Rake type double-fluid core sheath combined control nozzle, spinning device and spinning method

Abstract

The invention provides a rake type double-fluid core sheath combined control sprayer. The rake type double-fluid core sheath combined control sprayer comprises a flow guide wedge, at least two capillary tubes and a gathering inlet tube, a fluid inlet is formed in the top of the flow guide wedge, a long-strip-shaped fluid outlet gap is formed in the bottom of the flow guide wedge in the length direction in an extending mode, the upper ends of the capillary tubes extend into the lower end of the gathering inlet pipe, and any capillary tube penetrates into an inner cavity of the flow guide wedge from the upper side face of the flow guide wedge and then penetrates out of the fluid outlet gap of the flow guide wedge. The lower end of the capillary protrudes out of the lower edge of the fluid outlet gap. The invention further provides a multi-jet-flow electrospinning device and a method for preparing the core-sheath structure nanofibers through the multi-jet-flow electrospinning device. The batch preparation method of the core-sheath structure is simple in application, simple and convenient in process, convenient to operate and easy to control, and the scale for preparing the core-sheath structure nanofiber can be effectively expanded under a high-voltage electric field.

Description

Technical Field

[0001] The present invention belongs to the field of nanomaterial preparation, and particularly relates to a spike-rake type dual-fluid core-sheath combination control nozzle, a spike-rake type dual-fluid high-voltage electrospinning device, and a method for preparing nanofibers with core-sheath structural characteristics by single-step electrospinning in batches using the device. Background Art

[0002] High-voltage electrospinning (electrospinning) is a top-down nanofabrication technique that uses an external electric field to overcome the surface tension and viscoelastic forces of a droplet at the nozzle tip, forming a jet. Under the combined effects of electrostatic repulsion, Coulomb force, and surface tension, the atomized liquid jet is bent, stretched, and split at high frequencies, stretching tens of millions of times within tens of milliseconds. After solvent evaporation or melt cooling, nanofibers are formed at the receiving end. This technology offers a simple process, easy control, a wide range of materials, strong controllability, and the ability to produce nanofibers with unique microstructures through nozzle design. It is considered the most promising method for the industrial production of continuous nanofibers, and its application in the preparation of functional nanofibers holds great promise.

[0003] The greatest advantage of electrospinning is that, through the design and modification of the spinning head structure, polymer micro- and nanofibers with specific structural characteristics can be efficiently prepared in a single step. This is difficult to achieve using other "bottom-up" chemical synthesis methods. The most common methods are the use of a coaxial capillary metal sleeve as the spinning head to produce core-sheath nanofibers (Polym. Rev. 2008, 48, 353-377) and the use of a left-right spinneret to produce Janus-structured nanofibers (Chem. Rev. 2013, 113, 5194-5261). With the development of nanotechnology today, the concept of simply reducing the micro- and nanoscale dimensions of products to achieve corresponding nano-functionality has gradually become less mainstream. Currently, more attention is focused on nanodevices, complex micro- and nanostructures, and the structure-activity relationship at the nanoscale. How to effectively prepare micro- and nanofibers with complete structural integrity and complex features, and how to tailor their functions based on the structural characteristics of the fibers, is a research hotspot in nanotechnology and a key challenge in the field of micromanufacturing and the production of new micro- and nano-products.

[0004] The molecule is an interface. Below the molecule lies pure chemical synthesis based on covalent and ionic bonds (corresponding to the chemical industry). Above the molecule, below the visible to the human eye (approximately 0.1 mm), lies the micro- and nanoscale realm. This is a rich source of information for humanity's current understanding of the world and a focal point for its transformation of the material world (corresponding to micro- and nanofabrication of functional materials, and the new chemical molecular synthesis mentioned above also serves this purpose). In July 1990, the first International Conference on Nanoscience and Nanotechnology was held in Baltimore, USA, marking the official birth of nanoscience and technology. By 1999, nanotechnology had begun to gradually enter the market. Over the past 20 years, numerous countries and regions have formulated relevant strategies and plans, invested heavily in seizing strategic positions in nanotechnology, established nanomaterials research centers, and included nanotechnology as a research and development priority in basic science and technology plans. A search using the keyword "nano" in Web of Science yields over 1.5 million references and over 300,000 patents.

