CN100432307C - Directional magnetic electrical spinning Nano fibers, preparation method and equipment needed - Google Patents

Abstract

The invention provides a polymer fiber containing paramagnetic Fe ₃ O ₄ oriented arrangement at the nanoscale and its preparation technology, and also provides equipment for preparing the magnetic electrospinning fiber. The present invention uses Fe ₃ O ₄ magnetic fluid and polymer solution as raw materials, adopts the in-situ composite method, adjusts the solution concentration and the process parameters of electrospinning, and performs electrospinning under the action of high-voltage static electricity. A magnetic field is set at the place, and under the induction of the magnetic field, the polymer nanofibers containing Fe ₃ O ₄ are aligned along the direction of the magnetic field, thereby obtaining nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field. The fibers are arranged regularly and have consistent directions, which can produce consistent responses to external magnetic fields.

Description

Oriented magnetic electrospun nanofibers, preparation method and equipment used therefor

technical field

The invention belongs to magnetic macromolecule nanofiber and its preparation technology, in particular to a macromolecule fiber containing paramagnetic Fe ₃ O ₄ oriented arrangement at the nanometer scale, its preparation technology and the equipment used.

Background technique

With the development of electrospinning technology, people began to dope nanoparticles with special functions into nanofibers, hoping to obtain nanofibers with specific functions. For example, nanocomposites with high catalytic activity can be obtained by doping Pt nanoparticles into nanofibers; nanofibers with semiconducting properties can be prepared by doping Ag nanoparticles into polyacrylonitrile. But so far, the preparation method of magnetic nanofibers capable of directional arrangement has not been reported. Magnetic nanofibers have broad application prospects in the fields of targeted drug delivery, electronic components, nonlinear optical materials, sensors, electromagnetic shielding materials, and microwave absorbers. At present, the literature reports related to the preparation of superparamagnetic nanofibers by electrospinning are as follows: M.Wang, H.Singh.TAHatton, GCRutledge.Field-responsive super paramagnetic composite nanofibers by electrospinning.Polymer, 2004: 5505-5510 and Song Ting Tan , Joachim H. Wendorff, et al. Biocompatible and Biodegradable polymer nanofibers displaying superparamagnetic properties. ChemPhysChem, 2005, 6: 1461-1465 The above two documents studied the preparation and characterization methods of superparamagnetic nanofibers. The above literature reports are all nanofibers prepared by adding magnetic Fe ₃ O ₄ into the polymer solution and using common electrospinning technology, and the fibers are piled up randomly on the collecting device. If the magnetic field is designed on the collection device, the magnetic nanofibers can be oriented, so that the material can better respond to the external magnetic field in the application process and improve the application efficiency.

Contents of the invention

The object of the present invention is to provide a polymer fiber containing paramagnetic Fe ₃ O ₄ oriented arrangement at the nanometer scale and its preparation technology, as well as the equipment used to prepare the magnetic electrospun fiber.

The mechanism of the invention is as follows: _Fe3O4 nanoparticles are uniformly dispersed in the polymer solution, and the polymer _solution forms nanofibers under the action of high-voltage static electricity. Under the action of the magnetic field in the receiving device, Fe ₃ O ₄ tends to be arranged along the direction of the magnetic field, thereby preparing oriented magnetic nanofibers.

The present invention uses Fe ₃ O ₄ magnetic fluid and polymer solution as raw materials, adopts the in-situ composite method, adjusts the solution concentration and the process parameters of electrospinning, and performs electrospinning under the action of high-voltage static electricity. A magnetic field is set at the place, and under the induction of the magnetic field, the polymer nanofibers containing Fe ₃ O ₄ are oriented in the direction of the magnetic field, thereby obtaining oriented magnetic polymer nanofibers. The fibers are arranged regularly and have consistent directions, which can produce consistent responses to external magnetic fields.

The preparation steps of the present invention are as follows:

A. Dissolve FeCl ₂ .4H ₂ O and FeCl ₃ .6H ₂ O in distilled water to prepare FeCl ₂ solution with a concentration of 0.1-2mol·L and FeCl ₃ solution with a concentration of 0.1-2mol·L; In a reactor equipped with a strong magnet, mix the FeCl ₃ solution and the FeCl ₂ solution according to the ratio of molar ratio Fe ³⁺ : ^{Fe 2+} = 1 to 2: 1 to prepare a mixed solution, and feed nitrogen to remove the mixed solution. Oxygen; control the temperature of the reaction solution at 50-90°C, add ammonia water dropwise to the mixed solution until the pH value of the solution is 6.5-7, after reacting for 15-30 minutes, continue to slowly add ammonia water dropwise to the solution until the pH value is 9 ~10, continue to react for 30 minutes and then stop the reaction; pump off the upper liquid, wash the reaction product repeatedly with distilled water until the washing liquid is neutral, and freeze-dry the product to obtain Fe ₃ O ₄ nanoparticles;

During the mixing process of FeCl ₃ .6H ₂ O and FeCl ₂ .4H ₂ O solutions, the preferred molar ratio of Fe ³⁺ to Fe ²⁺ is 1.5˜1.75:1.

