CN106435776A - Four-stage coaxial high-voltage electrospinning device and spinning method - Google Patents

Abstract

The invention provides a four-stage coaxial microfluidic control nozzle, comprising a total capillary, a first curved capillary, a second curved capillary and a third curved capillary; the first curved capillary is arranged in the total capillary, and the other of the first curved capillary One end passes through the outlet end of the total capillary; the second curved capillary is arranged in the first curved capillary, the outlet end of the second curved capillary passes through the outlet end of the first curved capillary, and the other end of the second curved capillary passes through the first curved capillary A curved capillary; the third curved capillary is arranged in the second curved capillary, the outlet end of the third curved capillary passes through the outlet end of the second curved capillary, and the other end of the third curved capillary passes through the second curved capillary. Also provided is a high-voltage electrospinning device using the above nozzle, and a method for preparing nanofibers with a four-level core-sheath structure by using the above-mentioned device, which can effectively prepare nanofibers with four-level core-sheath structure characteristics in a single step.

Description

A four-stage coaxial high-voltage electrospinning device and spinning method

technical field

The invention belongs to the field of nanomaterials, in particular to a four-stage coaxial microfluidic control nozzle, an electrospinning device with a four-stage coaxial microfluidic control nozzle and the use of the four-stage coaxial microfluidic control nozzle. The electrospinning device of the nozzle carries out the preparation method of nanofibers with four-stage core-sheath structure characteristics.

Background technique

High-voltage electrospinning technology, referred to as electrospinning, is a top-down nano-manufacturing technology. The jet is formed by overcoming the liquid surface tension and viscoelastic force of the droplets at the tip of the nozzle by applying an electric field force. Under the joint action of force and surface tension, the atomized liquid jet is bent, stretched, and split by high frequency, and it is stretched tens of millions of times in tens of milliseconds, and the nano-scale is obtained at the receiving end through solvent volatilization or melt cooling. fiber. This technology has simple process, convenient operation, wide selection of materials, strong controllability, and can prepare nanofibers with microstructure characteristics through nozzle design. It is considered to be the most likely method to realize the industrial production of continuous nanofibers. The application of this technology to prepare functional nanofibers has a good prospect.

The biggest advantage of electrospinning is that polymer micro-nanofibers with corresponding structural characteristics can be effectively prepared in a single step through the design and transformation of the spinning head structure, which is impossible for other various "bottom-up" chemical synthesis methods. of. The most common method is to use a coaxial capillary metal sleeve to prepare core-sheath structure nanofibers for the spinning head (Moghe AK and GuptaBS. Co-axial electrospinning for nanofiber structures: Preparation and applications. Polym. Rev. 2008;48:353-377. ) and the preparation of side-by-side nanofibers by using a left-right relationship structure spinneret (Walther A and Müller AHE. Janus particles: synthesis, self-assembly, physical properties, and applications. Chem. Rev. 2013;113:5194-5261.). But based on this concept, there are more nanostructured products with complex structural features to be developed.

With the development of nanotechnology today, the concept of simply reducing the micro-nano size of products to obtain corresponding nano-effects has gradually deviated from the mainstream. At present, more attention is focused on nano-devices, complex micro-nano structures and the structure-activity relationship of the corresponding nano-level. How to effectively prepare micro-nano fibers with complete structures and complex structural features, and design their functions through the structural features of fibers is not only a research hotspot in nanotechnology, but also a problem that needs to be solved in the field of micro-manufacturing and the production of new micro-nano products key content.

On the basis of multiple tests, the present invention follows the behavioral characteristics and basic natural laws of the fluid under the high-voltage electric field, explores a four-stage coaxial microfluidic control nozzle, uses the nozzle to assemble the electrospinning device, and implements the electrospinning process. The four-level concentric fiber with complete structure and uniform size can be effectively prepared in a single step, which provides the possibility for the design, preparation, large-scale production and application of new structural nano functional materials.

