An electrospinning device for preparing fiber membranes with uniform thickness

Abstract

The present invention provides an electrospinning device for preparing a fiber membrane with uniform thickness, which belongs to the field of fuel cell technology and solves the problem in the prior art that the spinneret structure is easily blocked and affects production, and the thickness of the edge of the obtained electrospun fiber membrane is uneven. The device includes a high-voltage electrostatic generator, a solution storage device, an injection device arranged in an inclined array, a receiving device, and a controller. Among them, the output end of the high-voltage electrostatic generator is connected to the electrode of the injection device; the output end of the solution storage device is connected to the liquid supply port of the injection device; and the receiving device is grounded. The controller is used to establish a physical model of each needle solution advancement speed-spinning time-lateral thickness of a multi-needle electrospinning fiber membrane; and, taking the minimum unevenness of the fiber membrane thickness as the optimization target of the above physical model, solving to obtain the optimal solution advancement speed and optimal spinning time of each needle, and then adjusting the state of each needle at the next moment in real time to obtain a fiber membrane with uniform thickness.

Description

Technical Field

[0001] The invention relates to the technical field of fuel cells, and in particular to an electrostatic spinning device for preparing a fiber membrane with uniform thickness. Background Art

[0002] Nanofiber is a type of nanomaterial with a high specific surface area. It has higher application value than conventional fibers in terms of scale effect, surface effect, mechanical properties, etc., and can be widely used in energy, environmental protection, biomedicine, electronic information and other fields.

[0003] Electrospinning is a simple, effective and economical method for preparing nanofiber materials. It can produce fibers ranging from a few nanometers to several microns, which are 2 to 3 orders of magnitude smaller than conventional fibers. Unlike the traditional dry or wet method that uses mechanical force to achieve wire drawing, electrospinning uses electric field force to achieve wire drawing, which is divided into two types: needle-type and needle-free. Needle-type electrospinning has problems such as relatively complex structure, low output (single needle 0.1g / h~1g / h), easy clogging and damage, and difficult to clean. Needle-free electrospinning lacks control over the jet shape, resulting in different thicknesses and poor uniformity of the nanofiber membranes collected in the end.

[0004] Although the prior art has adopted different methods to improve the uniformity of the fiber membrane, for example, in terms of needle arrangement, a straight-line or spatial arrangement, or an elliptical, circular, triangular, trapezoidal, convex arc, rotating double needle and staggered double-row straight line arrangement are adopted, and arc or spherical surface collection is adopted in the receiving aspect to make the electric field of the receiving surface uniform, and the reciprocating motion between the needle and the receiving device is achieved in large-scale production. However, these methods have limited effects, and there is still a problem that the equipment needs to be shut down after the spinneret structure is blocked, which affects the production rhythm, and the edge thickness of the obtained electrospun fiber membrane is uneven, resulting in a poor user experience. Summary of the invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide an electrospinning device for preparing fiber membranes of uniform thickness, so as to solve the problems in the prior art that the spinneret structure is easily clogged, affecting production, and the edge thickness of the electrospun fiber membrane obtained is uneven.

[0006] On the one hand, an embodiment of the present invention provides an electrospinning device for preparing a fiber membrane of uniform thickness, comprising a high-voltage electrostatic generator, a solution storage device, an injection device arranged in an inclined array, a receiving device, and a controller; wherein,

[0007] The output end of the high-voltage electrostatic generator is connected to the electrode of the injection device; the output end of the solution storage device is connected to the liquid supply port of the injection device; the receiving device is grounded;

[0008] The controller is used to establish a physical model of the solution advancement speed of each needle-spinning time-lateral thickness of the multi-needle electrospinning fiber membrane; and to minimize the unevenness of the fiber membrane thickness as the optimization goal of the above physical model, to solve the optimal solution advancement speed and optimal spinning time for each needle, and then adjust the state of each needle at the next moment in real time to obtain a fiber membrane of uniform thickness.

