KR101688817B1 - Apparatus of forming patterns by electrospinning method - Google Patents

Abstract

An electrospinning pattern forming apparatus is disclosed. An electrospinning pattern forming apparatus includes a first injection nozzle and a nozzle unit coaxial with the first injection nozzle and including a second injection nozzle disposed inside the first injection nozzle, the nozzle unit being applied with a first voltage; A stage unit disposed at a lower portion of the nozzle unit to support a substrate on which a pattern is to be formed and to which a second voltage is applied; A solution injecting unit for receiving the spinning solution and connected to the first injection nozzle to inject the spinning solution into the first injection nozzle; And the second injection nozzle is connected to the second injection nozzle, and when the first injection nozzle radiates the spinning solution in the direction of the stage part to form the tail cone, the second injection nozzle sucks part of the spinning solution in the tail cone And a suction pump portion.

Description

[0001] APPARATUS OF FORMING PATTERNS BY ELECTROSPINING METHOD [0002]

The present invention relates to an electrospinning pattern forming apparatus, and more particularly, to an electrospinning pattern forming apparatus capable of arranging nanofibers formed in an electrospinning manner using a magnetic field in a predetermined direction.

Methods for manufacturing nanofibers include drawing, template synthesis, phase separation, self assembly, electrospinning, and the like. Among these methods, an electrospinning method is generally applied as a method for continuously producing nanofibers.

The electrospinning method applies a high voltage between the nozzle for spinning the spinning solution and the stage where the substrate is placed to form an electric field larger than the surface tension of the spinning solution so that the spinning solution is radiated in nanofiber form. Nanofibers produced by the electrospinning method are influenced by the physical properties of the spinning solution such as viscosity, elasticity, conductivity, dielectric properties, polarity and surface tension, the strength of the electric field, and the distance between the nozzle and the integrated electrode.

Nanofiber formation by electrospinning is a well known technique. On the other hand, attempts have been made to arrange the nanofibers thus formed in a desired direction. As a typical method thereof, there are a method of obtaining aligned nanofibers by electrospinning to adjoining electrodes, and a method of keeping the distance between the nozzle and the substrate very close , And arranging the nanofibers at desired positions. An electrospinning pattern forming apparatus is used as an apparatus for forming nanofibers in a predetermined pattern on a substrate by such a method.

In the case of aligning electrospun nanofibers using a conventional electrospinning pattern forming apparatus, it was difficult to obtain a nanofiber array having a high degree of alignment when a specific polymer solution was used. That is, when a nanofiber pattern is formed by a conventional electrospinning pattern forming apparatus, there is a nanofiber pattern bent in a coiled-loop shape as shown in FIG. This is because, when a Taylor-cone is formed on the nozzle tip for electrospinning, a relatively high voltage is applied to a specific polymer solution, bending instability due to high volume current density of the spun nanofiber Bending instability, it is difficult to form high quality aligned nanofiber arrays.

To compensate for this problem, the voltage applied to the nozzle can be set low, but it is difficult to maintain the shape of the tail cone stably due to the reduced electric field. In this case, droplets are formed during spinning and fall off to the substrate, which lowers the quality of the nanofiber array formed on the substrate.

On the other hand, in the case of near-field electrospinning using a method of arranging the nanofibers at a desired position by keeping the distance between the nozzle and the substrate very close to each other, It is difficult to obtain a linear nanofiber pattern. In this case, it is also possible to obtain a linear pattern by lowering the applied voltage and relieving the bending instability of the charged jet, but it is difficult to maintain a stable tail cone at a lower applied voltage.

Korean Patent No. 10-0934920

Accordingly, it is an object of the present invention to provide an electrospinning pattern forming apparatus capable of maintaining a stable Taylor cone shape even at a low applied voltage and forming a uniform linear pattern of nanofibers.

According to another aspect of the present invention, there is provided an apparatus for forming an electrospinning pattern, including a first injection nozzle and a second injection nozzle coaxial with the first injection nozzle and disposed in the first injection nozzle, 1 < / RTI > A stage unit disposed at a lower portion of the nozzle unit to support a substrate on which a pattern is to be formed and to which a second voltage is applied; A solution injecting unit for receiving the spinning solution and connected to the first injection nozzle to inject the spinning solution into the first injection nozzle; And the second injection nozzle is connected to the second injection nozzle, and when the first injection nozzle radiates the spinning solution in the direction of the stage part to form the tail cone, the second injection nozzle sucks part of the spinning solution in the tail cone And a suction pump portion.

