CN101787575A - Preparation method for micro-nano piezoelectric fiber - Google Patents

Abstract

The invention discloses a preparation method for micro-nano piezoelectric fibers. Using a micro-injection pump, the solution containing the piezoelectric material is extruded from the glass capillary micro-needle, and the solvent evaporates during the movement and stretching of the three-dimensional operating platform to prepare micro-nano-scale piezoelectric fibers, and then undergo subsequent polarization. deal with. In the present invention, by controlling the temperature and stretching speed of the solution on the microneedle, and the viscoelasticity and fluidity of the polyvinylidene fluoride solution system, the structural scale of the prepared micro-nano piezoelectric fiber can be adjusted to meet the different requirements of sensor design . Compared with the traditional method for preparing micro-nano-scale piezoelectric fibers, the invention has simple steps, convenient control, and can accurately locate the preparation position of the piezoelectric fibers.

Description

Preparation method for micro-nano-scale piezoelectric fibers

technical field

The invention relates to a method for preparing a micro-nano-scale fiber structure, in particular to a preparation method based on oriented micro-nano-scale piezoelectric fibers.

Background technique

Microciliated receptors are a mechano-stimuli perception system ubiquitous in the animal world. These microciliated receptors range in diameter from nanometer size to a few micrometers and lengths from 20 μm to 1500 μm, allowing them to sense vibrations, forces, velocities and accelerations at different specific frequencies. With the continuous improvement of micro-processing technology, the research on the artificial micro-cilia structure by simulating the biological micro-cilia sensing system has become a research hotspot in the field of sensors and micro-manufacturing in recent years. Launched the Nanofiber project of the Carnegie Mellon Nano Robotics Laboratory in the United States, the Artificial hair receptor project of the Nanomanufacturing Laboratory of the University of Illinois, and the Cilia project of the European Union.

The existing micro-nanofiber preparation technologies mainly include traditional etching microfabrication methods, phase separation methods, self-assembly methods, stretching filament methods and electrospinning methods. But their respective limitations limit their application prospects in the field of sensors. The traditional etching microfabrication method is too complicated for the preparation of the suspended fiber structure; the time required for the phase separation and self-organization method is too lengthy; and the stretching filament method is a commonly used method in the industry for continuous preparation of chemical fibers. method, but the obtained chemical fibers are generally large in size; although the electrospinning method can prepare polymer micro-nano fibers with diameters ranging from several nanometers to several microns, it usually only obtains fibers that are randomly bent and continuous. The non-woven mat structure cannot be prepared in a specific position. Therefore, it is necessary to develop a new preparation method of polymer micro-nano-scale fibers to achieve the purpose of preparing micro-nano-scale functional fiber structures at specific positions, so as to meet the needs of the sensor field.

Contents of the invention

The purpose of the present invention is to provide a preparation method for micro-nano-scale piezoelectric fibers, which reduces the preparation cost and simplifies the complicated preparation process, and meets the requirement of preparing micro-nano-scale functional fiber structures at specific positions.

The technical scheme that the present invention solves its technical problem adopts is:

The invention utilizes a micro-injection pump to extrude a solution in which a piezoelectric material is dissolved from a glass capillary micro-needle, and prepares a micro-nano-scale piezoelectric fiber by moving the three-dimensional operating platform and evaporating the solvent in the stretching process; the stretching preparation The specific steps of the subsequent polarization processing method are as follows:

(1) Dissolve polyvinylidene fluoride in dimethylformamide solution at room temperature, and mix them evenly by stirring, with a mixing mass ratio of 15%-30%;

(2) The heating plate is fixed on the automatic three-dimensional operation platform, the base is fixed on the heating plate, and the glass capillary microneedle is installed on the manual three-dimensional operation platform. Syringe pump connected;

(3) Adjust the manual three-dimensional manipulation platform to adjust the initial position of the glass capillary micro-needle relative to the substrate; control the temperature of the heating plate at 60°C-75°C; and extrude the solution from the glass capillary micro-needle to the substrate through a micro-injection pump The extruded solution is stretched by moving the automatic three-dimensional manipulation platform carrying the substrate. During the stretching process, the solvent in the solution evaporates and the solution solidifies, thereby forming suspended micro-nano-scale fibers with piezoelectric properties. , repeating the above steps (2) and (3) to prepare a micro-nano-scale piezoelectric fiber array on the substrate;

(4) Place the substrate together with the micro-nano-scale piezoelectric fiber array on it in a fiber polarization device composed of two metal plates and dielectric materials, and apply a 10kV voltage between the two metal plates to complete the piezoelectric Polarization of fiber arrays.