[0009] The beneficial effects of the above technical scheme are as follows: by solving the optimal target and controlling the spinning speed of each needle, the unevenness of the edge thickness of the fiber membrane is improved, and a fiber membrane with uniform thickness can still be obtained when some needles are blocked, avoiding shutting down the equipment to clean the needles and causing a large impact on the production progress. It is suitable for the preparation of fiber membranes with arbitrary thickness changes.

[0010] Based on the further improvement of the above device, each needle of the injection device includes at least one of a nozzle, a spinneret, a slit, and a needleless needle; and,

[0011] The controller controls the advancing speeds of the solutions of each needle to be unequal, so as to reduce the loss of spinning materials and keep it within a preset range.

[0012] Furthermore, the controller further comprises:

[0013] A data acquisition unit is used to collect the coordinates of each needle, the solution advancement speed, and the transverse thickness of the fiber membrane formed on the receiving device at the current moment, and send them to the data processing and control unit;

[0014] The data processing and control unit is used to establish a physical model of the solution advancement speed of each needle-spinning time-multi-needle electrospinning fiber membrane thickness; and to minimize the unevenness of the fiber membrane thickness as the optimization goal of the above physical model, and to obtain the optimal solution advancement speed and optimal spinning time for each needle according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device, and then adjust the state of each needle at the next moment in real time until a fiber membrane of uniform thickness is obtained.

[0015] Furthermore, the data acquisition unit further comprises:

[0016] A coordinate positioning subunit is used to obtain the three-dimensional coordinates of each needle at the current moment;

[0017] The speed positioning subunit is used to obtain the solution advancement speed of each needle at the current moment;

[0018] The thickness acquisition subunit is used to acquire the transverse thickness of the fiber membrane formed by each needle on the receiving device at the current moment.

[0019] Furthermore, the data processing and control unit executes the following program:

[0020] Identify whether each needle is blocked and determine the serial number of the blocked needle;

[0021] Establish a physical model of solution advancement speed of each needle without clogging - spinning time - multi-needle electrospinning fiber membrane thickness;

[0022] The minimum non-uniformity of fiber membrane thickness is taken as the optimization target of the above physical model. The optimal solution advancement speed and optimal spinning time of each needle without clogging are obtained according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device.

[0023] The state of each needle at the next moment is adjusted according to the optimal solution advancement speed and the optimal spinning time, and the above process is repeated until a fiber membrane with uniform thickness is obtained.

[0024] Further, the physical model of each needle solution advancement speed-spinning time-multi-needle electrospinning fiber membrane thickness is

[0025] D ( x )= a 1 d 1( x )+…+ a i d i ( x )+… a n d n ( x )

[0026] a i = f ( v i , t i )

[0027] Where i is the needle number, i=1...n; n is the total number of needles in the injection device; a i is the linear coefficient of the i-th needle and its solution advancement speed v i and spinning time t i related; d i ( x ) is the transverse thickness of the fiber film formed on the receiving device by the i-th needle per unit time, D ( x ) is the total transverse thickness of the fiber membrane.

[0028] Furthermore, the optimization goal is

[0029] Min{[ D’ ( x )- a 1 d 1( x )+…+ a i d i ( x )+… a n d n ( x )] 2 / 2}

[0030] 0≤ a i ≤ A

[0031] In the formula, D’ ( x ) is the theoretically expected transverse thickness of the fiber membrane, a 1…… a n is the target to be optimized, A is a i The maximum possible value.

[0032] Furthermore, the injection device adopts at least one of a linear array with multiple needles arranged at small intervals, a two-dimensional array with multiple needles arranged at large intervals and tilted, and a three-dimensional array with tilted arrangements; wherein,

[0033] The small spacing is 2~5 cm between the pointer heads, and the large spacing is 5.1~10 cm between the pointer heads.

[0034] Furthermore, the device also includes auxiliary electrodes arranged laterally and symmetrically between the injection device and the receiving device; wherein,

[0035] The auxiliary electrode is used to constrain the electric field between the injection device and the receiving device through an auxiliary device with electromagnetic shielding effect.

[0036] Furthermore, the controller is also used to identify areas where the fiber membrane thickness is uneven, and control each needle head to perform compensatory reciprocating motion in the area until the fiber membrane thickness reaches a preset range.