Contents of the invention

Aiming at the above-mentioned technical problems in the prior art, the present invention provides a four-stage coaxial high-voltage electrospinning device and a spinning method, and the four-stage coaxial high-voltage electrospinning device and the spinning method need to solve In the prior art, there is a technical problem that nanofibers with a four-level core-sheath structure cannot be prepared.

The present invention provides a four-stage coaxial microfluid control nozzle, a four-stage coaxial microfluid control nozzle, which is characterized in that it includes a total capillary, a first curved capillary, a second curved capillary, and a third curved capillary; The outer diameter of the first curved capillary is less than the inner diameter of the total capillary; the outer diameter of the second curved capillary is smaller than the inner diameter of the first curved capillary; the outer diameter of the third curved capillary Less than the inner diameter of the second curved capillary; the straight section of the first curved capillary is arranged in the total capillary, and the curved part of the first curved capillary passes through the side wall of the inlet end of the total capillary The other end of the first curved capillary passes through the outlet end of the total capillary; the straight section of the second curved capillary is set in the first curved capillary, and the second curved The outlet end of the capillary passes through the outlet end of the first curved capillary, and the other end of the second curved capillary passes through the first curved capillary; the curved part of the second curved capillary passes through the The sidewall of the inlet end of the total capillary passes through; the straight section of the third curved capillary is arranged in the second curved capillary, and the outlet end of the third curved capillary is connected from the outlet end of the second curved capillary The other end of the third curved capillary passes through the second curved capillary; the curved part of the third curved capillary passes through the side wall of the inlet end of the total capillary; Said first curved capillary, second curved capillary and third curved capillary are provided with annular projections on the outer wall of the inlet end of the curved part; said total capillary and first curved capillary, second curved capillary, third curved The straight segments of the capillary are arranged coaxially.

Further, the inlet end of the total capillary is provided with an interface, and the outer wall of the interface is provided with spiral reinforcing ribs.

Further, the outlet end of the first curved capillary passes through the outlet end of the total capillary by 0.2mm; the outlet end of the second curved capillary passes through the outlet end of the first curved capillary by 0.2mm ; The outlet end of the third curved capillary passes through the outlet end of the second curved capillary by 0.2 mm.

Further, the length of the total capillary is 70 mm, the length of the first curved capillary is 75 mm; the length of the second curved capillary is 80 mm; the length of the third curved capillary is 85 mm. mm; the first curved capillary and the second curved capillary 15 and the third curved capillary outside the total capillary are glued and sealed with epoxy resin.

The present invention also provides an electrospinning device, comprising a first syringe pump, a first syringe, a second syringe pump, a second syringe, a third syringe pump, a third syringe, a fourth syringe pump, a fourth syringe, a first Silicone hose, the second silicone hose, the third silicone hose, fiber receiving plate, DC electrostatic high voltage generator, and the four-stage coaxial microfluidic control nozzle described in claim 1; the first syringe is installed in In the first syringe pump, the first syringe is connected to the four-stage coaxial microfluidic control nozzle, the second syringe is installed in the second syringe pump, and the second syringe is installed in the second syringe pump. The second syringe is connected to the four-stage coaxial microfluidic control nozzle through the first silicone hose, the third syringe is installed in the third syringe pump, and the third syringe is connected through the second silicone soft tube. The tube is connected to the four-stage coaxial microfluidic control nozzle, the fourth syringe is installed in the fourth syringe pump, and the fourth syringe passes through the third silicone hose and the four-stage The coaxial microfluidic control nozzle is connected, the DC electrostatic high voltage generator is connected to the four-stage coaxial microfluidic control nozzle, and a fiber receiving plate is arranged at the lower end of the four-stage coaxial microfluidic control nozzle.

The present invention also provides a method for preparing four-level coaxial nanofibers by using the above-mentioned electrospinning device. The first spinning liquid is added to the first syringe, the second spinning liquid is added to the second syringe, and the third spinning liquid is added to the third syringe. Three spinning liquids, adding the fourth spinning liquid into the fourth syringe, and through the action of a high-voltage electrostatic field, nanofibers with a four-stage core-sheath structure can be prepared in a single step.