In one embodiment, the apparatus may further include a nozzle heating unit connected to the nozzle unit and heating the nozzle unit.

In one embodiment, the Taylor cone photographing unit is installed around the nozzle unit or the stage unit and photographs the formation state of the Taylor cone. And an image analyzing unit connected to the Taylor cone photographing unit and analyzing an image obtained through the Taylor cone photographing unit.

According to the electrospinning pattern forming apparatus of the present invention, stable Taylor cone shape can be maintained even at a low applied voltage, and bending instability of the jetting liquid jet emitted from the Taylor cone can be relieved to form uniform linear patterns of the nanofibers can do.

1 is a view showing a pattern shape of a nanofiber formed by a conventional electrospinning pattern forming apparatus.
2 is a conceptual diagram for explaining an electrospinning pattern forming apparatus according to an embodiment of the present invention.
Figs. 3A to 3C are diagrams showing an example of a graph included in the conventional literature.
Fig. 4 is a diagram showing a countercurrent flow of fluid formed in the Taylor cone shape.
5A to 5C are views for confirming volume change of the tail recovers according to whether the suction pump unit is turned ON or OFF.
FIG. 6 is a view for explaining a force applied to the nanofibers by the fiber guide portion shown in FIG. 1. FIG.
FIG. 7 is a view illustrating the arrangement of nanofibers aligned on a substrate using an electrospinning patterning apparatus according to an embodiment of the present invention. Referring to FIG.
8 is a conceptual diagram for explaining an electrospinning pattern forming apparatus according to another embodiment of the present invention.

Hereinafter, an electrospinning pattern forming apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are enlarged to illustrate the present invention in order to clarify the present invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

2 is a conceptual diagram for explaining an electrospinning pattern forming apparatus according to an embodiment of the present invention.

Referring to FIG. 2, an apparatus 1000 for forming an electrospinning pattern according to an embodiment of the present invention may directly form a desired fine pattern on a substrate (not shown) by electrospinning the spinning solution 10. [ To this end, an electrospinning pattern forming apparatus 1000 according to an embodiment of the present invention includes a nozzle unit 100; A stage unit 200; A solution injector 300; And a suction pump unit 400.

The nozzle unit 100 may include a first nozzle 110, a second nozzle 120, and a first voltage generator 130.

The first nozzle 110 is connected to the solution injecting unit 300 and can radiate the spinning solution supplied from the solution injecting unit 300 toward the stage unit 200. The first nozzle 110 may be formed of a conductive material, for example, a stainless material, and may have a micro tube shape having a constant inner diameter and outer diameter.

The second nozzle 120 is connected to the suction pump unit 400 and can suck a part of the spinning solution radiated from the first nozzle 110 by the suction pump unit 400. To this end, the second nozzle 120 may be located inside the first nozzle 110, and may be a microtubule shape having a diameter that is coaxial with the first nozzle 110 and smaller than the inner diameter of the first nozzle 110 Lt; / RTI > When the second nozzle 120 is positioned within the first nozzle 110, the outer surface of the second nozzle 120 and the inner surface of the first nozzle 110 may be spaced apart from each other. The spinning solution injected into the first nozzle 110 may be radiated to the outside through the spaced distance between the first nozzle 110 and the second nozzle 120.

The first voltage generator 130 may be electrically connected to the first nozzle 110 and may apply the first voltage to the first nozzle 110. For example, the first voltage generating device 130 may generate a DC voltage having a positive polarity to the first nozzle 110 and apply the generated DC voltage to the first nozzle 110. The magnitude of the first voltage applied to the first nozzle 110 can be appropriately adjusted as needed.

The stage unit 200 may include a stage 210 and a second voltage generator 220.

The stage 210 may be disposed at a predetermined distance from an end of the first nozzle 110 that emits the spinning solution 10. [ The stage 210 may be formed of a conductive material. A substrate (not shown) on which a pattern is to be formed may be disposed on the stage 210.

The second voltage generator 220 is electrically connected to the stage 210 and may generate a second voltage different from the first voltage applied to the first nozzle 110 and apply the second voltage to the stage 210. For example, the second voltage generator 220 can generate a ground voltage and apply it to the stage 210. Alternatively, the second voltage generator 220 may generate a negative voltage having a different polarity from the first voltage or a positive voltage having a different intensity from the first voltage and may apply the voltage to the stage 210 have.