[0037] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0038] 1. Aiming at the problem of low uniformity of multi-needle electrospinning fiber membrane thickness, the superimposed thickness of multi-needle spinning is decomposed into a linear combination of the spinning thickness of each needle, and the optimal method of linear combination is proposed. By controlling the spinning speed of each needle, a spun fiber membrane with uniform thickness can be obtained without the need for reciprocating motion of the injection device, and the effective range of uniform thickness is generally wider than that of constant-speed spinning, and the production loss caused by uneven thickness of the fiber membrane edge is further reduced. The thickness of the spun fiber membrane can be uniform and controllable without the need for reciprocating motion of the injection device.

[0039] 2. In order to solve the problem of needle clogging in the multi-needle electrospinning process, the superimposed thickness of the multi-needle spinning is decomposed into a linear combination of the thickness of the remaining unblocked needles. Similarly, based on the optimal solution of the linear combination and adjusting the spinning speed of the remaining needles, a spinning fiber membrane with uniform thickness can still be obtained, and the effective range of uniform thickness is basically the same as before the needle is clogged, ensuring that the electrospinning production process will not be paused due to needle clogging, which is conducive to continuous and efficient production.

[0040] 3. In order to solve the problem that the needle spacing is too small, resulting in uneven distribution of spinning thickness of each needle, which affects the solution accuracy and control effect, the multi-needle small-pitch linear array arrangement (one-dimensional direction) is expanded to a large-pitch inclined array arrangement (two-dimensional plane), which can not only reduce the mutual influence of the electric field between the needles, making the distribution and morphology of the spinning fiber controllable, but also shorten the actual distribution distance of the spinning fiber of each needle, which is conducive to the optimal solution of the linear combination to meet the production requirements and achieve uniform and controllable fiber membrane thickness. The effective width of the uniform spinning fiber membrane thickness obtained by this device is maximized, reducing the production loss caused by the uneven thickness of the fiber membrane edge (if combined with the reciprocating motion of the injection device, the effect is better).

[0041] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0043] Figure 1 The schematic diagram of the composition of the electrospinning device for preparing a fiber membrane with uniform thickness in Example 1 is shown;

[0044] Figure 2 A schematic diagram showing the lateral variation trend of the thickness of single-needle electrospinning in Example 1 is shown;

[0045] Figure 3A schematic diagram showing the lateral variation trend of the thickness of three-needle electrospinning in Example 1 is shown;

[0046] Figure 4 A schematic diagram of the thickness of multi-needle electrospinning with a small needle spacing in Example 1 is shown;

[0047] Figure 5 A schematic diagram of the thickness of multi-needle electrospinning with a large needle spacing in Example 1 is shown;

[0048] Figure 6 A schematic diagram of the thickness comparison of multi-needle electrospinning in Example 2 (10 needles, equal spacing) is shown;

[0049] Figure 7 A schematic diagram showing thickness comparison of multi-needle electrospinning in Example 2 (6 needles, unequal spacing) is shown;

[0050] Figure 8 The tilted multi-needle array arrangement of Example 2 is shown;

[0051] Fig. 9 A schematic diagram showing the projection results of a linear array of multiple needles arranged at large intervals and tilted in Example 2 and a conventional array arrangement in the horizontal one-dimensional direction. DETAILED DESCRIPTION

[0052] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0053] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0054] Example 1

[0055] One embodiment of the present invention discloses an electrospinning device for preparing a fiber membrane with uniform thickness, such as Figure 1 As shown, it includes a high-voltage electrostatic generator, a solution storage device, an injection device arranged in an inclined array, a receiving device, and a controller.

[0056] The output end of the high-voltage electrostatic generator is connected to the electrode of the injection device; the output end of the solution storage device is connected to the liquid supply port of the injection device; and the receiving device is grounded.