Specifically, the above-mentioned method for preparing nanofibers with a four-stage core-sheath structure includes the following steps:

1) A step of preparing a spinning solution, the first spinning solution is an ethanol solution with a mass percentage concentration of polyvinylpyrrolidone of 8%; the second spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid, and after mixing In the solution, the mass percent concentration of polyvinylpyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 0.1%; the third spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid. In the mixed solution, polyethylene The mass percent concentration of pyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 0.3%; the fourth spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid. In the mixed solution, the mass percent concentration of polyvinylpyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 1%;

2) Add the first spinning solution to the fourth spinning solution obtained in step 1 into corresponding syringes respectively, and then turn on the first to fourth syringe pumps;

3) From the first injector to the fourth injector, control the flow rate of each layer to 1.5, 0.6, 0.3, 0.2mL/h respectively, turn on the DC high-voltage electrostatic generator, and raise the voltage to 18kV for parallel electrospinning to obtain a four-stage core Sheath structure characteristic of nanofibers.

The principle of the present invention is: the four-stage coaxial structure of the four-stage coaxial microfluidic control nozzle provides a macroscopic template for the preparation of nanomaterials with corresponding structures. The liquid spinning solution is stretched into solid nanofibers with clear structure. On the other hand, the outlet heights of each layer of the nozzle are inconsistent, which effectively prevents the mutual diffusion of fluid between layers at the position of the nozzle. The above principles work together to ensure the accurate "replication" of nanofibers with a four-level core-sheath structure from a macroscopic template to a microscopic four-level core-sheath structure under a high-voltage electrostatic field.

Compared with the prior art, the technical progress of the present invention is remarkable. A four-stage coaxial high-voltage electrospinning method of the present invention is simple in application, convenient in operation, and easy to control, and can effectively prepare four-stage core-sheath structure nanofibers in a single step under a high-voltage electric field, and can increase the number of spinning heads Carry out large-scale scale-up production.

Description of drawings

Figure 1 is a schematic diagram of the overall appearance of a four-stage coaxial microfluidic control nozzle of the present invention, 13-total capillary, 16-first curved capillary, 15-second curved capillary, 14-third curved capillary.

Fig. 2 is a photographic view of the exit of a four-stage coaxial microfluidic control nozzle of the present invention.

Fig. 3 is a schematic structural view of the electrospinning device of the present invention, 1-DC electrostatic high voltage generator, 2-the first syringe pump, 3-the second syringe pump, 4-the third syringe pump, 5-the fourth syringe pump, 6- Fiber receiving plate, 7-four-stage coaxial microfluidic control nozzle, 8-first high elastic silicone hose, 9-first syringe, 10-second syringe, 11-third syringe, 12-fourth syringe, 18 - the second high elastic silicone hose, 19 - the third high elastic silicone hose.

Fig. 4 is a connection mode between a four-stage coaxial microfluidic control nozzle and all fluid injectors of the present invention.

Fig. 5 is a composite Taylor cone pattern photographed during the process of preparing nanofibers with a four-level coaxial structure by the electrospinning device of the present invention.

Fig. 6 is a scanning electron microscope electron micrograph of the four-stage core-sheath structure nanofiber obtained in the application example;

Fig. 7 is a transmission electron microscope image of nanofibers with a four-stage core-sheath structure obtained in the application example.

detailed description

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

The present invention provides a four-stage coaxial microfluidic control nozzle, comprising a total capillary 13, a first curved capillary 16, a second curved capillary 15 and a third curved capillary 14; the outer diameter of the first curved capillary 16 Less than the inner diameter of the total capillary 13; the outer diameter of the second curved capillary 15 is less than the inner diameter of the first curved capillary 16; the outer diameter of the third curved capillary 14 is smaller than the second curved capillary 15 inner diameter;