[0005] In the existing technology, nanofibers with a core-sheath structure have broad commercial application prospects. However, due to the complex manufacturing process, it is currently impossible to effectively and mass-produce nanofibers with a complete core-sheath structure in a single step. Summary of the Invention

[0006] The purpose of the present invention is to provide a rake-type dual-fluid core-sheath combination control nozzle, a spinning device and a spinning method, which are used to solve the technical problem in the prior art that it is impossible to effectively and batch-scale prepare core-sheath structured nanofibers with complete structure in a single step.

[0007] The present invention provides a spike rake type dual-fluid core-sheath combination control nozzle, comprising a guide wedge, at least two capillaries and a summary inlet pipe; the guide wedge is provided with an inner cavity, the top of the guide wedge is provided with a fluid inlet, the fluid inlet is connected to the inner cavity of the guide wedge, the bottom of the guide wedge is provided with an elongated fluid outlet slit extending along the length direction, the fluid outlet slit is connected to the inner cavity of the guide wedge, the summary inlet pipe is located above the guide wedge, the upper ends of the capillaries extend to the lower end of the summary inlet pipe, any capillary penetrates into the inner cavity of the guide wedge from the upper side of the guide wedge and then passes out from the fluid outlet slit of the guide wedge, the lower end of the capillary protrudes from the lower edge of the fluid outlet slit, and the capillaries in the inner cavity of the guide wedge are arranged at intervals along the length direction of the guide wedge.

[0008] Furthermore, the lower end of the capillary tube protrudes from the lower edge of the fluid outlet gap by 1 mm.

[0009] Furthermore, the distance between any two adjacent capillaries in the inner cavity of the guide wedge is 3 cm.

[0010] Furthermore, a spring is provided in the fluid outlet gap, and both ends of the spring are respectively connected to the inner side surfaces on both sides of the fluid outlet gap.

[0011] Furthermore, the capillary tube, the collecting inlet pipe and the guide wedge are all fixed and sealed by using epoxy resin adhesive.

[0012] Furthermore, a strip-shaped flat steel bracket is bonded to the outer side of the guide wedge through epoxy resin.

[0013] Furthermore, the outer side of the guide wedge is evenly coated with insulating silicone.

[0014] The present invention also provides a multi-jet electrospinning device, including a high-voltage generator, a first injection pump, a second injection pump, the spike rake type dual-fluid core sheath combination control nozzle, a fiber receiving plate, a first syringe, a second syringe, a first silicone hose and a second silicone hose; the first syringe is installed in the first injection pump, the second syringe is installed in the second injection pump, the outlet of the first syringe is connected to the fluid inlet of the guide wedge through the first silicone hose, the outlet of the second syringe is connected to the upper end of the capillary through the second silicone hose, one end of the current output end of the high-voltage generator is connected to one of the capillaries, the other end of the current output end of the high-voltage generator is grounded, the fiber receiving plate is located below the spike rake type dual-fluid core sheath combination control nozzle, and the fiber receiving plate is grounded.

[0015] The present invention also provides a method for preparing core-sheath structured nanofibers using the multi-jet electrospinning device, comprising the following steps: adding a first spinning solution into a first syringe, adding a second spinning solution into a second syringe, turning on the first injection pump, the second injection pump and the high-voltage generator, the first spinning solution being transported from the first syringe through the first silicone hose and the fluid inlet to the inner cavity of the guide wedge and then flowing out from the fluid outlet gap at the bottom of the guide wedge, the second spinning solution being transported from the second syringe through the second silicone hose to the capillary and then flowing out from the lower end of the capillary, and the core-sheath structured nanofibers are prepared through the action of a high-voltage electrostatic field and received by a fiber receiving plate.

[0016] Furthermore, the first spinning solution is an ethyl cellulose ethanol solution containing a mass percentage concentration of 25%, the second spinning solution is an ethyl pyrrolidone ethanol solution containing a mass percentage concentration of 8%, the sheath liquid flow rate of the first syringe is 12 mL / h, the flow rate of the second syringe is 8 mL / h, the receiving distance of the fiber receiving plate is 15 cm, and the voltage of the high-voltage generator is 24 kV.