[0057] The controller is used to establish a physical model of the solution advancement speed of each needle-spinning time-lateral thickness of the multi-needle electrospinning fiber membrane; and to minimize the unevenness of the fiber membrane thickness as the optimization goal of the above physical model, to solve the optimal solution advancement speed and optimal spinning time for each needle, and then adjust the state of each needle at the next moment in real time to obtain a fiber membrane of uniform thickness.

[0058] During spinning, the injection device or the receiving device reciprocates in one direction to obtain a multi-needle electrospun fiber membrane, or the electrospun fiber membrane is obtained without reciprocating motion, which can be understood by those skilled in the art.

[0059] The above device is suitable for preparing fiber membranes with various thickness variations (not limited to equal thickness). The inclined array units of the injection device are not limited to being arranged at equal or unequal intervals. The principle of the device is described in detail below.

[0060] Single-needle electrospinning can form a fiber membrane on the receiving device. Its shape is generally circular, and its thickness tends to be large in the center and small at the outer edge. For example, along the diameter direction of the circle, Figure 2~3 As shown, it is bilaterally symmetrical, and the position corresponding to the highest point (maximum thickness point) is the center of the circle. It should be noted that the shape of the thickness curve is not unique, and it can also be a triangle or a trapezoid, etc., and the thickness peaks can also be unequal, which does not affect the design, simulation and conclusion of the method involved in this embodiment.

[0061] In the conventional multi-needle spinning process, each needle is controlled according to the same parameters, that is, a i Take the same value. Figure 4 This is the conventional multi-needle spinning thickness result when the needle spacing is small. Here, we will not consider the situation where the spinning thickness curves of each needle are different due to the small needle spacing. Figure 5 This is the result of conventional multi-needle spinning thickness when the needle spacing is large. It can be seen that when the needle spacing is small, the multi-needle spinning superposition thickness (except for the two ends of the edge) is relatively stable in the horizontal direction; when the needle spacing is large, the multi-needle spinning superposition thickness fluctuates in the horizontal direction, and the thickness uniformity becomes worse. If the relative error of the film thickness is required to be controlled within ±10% in production, then Figure 5 The fluctuation is unacceptable. At this time, reciprocating operation can be performed to eliminate Figure 5 The thickness fluctuation shown improves the uniformity of the superimposed thickness of multi-needle spinning.

[0062] In case of multi-needle electrospinning, due to the interaction of the electric fields between the needles, the fiber membrane formed on the receiving device will have multiple aggregation areas, generally irregular ovals of varying sizes. Here, taking three-needle electrospinning as an example (moderate spacing), the transverse (along the single-row needle arrangement direction) curve of the fiber membrane thickness changes as shown in the figure below: Figure 2 As shown, there are three peaks (not necessarily equal), which can also be regarded as the linear superposition of the spinning results of each needle.

[0063] Compared with the prior art, the device provided in this embodiment improves the unevenness of the thickness of the edge of the fiber membrane by solving the optimal target and controlling the spinning speed of each needle. In addition, a fiber membrane with uniform thickness can still be obtained when some needles are blocked, thereby avoiding shutting down the equipment to clean the needles and causing a significant impact on the production progress. The device can be applied to the preparation of fiber membranes with any thickness variation.

[0064] Example 2

[0065] An improvement is made on the basis of Example 1, where each needle of the injection device comprises at least one of a nozzle, a spinneret, a slit, and a needleless device.

[0066] Preferably, the controller controls the advancing speeds of the solutions of each needle to be unequal, so as to reduce the loss of spinning materials and keep it within a preset range.

[0067] Figure 6 This is a comparison of the simulation results of 10-needle electrospinning. The spinning coefficient of each needle a i (See the following description) are 0.53, 0.60, 0, 0.69, 0.24, 0.30, 0.65, 0, 0.64, 0.48. It can be seen that although the thickness of the fiber membrane of unequal-speed spinning fluctuates in the middle section and its uniformity is not as good as that of constant-speed spinning, from the perspective of actual production, if the relative error of the membrane thickness is controlled within ±10% as the judgment standard, the effective range of unequal-speed spinning is 23% wider than that of constant-speed spinning, the former is [1.98, 7.98], and the latter is [2.50, 7.50]; the part with a relative error exceeding ±10% belongs to the unqualified area, and the fiber membrane in this area is calculated as loss material. The material loss of unequal-speed spinning is 33% less than that of constant-speed spinning. The loss of the former accounts for 17.60% of the total amount, and the loss of the latter accounts for 26.21% of the total amount. Although the reciprocating motion of the needle is used to improve the unevenness of the edge film thickness in actual production, this does not affect the qualitative conclusions drawn from the above simulation.

