Metal halide piezoelectric / P (VDF-TrFE) composite piezoelectric nanofiber and preparation method thereof
By in-situ growth of metal halide nanocrystals inside P(VDF-TrFE) using electrospinning, composite nanofibers with high piezoelectric properties and flexibility are prepared, overcoming the application limitations of existing piezoelectric materials in flexible devices and achieving excellent performance in the fields of energy harvesting and sensing.
Patent Information
- Application Number
- CN202511984237.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-04-07
AI Technical Summary
The application of existing piezoelectric materials in flexible devices is limited, especially due to the brittleness and high processing temperature of inorganic piezoelectric materials, as well as the low piezoelectric coefficient and processing complexity of organic piezoelectric materials, making it difficult to prepare materials that combine high piezoelectric properties, excellent mechanical properties, and ease of processing.
Metal halide piezoelectric/P(VDF-TrFE) composite piezoelectric nanofibers were prepared by electrospinning. Metal halide nanocrystals were grown in situ inside P(VDF-TrFE) and then uniaxially stretched under a high voltage field to promote the formation of the polar β phase, thus preparing nanofibers with high voltage and high flexibility.
Composite nanofibers that achieve high voltage electrical performance and excellent mechanical properties can perform well in the fields of energy harvesting and sensing. They have high wear resistance, high air permeability and high mechanical flexibility. When subjected to external force, they can generate electrical signals that can be used for energy harvesting and sensing applications.
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Figure CN121802571A_ABST
Abstract
Description
(I) Technical Field:
[0001] This invention belongs to the field of functional composite materials technology, and relates to a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber material and its preparation method. (II) Background Technology:
[0002] In recent years, with the advancement of internet technology and artificial intelligence, the wearable electronic device industry has developed rapidly. However, traditional energy storage components such as rechargeable and replaceable batteries hinder this development. Therefore, self-powered devices that can use mechanical energy from natural sources such as wind, waves, and human activities as an energy source have significant development prospects. Piezoelectric materials have the ability to convert mechanical energy into electrical energy or the reverse process, and are widely used in sensors, ultrasonic testing equipment, energy harvesters, and other fields. Currently, the most commonly used piezoelectric materials are inorganic piezoelectric materials with high piezoelectric properties, but their brittleness and high processing temperature limit their application in flexible devices.
[0003] Piezoelectric polymers such as polyvinylidene fluoride (PVDF) and its copolymers possess excellent biocompatibility and mechanical properties, making them ideal materials for fabricating flexible wearable devices. Among PVDF copolymers, P(VDF-TrFE) (polyvinylidene fluoride-trifluoroethylene) exhibits the highest piezoelectric coefficient (d). 33 With a piezoelectric coefficient of ~38 pC / N, it can be better applied to flexible sensing, wearable fabrics, etc. However, its piezoelectric coefficient is relatively lower than that of commercial ceramics such as lead zirconate titanate (PZT, d). 33 The temperature (~265pC / N) is still relatively poor, and the processing is quite complex, often requiring high-temperature annealing, high-pressure polarization and other processes.
[0004] Organic-inorganic hybrid metal halide piezoelectrics possess the advantages of simple fabrication and high piezoelectric performance, with piezoelectric coefficients surpassing those of commercially available inorganic piezoelectric ceramics. For example, the d... 33 It has reached 220 pC / N (Science. 2017, 357, 306-309), while the d of heavily halogen-doped TMCM-CdBrCl2... 33 It even reaches 440 pC / N (J. Am. Chem. Soc. 2023, 145, 1936-1944), higher than commercial piezoelectric ceramic PZT. However, most of these molecules are connected by coordination bonds, resulting in poor flexibility and stability.
[0005] Therefore, how to prepare a piezoelectric material that combines high voltage electrical properties, excellent mechanical properties, and easy processing, and thus expand its application in energy harvesting and flexible sensing, is a major challenge. (III) Summary of the Invention:
[0006] The purpose of this invention is to provide a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber and its preparation method, aiming to solve the aforementioned problems of existing piezoelectric materials. The obtained composite piezoelectric nanofiber material is prepared by electrospinning of an organic-inorganic hybrid metal halide piezoelectric and a piezoelectric polymer P(VDF-TrFE). The metal halide piezoelectric grows in situ as nanocrystals within P(VDF-TrFE) and is uniformly dispersed in the nanofibers, thereby interacting with the entire polymer molecular chain. Combined with the uniaxial stretching effect of the high-voltage electric field during electrospinning, this promotes the formation of the all-trans polar β phase (piezoelectric phase) of the polymer, thus greatly enhancing the piezoelectric properties. This material exhibits excellent piezoelectric properties and performs exceptionally well in energy harvesting and human body sensing applications. This invention uses an electrospinning process to process the composite material into nanofiber mats with high wear resistance, high air permeability, and high mechanical flexibility. This invention employs a one-step in-situ growth preparation process, which has a short cycle time, low energy consumption, and is a green, environmentally friendly, and simple preparation method.