Compared with other micro-nano-scale fiber preparation technologies, the present invention has the following beneficial effects:

Using the viscoelastic properties of the polymer solution, it is stretched into filaments, avoiding the complicated process of traditional micro-processing technology; the entire preparation process is time-consuming and efficient; only a small amount of polymer solution is used in terms of materials. Low cost; a single micro-nano-scale fiber or micro-nano-scale fiber array can be prepared at a specific position, and its array structure can be adjusted freely; it is suitable for the preparation of polymer fibers; the diameter of the prepared micro-nano-scale fiber is generally 370 nm to 20 nm Micron, with piezoelectric properties; by changing the components in the solvent, this fiber preparation method can also be used to prepare functional micro-nano-scale fibers with other properties.

Description of drawings

Fig. 1 is a schematic diagram of a test bench for stretching and preparing micro-nano-scale piezoelectric fibers.

Figure 2 is a schematic diagram of the micro-nano fiber stretching preparation process.

Fig. 3 is a schematic diagram of a micro-nanoscale piezoelectric fiber polarization device.

In the figure: 1. Experimental platform, 2. Automatic three-dimensional operation platform, 3. Heating plate, 4. Micro injection pump, 5. Glass capillary micro needle, 6. Base, 7. Manual three-dimensional operation platform, 8. Metal electrodes, 9. Dielectric material, 10. Micro-nano piezoelectric fiber array, (a) the position of the needle and the substrate before stretching, (b) adjust the manual three-dimensional manipulation platform to initialize the position of the glass capillary micro-needle relative to the substrate, (c ) Move the automatic three-dimensional operation platform carrying the substrate to stretch the extruded solution, (d) the solvent in the solution evaporates during the stretching process, and the material is solidified, (e) the stretching is completed, the needle leaves the substrate, and the suspended Formation of micro-nano-scale fiber structures with piezoelectric properties,

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

The invention utilizes a micro-injection pump to extrude a solution in which piezoelectric materials are dissolved from a glass capillary micro-needle, and prepares micro-nano-scale piezoelectric fibers at a specific position of a substrate through movement of a three-dimensional operating platform and solvent evaporation during stretching.

As shown in Figure 1, the preparation platform of micro-nano piezoelectric fibers consists of an experimental bench 1, an automatic three-dimensional operation platform 2, a heating plate 3, a substrate 6, a glass capillary microneedle 5 and a micro-injection pump 4. The heating plate 3 is fixed on the automatic three-dimensional operation platform 2, the base 6 is fixed on the heating plate 3, and the material used for the base is polyimide. The glass capillary micro-needle 5 is clamped and installed on the manual three-dimensional operation platform 7. The front end of the micro-needle is vertically facing the substrate 6, and the rear end is connected with the micro-injection pump 4. Both the automatic three-dimensional operation platform 2 and the manual three-dimensional operation platform 7 are installed on the On the experimental bench 1.

The solution required in the preparation is prepared by mixing polyvinylidene fluoride powder and dimethylformamide solvent at normal temperature, and the mixture is uniformly mixed by means of stirring, and the mixing mass ratio is 15%-30%. In order to achieve a uniform mixing effect, the mixing time required for different concentrations of solutions is shown in the table below:

Before preparing the micro-nano-scale piezoelectric fiber, the position of the glass capillary microneedle 5 relative to the substrate 6 should be initialized by adjusting the manual three-dimensional manipulation platform 2; The stretching preparation process of nanoscale piezoelectric fibers is shown in Figure 2. After the needle position is set, the manual three-dimensional operation platform is locked, and the solution is extruded from the glass capillary microneedle 5 to the substrate 6 through the micro-injection pump 4 Above, after waiting for a period of time, move the automatic three-dimensional manipulation platform 2 carrying the substrate 6 to stretch the extruded solution. During the stretching process, the solvent in the solution evaporates and the material solidifies, thereby forming a suspended structure with Micro-nanoscale fibers with piezoelectric properties. By repeating the above positioning-stretching steps, the micro-nano scale piezoelectric fiber array 10 can be prepared on the substrate 6 . The preparation results are shown in the table below:

Solution concentration heating temperature waiting time stretching speed Microsyringe Pump Pumping Rate Prepared fiber diameter Prepared fiber length 15% 70℃ 2 minutes 25 mm/s 1 microliter/hour 375nm 5 microns 30% 70℃ 30 seconds 25 mm/s 1 microliter/hour 20 microns 2mm

As shown in Figure 3, micro-nano fibers with piezoelectric properties prepared from polyvinylidene fluoride and dimethylformamide solutions need to be polarized before packaging to increase their piezoelectric coefficients. Place the substrate 6 together with the micronanoscale piezoelectric fiber array 10 on it in a fiber polarization device composed of two metal plates 8 and a dielectric material 9, and apply a voltage of 10 kV between the two metal plates 8 for 1 Hours, the polarization of the piezoelectric fiber array 10 is completed.