[0068] Preferably, the controller further comprises a data acquisition unit and a data processing and control unit which are connected in sequence.

[0069] The data acquisition unit is used to collect the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device, and send them to the data processing and control unit.

[0070] The data processing and control unit is used to establish a physical model of the solution advancement speed of each needle-spinning time-multi-needle electrospinning fiber membrane thickness; and to minimize the unevenness of the fiber membrane thickness as the optimization goal of the above physical model, and to obtain the optimal solution advancement speed and optimal spinning time for each needle according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device, and then adjust the state of each needle at the next moment in real time until a fiber membrane of uniform thickness is obtained.

[0071] Preferably, the data acquisition unit further comprises a coordinate positioning subunit, a speed positioning subunit, and a thickness acquisition subunit.

[0072] The coordinate positioning subunit is used to obtain the three-dimensional coordinates of each needle at the current moment.

[0073] The speed positioning subunit is used to obtain the solution advancement speed of each needle at the current moment.

[0074] The thickness acquisition subunit is used to acquire the transverse thickness of the fiber membrane formed by each needle on the receiving device at the current moment.

[0075] Preferably, the data processing and control unit executes the following program:

[0076] S1. Identify whether each needle is blocked and determine the serial number of the blocked needle; illustratively, each needle can be directly started to spin to determine whether it is blocked. If it can spin, it is determined that the needle is not blocked, otherwise it is blocked; for the blocked needle, it does not participate in the subsequent modeling and optimization control process;

[0077] S2. Establishing a physical model of the solution advancement speed of each needle without clogging - spinning time - multi-needle electrospinning fiber membrane thickness; the physical model of the solution advancement speed of each needle - spinning time - multi-needle electrospinning fiber membrane thickness can be

[0078] D ( x )= a 1 d 1( x )+…+ a i d i ( x )+… a n d n ( x )

[0079] a i = f ( v i , t i ) (1)

[0080] Where i is the needle number, i=1...n; n is the total number of needles in the injection device; a i is the linear coefficient of the i-th needle and its solution advancement speed v i and spinning time t i related; d i ( x ) is the transverse thickness of the fiber film formed on the receiving device by the i-th needle per unit time, D ( x ) is the total transverse thickness of the fiber membrane;

[0081] S3. Taking the minimum unevenness of the fiber membrane thickness as the optimization goal of the above physical model, the optimization solution is solved according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device to obtain the optimal solution advancement speed and optimal spinning time for each needle without clogging; the optimization goal is

[0082] Min{[ D’ ( x )- a 1 d 1( x )+…+ a i d i ( x )+… a n d n ( x )] 2 / 2}

[0083] 0≤ a i ≤ A

[0084] In the formula, D’ ( x ) is the theoretically expected transverse thickness of the fiber membrane, a 1…… a n is the target to be optimized, A is a i The maximum value possible;

[0085] S4. The state of each needle at the next moment is adjusted according to the optimal solution advancement speed and the optimal spinning time, and the above process is repeated until a fiber membrane with uniform thickness is obtained.