The straight section of the first curved capillary 16 is arranged in the total capillary 13, and the curved part of the first curved capillary 16 passes through the side wall of the inlet end of the total capillary 13, the The other end of the first curved capillary 16 passes through the outlet end of the total capillary 13; the straight section of the second curved capillary 15 is arranged in the first curved capillary 16, and the second curved The outlet end of the capillary 15 passes through the outlet end of the first curved capillary 16, and the other end of the second curved capillary 15 passes through the first curved capillary 16; the bending of the second curved capillary 15 Part passes from the side wall of the inlet end of the total capillary 13; the straight section of the third curved capillary 14 is arranged in the second curved capillary 15, and the outlet of the third curved capillary 14 end passes through the outlet end of the second curved capillary 15, and the other end of the third curved capillary 14 passes through the second curved capillary 15; The side wall of the inlet end of the total capillary 13 is passed; the outer wall of the inlet end of the curved part of the first curved capillary 16, the second curved capillary 15 and the third curved capillary 14 is provided with an annular protrusion 18; The total capillary 13 described above and the straight sections of the first curved capillary 16, the second curved capillary 15, and the third curved capillary 14 are arranged coaxially.

Further, the connection between the second curved capillary 15 and the first curved capillary 16 is sealed; the connection between the third curved capillary 14 and the second curved capillary 15 is sealed.

Further, the inlet end of the total capillary 13 is provided with an interface 17, and the outer wall of the interface 17 is provided with spiral reinforcing ribs. The inner diameter of the interface 17 decreases successively from outside to inside.

Further, the junction of the first curved capillary 16 and the second curved capillary 15 is sealed; the junction of the third curved capillary 14 and the second curved capillary 15 is sealed.

Further, the outlet end of the first curved capillary 16 passes through the outlet end of the total capillary 13 by 0.2 mm; the outlet end of the second curved capillary 15 passes through the outlet end of the first curved capillary 16 Outlet end 0.2mm; The outlet end of the third curved capillary 14 passes through the outlet end 0.2mm of the second curved capillary 15, and the side shot pattern of the outlet part of the four-stage coaxial microfluidic control nozzle is shown in Figure 2. Show.

Further, the length of the total capillary 13 is 70 mm, the length of the first curved capillary 16 is 75 mm; the length of the second curved capillary 15 is 80 mm; the third curved capillary The length of 14 is 85 mm; the parts of the first curved capillary 16, the second curved capillary 15 and the third curved capillary outside the total capillary 13 are glued and sealed with epoxy resin.

Example 2

An electrospinning device with a four-stage coaxial microfluidic control nozzle described in Example 1, its composition schematic diagram is shown in Figure 3, including a DC electrostatic high voltage generator 1, a first injection pump 2, a second injection pump Pump 3, third syringe pump 4, fourth syringe pump 5, fiber receiving plate 6, four-stage coaxial microfluidic control nozzle 7, first high elastic silicone hose 8, first syringe 9, second syringe 10, second syringe Three syringes 11, a fourth syringe 12, a total capillary 13, a second high elastic silicone hose 19, and a second high elastic silicone hose 20.

Add the first outermost layer spinning liquid in the first syringe 9 on the first syringe pump 2, the first syringe 9 is directly connected with the interface 17 of the four-stage coaxial microfluidic control nozzle 7, in the second syringe pump 3 Add the second second outer layer spinning liquid in the second syringe 10 on the top, the second syringe 10 is connected by the first high elastic silicone hose 8 and the first curved capillary 16, the third syringe on the third syringe pump 4 11, add the third spinning liquid from the outside to the inside, the third syringe 11 is connected with the first curved capillary 15 through the second high elastic silicone hose 19, in the fourth syringe 12 on the fourth syringe pump 5 The fourth inner core spinning liquid is added, and the fourth syringe 12 is connected with the first curved capillary 14 through the third high elastic silicone hose 20 . The spinning liquid is synchronously injected into the four-stage coaxial microfluidic control nozzle 7 through respective syringe pumps. The high-pressure generator 1 is connected with the four-stage coaxial microfluidic control nozzle 5 . The lower end of the four-stage coaxial microfluidic control nozzle 5 is provided with a fiber receiving plate 6, the receiving plate 4 is a cardboard wrapped in aluminum foil, and the receiving plate is grounded. By starting the DC high-voltage electrostatic generator 1 and raising it to an appropriate voltage, nanofibers with a four-level core-sheath structure can be effectively prepared in a single step.