[0007] The technical solution of the present invention is a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, which utilizes the metal halide piezoelectric to form nanocrystals in situ inside the P(VDF-TrFE) matrix, thereby inducing the formation of the polar β phase of P(VDF-TrFE).
[0008] The composite piezoelectric nanofibers are white, and the diameter of a single fiber is less than 300 nm.
[0009] The mass of the metal halide piezoelectric in the composite piezoelectric nanofiber is at most 15% of the mass of P(VDF-TrFE).
[0010] The metal halide piezoelectric is an organic-inorganic hybrid metal halide piezoelectric molecule formed by the coordination of organic ammonium molecules with metal halides.
[0011] The metal halide piezoelectric is an organic-inorganic hybrid metal halide piezoelectric molecule formed by the coordination of organic ammonium molecules and metal halides in a 1:1 molar ratio.
[0012] The organic ammonium molecule is trimethylchloromethylammonium chloride, trimethylchloromethylammonium bromide, or trimethylfluoromethylammonium chloride.
[0013] The metal halide is manganese chloride or cadmium chloride.
[0014] The metal halide piezoelectric is one or a combination of trimethylchloromethylammonium-manganese chloride (TMCM-MnCl3), trimethylchloromethylammonium-cadmium chloride (TMCM-CdCl3), trimethylchloromethylammonium-manganese chlorobromide (TMCM-MnBrCl2), trimethylchloromethylammonium-cadmium chlorobromide (TMCM-CdBrCl2), trimethylfluoromethylammonium-manganese chloride (TMFM-MnCl3), and trimethylfluoromethylammonium-cadmium chloride (TMFM-CdCl3).
[0015] The preferred metal halide piezoelectric is trimethylchloromethylammonium-cadmium chlorobromide (TMCM-CdBrCl2).
[0016] A method for preparing metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers involves dissolving both the metal halide piezoelectric and P(VDF-TrFE) in an organic solvent and preparing nanofibers in one step via electrospinning. The metal halide piezoelectric grows nanocrystals in situ within the polymer, and the uniaxial stretching effect during electrospinning further promotes the formation of a polar β phase in P(VDF-TrFE). The method specifically includes the following steps:
[0017] Step 1: Add P(VDF-TrFE) powder to mixed organic solvent A, stir at room temperature until completely dissolved, to obtain transparent solution B;
[0018] Step 2: Add a metal halide piezoelectric to solution B, stir and dissolve at room temperature to obtain a viscous, transparent solution C;
[0019] Step 3: Electrospin the transparent solution C under a high-voltage electric field to obtain nanofibers;
[0020] Step four: Dry the nanofibers obtained in step three to obtain white metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers.
[0021] In step one, the mixed organic solvent A is composed of solvent one and solvent two. Solvent one is N,N-dimethylformamide (DMF), and solvent two is at least one of tetrahydrofuran, acetone, ethyl acetate, and acetonitrile.
[0022] In step one, the mixed organic solvent A is prepared by mixing solvent one and solvent two in a volume ratio of 1:1 to 1:4.
[0023] In step one, the mixed organic solvent A is preferably a mixed organic solvent in which the volume ratio of DMF to acetone is 1:1.
[0024] In step one, the concentration of solution B is 0.08 g / mL to 0.2 g / mL.
[0025] The mass of the metal halide piezoelectric added in step two is at most 15% of the mass of P(VDF-TrFE);
[0026] In step two, the mass of the metal halide piezoelectric is 1% of P(VDF-TrFE).
[0027] The method for preparing metal halide piezoelectrics in step two involves dissolving equimolar amounts of organic ammonium molecules and metal halides in water, and obtaining small molecule crystals of metal halide piezoelectric molecules after the solvent evaporates at room temperature.
[0028] The high-voltage electric field mentioned in step three is 10-22kV.
[0029] In step three, the transparent solution C is transferred into a syringe, a metal microporous needle is installed, and electrospinning is performed; the nanofibers are received by a roller, and a working gap is provided between the needle and the roller.