[0086] In the prior art multi-needle spinning process, if the needle is blocked, it is generally necessary to shut down the equipment to clean the needle, otherwise it will affect the uniformity of the thickness of the spun fiber film. The control method of steps S1 to S4 can timely adjust the spinning coefficient of each needle when some needles are blocked. a i , so that the thickness of the spun fiber membrane remains uniform and ensures the continuity of production. Figure 6 The 2nd, 5th, 8th and 10th needles were blocked, leaving only 6 needles spinning normally, and the spacing was unequal. Figure 7 The black dotted line is the spinning thickness corresponding to the missing needle. It can be seen that if the conventional multi-needle electrospinning method is continued, the uniformity of the fiber membrane thickness will be greatly reduced; if the control method of steps S1 to S4 above is used, the 6-needle spinning coefficient is re-solved. a i , respectively 0.90, 0.40, 0.60, 0.60, 0.40, 0.90, the uniformity of spinning thickness is well maintained. Among them, the effective range of unequal-speed spinning is 69% wider than that of equal-speed spinning, the former is [1.75, 7.60], and the latter is [2.94, 6.40]; the material loss of unequal-speed spinning is 60% less than that of equal-speed spinning, the former loss accounts for 17.03% of the total amount, and the latter loss accounts for 42.18% of the total amount.

[0087] Further comparison of the effects before and after needle blockage showed that the effective interval of unequal-speed spinning changed from [1.98, 7.98] to [1.75, 7.60], that is, only the interval [7.60, 7.98] was affected, no longer meeting the requirement of relative error within ±10%, accounting for 6.33% of the original effective interval width, and the material loss rate changed from 17.60% to 17.03%, which was basically unaffected; the effective interval of equal-speed spinning changed from [2.50, 7.50] to [2.94, 6.40], and the intervals [2.50, 2.94] and [6.40, 7.50] were affected, accounting for 44.51% of the original effective interval width, and the material loss rate changed from 26.21% to 42.18%, an increase of 60.93%.

[0088] Based on the above comparison, the existing isospeed spinning method requires shutting down the equipment to clean the blocked needles, while the method provided in this embodiment can continue production. The above conclusion is not limited to the case where the needles are reduced from 10 to 6, but is applicable to various combinations of needle blockages. As long as the relative error of the simulation results remains within the acceptable range for production, theoretically, production can continue, and the blocked needles can be cleaned uniformly after production is stopped.

[0089] Preferably, the injection device adopts a linear array with multiple needles arranged at a small pitch, such as Fig. 9 As shown, or a two-dimensional array with multiple needles arranged at large intervals and tilted is used, such as Figure 8 As shown, or a tilted three-dimensional array. The latter two can be projected in the one-dimensional direction of the receiving device to obtain a small-pitch linear array arrangement effect. Among them, the small pitch is the pointer head spacing of 2~5 cm, and the large pitch is the pointer head spacing of 5.1~10 cm, or a larger spacing.

[0090] Figure 8 This is a schematic diagram of the tilted array arrangement. Assume that the width of the multi-needle plate is 1 m (horizontally) and the length is 1 m (vertically), that is, the area is 1 m 2 , the vertical row spacing is 5 cm, with a total of 21 rows; the horizontal needle spacing in each row is 5 cm, and 20 needles are arranged. The starting position of the first needle in the horizontal direction increases row by row (the order of each row is not unique, and here it is selected to increase row by row for demonstration effect). In the actual spinning production process, the receiving device moves longitudinally under the multi-needle injection device, and any row on the receiving device can receive the spinning fibers from the needles in each row, that is, Figure 8 Although it is a large-pitch two-dimensional array arrangement, after a one-dimensional projection on any row of the receiving device, it can greatly reduce the spinning distance between each needle, which is equivalent to a one-dimensional linear array arrangement with a spacing of 0.24 cm, similar to Fig. 9 Therefore, the two-dimensional array with multiple needles arranged at large intervals and tilted can not only reduce the mutual influence of the electric field between the needles, making the distribution and morphology of the spun fibers controllable, but also shorten the actual distribution distance of the spun fibers of each needle, which is conducive to making the optimal solution of the optimization solution meet the production requirements and realize the uniform and controllable thickness of the fiber membrane.

[0091] Fig. 9It is the projection result of the linear array with multiple needles arranged at large spacing and the conventional array (non-inclined array) arranged in the horizontal one-dimensional direction. It can also be seen that the former has the effect of encrypting the spacing, while the latter does not. The total number of needles in the multi-needle inclined array is 420, which is less than the 441 needles in the conventional array. The needle density per unit area is reduced by 1 / N (N is the number of needles in the horizontal direction, and 1 / N=5% is taken here), which reduces the production capacity to a certain extent. If the number of needles in the horizontal direction N is increased, the needle density loss can be further reduced. On the whole, if the loss of production capacity is acceptable, a two-dimensional array with multiple needles arranged at large spacing and inclination can be considered.