Application Example 1

The electrospinning device of the four-stage coaxial microfluidic control nozzle described in Example 2 is used to electrospin two streams of fluids to prepare nanofibers with four-stage core-sheath structure characteristics. The specific steps are as follows:

1. Preparation of spinning solution

The first spinning solution, mass percent concentration is 8% polyvinylpyrrolidone (PVP) ethanol solution, its preparation method is as follows: be about to join the PVP of 8g in the ethanol of 92g, stir to obtain the PVP that mass percent concentration is 8% weak;

The second spinning solution, polyvinylpyrrolidone (PVP) with a mass percent concentration of 8% and a low-concentration phosphotungstic acid ethanol solution, its preparation method is as follows: 8g of PVP and 0.1g of phosphotungstic acid are added to 91.9g of ethanol , stir evenly to get the PVP ethanol solution whose mass percent concentration is 8%;

The third spinning solution, polyvinylpyrrolidone (PVP) with a mass percentage concentration of 8% and a medium-concentration phosphotungstic acid ethanol solution, its preparation method is as follows: 8g of PVP and 0.3 g of phosphotungstic acid are added to 91.7g of ethanol , stir evenly to get the PVP ethanol solution whose mass percent concentration is 8%;

The fourth spinning solution, the mass percent concentration is 8% polyvinylpyrrolidone (PVP) and high-concentration phosphotungstic acid ethanol solution, its preparation method is as follows: 8g of PVP and 1.0 g of phosphotungstic acid are added to 91g of ethanol, Stir evenly to obtain a PVP ethanol solution with a mass percentage concentration of 8%;

2. Add the first spinning solution to the fourth spinning solution obtained in step 1 into corresponding syringes respectively, and then turn on the first to fourth syringe pumps 2, 3, 4, 5;

3. From the first injector 9 to the fourth injector 12, the flow rate of each layer is controlled to be 1.5, 0.6, 0.3, 0.2 mL/h respectively, and the DC high-voltage electrostatic generator 1 is turned on, and the voltage is increased to 18kV for parallel electrospinning, which has Nanofibers characterized by a four-level core-sheath structure.

Application Example 2

The surface of the nanofiber with four-stage core-sheath structure prepared in Example 1 was sprayed with gold by using a field scanning electron microscope, and the results are shown in FIG. 6 . The as-prepared quaternary core-sheath nanofibers were collected uniformly and exhibited a good linear state, with a diameter of 720 ± 150 nm. A high-resolution transmission electron microscope was used to observe the prepared nanofibers with a four-level core-sheath structure. The results are shown in Figure 7. Due to the effect of the contrast agent phosphotungstic acid, the four-level core-sheath structure of the nanofibers is clear.

The above description is only an example of the embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements can be made without departing from the technical principles of the present invention. These improvements should also be considered Be the protection scope of the present invention.

Claims (7)