The solution injection unit 300 may include a syringe 310 and a syringe pump 320.

The syringe 310 can receive the spinning solution 10. The spinning liquid 10 may be an organic material solution such as a polymer or the like or an organic or inorganic composite material in which an organic material and an inorganic material are mixed. Or a solution prepared by dissolving polyacrylonitrile (PAN) polymer in a solvent of N, N-dimethylformamide (DMF) at a concentration of 10 wt%. The spinning solution 10 may have a viscosity of about 1 to 200 poise. The first nozzle 110 is connected to the syringe 310 so that the first nozzle 110 can radiate the spinning solution 10 received in the syringe 310 toward the stage 210 .

The syringe pump 320 can apply pressure to the spinning solution 10 contained in the syringe 310 so that the spinning solution 10 contained in the syringe 310 can be discharged to the outside through the first nozzle 110 have. The pressure applied to the spinning solution 10 by the syringe pump 320 can be adjusted so that the flow rate of the spinning solution 10 supplied to the first nozzle 110 can be controlled.

The suction pump unit 400 may include a vacuum pump 410 and a pump control unit 420.

The vacuum pump 410 is connected to the second nozzle 120 and suction pressure may be applied to the second nozzle 120 by driving the vacuum pump 410.

The pump control unit 420 may be connected to the vacuum pump 410 to control the suction intensity of the vacuum pump 410. For example, the pump control section 420 may be manually operated or may be remotely operated through a control computer in communication with a remote control computer.

In order to form a pattern on a substrate, an apparatus for patterning an electrospinning pattern according to an embodiment of the present invention includes a first nozzle 110 for spinning the spinning solution 10 in the direction of the stage 210, A Taylor cone may be formed from the end of the first nozzle 110.

That is, since different voltages are applied to the first and second nozzles 110 and 210 by the first voltage generating device 130 and the second voltage generating device 220, An electric field due to a voltage difference is formed between the first nozzle 110 and the stage 210 and the spinning solution 10 is hanged at the end of the first nozzle 110 in a droplet form. At this time, a charge of polarity opposite to the voltage applied to the first nozzle 110 is induced on the surface of the droplet of the spinning solution 10, and the electric charge induced on the surface of the spinning solution 10 is applied to the electrostatic force . Due to the action of the electrostatic force, the droplet of the spinning solution 10 hanging from the end of the first nozzle 110 expands in a conical shape known as Taylor cone.

Thus, the shape of the Taylor cone of the spinning liquid 10 formed at the end of the first nozzle 110 must be stably maintained.

Generally, the voltage magnitude for forming a stable conformation of Taylor cone is known. Specifically, according to the conventional literature, Journal of Electrostatics 68 (2010) 458-464, there is provided evidence that it is desirable to apply a voltage higher than a certain level in order to stably maintain the volume of the tail cone. Figs. 3A to 3C are diagrams showing an example of a graph included in the conventional literature.

Referring to FIG. 3A, when the applied voltage is maintained at 13.7 kV, the volume deviation of the Taylor cone is about 14%. Referring to FIG. 3B, when the applied voltage is 14.6 kV, And 3.5%, respectively. Referring to FIG. 3C, although the range of the applied voltage for forming the tail cone is 13.7 to 16 kV, it is preferable to use an applied voltage of 14.6 to 16 kV to maintain the volume at a constant level.

In this way, the Taylor cone shape can be stably maintained when the applied voltage for stable Taylor cone shape stably known in the conventional art, that is, the most preferable applied voltage of 14.6 to 16 kV is used, When the structure of the suction pump unit 120 and the suction pump unit 400 is used, a stable Taylor cone shape can be maintained even at a minimum applied voltage of 13.7 kV. Hereinafter, the operation of the second nozzle 120 and the suction pump unit 400 that enable this will be described.

The present invention operates the second nozzle 120 and the suction pump unit 400 to maintain the stable Taylor cone shape.

When the vacuum pump 410 of the suction pump unit 400 is driven, a suction pressure is applied to the second nozzle 120. As a result, the second nozzle 120 sucks a portion of the spinning solution inside the Taylor cone of the spinning solution 10 formed at the end of the first nozzle 110, Not shown). The process of sucking a part of the spinning liquid through the second nozzle 120 reduces the instability of the flow due to the backflow (see FIG. 4) of the fluid formed inside the tail cone when the Taylor cone is formed, Thereby preventing it from being destroyed. Therefore, it is possible to stably maintain the Taylor cone having a constant volume even at the minimum applied voltage suggested in the above-mentioned conventional literature.