_B. dispersing dry _Fe3O4 nanoparticles in an aqueous solution to prepare a mass percentage of 5 to 30% _Fe3O4 suspension, then adding a mass percentage of 0.1 to 1% surfactant in _the solution, Using ultrasonic dispersion;

Surfactant is a kind of in sodium lauryl sulfonate, sodium lauryl sulfate, Tween 80 (polysorbate), ammonium oleate, alkyl quaternary ammonium salt.

C. Take the above-mentioned Fe ₃ O ₄ suspension and add it to the electrospinning polymer solution to configure the spinning solution. The mass ratio of Fe ₃ O ₄ to the polymer is 5-40:100, and perform ultrasonic oscillation for 1-12 hours; The polymer material used for electrospinning can be one of all spinnable polymer materials such as polyvinyl alcohol, polycarbonate, polyhydroxybutyrate, chitosan, gelatin, and polyoxyethylene.

D. Put the above spinning liquid into the storage tank, and make the spinning liquid spray out from the nozzle under the action of pump pressure or gravity. Due to the repulsion of the surface charge of the polymer solution, the droplet stretches into a Taylor cone shape. Under the action of stretching into fibers, the fibers split several times before reaching the receiving plate. On the receiving plate with a magnetic field, nanofibers with a fiber diameter distribution of 100-600nm and oriented arrangement along the magnetic field direction were collected.

The electrospinning device of the present invention comprises:

A DC high-voltage electrostatic generator, a storage tank, a syringe pump connected to the storage tank, a set of metal nozzles connected to the bottom of the storage tank, the nozzles are connected to the positive pole of the high-voltage electrostatic generator, and a metal nozzle connected to the negative pole (or ground) Receiver board, set two facing N pole and S pole magnets on the receiver board; the voltage of the electrostatic generator is 10-60KV, the distance between the two magnets is 10-30cm, the magnetic strength of the magnet surface is 200-2000 Gauss, and the metal receiver board Aluminum foil boards are commonly used, and the distance from the nozzle is 10-30cm. The inner diameter of the metal nozzle is 0.4-1.4mm. The magnetic field can also be generated by placing conductive coils on the metal receiving plate, the distance between the conductive coils is 5-10 cm, and the magnetic field strength generated by the coils is 200-2000 Gauss.

The process flow of electrospinning is: add the prepared polymer spinning liquid into the storage tank 2, and make the spinning liquid spray out from the nozzle 3 under the pump pressure of the syringe pump 5 or gravity. The ejected droplets are spherical. Due to the repulsion of the surface charge of the polymer solution, the droplets are stretched into a Taylor cone shape, and further stretched into fibers under the action of the electric field generated by the DC high-voltage electrostatic generator 1. The fibers reach Multiple splits occur before the receiving plate, and on the receiving plate 4 with a magnetic field, fiber membranes with diameters of micrometers and nanometers arranged along the direction of the magnetic field are collected.

The prepared Fe ₃ O ₄ particles and fibers were characterized by SEM, TEM, etc. The results are shown in Fig. 2-4. It can be seen from Figure 2 that the Fe ₃ O ₄ particles are more uniformly distributed in the polyvinyl alcohol nanofibers.

It can be seen from Figure 3 and Figure 4 that when there is no magnetic field in the receiving field, the direction of the received fibers is randomly distributed, and when a magnetic field is set in the receiving field, the received nanofibers are oriented along the direction of the magnetic field.

The invention successfully disperses Fe ₃ O ₄ nanoparticles in polymer nanofibers, and utilizes an external magnetic field to arrange the fibers in an orientation. It has the advantages of simple preparation process, easy operation and repetition, and is convenient for popularization and application.

Description of drawings:

Fig. 1 is a diagram of an electrospinning device, 1 is a DC high-voltage electrostatic power supply 2, a material storage tank 3, a nozzle 4, and a receiving plate with a magnetic field, and 5 is a syringe pump.

Fig. 2 is a polyvinyl alcohol nanofiber containing Fe ₃ O ₄ nanoparticles prepared in the present invention.

Fig. 3 is a transmission electron micrograph of Fe ₃ O ₄ nanoparticles contained in polyvinyl alcohol nanofibers.

Fig. 4 is the magnetic response curve of the polyvinyl alcohol nanofiber membrane.

