JP5224704B2 - Nano-fiber manufacturing method and apparatus - Google Patents

Description

  The present invention relates to a nanofiber manufacturing method and apparatus using an electrospinning method.

  Healthcare fields such as regenerative medicine engineering, wound materials, drug delivery, biotechnology and environmental engineering fields such as affinity membranes and sensors for the purification of biomolecules and contaminated water, polymer batteries, dye-sensitized solar Less than a micron (μm) in a wide range of energy fields such as batteries, polymer membrane fuel cells, composite material reinforcements, anti-terrorism attacks against bioterrorism, or protection / security fields such as protective clothing assuming gas attacks A fiber (nanofiber) having a nano-order diameter (for example, several nm to several hundred nm) has attracted attention.

  One technique for producing such nanofibers is the electrospinning method. An outline of this electrospinning method is shown in FIGS. 4 shows electric lines of force, and FIG. 5 shows a spinning jet. As shown in these drawings, as a basic structure, the nozzle 20 has a spinneret 20a and injects a solution of a polymer as a fiber material and a volatile solvent, a flat collector 21, and a nozzle 20 And a collector 21 is provided with a high voltage power supply 22 for applying a high voltage. In a state where a high voltage is not applied, the polymer solution remains at the surface tension at the tip of the spinning port 20a at the tip of the nozzle 20. When a voltage of several kV to 30 kV is applied between the spinneret 20a and the collector 21, the droplet of the polymer solution at the tip of the spinneret 20a is charged to + (or-) and charged to a different polarity (ground). It is attracted by the electrostatic force (Coulomb force) acting along the electric lines of force (see FIG. 4) toward the collector 21. When the electrostatic force exceeds the surface tension, the spinning jet 23 of the polymer solution is continuously jetted toward the collector 21 as shown in FIG. At this time, the solvent in the polymer solution is volatilized, and when it reaches the collector 21, only the polymer fibers are formed, and nano-fibers with nano-level fineness are formed. In addition, as a raw material of the nanofiber, not only an organic polymer but also an inorganic material such as a metal oxide or ceramic can be spun into a nanofiber shape by a sol-gel method.

  It is known that the spinning jet 23 ejected from the spinneret 20a draws a spiral trajectory due to the influence of the distribution of electric lines of force between the spinneret 20a and the collector 21 while reaching the collector 21 from the spinneret 20a. (For example, see Non-Patent Documents 1 and 2).

  Thus, since the spinning jet 23 between the spinneret 20a and the collector 21 draws a spiral trajectory, the nanofibers integrated in the flat plate-like letter 21 are as shown in the enlarged view of part A (SEM photograph) in FIG. , Randomly oriented to form a nonwoven fabric. However, it is difficult to evaluate the physical properties of nanofibers in the form of nonwoven fabric. Therefore, various techniques for aligning the orientation of nanofibers in one direction have been proposed.

  7 and 8 show a method using a disk collector which is a rotating disk with a sharp edge (see, for example, Non-Patent Document 3). FIG. 7 shows electric lines of force, and FIG. 8 shows a spinning jet. In this method, a fiber sample with high orientation is produced by using a disk collector 24 that rotates around a rotating shaft 24a and reducing the target of the spinning jet 23, as shown in the enlarged view of part B of FIG. Technology has been proposed.

  However, this technique cannot produce a sample with a large area. Further, when the peripheral surface of the disk collector 24 is covered with a fiber, there is a problem that the effect of the target is reduced and the orientation of the sample is lowered.

  Further, as shown in FIGS. 10 and 11 (FIG. 10 shows lines of electric force and FIG. 11 shows a spinning jet), two parallel metal plates arranged on the same plane at a predetermined interval are belt-shaped. 12 is used as the first collector 25 and the strip-shaped second collector 26, and the spinning jet 23 having a spiral trajectory drawn between the parallel strip-shaped first and second collectors 25 and 26 is integrated into the enlarged view of part C of FIG. As shown, a technique for obtaining nanofibers oriented in one direction has been proposed (see, for example, Non-Patent Document 4).