[0017] The principle of the present invention is that multiple core-sheath nozzle outlets can be simultaneously arranged in the nozzle, and two different fluids can be synchronously guided into a high-voltage electrostatic field. Using the multiple core-sheath nozzle outlets as a macro template, under the high-voltage electrostatic field, through the interaction between the high-voltage electrostatic field and the fluid, multiple core-sheath spinning fluids are stretched into solid nanofibers with a clear core-sheath structure within a few milliseconds. On the other hand, the nozzles of the nozzle are a combination of a needle-like metal tip and a confined free liquid surface with a guide wedge, which is conducive to the guiding effect of the "needle" and the easy-to-scale preparation characteristics of free liquid surface electrospinning, ensuring that under the high-voltage electrostatic field, the two different fluids can be quickly stretched and dried under the high-voltage electric field to form solid nanofibers with a core-sheath structure.

[0018] Based on repeated experiments, the present invention follows the behavioral characteristics of fluids under high-voltage electric fields and basic natural laws to develop a rake-type dual-fluid combination control nozzle. By using this nozzle to assemble an electrospinning device and implement an electrospinning process, it is possible to effectively and batch-scale prepare core-sheath structured nanofibers with complete structure in a single step, providing possibilities for the design, preparation and commercialization of new core-sheath structured nanofunctional materials.

[0019] The core-sheath structure batch preparation method of the present invention is simple to apply, simple in process, convenient in operation, and easy to control. It can effectively expand the scale of preparing core-sheath structure nanofibers under a high-voltage electric field, providing strong support for the development and production of core-sheath structure nanoproducts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a spike-rake-type dual-fluid core-sheath combination control nozzle of the present invention. Reference numerals: 1-flow guide wedge, 2-fluid inlet, 3-spring, 4-capillary tube, 5-collecting inlet pipe, 6-fixed flat steel bracket.

[0021] Figure 2 This is a schematic diagram of the structure of a multi-jet electrospinning device according to the present invention. Reference numerals: 7 - high-voltage generator, 8 - first syringe pump, 9 - second syringe pump, 10 - rake-type dual-fluid core-sheath combination control nozzle, 11 - fiber receiving plate, 12 - first syringe, 13 - second syringe, 14 - first silicone hose, 15 - second silicone hose, 16 - alligator clip.

[0022] Figure 3 This is a representative picture taken during the fluid stretching process of the single-step batch preparation of core-sheath structured nanofibers according to the present invention.

[0023] Figure 4 This is a representative composite Taylor cone image of the core-sheath structured nanofibers prepared in a single step batch process according to the present invention.

[0024] Figure 5This is a scanning electron microscope observation image of the core-sheath structured nanofibers prepared in a single step batch according to the present invention.

[0025] Figure 6 This is a transmission electron microscope observation image of the core-sheath structured nanofibers prepared in a single step batch according to the present invention. DETAILED DESCRIPTION

[0026] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application. Example

[0027] like Figure 1 As shown, the present invention provides a rake-type dual-fluid core-sheath combination control nozzle, comprising a guide wedge 1, at least two capillaries 4 and a summary inlet pipe 5; the guide wedge 1 is provided with an inner cavity, the top of the guide wedge 1 is provided with a fluid inlet 2, the fluid inlet 2 is connected to the inner cavity of the guide wedge 1, the bottom of the guide wedge 1 is provided with a long strip of fluid outlet slit extending along the length direction, the fluid outlet slit is connected to the inner cavity of the guide wedge 1, the summary inlet pipe 5 is located above the guide wedge 1, the upper end of the capillary 4 extends to the lower end of the summary inlet pipe 5, any capillary 4 penetrates into the inner cavity of the guide wedge 1 from the upper side of the guide wedge 1 and then passes through the fluid outlet slit of the guide wedge 1, the lower end of the capillary 4 protrudes from the lower edge of the fluid outlet slit, and the capillaries 4 in the inner cavity of the guide wedge 1 are arranged at intervals along the length direction of the guide wedge 1.

[0028] Furthermore, the lower end of the capillary tube 4 protrudes from the lower edge of the fluid outlet gap by 1 mm.

[0029] Furthermore, the distance between any two adjacent capillaries 4 in the inner cavity of the guide wedge 1 is 3 cm.

[0030] Furthermore, a spring 3 is provided in the fluid outlet gap, and both ends of the spring 3 are respectively connected to the inner side surfaces of both sides of the fluid outlet gap. During the manufacturing process, the width of the fluid outlet gap can be changed by changing the size of the spring 3.