[0030] The needle's liquid delivery rate is 0.2-1 mL / h, the roller's rotation speed is 100-1000 rpm, and the distance between the needle and the roller is 5-20 cm.
[0031] In step three, the electrospinning high-voltage electric field is selected as 18kV, the liquid supply rate is selected as 0.8mL / h, the rotation speed of the receiving roller is selected as 800rpm, and the distance between the needle and the roller is selected as 10cm.
[0032] In step four, the nanofibers are placed in an oven to dry thoroughly.
[0033] In step four, the drying temperature is 50-80℃ and the drying time is 8-20h.
[0034] In step four, drying is preferably carried out at a temperature of 60°C for 12 hours.
[0035] The composite piezoelectric nanofibers are used for energy harvesting.
[0036] The composite piezoelectric nanofibers are used for sensing.
[0037] The composite piezoelectric nanofibers are used to prepare nanofiber mats. Electrodes and wires are attached to the top and bottom of the nanofiber mats, and after encapsulation, a flexible device that can be used as an energy harvester or sensor is obtained.
[0038] The technical effects and advantages of this invention are as follows: 1. This invention prepares nanofibers from a mixed solution of metal halide piezoelectrics and piezoelectric polymer P(VDF-TrFE) using electrospinning. This method is room temperature preparation, with advantages such as simple and rapid operation and low energy consumption, making it an excellent method for obtaining high-voltage piezoelectric properties and highly flexible polymer nanocomposites. 2. The composite piezoelectric nanofibers of this invention are composed of metal halide piezoelectrics and P(VDF-TrFE). The metal halide piezoelectrics grow in situ into nanocrystals within the polymer and are uniformly dispersed in the polymer substrate, thereby interacting with the entire polymer chain. Utilizing the interaction between the nanocrystals and P(VDF-TrFE) molecules, as well as the uniaxial stretching effect of the high-voltage electric field during electrospinning, the formation of the β phase is effectively promoted, increasing the β phase content of P(VDF-TrFE), and thus improving the piezoelectric output performance of the composite nanofibers. 3. The obtained metal halide piezoelectric / P(VDF-TrFE) composite nanofibers possess both high-voltage piezoelectric properties and excellent flexibility. Flexible devices fabricated from these nanofibers exhibit polarization of the polar β-phase molecular chains within the fiber felt when an external force is applied, resulting in charge accumulation at the interface and a potential difference across the fiber felt. A certain voltage and current can be monitored using devices such as oscilloscopes and current amplifiers. When the external force is removed, the fiber felt returns to its initial uncharged state. This voltage and current generated by external mechanical force can be used for energy harvesting. 4. The electrical signal of the metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers prepared in this invention varies with the magnitude, period, and direction of the external stimulus, thus possessing great application potential in the field of sensing. (iv) Description of the attached drawings:
[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0040] Figure 1 This is a schematic diagram of the invention. Metal halide piezoelectrics are grown in situ as nanocrystals in a P(VDF-TrFE) matrix and interact with polymer chains, thereby inducing the formation of the β phase.
[0041] Figure 2-1 SEM image of the metal halide piezoelectric / P(VDF-TrFE) composite nanofibers of Example 1 of this invention.
[0042] Figure 2-2This is a radial scale distribution diagram of the metal halide piezoelectric / P(VDF-TrFE) composite nanofibers of Example 1 of the present invention.
[0043] Figure 3 This is a comparison of the XRD phase purity of pure P(VDF-TrFE) nanofibers and metal halide piezoelectric / P(VDF-TrFE) composite nanofibers in Example 1 of the present invention.
[0044] Figure 4 The image shows a comparison of the FTIR-ATR spectra of pure P(VDF-TrFE) nanofibers and metal halide piezoelectric / P(VDF-TrFE) composite nanofibers in Example 1 of this invention.
[0045] Figure 5 The DSC curves of pure P(VDF-TrFE) nanofibers and metal halide piezoelectric / P(VDF-TrFE) composite nanofibers in Example 1 of this invention are compared.
[0046] Figure 6 This is a comparison of the dielectric constants of pure P(VDF-TrFE) nanofibers and metal halide piezoelectric / P(VDF-TrFE) composite nanofibers in Example 1 of the present invention.
[0047] Figure 7-1 The output voltage of the metal halide piezoelectric / P(VDF-TrFE) composite nanofiber in Example 1 of this invention is shown.
[0048] Figure 7-2 The output current of the metal halide piezoelectric / P(VDF-TrFE) composite nanofiber in Example 1 of this invention is shown.