  However, when the distance between the strip-shaped first and second collectors 25 and 26 is increased, the effect is reduced, and an oriented fiber cannot be produced. That is, this method cannot produce a wide-area oriented fiber sample.

  On the other hand, as shown in FIGS. 13 and 14 (FIG. 13 shows lines of electric force and FIG. 14 shows a spinning jet), there is a method using a rotating body collector 27 such as a cylindrical electrode rotating around a rotating shaft 27a. (For example, see Non-Patent Documents 5 and 6). In this method, when the rotating body collector 27 is rotated at a low speed, the orientation is poor as shown in the enlarged view of part D (low speed) in FIG. 15, but the spinning jet 23 is wound around the rotating body collector 27 at a high speed. As shown in the enlarged view of portion D of FIG. 15 (high speed), a fiber sample with a certain degree of orientation can be produced. In this case, the spinning jet 23 is charged, and the spinning jet 23 can be blown toward the rotating body collector 27 connected to the ground.

AL Yarin et al., "Bending instability in electrospinning of nanofibers", Journal of Applied Physics, 89, No. 5, March 1, 2001, p. 3018-3026 AL Yarin et al., “Taylor cone and jetting from liquid droplets in electrospinning of nanofibers” ", Journal of Applied Physics, Vol. 90, No. 9, November 1, 2001, p. 4836-4846 AL Yarin et al., "Electrospinning of Nanofibers from Polymer Solutions", 21st International Conference on Theoretical and Applied Mechanics (ICTAM), August 2004 15-21 days, Warsaw, Poland D. Li, Y. Xia, "Electrospinning of Nanofibers: Reinventing the Wheel?", Advanced Materials ( Advanced Materials), Vol. 16, p. 1151-1170 (2004) ED Boland et al., “Tailoring tissue engineering scaffolds using electrostatic: Tailoring tissue engineering scaffolds using electrostatic processing techniques: A study of poly (glycolic acid) electrospinning), J. Macromol. Sci. Pure Appl. Chem. A38, No. 12, p. 1231-1243 (2001) J. A. Matthews et al., “Electrospinning of collagen nanofibers”, Biomacromolecules, 3, p. 232-238 (2002)

However, in the spinning method using the rotating body collector, the spinning jet before winding has a spiral orbit, so that even if high-speed winding is performed, as shown in the enlarged view of D part (high speed) in FIG. However, there is a problem that it is difficult to align the alignment properly and the fibers are not aligned in one direction.
Therefore, an object of the present invention is to improve the orientation of nanofibers stacked on a collector.

In order to solve the above problems, a first configuration of the present invention is that a high voltage is applied between a spinneret and a cylindrical rotating body collector, and a charged fiber raw material and a solvent solution are rotated from the spinneret. In a nanofiber manufacturing method using an electrospinning method in which nanofibers are integrated on the rotating body collector by spraying and sucking toward the body collector,
In the spinning space between the spinneret and the rotating body collector , an inverted cone-shaped electrode body arranged so as to surround the spinning jet ejected from the spinneret is disposed, and a predetermined potential is applied to the electrode body. Thus, the trajectory of the spinning jet ejected from the spinneret is guided, and nanofibers aligned in one direction are spun on the surface of the rotating body collector.

In the second configuration of the present invention, a high voltage is applied between the spinneret and the cylindrical rotator collector, and the charged fiber raw material and solvent solution are directed from the spinneret toward the rotator collector. In a nanofiber manufacturing apparatus using an electrospinning method in which nanofibers are integrated on the rotating body collector by spraying and sucking,
A reverse cone-shaped electrode for guiding a spinning jet trajectory in which a predetermined potential is applied to a spinning space between the spinning port and the rotating body collector and arranged around the spinning jet ejected from the spinning port. The body is arranged.