[0092] It should be emphasized that expanding the multi-needle small-pitch one-dimensional linear array arrangement to a large-pitch two-dimensional inclined array arrangement is only an example. Any method of arranging the array combination so that it is projected in the one-dimensional direction of the receiving device to obtain a small-pitch linear array arrangement effect (not limited to equal spacing or unequal spacing) is in line with the spirit of this embodiment.

[0093] Preferably, the device further comprises auxiliary electrodes arranged laterally and symmetrically between the injection device and the receiving device, wherein the auxiliary electrodes are used to constrain the electric field between the injection device and the receiving device through auxiliary devices having an electromagnetic shielding effect.

[0094] Preferably, the controller is also used to identify the area with uneven fiber membrane thickness (data can be obtained by the thickness acquisition subunit to determine whether the fiber membrane thickness in the area has reached a preset range. If not, it is determined to be an area with uneven fiber membrane thickness), and control each needle to perform compensatory reciprocating motion in the area until the fiber membrane thickness reaches the preset range. The above-mentioned compensatory reciprocating motion is not limited to the case of one-dimensional superposition, but also applicable to the case of two-dimensional and three-dimensional superposition.

[0095] Compared with Example 1, the device provided in this embodiment has the following beneficial effects:

[0096] 1. Aiming at the problem of low uniformity of multi-needle electrospinning fiber membrane thickness, the superimposed thickness of multi-needle spinning is decomposed into a linear combination of the spinning thickness of each needle, and the optimal method of linear combination is proposed. By controlling the spinning speed of each needle, a spun fiber membrane with uniform thickness can be obtained without the need for reciprocating motion of the injection device, and the effective range of uniform thickness is generally wider than that of constant-speed spinning, and the production loss caused by uneven thickness of the fiber membrane edge is further reduced. The thickness of the spun fiber membrane can be uniform and controllable without the need for reciprocating motion of the injection device.

[0097] 2. In order to solve the problem of needle clogging in the multi-needle electrospinning process, the superimposed thickness of the multi-needle spinning is decomposed into a linear combination of the thickness of the remaining unblocked needles. Similarly, based on the optimal solution of the linear combination and adjusting the spinning speed of the remaining needles, a spinning fiber membrane with uniform thickness can still be obtained, and the effective range of uniform thickness is basically the same as before the needle is clogged, ensuring that the electrospinning production process will not be paused due to needle clogging, which is conducive to continuous and efficient production.

[0098] 3. In order to solve the problem that the needle spacing is too small, resulting in uneven distribution of spinning thickness of each needle, which affects the solution accuracy and control effect, the multi-needle small-pitch linear array arrangement (one-dimensional direction) is expanded to a large-pitch inclined array arrangement (two-dimensional plane), which can not only reduce the mutual influence of the electric field between the needles, making the distribution and morphology of the spinning fiber controllable, but also shorten the actual distribution distance of the spinning fiber of each needle, which is conducive to the optimal solution of the linear combination to meet the production requirements and achieve uniform and controllable fiber membrane thickness. The effective width of the uniform spinning fiber membrane thickness obtained by this device is maximized, reducing the production loss caused by the uneven thickness of the fiber membrane edge (if combined with the reciprocating motion of the injection device, the effect is better).