[0049] Figure 8 This is a power density diagram of the metal halide piezoelectric / P(VDF-TrFE) composite nanofibers of Example 1 of the present invention.
[0050] Figure 9-1 To light up an LED lamp using a device fabricated using the metal halide piezoelectric / P(VDF-TrFE) composite nanofibers of Example 1 of this invention.
[0051] Figure 9-2 The results of finger tapping sensing tests are for devices fabricated using the metal halide piezoelectric / P(VDF-TrFE) composite nanofibers of Example 1 of this invention. (V) Specific Implementation Methods:
[0052] The metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber material of the present invention is prepared in situ in one step to obtain a high β phase composite material. Compared with other types of PVDF-based composite materials, it does not require subsequent annealing, polarization and other steps, which is a simple, efficient and environmentally friendly method.
[0053] Example 1: A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, such as Figure 1 As shown, it utilizes the metal halide piezoelectric TMCM-CdBrCl2 to form nanocrystals in situ within the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
[0054] Preparation of metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0055] Weigh 1.2 g of white P(VDF-TrFE) powder and add 10 mL of a 1:1 mixture of DMF and acetone. Stir at room temperature until completely dissolved. Add 0.012 g of TMCM-CdBrCl2 and stir at room temperature until completely dissolved. Transfer the mixture to a 10 mL syringe, attach a metal microporous needle, and place it in an electrospinning machine. Set the high-voltage electric field to 18 kV, the syringe advance speed to 0.8 mL / h, the receiving roller rotation speed to 800 rpm, and the distance between the needle and the roller to 10 cm. Place the resulting spun membrane in an oven and dry at 60 °C for 12 h to obtain a white nanofiber mat.
[0056] The surface morphology of the nanofiber mat was observed using scanning electron microscopy (SEM). Figure 2-1 As shown, the obtained nanofiber felt is composed of a large number of nanofibers intricately interwoven in three dimensions, exhibiting a network structure with gaps, and the nanofibers are at the nanometer scale in the radial direction. Figure 2-2 As shown, radial scalar statistical analysis reveals that the average diameter of the fiber is approximately 200 nm.
[0057] The phase structure of the nanofibers was characterized using X-ray diffraction (XRD). Pure P(VDF-TrFE) nanofibers prepared using the same process were compared with metal halide piezoelectric / P(VDF-TrFE) composite nanofibers; the results are as follows. Figure 3 As shown, pure P(VDF-TrFE) nanofibers consist of both nonpolar α-phase and polar β-phase, while the composite nanofibers prepared by this invention are almost entirely β-phase structures, indicating that the method of this invention can obtain a higher β-phase content.
[0058] The nanofibers were characterized using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) to further determine their phase structure. The spectra of pure P(VDF-TrFE) nanofibers were compared with those of metal halide piezoelectric / P(VDF-TrFE) composite nanofibers, and the results are as follows: Figure 4 As shown, the transmission peaks of the α and β phases of P(VDF-TrFE) are located at 766 cm⁻¹. -1 and 841cm -1 Based on the peak intensity, the relative content of the β phase in the α and β phases can be calculated. The calculation results show that the β phase accounts for 87.2% of the composite nanofibers prepared by this invention, while that of pure P(VDF-TrFE) nanofibers is 81.2%, further indicating that the method of this invention can obtain a higher β phase content.
[0059] Differential scanning calorimetry (DSC) was used to characterize the nanofibers and determine their crystallization behavior. Figure 5 As shown, the Curie temperatures (ferroelectric to paraelectric phase transition temperatures) of both P(VDF-TrFE) nanofibers and composite nanofibers are approximately 112 °C, indicating a wide applicable temperature range. The first melting peak is at approximately 152 °C. Calculations of the endothermic enthalpy yielded crystallinity of 41% for P(VDF-TrFE) nanofibers and 47% for composite nanofibers, indicating that the composite nanofibers exhibit better crystallinity.
[0060] The dielectric constant of P(VDF-TrFE) nanofibers and metal halide piezoelectric / P(VDF-TrFE) composite nanofibers was measured. Figure 6 As shown, the dielectric constant ε of the composite nanofibers r The value is 15.2, which is much greater than that of pure P(VDF-TrFE) nanofibers, indicating that the composite nanofibers have excellent charge storage capacity and piezoelectric output performance.