In the present invention, an electrode body is arranged in a spinning space between the spinning port and the rotating body collector, and a predetermined potential is applied to the electrode body to induce a trajectory of the spinning jet ejected from the spinning port. Thus, by guiding the trajectory of the spinning jet, nanofibers aligned in one direction can be spun on the surface of the rotating body collector. here,
By using a cylindrical rotating collector as the collector, a highly oriented unidirectional nano-fiber assembly can be obtained.
By using an inverted cone electrode body arranged in a state surrounding the periphery of the spinning jet ejected from the spinneret as the electrode body, the spinning jet reaches the collector while being converged by the inverted cone electrode body. A highly oriented nano-fiber is obtained.

According to the present invention, in the spinning space between the spinneret and the rotating body collector, the inverted cone electrode body disposed in a state surrounding the periphery of the spinning jet ejected from the spinneret is disposed, and this electrode body has a predetermined By inducing the trajectory of the spinning jet ejected from the spinneret by applying the potential, it is possible to enhance the orientation of the nanofibers laminated on the rotating body collector.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing a basic configuration of a nano-fiber manufacturing apparatus according to a first reference example . FIG. 2 is an explanatory diagram showing a basic configuration of a nano-fiber manufacturing apparatus according to a second reference example . 3 is an explanatory view showing a basic configuration of a nano-fiber manufacturing apparatus according to an embodiment of the present invention.

<First Reference Example >
Although not an embodiment of the present invention, as a basic configuration of the nano-fiber manufacturing apparatus according to the first reference example , as shown in FIG. 1, a solution of a polymer as a fiber material and a volatile solvent is used. Syringe 1 inserted, syringe pump 2 for extruding a solution of the raw material and the solvent in syringe 1, solution supply tube 3, nozzle 4 having a spinneret 4a, and a rotating body that is rotationally driven around rotating shaft 5a A collector 5, a high-voltage power source 6 that applies a high voltage between the nozzle 4 and the rotating body collector 5, a pair of parallel first electrode 8 and second electrode 9, and first electrode 8 and second electrode 9. It is the structure provided with the 2nd high voltage power supply 10 which provides an electric potential. In addition, the solution supply tube 3 may connect the syringe pump 2 and the nozzle 4 directly, and is not essential.

  The first electrode 8 and the second electrode 9 are the upper part of the rotating body collector 5, on both sides of the spinning space between the spinning port 4 a and the rotating body collector 5, and in parallel with the rotating shaft 5 a of the rotating body collector 5. Almost equidistant. The first electrode 8 and the second electrode 9 are applied with a voltage lower than the high voltage applied to the spinning port 4a. Alternatively, it may be connected to ground. In that case, the second high-voltage power supply 10 becomes unnecessary. The polarity of the voltage to be applied is positive in the nozzle 4 and negative (or grounded) in the rotating body collector 5 in the illustrated example, but may be in the opposite polarity.

Next, operation | movement of this nano fiber manufacturing apparatus is demonstrated.
In a state where a high voltage is not applied between the nozzle 4 and the rotating body collector 5, the polymer solution remains at the surface tension at the tip of the spinning port 4a at the tip of the nozzle 4. When a high voltage of, for example, several kV to 30 kV is applied between the spinning port 4a and the rotating body collector 5, the polymer solution droplet at the tip of the spinning port 4a is charged to + and charged to a different polarity (or ground potential). It is attracted by the electrostatic force directed to the rotating collector 5 that is rotating. When the electrostatic force exceeds the surface tension, the spinning jet 7 of the polymer solution is continuously jetted toward the rotating body collector 5.

At this time, as described above, the spinning jet 7 tries to draw a spiral trajectory without the first electrode 8 and the second electrode 9. In this reference example , the first electrode 8 and the second electrode 9 are installed in the spinning space before reaching the rotating body collector 5, and the electrodes 8, 9 are charged with a polarity different from that of the spinning jet 7. Therefore, the spinning jet 7 is alternately attracted to the first electrode 8 and the second electrode 9.