Detailed ways:

Example 1:

A. In a 100mL volumetric flask, use distilled water to prepare FeCl ₂ and FeCl ₃ solutions with a concentration _of 0.1mol L; ·L FeCl ₂ solution is mixed evenly, and nitrogen gas is passed under the liquid surface to remove oxygen in the water. The temperature of the reaction device was raised to 80°C, and the ammonia water was slowly added dropwise to the solution until the pH value of the solution was 6.5. After 15 minutes of reaction, the ammonia water was slowly added dropwise to the solution until the pH value was 9.5, and the reaction was stopped after 30 minutes of reaction; Hold the bottom of the flask with a strong magnet, pour off the upper liquid, and wash the reaction product repeatedly with distilled _water until the washing liquid is neutral; freeze-dry the product _Fe3O4 ;

B. _Disperse the dried _Fe3O4 nanoparticles in the aqueous solution, add 0.1% surfactant sodium dodecylsulfonate to the solution, and disperse by ultrasonic wave;

C. Take the above-mentioned Fe ₃ O ₄ suspension and add it to a polyvinyl alcohol aqueous solution with a concentration of 10%, and the mass ratio of Fe ₃ O ₄ to polyvinyl alcohol is 30%, and perform ultrasonic oscillation for 1 hour;

D. In the electric field, add the above solution into the syringe 2, the nozzle 3 is a 10# syringe needle, the syringe needle is connected to the positive stage of the high-voltage electrostatic generator 1, and the aluminum foil plate is used as the cathode receiving plate 4, and the distance between the aluminum foil plate and the syringe needle is 10cm; two facing N pole and S pole magnets are placed on the aluminum foil plate, the surface magnetic field is 1200 gauss, the adsorption force is 6kg, the distance between the two magnets is 10cm, and a voltage of 20KV is applied for electrospinning.

Example 2:

The mass ratio of Fe ₃ O ₄ to polyvinyl alcohol was 1:100, and the rest of the experimental conditions and the amount of reaction substances were the same as in Example 1. Nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field were obtained.

Example 3:

The mass ratio of Fe ₃ O ₄ to polyvinyl alcohol was 50:100, and the rest of the experimental conditions and the amount of reaction substances were the same as in Example 1. Nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field were obtained.

Example 4:

The polymer involved in electrospinning is polyoxyethylene, and the rest of the experimental conditions and the amount of reacting substances are the same as in Example 1, and nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the magnetic field direction are obtained.

Example 5:

The polymer involved in electrospinning is polycarbonate, using chloroform as the solvent, the solution concentration is still 10%, the rest of the experimental conditions and the amount of reaction substances are the same as in Example 1, and the obtained fiber diameter distribution is 100-600nm and is oriented along the direction of the magnetic field arranged nanofibers.

Embodiment 6:

The surface magnetic field of the N pole and S pole magnet at the receiving device is 1300 Gauss, and the adsorption force is 0.6kg. The rest of the experimental conditions and the amounts of the reacting substances were the same as in Example 1, and nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the magnetic field direction were obtained.

Embodiment 7:

The surfactant used in the experiment was ammonium oleate, and the rest of the experimental conditions and the amount of reaction substances were the same as in Example 1, and nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field were obtained.

Embodiment 8:

The surfactant used in the experiment was Tween 80, and the rest of the experimental conditions and the amount of reaction substances were the same as in Example 1, and nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field were obtained.

Embodiment 9:

The surfactant used in the experiment is an alkyl quaternary ammonium salt, and the rest of the experimental conditions and the amount of the reaction substance are the same as in Example 1, to obtain nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field.

Example 10:

The polymer involved in the electrospinning is gelatin, and the rest of the experimental conditions and the amount of the reacting substance are the same as in Example 1, and nanofibers with a fiber diameter distribution of 100-600 nm and aligned along the direction of the magnetic field are obtained.

Example 11:

In a _100mL volumetric _flask , prepare FeCl ₂ and FeCl ₃ solutions with a concentration of 2mol L with distilled water; Mix evenly, and nitrogen gas is passed under the liquid surface to remove oxygen in the water. The temperature of the reaction device was raised to 80°C, and the ammonia water was slowly added dropwise to the solution until the pH value of the solution was 6.5. After 15 minutes of reaction, the ammonia water was slowly added dropwise to the solution until the pH value was 9.5, and the reaction was stopped after 30 minutes of reaction; Hold the bottom of the flask with a strong magnet, pour off the upper liquid, and wash the reaction product repeatedly with distilled water until the washing liquid is neutral; freeze-dry the product Fe ₃ O ₄ ; disperse the dried Fe ₃ O ₄ nanoparticles in the aqueous solution, Add 0.1% surfactant sodium dodecyl sulfonate to the solution, and disperse by ultrasonic wave; take the above-mentioned Fe ₃ O ₄ suspension and add it to the polyhydroxybutyrate-chloroform solution (concentration is 10%), and Fe ₃ The mass ratio of O _added to polyhydroxybutyrate is 30%, and ultrasonic oscillation is carried out for 1h;