[0061] The piezoelectric output performance of metal halide piezoelectric materials / P(VDF-TrFE) composite nanofibers was tested using a self-designed and constructed piezoelectric testing device. The applied force was 2 N, and the frequency was 10 Hz. The measured output voltage and output current are as follows: Figure 7-1 , Figure 7-2 As shown, the composite piezoelectric nanofibers can generate a peak voltage of approximately 18V and a peak current of approximately 7μA, and produce signals of opposite signs when connected in both directions, indicating that this signal is a piezoelectric signal. The power density of the composite nanofibers was measured to be 60.2μW / cm² by applying resistors of varying sizes. -2 ,like Figure 8 As shown, the extremely high power density indicates that this composite nanofiber possesses strong electrical output performance.
[0062] Example 2: A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, which utilizes the metal halide piezoelectric TMCM-CdCl3 to form nanocrystals in situ inside the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
[0063] Preparation of metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0064] Weigh 1.4 g of white P(VDF-TrFE) powder and add 10 mL of a mixed solvent of DMF and tetrahydrofuran in a volume ratio of 1:2. Stir at room temperature until completely dissolved. Add 0.14 g of TMCM-CdCl3 and stir at room temperature until completely dissolved. Transfer the mixed solution to a 10 mL syringe, attach a metal microporous needle, and place it in an electrospinning machine. Set the high-voltage electric field to 20 kV, the syringe advance speed to 0.6 mL / h, the receiving roller rotation speed to 700 rpm, and the distance between the needle and the roller to 12 cm. Place the resulting spun membrane in an oven and dry at 50 °C for 20 h to obtain a white nanofiber mat with a fiber diameter of less than 150 nm.
[0065] Example 3: A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, which utilizes the metal halide piezoelectric TMCM-MnCl3 to form nanocrystals in situ inside the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
[0066] Preparation of metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0067] Weigh 1.0 g of white P(VDF-TrFE) powder and add 10 mL of a mixed solvent of DMF and ethyl acetate in a volume ratio of 1:3. Stir at room temperature until completely dissolved. Add 0.05 g of TMCM-MnCl3 and stir at room temperature until completely dissolved. Transfer the mixed solution to a 10 mL syringe, attach a metal microporous needle, and place it in an electrospinning machine. Set the high-voltage electric field to 15 kV, the syringe advance speed to 0.4 mL / h, the receiving roller rotation speed to 200 rpm, and the distance between the needle and the roller to 8 cm. Place the resulting spun membrane in an oven and dry at 70 °C for 12 h to obtain a powdery white nanofiber mat with a nanofiber diameter of less than 300 nm.
[0068] Example 4: A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, which utilizes the metal halide piezoelectric TMCM-MnBrCl2 to form nanocrystals in situ inside the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
[0069] Preparation of metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0070] Weigh 0.8 g of white P(VDF-TrFE) powder and add 10 mL of a mixed solvent of DMF and acetonitrile in a volume ratio of 1:4. Stir at room temperature until completely dissolved. Add 0.012 g of TMCM-MnBrCl2 and stir at room temperature until completely dissolved. Transfer the mixed solution to a 10 mL syringe, attach a metal microporous needle, and place it in an electrospinning machine. Set the high-voltage electric field to 22 kV, the syringe advance speed to 1 mL / h, the receiving roller rotation speed to 1000 rpm, and the distance between the needle and the roller to 15 cm. Place the resulting spun membrane in an oven and dry at 80 °C for 8 h to obtain a powdery white nanofiber mat with a fiber diameter of less than 240 nm.
[0071] Example 5: A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, which utilizes the metal halide piezoelectric TMFM-CdCl3 to form nanocrystals in situ inside the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
[0072] Preparation of metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0073] Weigh 2g of white P(VDF-TrFE) powder and add 10mL of a 1:3 mixture of DMF and acetone. Stir at room temperature until completely dissolved. Add 0.16g of TMFM-CdCl3 and stir at room temperature until completely dissolved. Transfer the mixture to a 10ml syringe, attach a metal microporous needle, and place it in an electrospinning machine. Set the high-voltage electric field to 10kV, the syringe advance speed to 0.2mL / h, the receiving roller rotation speed to 100rpm, and the distance between the needle and the roller to 6cm. Place the resulting spun membrane in an oven and dry at 55℃ for 16h to obtain a white nanofiber mat with a fiber diameter of less than 300nm.