For example, when the spinning jet 7 is sucked by the first electrode 8, the spinning jet 7 is continuously ejected from the spinning port 4 a, so that the subsequent spinning jet is sucked by the other second electrode 9. . In this way, the spinning jet 7 is fed out so as to reciprocate between the flat first electrode 8 and the second electrode 9. The tip of the spinning jet 7 is continuously wound up by the rotating body collector 5. At this time, the nanofiber can be wound up within a predetermined length range by reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5a.
Instead of reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5 a, the nozzle 4 may be reciprocated in the longitudinal direction of the rotating shaft 5 a of the rotating body collector 5.

  In addition, the voltage applied to the rotator collector 5 and the voltage applied to the first electrode 8 and the second electrode 9 are different from each other, or the interval between the first electrode 8 and the second electrode 9 is adjusted to perform spinning. The jet 7 is adjusted so as not to be adsorbed to the first electrode 8 and the second electrode 9 but to be adsorbed to the rotating body collector 5 reliably.

  A unidirectional nano-fiber assembly having a large area can be manufactured by replacing the cylindrical rotating body collector 5 with a belt conveyor-like collector.

<Second Reference Example >
This also is not the embodiment of the present invention, the nano-fiber manufacturing apparatus according to the second reference example, as shown in FIG. 2, a syringe 1 similar to the first reference example, a syringe pump 2, A solution supply tube 3, a nozzle 4 having a spinning port 4a, a rotating body collector 5 that is driven to rotate about a rotating shaft 5a, and a high-voltage power source 6 that applies a high voltage between the nozzle 4 and the rotating body collector 5. A plurality of (three in this example) ring-shaped electrodes 11a, 11b, 11c arranged in a state surrounding the periphery of the spinning jet 7 ejected from the spinning port 4a, and the ring-shaped electrodes 11a, 11b, It is the structure provided with the 2nd high voltage power supply 10 which provides an electric potential to 11c. In addition, the solution supply tube 3 may connect the syringe pump 2 and the nozzle 4 directly, and is not essential.

  For example, the upper ring-shaped electrode 11 a is arranged at a position slightly closer to the rotating body collector 5 than a substantially intermediate position of the spinning space where the maximum diameter of the spinning jet 7 is set, and has a diameter surrounding the spinning jet 7. The lower ring-shaped electrode 11b has a slightly smaller diameter so as to surround the spinning jet 7 that has been slightly narrowed down. Further, the lower ring-shaped electrode 11c has a smaller diameter. A voltage lower than the high voltage applied to the spinneret 4a is applied to the ring electrodes 11a, 11b, and 11c. Alternatively, it may be connected to ground. In that case, the second high-voltage power supply 10 becomes unnecessary. Furthermore, different values of voltage can be applied to the ring-shaped electrodes 11a, 11b, and 11c. The polarity of the voltage to be applied is positive in the nozzle 4 and negative (or grounded) in the rotating body collector 5 in the illustrated example, but may be in the opposite polarity.

Next, operation | movement of this nano fiber manufacturing apparatus is demonstrated.
In a state where a high voltage is not applied between the nozzle 4 and the rotating body collector 5, the polymer solution remains at the surface tension at the tip of the spinning port 4a at the tip of the nozzle 4. When a high voltage of, for example, several kV to 30 kV is applied between the spinning port 4a and the rotating body collector 5, the polymer solution droplet at the tip of the spinning port 4a is charged to + and charged to a different polarity (or ground potential). It is attracted by the electrostatic force directed to the rotating collector 5 that is rotating. When the electrostatic force exceeds the surface tension, the spinning jet 7 of the polymer solution is continuously jetted toward the rotating body collector 5.