1. A four-stage coaxial microfluidic control nozzle, characterized in that: comprise a total capillary, the first curved capillary and the second curved capillary and the third curved capillary; the outer diameter of the first curved capillary is smaller than the The inner diameter of the total capillary; the outer diameter of the second curved capillary is less than the inner diameter of the first curved capillary; the outer diameter of the third curved capillary is smaller than the inner diameter of the second curved capillary; the first curved capillary The straight section of the curved capillary is arranged in the total capillary, the curved part of the first curved capillary passes through the side wall of the inlet end of the total capillary, and the other end of the first curved capillary passes through out the outlet end of the total capillary; the straight section of the second curved capillary is set in the first curved capillary, and the outlet end of the second curved capillary is from the outlet end of the first curved capillary Passing out, the other end of the second curved capillary passes through the first curved capillary; the curved part of the second curved capillary passes through the side wall of the inlet end of the total capillary; the The straight section of the third curved capillary is arranged in the second curved capillary, the outlet end of the third curved capillary passes through the outlet end of the second curved capillary, and the other part of the third curved capillary One end passes through the second curved capillary; the curved part of the third curved capillary passes through the side wall of the inlet end of the total capillary; the first curved capillary, the second curved capillary and the first curved capillary Annular projections are arranged on the outer walls of the inlet ends of the curved parts of the three curved capillaries; the total capillary is arranged coaxially with the straight sections of the first curved capillary, the second curved capillary, and the third curved capillary. 2. A four-stage coaxial microfluidic control nozzle according to claim 1, characterized in that: the inlet end of the total capillary is provided with an interface, and the outer wall of the interface is provided with a spiral Ribs. 3. A four-stage coaxial microfluidic control nozzle according to claim 1, characterized in that: the outlet end of the first curved capillary passes through the outlet end of the total capillary by 0.2 mm; The outlet end of the second curved capillary passes through the outlet end of the first curved capillary by 0.2mm; the outlet end of the third curved capillary passes through the outlet end of the second curved capillary by 0.2mm. 4. a kind of four-stage coaxial microfluid control nozzle according to claim 1, is characterized in that: the length of described total capillary is 70 mm, and the length of described first curved capillary is 75 mm; The length of the second curved capillary is 80 mm; the length of the third curved capillary is 85 mm; the outer part of the first curved capillary, the second curved capillary and the third curved capillary adopts a ring Oxygen glued and sealed. 5. An electrospinning device, characterized in that: comprising a first syringe pump, a first syringe, a second syringe pump, a second syringe, a third syringe pump, a third syringe, a fourth syringe pump, a fourth syringe, a One silicone hose, the second silicone hose, the third silicone hose, fiber receiving plate, DC electrostatic high voltage generator, and the four-stage coaxial microfluidic control nozzle described in claim 1; the first syringe is installed In the first syringe pump, the first syringe is connected to the four-stage coaxial microfluidic control nozzle, the second syringe is installed in the second syringe pump, and the The second syringe is connected to the four-stage coaxial microfluidic control nozzle through the first silicone hose, the third syringe is installed in the third syringe pump, and the third syringe is connected through the second silica gel The hose is connected to the four-stage coaxial microfluidic control nozzle, the fourth syringe is installed in the fourth syringe pump, and the fourth syringe passes through the third silicone hose and the four The first-stage coaxial microfluidic control nozzle is connected, the DC electrostatic high voltage generator is connected to the four-stage coaxial microfluidic control nozzle, and the lower end of the four-stage coaxial microfluidic control nozzle is provided with a fiber receiving plate . 6. Utilize the described electrospinning device of claim 4 to prepare the method for quadruple coaxial nanofiber, it is characterized in that: add the first spinning liquid in the first injector, add the second spinning liquid in the second injector, the second The third spinning liquid is added to the three syringes, the fourth spinning liquid is added to the fourth syringe, and nanofibers with a four-stage core-sheath structure can be prepared in a single step through the action of a high-voltage electrostatic field. 7. the method for preparing four-stage core-sheath structure nanofiber according to claim 5, is characterized in that comprising the steps: 1) A step of preparing spinning solution, the first spinning solution is an ethanol solution with a concentration of 8% polyvinylpyrrolidone by mass; the second spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid, after mixing In the solution, the mass percent concentration of polyvinylpyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 0.1%; the third spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid. In the mixed solution, polyethylene The mass percent concentration of pyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 0.3%; the fourth spinning solution is a mixed ethanol solution of polyvinylpyrrolidone and phosphotungstic acid. In the mixed solution, the mass percent concentration of polyvinylpyrrolidone is 8%, and the mass percent concentration of phosphotungstic acid is 1%; 2) Add the first spinning solution to the fourth spinning solution obtained in step 1 into corresponding syringes respectively, and then turn on the first to fourth syringe pumps; 3) Control the flow rate of each layer from the first injector to the fourth injector to be 1.5, 0.6, 0.3, 0.2 mL/h respectively, turn on the DC high-voltage electrostatic generator, increase the voltage to 18kV for parallel electrospinning, and obtain a four-stage core Sheath structure characteristic of nanofibers.