple protrusions are integrally arranged and the voltage is set to be the same. However, the present disclosure is not limited thereto. It can be conceived that an additional controller is provided between the multiple protrusions of the receiving electrode and the negative high-voltage power supply (the additional controller can also be omitted and controlled by an automatic control system), so that the additional controller can independently control the voltages of multiple electrodes. For example, according to needs, the voltage of the protrusions at the end part is set to be lower than the voltage of the protrusions at the middle part, so that the edge effect can also be weakened.

[0072] Figures 12a - 12b And Figure 13 show schematic diagrams of different forms of the auxiliary cover 12 according to the electrospinning device of the present invention, where Figure 13An assembly diagram of the auxiliary cover and the receiving electrode is also shown. The auxiliary cover 12 is disposed above the receiving electrode in the vertical direction and blows air or sucks air depending on the shape and voltage of the receiving electrode.

[0073] In the case where the shape and voltage of the receiving electrode in the first to third embodiments are set such that air ionization occurs, the auxiliary cover is configured to blow air, that is, the cases shown in FIGS. 12a - 12b and Figure 13 As shown, by blowing air, the ion wind generated by ionization can be accelerated and blown towards the upper surface of the substrate, so that negative charges can be replenished to the upper surface of the substrate faster, better neutralizing the positive charges carried by the fibers deposited on the substrate, and increasing the evaporation rate of the solvent by increasing air flow.

[0074] In the case where the shape and voltage of the receiving electrode in the first to third embodiments are set such that air ionization does not occur, the auxiliary cover is configured to suck air (not shown), and the air suction direction is opposite to the direction indicated by the arrows in Figures 12a - 12b and Figure 13 By sucking air, the fibers generated from the spinning electrode can be accelerated to fly towards the lower surface of the substrate faster, improving production efficiency, and also increasing the evaporation rate of the solvent by increasing air flow.

[0075] As Figures 12a - 12b and Figure 13 shown, the auxiliary cover can be set in a bowl shape ( Figure 12a ), U shape ( Figure 12b ), T shape ( Figure 13 ). In the bowl - shaped and U - shaped configurations, the air flow is divided into two streams in the vertical direction by a partition located inside the bowl - shaped configuration. In the T - shaped configuration, a plurality of vertical channels are provided in the long - side direction of the receiving electrode (i.e., the traveling direction of the substrate), and the plurality of vertical channels are connected together by a common horizontal channel located above.

[0076] The electron microscope images of the nanofibers provided by the electrospinning device according to the present invention are shown in FIGS. 14a - 14b. It can be clearly seen from Figures 14a - 14b that the nanofibers formed by the electrospinning device of the present invention are not only uniform in thickness but also relatively uniform in distribution. This is because the electrospinning device of the present invention can provide a stable and excellent electrostatic field, enabling continuous and effective spinning.

[0077] Although exemplary embodiments of the present disclosure have been described, those skilled in the art should understand that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure in essence. Therefore, all such changes and modifications are included within the protection scope of the present disclosure defined by the claims. The present disclosure is defined by the appended claims, and equivalents of these claims are also included.

Claims

1. An electrospinning device for electrospinning on a substrate, wherein the substrate includes a first surface and a second surface opposite to each other in a first direction, the first direction being perpendicular to the traveling direction and the lateral direction of the substrate, and the electrospinning device includes: A spinning electrode, which is disposed at a distance from the first surface of the substrate on the same side as the first surface of the substrate in the first direction; A receiving electrode, which is disposed at a distance from the second surface of the substrate on the same side as the second surface of the substrate in the first direction, wherein the polarity of the receiving electrode is set to be opposite to the polarity of the spinning electrode, and through the receiving electrode and the spinning electrode, charges with a polarity opposite to that of the spinning electrode are induced on the first surface of the substrate, and charges with a polarity opposite to that of the first surface are induced on the second surface of the substrate, whereby during the electrospinning process, filaments are deposited from the spinning electrode on the first surface of the substrate through the electric field between the spinning electrode and the receiving electrode; Wherein, at a position upstream of the spinning electrode and the receiving electrode in the traveling direction of the substrate, the electrospinning device is provided with a pretreatment device, and through the pretreatment device, the first surface of the substrate will carry charges with a polarity opposite to that of the spinning electrode before entering the electric field formed by the spinning electrode and the receiving electrode; Wherein, the receiving electrode is formed such that the distance between the end portion of the receiving electrode in the lateral direction of the substrate and the corresponding portion of the spinning electrode is greater than the distance between the middle portion of the receiving electrode in the lateral direction of the substrate and the corresponding portion of the spinning electrode; Wherein the receiving electrode is formed such that the distance between the end portion of the receiving electrode in the traveling direction of the substrate and the corresponding portion of the spinning electrode is greater than the distance between the middle portion of the receiving electrode in the traveling direction of the substrate and the corresponding portion of the spinning electrode.

2. The electrospinning device according to claim 1, wherein, The pretreatment device is provided with an additional electrode, the polarity of the additional electrode is set to be opposite to the polarity of the spinning electrode, and the additional electrode is in contact with the substrate.

3. The electrospinning device according to claim 1, wherein, The pretreatment device is provided with an auxiliary emitting electrode and an auxiliary receiving electrode, the auxiliary emitting electrode is disposed at a distance from the first surface of the substrate on the same side as the first surface of the substrate and the polarity is set to be the same as the polarity of the spinning electrode, and the auxiliary receiving electrode is disposed at a distance from the second surface of the substrate on the same side as the second surface of the substrate and the polarity is set to be opposite to the polarity of the spinning electrode.

4. The electrospinning device according to claim 1, wherein, The outer peripheral dimension of the receiving electrode at the end portion in the lateral direction of the substrate gradually increases towards the outer peripheral dimension of the middle portion between the end portions of the receiving electrode.

5. The electrospinning device according to claim 1, wherein, The receiving electrode is formed as a hollow closed body formed by filaments.

6. The electrospinning device according to claim 1, wherein The receiving electrode is composed of a plurality of linear sub-electrodes, the plurality of linear sub-electrodes are spaced apart along the traveling direction of the substrate, and each of the plurality of linear sub-electrodes extends along the transverse direction of the substrate.

7. The electrospinning device according to claim 6, wherein, One or more of the plurality of linear sub-electrodes are arranged in an arc shape or an inclined linear shape.

8. The electrospinning device according to claim 7, wherein, When observed along the transverse direction, the plurality of linear sub-electrodes are formed to be arranged in a staggered high and low manner in sequence, a periodically staggered high and low manner, or a circular arc-shaped high and low arrangement.

9. The electrospinning device according to claim 7, wherein, When observed along the first direction, the plurality of linear sub-electrodes are formed to be arranged symmetrically adjacent to each other, symmetrically centered, or cross-arranged.

10. The electrospinning device according to any one of claims 1-3, wherein, An auxiliary cover is provided above the receiving electrode in the first direction. When the shape or voltage of the receiving electrode can cause ionization, the auxiliary cover is arranged to blow air downward. When the shape or voltage of the receiving electrode is set such that no ionization occurs, the auxiliary cover is arranged to extract air upward.

11. A method for electrospinning, the method uses the electrospinning device according to any one of claims 1-10 to perform electrospinning, and the method includes: Form an electrostatic field between the spinning electrode and the receiving electrode so that the filaments can be emitted from the spinning electrode and deposited on the substrate; Before the substrate enters the electrostatic field, make its first surface carry a charge opposite to the polarity of the spinning electrode through the pretreatment device.

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