Meanwhile, the volume of the tail cone may be excessively increased or decreased by adjusting the volume change of the tail cone formed at the end of the first nozzle 110 according to the operation of the second nozzle 120 and the suction pump unit 400 Thus, the Taylor cone shape can be stably maintained to have a certain level of volume. Hereinafter, the volume change of the tail cone formed at the end of the first nozzle 110 according to whether the suction pump unit 400 is on or off will be described with reference to FIGS. 5A to 5C. 5A to 5C are views for confirming the volume change of the tail recovers according to whether the suction pump unit is ON / OFF.

Referring to FIG. 5A, it can be seen that the volume of the Taylor cone increased due to the low applied voltage is maintained at a constant level without increasing the volume from the point A where the suction pump unit 400 is operated. Referring to FIG. 5B, it can be seen that the volume of the tail cone increases sharply from point A where the suction pump unit 400 is stopped. Referring to FIG. 5C, it can be seen that the volume of the Taylor cone decreases rapidly as the volume of the Taylor cone reaches its limit and the droplet occurs (at the A point), and then the volume of the Taylor cone decreases steadily from the A point. And the volume decreases from point B where the suction pump unit 400 is operated. Then, as the volume of the tail cone decreases from point B, the suction intensity of the suction pump unit 400 is set to be weaker in order to control the degree of decrease in volume.

The intensity of the electric field formed between the first nozzle 110 and the stage 210 can be adjusted to the intensity at which jetting solution 10 jet can be emitted while the Taylor cone shape is stably maintained. (10) jet from the end of the spinning solution (10) cone.

The discharged spinning solution 10 jet is radiated in the direction of the stage 210 in a continuous fiber form without collapsing. Spray Solution (10) Spray Solution from Taylor Cone (10) Fibers may have a nanoscale diameter. Hereinafter, the "spinning solution (10) fiber" emitted from the spinning solution (10) Taylor cone is referred to as "nanofiber" for convenience of explanation.

The fiber guide portion 500 shown in Fig. 1 may be used to advance the nanofibers to be arranged in a specific direction on the substrate.

The fiber guide part 500 guides the traveling direction of the nanofibers radiated from the first nozzle 110. For this purpose, the fiber guide part 500 may include a first guide magnet 510 and a second guide magnet 520. The first and second guide magnets 510 and 520 are positioned adjacent to the end of the first nozzle 110 through which nanofibers are emitted and extend in one direction Y and are parallel to each other, Are spaced apart from each other by a predetermined distance therebetween. That is, the first and second guide magnets 510 and 520 are disposed between the first nozzle 110 and the stage 210 and are spaced apart from each other at a position adjacent to the end of the first nozzle 110. For example, the first and second guide magnets 510 and 520 may be made of a neodymium magnet that is a permanent magnet forming a strong magnetic field. The shape of each of the first and second guide magnets 510 and 520 is not particularly limited and may have various shapes. For example, each of the first and second guide magnets 510 and 520 may have a rod shape having a section such as a circular shape, a polygonal shape, a semicircular shape, an ellipse, or the like, or may have a plate shape. Each of the first and second guide magnets 510 and 520 may have a bar shape that is rectangular in cross section perpendicular to the stage 210 and extends in a direction Y parallel to the stage 210 .

When the first and second guide magnets 510 and 520 are disposed as described above, a magnetic field is formed between the first and second guide magnets 510 and 520, and these magnetic fields exert a constant force on the nanofibers, As a result, the nanofibers can be arranged to be arranged in a specific direction on the substrate to form a linear pattern on the substrate. For example, the magnetic field formed between the first and second guide magnets 510 and 520 is directed to the nanofibers ejected from the first nozzle 110 in a direction perpendicular to the magnetic field direction X (Y), and as a result, the nanofibers are advanced on the substrate so as to be arranged in the direction (Y) perpendicular to the magnetic field, and are linearly extended in the direction (Y) perpendicular to the magnetic field direction (X) A pattern can be formed.

FIG. 7 is a view showing the arrangement of nanofibers aligned on a substrate using the apparatus for forming an electrospinning pattern according to an embodiment of the present invention. The arrangement of the nanofibers shown in FIG. 7 is in an enlarged state using an optical microscope.