[0074] Application example:
[0075] Fabrication of flexible energy harvesters and sensors based on metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers:
[0076] (1) Cut piezoelectric nanofibers of a specific size, and cut Cu@Ni conductive cloth or copper foil of appropriate size as top and bottom electrodes;
[0077] (2) Attach the electrodes to the top and bottom of the nanofiber felt, and then attach wires to the electrodes;
[0078] (3) The device is encapsulated using polyimide (PI) tape, polyethylene terephthalate (PET) tape, or polydimethylsiloxane (PDMS) to obtain a flexible device with a sandwich structure.
[0079] Flexible devices fabricated using metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers can be used for energy harvesting. For example, after connecting the device to a rectifier, a gentle tap can light up several small LED lights, such as... Figure 9-1 As shown.
[0080] Flexible devices fabricated using metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers can also be used as human body sensors. For example, gently tapping the sensing device with a finger can generate a high voltage of approximately 30V, the result of which is as follows: Figure 9-2 As shown. The voltage is related to the contact area of the finger and the magnitude of the force, and can be used to monitor finger activities in various scenarios, such as typing on a keyboard, playing the piano, etc.
[0081] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, characterized in that... It utilizes metal halide piezoelectrics to form nanocrystals in situ within the P(VDF-TrFE) matrix, inducing the formation of the polar β phase of P(VDF-TrFE).
2. The metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 1, characterized in that... The composite piezoelectric nanofibers are white, and the diameter of a single fiber is less than 300 nm.
3. The metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 1, characterized in that... The mass of the metal halide piezoelectric in the composite piezoelectric nanofiber is at most 15% of the mass of P(VDF-TrFE).
4. The metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 1 or 3, characterized in that... The metal halide piezoelectric is an organic-inorganic hybrid metal halide piezoelectric molecule formed by the coordination of organic ammonium molecules with metal halides; The metal halide piezoelectric is one or a combination of trimethylchloromethylammonium-manganese chloride (TMCM-MnCl3), trimethylchloromethylammonium-cadmium chloride (TMCM-CdCl3), trimethylchloromethylammonium-manganese chlorobromide (TMCM-MnBrCl2), trimethylchloromethylammonium-cadmium chlorobromide (TMCM-CdBrCl2), trimethylfluoromethylammonium-manganese chloride (TMFM-MnCl3), and trimethylfluoromethylammonium-cadmium chloride (TMFM-CdCl3).
5. A method for preparing a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, characterized in that... Metal halide piezoelectrics and P(VDF-TrFE) are dissolved together in an organic solvent and nanofibers are prepared in one step by electrospinning. The metal halide piezoelectrics grow nanocrystals in situ inside the polymer, and the uniaxial stretching effect of the electrospinning process promotes the formation of the polar β phase of P(VDF-TrFE). The specific steps include: Step 1: Add P(VDF-TrFE) powder to mixed organic solvent A, stir at room temperature until completely dissolved, to obtain transparent solution B; Step 2: Add a metal halide piezoelectric to solution B, stir and dissolve at room temperature to obtain a viscous, transparent solution C; Step 3: Electrospin the transparent solution C under a high-voltage electric field to obtain nanofibers; Step four: Dry the nanofibers obtained in step three to obtain white metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofibers.
6. The method for preparing a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 5, characterized in that... In step one, the mixed organic solvent A is composed of solvent one and solvent two. Solvent one is N,N-dimethylformamide (DMF), and solvent two is at least one of tetrahydrofuran, acetone, ethyl acetate, and acetonitrile. In step one, the mixed organic solvent A is prepared by mixing solvent one and solvent two in a volume ratio of 1:1 to 1:
4. In step one, the concentration of solution B is 0.08 g / mL to 0.2 g / mL.
7. The method for preparing a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 5, characterized in that... The mass of the metal halide piezoelectric added in step two is at most 15% of the mass of P(VDF-TrFE).
8. The method for preparing a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 5, characterized in that... The high-voltage electric field mentioned in step three is 10-22kV; In step three, the transparent solution C is transferred into a syringe, a metal microporous needle is installed, and electrospinning is performed. The nanofibers are received by a roller, and a working gap is provided between the needle and the roller. The liquid supply rate of the needle is 0.2-1 mL / h, the rotation speed of the roller is 100-1000 rpm, and the gap between the needle and the roller is 5-20 cm.
9. The method for preparing a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber according to claim 5, characterized in that... In step four, the drying temperature is 50-80℃ and the drying time is 8-20h. In step four, drying is preferably carried out at a temperature of 60°C for 12 hours.
10. An application of a metal halide piezoelectric / P(VDF-TrFE) composite piezoelectric nanofiber, characterized in that... It is used for energy harvesting or for sensing.