[0031] Furthermore, the capillary tube 4, the collecting inlet tube 5 and the guide wedge 1 are all fixed and sealed by using epoxy resin adhesive.

[0032] Furthermore, a strip-shaped flat steel bracket 6 is bonded to the outer side of the guide wedge 1 through epoxy resin, so as to facilitate fixing on the operating table.

[0033] Furthermore, the outer side of the guide wedge 1 is evenly coated with insulating silicone to prevent high-voltage static electricity from escaping and saving energy.

[0034] Specifically, there are nine capillaries 4. The central inlet pipe 5 is a polypropylene plastic pipe. The guide wedge 1 is formed by bending a copper plate. Example

[0035] like Figure 2 As shown, the present invention also provides a multi-jet electrospinning device, including a high-voltage generator 7, a first injection pump 8, a second injection pump 9, a spike rake type dual-fluid core sheath combination control nozzle 10, a fiber receiving plate 11, a first syringe 12, a second syringe 13, a first silicone hose 14 and a second silicone hose 15; the first syringe 12 is installed in the first injection pump 8, and the second syringe 13 is installed in the second injection pump 9. The outlet of the first syringe 12 is connected to the fluid inlet 2 of the guide wedge 1 through the first silicone hose 14, and the outlet of the second syringe 13 is connected to the upper end of the capillary 4 through the second silicone hose 15. One end of the current output end of the high-voltage generator 7 is connected to one of the capillaries 4, and the other end of the current output end of the high-voltage generator 7 is grounded. The fiber receiving plate 11 is located below the spike rake type dual-fluid core sheath combination control nozzle 10, and the fiber receiving plate 11 is grounded.

[0036] Specifically, the high voltage generator 7 is connected to the capillary tube 4 via an alligator clip 16. The receiving plate 11 is a cardboard wrapped with aluminum foil.

[0037] The present invention also provides a method for preparing core-sheath structured nanofibers using the multi-jet electrospinning device, comprising the following steps: adding a first spinning solution into a first syringe 12, adding a second spinning solution into a second syringe 13, turning on the first injection pump 8, the second injection pump 9 and the high-voltage generator 7, the first spinning solution being transported from the first syringe 12 through the first silicone hose 14 and the fluid inlet 2 to the inner cavity of the guide wedge 1 and then flowing out from the fluid outlet gap at the bottom of the guide wedge 1, the second spinning solution being transported from the second syringe 13 through the second silicone hose 15 to the capillary 4 and then flowing out from the lower end of the capillary 4, and the core-sheath structured nanofibers being prepared through the action of a high-voltage electrostatic field and received by the fiber receiving plate 11.

[0038] Electrospinning was performed using a multi-jet electrospinning device containing a rake-type dual-fluid core-sheath combination control nozzle as described in Example 2 to directly prepare core-sheath structured nanofibers in batches in a single step. The steps are as follows: (1) Preparation of spinning solution The first spinning solution is an ethyl cellulose ethanol solution containing 25% by mass, and the preparation method is as follows: add 25g of ethyl cellulose to 75g of ethanol and stir evenly; The second spinning solution is an ethanol solution containing 8% polyvinyl pyrrolidone by weight, and the preparation method is as follows: add 8g of polyvinyl pyrrolidone to 92g of ethanol and stir evenly; (2) Add the first spinning solution and the second spinning solution obtained in step (1) into the corresponding syringes respectively, and then start the first injection pump 8 and the second injection pump 9; (3) The sheath liquid flow rate of the first syringe 12 is controlled to 12 mL / h by the first syringe pump 8, and the flow rate of the second syringe 13 is controlled to 8 mL / h by the second syringe pump 9. The high-voltage generator 7 is turned on, and the receiving distance of the fiber receiving plate 11 (i.e., the vertical distance from the lower end outlet of the capillary 4 to the fiber receiving plate 11) is adjusted to 15 cm. The voltage is increased to 24 kV for electrospinning, and core-sheath structure nanofibers can be prepared in a single step. The representative fluid stretching process of single-step batch preparation of core-sheath structure nanofibers is shown in the figure below. Figure 3 As shown, the representative composite Taylor cone images of single-step batch preparation of core-sheath structure nanofibers are shown in Figure 4 shown.