[0099] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or improvements over the prior art, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. An electrospinning device for preparing a fiber membrane of uniform thickness, characterized in that: It includes a high-voltage electrostatic generator, a solution storage device, an injection device arranged in an inclined array, a receiving device, and a controller; wherein, The output end of the high-voltage electrostatic generator is connected to the electrode of the injection device; the output end of the solution storage device is connected to the liquid supply port of the injection device; the receiving device is grounded; A controller is used to establish a physical model of solution advancement speed of each needle-spinning time-lateral thickness of multi-needle electrospinning fiber membrane; and to minimize the non-uniformity of fiber membrane thickness as the optimization target of the above physical model, to solve and obtain the optimal solution advancement speed and optimal spinning time of each needle, and then to adjust the state of each needle at the next moment in real time to obtain a fiber membrane with uniform thickness; Each needle of the injection device includes at least one of a nozzle, a spinneret, a slit, and a needleless needle; and The controller controls the solution advancing speeds of each needle to be unequal, so as to reduce the loss of spinning materials and keep it within a preset range; The controller further comprises: A data acquisition unit is used to collect the coordinates of each needle, the solution advancement speed, and the transverse thickness of the fiber membrane formed on the receiving device at the current moment, and send them to the data processing and control unit; The data processing and control unit is used to establish a physical model of solution advancement speed of each needle-spinning time-multi-needle electrospinning fiber membrane thickness; and to minimize the non-uniformity of fiber membrane thickness as the optimization target of the above physical model, and to obtain the optimal solution advancement speed and optimal spinning time of each needle according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device, and then adjust the state of each needle at the next moment in real time until a fiber membrane of uniform thickness is obtained; The data acquisition unit further comprises: A coordinate positioning subunit is used to obtain the three-dimensional coordinates of each needle at the current moment; The speed positioning subunit is used to obtain the solution advancement speed of each needle at the current moment; The thickness acquisition subunit is used to acquire the transverse thickness of the fiber film formed by each needle on the receiving device at the current moment; The data processing and control unit executes the following procedures: Identify whether each needle is blocked and determine the serial number of the blocked needle; Establish a physical model of solution advancement speed of each needle without clogging - spinning time - multi-needle electrospinning fiber membrane thickness; The minimum non-uniformity of fiber membrane thickness is taken as the optimization target of the above physical model. The optimal solution advancement speed and optimal spinning time of each needle without clogging are obtained according to the coordinates of each needle at the current moment, the solution advancement speed, and the lateral thickness of the fiber membrane formed on the receiving device. According to the optimal solution advancement speed and the optimal spinning time, the state of each needle at the next moment is adjusted, and the above process is repeated until a fiber membrane with uniform thickness is obtained; The physical model of each needle solution advancement speed-spinning time-multi-needle electrospinning fiber membrane thickness is: D(x)=a1d1(x)+…+a i d i (x)+…a n d n (x) a i =f(v i ,t i ) Where i is the needle number, i=1...n; n is the total number of needles in the injection device; a i is the linear coefficient of the i-th needle and its solution advancing speed v i and spinning time t i Related;d i (x) is the transverse thickness of the fiber film formed on the receiving device by the i-th needle per unit time, and D(x) is the total transverse thickness of the fiber film; The optimization objective is Min{[D'(x)-a1d1(x)+…+a i d i (x)+…a n d n (x)] 2 / 2} 0≤a i ≤A Where D'(x) is the theoretically expected transverse thickness of the fiber membrane, a1...a n is the target to be optimized, A is a i The maximum value possible.

2. The electrospinning device for preparing a fiber membrane of uniform thickness according to claim 1, characterized in that: The injection device adopts at least one of a linear array with multiple needles arranged at small intervals, a two-dimensional array with multiple needles arranged at large intervals and tilted, and a three-dimensional array with tilted arrangements; wherein, The small spacing is that the distance between the pointer heads is 2 to 5 cm, and the large spacing is that the distance between the pointer heads is 5.1 to 10 cm.

3. The electrospinning device for preparing a fiber membrane of uniform thickness according to claim 2, characterized in that: It also includes auxiliary electrodes arranged laterally and symmetrically between the injection device and the receiving device; wherein, The auxiliary electrode is used to constrain the electric field between the injection device and the receiving device through an auxiliary device with electromagnetic shielding effect.

4. The electrospinning device for preparing a fiber membrane of uniform thickness according to any one of claims 1 or 3, characterized in that: The controller is also used to identify the area where the fiber membrane thickness is uneven, and control each needle to perform compensatory reciprocating motion in the area until the fiber membrane thickness reaches a preset range.

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