As shown in Figure 1, Figure 2, and Figure 3, the solution containing the piezoelectric material is extruded from the microneedle of the glass capillary using a micro-injection pump, and a part of the solution is stretched into filaments by the movement of the three-dimensional positioning platform. During the silking process, the solvent in the solution evaporates and the material solidifies to form a micro-nano-scale fiber structure at the required position. After the fiber structure is prepared, the fiber is polarized to obtain a micro-nano-scale suspended fiber with piezoelectric properties. . Its preparation and polarization treatment method is divided into four steps:

(1) At room temperature, dissolve the polyvinylidene fluoride powder in the dimethylformamide solution, and mix it evenly by stirring. The tensile spinnability of the solution system can be judged by the following formula,

P＝h _s ·μ/σ

Among them, P is a parameter used to describe the stretching spinnability of the solution system, a small value of P means that the solution system is more suitable for stretching and spinning, h _s is the evaporation rate of the solvent, μ is the viscosity of the solution system, and σ is The surface tension of the solution, in the present invention, in order to make the rheological properties of the solution system suitable for fiber drawing, the mixing mass ratio is controlled at 15%-30%.

(2) The stretching preparation platform of micro-nano-scale piezoelectric fibers is shown in Fig. 1 . The heating plate 3 is fixed on the automatic three-dimensional operation platform 2, the base 6 is fixed on the heating plate, and the glass capillary microneedle 5 is installed on the manual three-dimensional operation platform 7. The front end of the needle is perpendicular to the base, and the rear end is connected to the micro injection Pump 4 is connected. Among them, the glass capillary microneedle is stretched by glass tube stretching equipment under heating and melting. The needle is installed on the manual three-dimensional operation platform to initialize the position of the microneedle relative to the substrate before stretching, so that The liquid can come into contact with the base material and bond firmly with the base material after a period of time;

(3) The stretching preparation process of the micro-nano piezoelectric fiber is shown in Fig. 2 . First, adjust the manual three-dimensional manipulation platform 7 to adjust the initial position of the glass capillary microneedle 5 relative to the substrate 6; control the temperature of the heating plate 3 to 60°C-75°C; after the needle position is set, lock the manual three-dimensional manipulation platform, and pass The micro-injection pump extrudes 0.01-0.03ml of solution from the microneedle onto the substrate, and after waiting for one minute, the automatic three-dimensional manipulation platform loaded with the substrate moves along the stretching direction at a speed of 20-30mm/s, thereby The resulting solution is stretched. During the stretching process, the solvent in the solution evaporates and the material solidifies, forming suspended micro-nano-scale fibers with piezoelectric properties.

(4) Micro-nano-scale piezoelectric fibers still need subsequent polarization treatment to increase their piezoelectric coefficients before application, and the polarization process is shown in Figure 3. The substrate 6 together with the micro-nano-scale piezoelectric fiber array 10 thereon is placed in the high-voltage electric field formed by the metal electrode 8, and a voltage of 12 kV is applied between the two electrodes to complete the polarization of the piezoelectric fiber. Due to the small size, a thin film of dielectric material 9 is placed between the two plates in order to avoid breakdown.

Claims (1)

1. preparation method at micro-nano piezoelectric fiber, it is characterized in that: utilize micro-injection pump will be dissolved with the solution of piezoelectric by extruding in the miniature syringe needle of capillary glass tube, by the solvent evaporation in the mobile and drawing process of three-dimensional manipulating platform, preparation micro-nano piezoelectric fiber; Its concrete steps that prepare with follow-up method for polarized treatment that stretch are as follows:

(1) under the normal temperature, Kynoar is dissolved in dimethyl formamide solution, by the mode that stirs it is mixed all, mixing quality compares 15%-30%;

(2) heating plate (3) is fixed on the automatic three-dimensional manipulating platform (2), substrate (6) is fixed on this heating plate (3), the miniature syringe needle of capillary glass tube (5) is installed on the manual three-dimensional manipulating platform (7), the front end of the miniature syringe needle of this capillary glass tube (5) vertically is right against substrate (6), and the rear end links to each other with micro-injection pump (4);

(3) regulate manual Three dimensional steerable platform (7) to adjust the initial position of the miniature syringe needle of capillary glass tube (5) with respect to substrate (6); Control heating plate (3) temperature is 60 ℃-75 ℃; And from the miniature syringe needle of capillary glass tube (5), be expressed into solution on the substrate (6) by micro-injection pump (4), move be loaded with the automatic Three dimensional steerable platform (2) of substrate (6) thus the solution of extruding is stretched, in drawing process, solvent evaporation in the solution, solution solidifies, thereby form unsettled micro nano-scale fiber, repeat above (2) step and (3) step, in substrate (6), prepare micro-nano piezoelectric fiber array (10) with piezoelectric property;

(4) substrate (6) is together placed by two metal polar plates (8) and dielectric material (9) together with the micro-nano piezoelectric fiber array (10) on it formed the fiber polarization device, between two metal polar plates (8), apply 10kV voltage, to finish the polarization of array of piezoelectric fibres (10).

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