At this time, as described above, the spinning jet 7 tries to draw a spiral trajectory without the ring-shaped electrodes 11a, 11b, and 11c. In this reference example , ring-shaped electrodes 11 a, 11 b, 11 c are installed in the spinning space before reaching the rotating body collector 5, and the ring-shaped electrodes 11 a, 11 b, 11 c are charged with the same polarity as the charge of the spinning jet 7. Therefore, the spinning jet 7 repels the ring-shaped electrodes 11a, 11b, and 11c. In this respect, in the first reference example , the electrodes 8 and 9 are charged to have different polarities from the electric charge of the spinning jet 7, so that the spinning jet 7 is alternately arranged on the first electrode 8 and the second electrode 9. It is different from being attracted to. In addition, the spinning jet 7 is caused by the ring-shaped electrodes 11a, 11b, and 11c by increasing the magnitude of the electric force lines that are directed to the rotating body collector 5 rather than the electric-force lines that are directed to the ring-shaped electrodes 11a, 11b, and 11c. While converging, it finally reaches the rotating body collector 5 and is wound.

  The tip of the spinning jet 7 is continuously wound up by the rotating body collector 5. At this time, the nanofiber can be wound up within a predetermined length range by reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5a. Instead of reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5a, the nozzle and the electrode may be reciprocated in the longitudinal direction of the rotating shaft 5a of the rotating body collector 5.

<Implementation of the form>
As shown in FIG. 3, the nano-fiber manufacturing apparatus according to the embodiment of the present invention includes a syringe 1, a syringe pump 2, a solution supply tube 3, and a spinning port 4a similar to those in the first reference example. The nozzle 4, the rotating body collector 5 that is driven to rotate around the rotating shaft 5a, the high-voltage power source 6 that applies a high voltage between the nozzle 4 and the rotating body collector 5, and the spinning jet that is ejected from the spinning port 4a 7 includes a reverse cone-shaped electrode 12 disposed so as to surround the periphery of 7 and a second high-voltage power supply 10 that applies a potential to the reverse cone-shaped electrode 12. In addition, the solution supply tube 3 may connect the syringe pump 2 and the nozzle 4 directly, and is not essential.

Implementation form of this, the ring-shaped electrode 11a of the second reference example, 11b, is obtained by a reverse conical electrodes 12 by connecting 11c. A voltage lower than the high voltage applied to the spinneret 4a is applied to the inverted cone electrode 12. Alternatively, it may be connected to ground. In that case, the second high-voltage power supply 10 becomes unnecessary. The polarity of the voltage to be applied is positive in the nozzle 4 and negative (or grounded) in the rotating body collector 5 in the illustrated example, but may be in the opposite polarity.

Next, operation | movement of this nano fiber manufacturing apparatus is demonstrated.
In a state where a high voltage is not applied between the nozzle 4 and the rotating body collector 5, the polymer solution remains at the surface tension at the tip of the spinning port 4a at the tip of the nozzle 4. When a high voltage of, for example, several kV to 30 kV is applied between the spinning port 4a and the rotating body collector 5, the polymer solution droplet at the tip of the spinning port 4a is charged to + and charged to a different polarity (or ground potential). It is attracted by the electrostatic force directed to the rotating collector 5 that is rotating. When the electrostatic force exceeds the surface tension, the spinning jet 7 of the polymer solution is continuously jetted toward the rotating body collector 5.

At this time, as described above, the spinning jet 7 tries to draw a spiral trajectory without the inverted cone electrode 12. In the present embodiment, the reverse cone electrode 12 is installed in the spinning space before reaching the rotating body collector 5, and the reverse cone electrode 12 is charged with the same polarity as the electric charge of the spinning jet 7. The jet 7 repels the inverted cone electrode 12. In this respect, in the first reference example , the electrodes 8 and 9 are charged to have different polarities from the electric charge of the spinning jet 7, so that the spinning jet 7 is alternately arranged on the first electrode 8 and the second electrode 9. It is different from being attracted to. The spinning jet 7 is finally converged by the inverse cone-shaped electrode 12 by making the magnitude of the electric force lines toward the rotating body collector 5 larger than the magnitude of the electric force lines directed toward the inverted cone-shaped electrode 12. Reaches the rotator collector 5.