When the nanofibers are formed in a linear pattern on the substrate using the electrospinning pattern forming apparatus according to an embodiment of the present invention, the arrangement of the nanofibers can be clearly removed A uniform linear pattern can be formed. This uniform linear patterning is achieved by keeping the voltage applied for formation of the tail cone relatively low by the second nozzle 120 and the suction pump portion 400 and thereby relieving the bending instability of the charged jet It becomes possible.

The use of such an electrospinning pattern forming apparatus according to an embodiment of the present invention can maintain a stable Taylor cone shape even at a low applied voltage and relieve the bending instability of the jet 10 liquid jet emitted from the Taylor cone A uniform linear pattern of the nanofibers can be formed.

8 is a conceptual diagram for explaining an electrospinning pattern forming apparatus according to another embodiment of the present invention.

8, an apparatus 2000 for patterning an electrospinning pattern according to another embodiment of the present invention further includes a nozzle heating unit 600, a tailor cone photographing unit 700, and an image analyzing unit 800 The Taylor cone photographing unit 700 and the image analyzing unit 800 will be described below with reference to the nozzle heating unit 600, .

The nozzle heating unit 600 is connected to the nozzle unit 100 to heat the nozzle unit 100. For example, the nozzle heating unit 600 may be an electric heater. The nozzle heating unit 600 heats the nozzle unit 100 to maintain the nozzle unit 100 at a specific temperature. The nozzle unit 100 is heated by the spinning solution 10 during the spinning and sucking of the spinning liquid 10 through the nozzle unit 100 as the nozzle unit 100 is heated, 2 nozzle 120 can be prevented from being clogged. The temperature of the nozzle part may be set according to the viscosity of the spinning solution 10 and may not be used when the spinning solution 10 has a low viscosity.

The tailor cone photographing unit 700 can photograph the formation state of the tail cone formed from the end of the first nozzle 110. [ To this end, the tailor cone photographing unit 700 may be installed around the nozzle unit 100 or the stage unit 200. The tailor cone photographing unit 700 may include a camera 710 and a lamp 720. The camera 710 photographs the Taylor cone and the lamp 720 illuminates the Taylor cone formation point to assist in photographing the Taylor cone through the camera 710.

The image analyzing unit 800 analyzes the image obtained through the Taylor cone photographing unit 700. The image analysis unit 800 may be provided with a Taylor cone image which is electrically connected to the camera 710 and photographed through the camera 710. The image analysis unit 800 may be a conventional PC. The PC may be provided with an image analysis program for analyzing the Taylor cone image provided from the camera 710 and a control unit (not shown) for controlling the solution injection unit 300 and the suction pump unit 400, , It is possible to confirm and analyze whether or not the tail cone is formed stably.

The use of the electrospinning pattern forming apparatus according to another embodiment of the present invention can prevent the nozzle unit 100 of the spinning solution 10 being radiated and sucked through the nozzle unit 100 from being blocked, The shape of the tail cone can be confirmed and analyzed in real time.

100: nozzle unit 110: first nozzle
120: second nozzle 130: first voltage generating device
200: stage unit 210: stage
220: second voltage generator 300: solution injecting part
310: syringe 320: syringe pump
400: suction pump unit 410: vacuum pump
420: pump control part 500: fiber guide part
510: first guide magnet 520: second guide magnet
600: Nozzle heating part 700: Taylor cone part
710: Camera 720: Lamp
800: Image analysis unit

Claims (3)

A nozzle unit including a first injection nozzle and a second injection nozzle disposed inside the first injection nozzle, the nozzle unit being applied with a first voltage;
A stage unit disposed at a lower portion of the nozzle unit to support a substrate on which a pattern is to be formed and to which a second voltage is applied;
A solution injecting unit for receiving the spinning solution and connected to the first injection nozzle to inject the spinning solution into the first injection nozzle; And
Wherein a part of the spinning solution existing in the Taylor cone of the spinning solution formed at the end of the first injection nozzle is partially injected into the second injection nozzle And a vacuum pump connected to the second injection nozzle to apply a suction pressure to the second injection nozzle so as to be sucked into the second injection nozzle. The method according to claim 1,
And a nozzle heating unit connected to the nozzle unit and heating the nozzle unit. 3. The method of claim 2,
A Taylor cone photographing part installed around the nozzle part or the stage part and photographing the formation state of the Taylor cone; And
And an image analysis unit connected to the Taylor cone photographing unit and analyzing an image obtained through the Taylor cone photographing unit.

Images