Add the above solution into the syringe, select 10# needle for the syringe needle, connect the syringe needle with the positive stage of the high-voltage electrostatic generator, use an aluminum foil plate as the cathode receiving plate, and the distance between the aluminum foil plate and the syringe needle is 10cm; place two pieces facing each other on the aluminum foil plate The N-pole and S-pole magnets have a surface magnetic field of 1200 Gauss, and the distance between the two magnets is 10cm. Applying a voltage of 20KV for electrospinning can obtain Fe ₃ O ₄ nanofibers with a particle size of about 30nm and a fiber diameter distribution of 100-600nm, which are oriented along the direction of the magnetic field.

Claims (6)

1. A preparation method for oriented magnetic electrospinning nanofibers, the specific preparation steps are as follows: A. Dissolve FeCl ₂ .4H ₂ O and FeCl ₃ .6H ₂ O in distilled water to prepare FeCl ₂ solution with a concentration of 0.1-2mol·L and FeCl ₃ solution with a concentration of 0.1-2mol·L; In a reactor equipped with a strong magnet, mix the FeCl ₃ solution and the FeCl ₂ solution according to the ratio of molar ratio Fe ³⁺ : ^{Fe 2+} = 1 to 2: 1 to prepare a mixed solution, and pass nitrogen to remove the mixed solution. Oxygen; control the temperature of the reaction solution at 50-90°C, add ammonia water dropwise to the mixed solution until the pH value of the solution is 6.5-7, after reacting for 15-30 minutes, continue to slowly add ammonia water dropwise to the solution until the pH value is 9-10, continue to react for 30 minutes and then stop the reaction; remove the upper layer liquid, wash the reaction product repeatedly with distilled water until the washing liquid is neutral, and _freeze -dry the product to obtain _Fe3O4 nanoparticles; _B. dispersing dry _Fe3O4 nanoparticles in an aqueous solution to prepare a mass percentage of 5 to 30% _Fe3O4 suspension, then adding a mass percentage of 0.1 to 1% surfactant in _the solution, Disperse with ultrasonic waves; the surfactant is one of sodium dodecyl sulfate, sodium lauryl sulfate, Tween 80, ammonium oleate, and alkyl quaternary ammonium salt; C. Take the above-mentioned Fe ₃ O ₄ suspension and add it to the electrospinning polymer solution to configure the spinning solution. The mass ratio of Fe ₃ O ₄ to the polymer is 5-40:100, and perform ultrasonic oscillation for 1-12 hours; Electrospinning polymer solution is one of all spinnable polymer materials; D. Put the above spinning liquid into the storage tank, and make the spinning liquid spray out from the nozzle under the action of pump pressure or gravity. Due to the repulsion of the surface charge of the polymer solution, the droplet stretches into a Taylor cone shape. The fiber is stretched under the action of the fiber, and the fiber splits several times before reaching the receiving plate. On the receiving plate with a magnetic field, the fiber film with a diameter of 100-600nm is collected along the direction of the magnetic field. 2. the preparation method of directional magnetic electrospinning nanofiber according to claim 1 is characterized in that in the mixed solution described in step A, the mol ratio of Fe ³⁺ and Fe ²⁺ is 1.5～1.75: 1; Step B The electrospinning polymer solution is one of polyvinyl alcohol, polycarbonate, polyhydroxybutyrate, chitosan, gelatin and polyoxyethylene. 3. A directional magnetic electrospun nanofiber prepared by the method of claim 1, characterized in that the fiber contains nanometer Fe ₃ O ₄ magnetic particles, the fiber diameter distribution is 100-600nm, and the fiber is oriented along the direction of the magnetic field. cloth. 4. A used electrospinning equipment for preparing the directional magnetic electrospinning nanofibers described in claim 3, comprising a DC high-voltage electrostatic generator, a storage tank, a syringe pump connected to the storage tank, and a storage tank The bottom is connected to a group of metal nozzles, the nozzles are connected to the positive pole of the high-voltage electrostatic generator, a metal receiving plate is connected to the negative pole or ground, and a magnetic field is set on the metal receiving plate. 5. The electrospinning device according to claim 4, characterized in that two N-pole and S-pole magnets facing each other are arranged on the metal receiving plate, the distance between the two magnets is 10-30cm, and the magnetic strength on the surface of the magnet is 200 ~2000 Gauss. 6. The electrospinning device according to claim 4, characterized in that conductive coils are placed on the metal receiving plate, the distance between the conductive coils is 5-10 cm, and the magnetic field strength generated by the conductive coils is 200-2000 Gauss.

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