[0039] The core-sheath structure nanofibers prepared in Example 1 were observed by using a field scanning electron microscope after surface spraying with gold. Figure 5 The core-sheath structure nanofibers prepared were collected evenly and showed a good linear state, with a diameter of 750±110nm. The core-sheath structure nanofibers prepared were observed using a high-resolution transmission electron microscope, and the results were as follows: Figure 6 As shown, the inside and outside of the nanofiber are composed of two different grayscale parts, reflecting the core-sheath structural characteristics of the nanofiber.

[0040] The above description is merely an example of the implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the technical principles of the present invention. These improvements should also be regarded as within the scope of protection of the present invention.

Claims

1. A rake type dual fluid core sheath combination control nozzle, characterized in that: It includes a guide wedge, at least two capillaries and a summary inlet pipe; the guide wedge is provided with an inner cavity, the top of the guide wedge is provided with a fluid inlet, the fluid inlet is connected to the inner cavity of the guide wedge, the bottom of the guide wedge is provided with a long strip of fluid outlet slit extending along the length direction, the fluid outlet slit is connected to the inner cavity of the guide wedge, the summary inlet pipe is located above the guide wedge, the upper end of the capillary extends to the lower end of the summary inlet pipe, any capillary penetrates into the inner cavity of the guide wedge from the upper side of the guide wedge and then passes out from the fluid outlet slit of the guide wedge, the lower end of the capillary protrudes from the lower edge of the fluid outlet slit, and the capillaries in the inner cavity of the guide wedge are arranged at intervals along the length direction of the guide wedge.

2. A rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: The lower end of the capillary tube protrudes 1 mm from the lower edge of the fluid outlet gap.

3. The rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: The distance between any two adjacent capillaries in the inner cavity of the guide wedge is 3 cm.

4. The rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: A spring is provided in the fluid outlet gap, and both ends of the spring are respectively connected to the inner side surfaces on both sides of the fluid outlet gap.

5. The rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: The capillary tube, the collecting inlet pipe and the guide wedge are all fixed and sealed by using epoxy resin adhesive.

6. The rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: The outer side of the guide wedge is bonded with a strip flat steel bracket through epoxy resin.

7. The rake-type dual-fluid core-sheath combination control nozzle according to claim 1, characterized in that: The outer side of the guide wedge is evenly coated with insulating silica gel.

8. A multi-jet electrospinning device, characterized in that: It includes a high-voltage generator, a first injection pump, a second injection pump, the spike rake type dual-fluid core sheath combination control nozzle according to claim 1, a fiber receiving plate, a first syringe, a second syringe, a first silicone hose and a second silicone hose; the first syringe is installed in the first injection pump, the second syringe is installed in the second injection pump, the outlet of the first syringe is connected to the fluid inlet of the guide wedge through the first silicone hose, the outlet of the second syringe is connected to the upper end of the capillary through the second silicone hose, one end of the current output end of the high-voltage generator is connected to one of the capillaries, the other end of the current output end of the high-voltage generator is grounded, the fiber receiving plate is located below the spike rake type dual-fluid core sheath combination control nozzle, and the fiber receiving plate is grounded.

9. A method for preparing core-sheath structure nanofibers using the multi-jet electrospinning device according to claim 8, characterized in that: The method comprises the following steps: adding a first spinning solution into a first syringe, adding a second spinning solution into a second syringe, turning on a first injection pump, a second injection pump and a high-voltage generator, conveying the first spinning solution from the first syringe through a first silicone hose and a fluid inlet to the inner cavity of a guide wedge and then flowing out from a fluid outlet gap at the bottom of the guide wedge, conveying the second spinning solution from the second syringe through a second silicone hose to a capillary and then flowing out from the lower end of the capillary, preparing core-sheath structure nanofibers through the action of a high-voltage electrostatic field, and receiving them through a fiber receiving plate.

10. The method for preparing core-sheath structure nanofibers according to claim 9, characterized in that: The first spinning solution is an ethyl cellulose ethanol solution with a mass percentage concentration of 25%, the second spinning solution is an ethyl pyrrolidone ethanol solution with a mass percentage concentration of 8%, the sheath liquid flow rate of the first syringe is 12 mL / h, the flow rate of the second syringe is 8 mL / h, the receiving distance of the fiber receiving plate is 15 cm, and the voltage of the high-voltage generator is 24 kV.

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