  In this way, the tip of the spinning jet 7 is continuously wound up by the rotating body collector 5. At this time, the nanofiber can be wound up within a predetermined length range by reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5a. Instead of reciprocating the rotating body collector 5 in the longitudinal direction of the rotating shaft 5a, the nozzle and the electrode may be reciprocated in the longitudinal direction of the rotating shaft 5a of the rotating body collector 5.

  The present invention is used as a method and apparatus for producing highly oriented nano-fibers in a wide range of fields such as healthcare, biotechnology / environmental engineering, energy, or protection / security. Can do.

It is explanatory drawing which shows the basic composition of the nano fiber manufacturing apparatus which concerns on a 1st reference example . It is explanatory drawing which shows the basic composition of the nano fiber manufacturing apparatus which concerns on a 2nd reference example . It is explanatory drawing which shows the basic composition of the nano fiber manufacturing apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows the outline | summary of the electrospinning method using a flat collector with an electric force line. It is explanatory drawing which shows the outline | summary of the electrospinning method using a flat collector with a spinning jet. It is explanatory drawing which shows the nano fiber formed by the electrospinning method shown in FIG. 4 and FIG. It is explanatory drawing which shows the outline | summary of the electrospinning method using a disk collector with an electric force line. It is explanatory drawing which shows the outline | summary of the electrospinning method using a disk collector with a spinning jet. It is explanatory drawing which shows the nano fiber formed by the electrospinning method shown in FIG.7 and FIG.8. It is explanatory drawing which shows the outline | summary of the electrospinning method using two strip | belt-shaped collectors with an electric force line. It is explanatory drawing which shows the outline | summary of the electrospinning method using two strip | belt-shaped collectors with a spinning jet. It is explanatory drawing which shows the nano fiber formed by the electrospinning method shown in FIG. 10 and FIG. It is explanatory drawing which shows the outline | summary of the electrospinning method using a rotary body collector with a line of electric force. It is explanatory drawing which shows the outline | summary of the electrospinning method using a rotary body collector with a spinning jet. It is explanatory drawing which shows the nano fiber formed by the electrospinning method shown to FIG. 13 and FIG.

DESCRIPTION OF SYMBOLS 1 Syringe 2 Syringe pump 3 Solution supply tube 4 Nozzle 4a Spinning port 5 Rotating body collector 5a Rotating shaft 6 High voltage power supply 7 Spinning jet 8 1st electrode 9 2nd electrode 10 2nd high voltage power supply 11a, 11b, 11c Ring-shaped electrode 12 Reverse Cone-shaped electrode 20 Nozzle 20a Spinning port 21 Flat plate collector 22 High-voltage power supply 23 Spinning jet 24 Disc collector 25 Band-shaped first collector 26 Band-shaped second collector 27 Rotating body collector

Claims (2)

A high voltage is applied between the spinneret and the cylindrical rotary member collector, wherein the spinneret, injecting a solution of charged fiber material and a solvent toward the rotating body collector, the rotating body collector on by sucking In a nanofiber manufacturing method using an electrospinning method in which nanofibers are integrated in
In the spinning space between the spinneret and the rotating body collector , an inverted cone-shaped electrode body arranged so as to surround the spinning jet ejected from the spinneret is disposed, and a predetermined potential is applied to the electrode body. In this way, the orbit of a spinning jet ejected from the spinneret is guided, and nanofibers aligned in one direction are spun on the surface of the rotating body collector. A high voltage is applied between the spinneret and the cylindrical rotor collector, and a charged fiber raw material and solvent solution is jetted and sucked from the spinner toward the rotor collector. In the nano-fiber manufacturing equipment using the electrospinning method to integrate the nano-fiber in
A reverse cone-shaped electrode for guiding a spinning jet trajectory in which a predetermined potential is applied to a spinning space between the spinning port and the rotating body collector and arranged around the spinning jet ejected from the spinning port. An apparatus for producing nano-fibers for spinning nano-fibers arranged in one direction, characterized in that a body is arranged.

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