KR102465218B1 - Piezoelectric organic-inorganic hybrid nanoparticles manufacturing method and piezoelectric application products using the same - Google Patents

Abstract

The present invention relates to a piezoelectric material and a method for manufacturing the same, and more specifically, piezoelectric organic-inorganic hybrid nanoparticles having improved dispersibility with a polymer matrix by forming a coating layer with a piezoelectric polymer on the surface of the piezoelectric inorganic nanoparticles to lipophilize them; It relates to a manufacturing method thereof, a PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles, and a piezoelectric application product including the polymer thin film.

Description

Piezoelectric organic-inorganic hybrid nanoparticles manufacturing method and piezoelectric application products using the same

The present invention relates to a piezoelectric material and a method for manufacturing the same, and more specifically, piezoelectric organic-inorganic hybrid nanoparticles having improved dispersibility with a polymer matrix by forming a coating layer with a piezoelectric polymer on the surface of the piezoelectric inorganic nanoparticles to lipophilize them; It relates to a manufacturing method thereof, a PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles, and a piezoelectric application product including the polymer thin film.

Inorganic particles such as functional ceramics having dielectric properties and piezoelectric properties are used in a wide range of fields as various electrical and electronic components. For example, it is used in piezoelectric elements such as various actuators, sensors, and resonators. As such functional ceramics, inorganic particles having dielectric properties include silica glass, alumina, aluminum nitride, and barium titanate, and inorganic particles having piezoelectric properties include lead zirconate titanate.

However, in order to shape the inorganic particles into a desired shape, a firing process is required, and mechanical processing is generally performed after firing. As such, since inorganic particles have no plasticity, it is difficult to obtain a molded article having a complicated shape, and thus, there is a drawback in that the degree of freedom of molding is insufficient. In addition, compared to plastics, the molding process is complicated, productivity is lowered, and molding cost is expensive at the same time. Therefore, there is a need for a technique for imparting flexibility to inorganic particles having dielectric properties and piezoelectric properties without affecting piezoelectric properties.

Piezoelectric or pyroelectric polymer materials including polyvinylidene fluoride (PVDF) are very flexible, lightweight, and have a wide vibration range, so they are being widely applied to flat speakers, various switches, medical sensors, space and aviation materials, etc. , it has a low dielectric constant and low electromechanical coupling coefficient, which has several limitations in its use.

Accordingly, a method for manufacturing an extrusion or injection-molded product that can be applied to various piezoelectric elements by mixing and composing inorganic particles with excellent piezoelectric properties and a polymer material such as plastic with excellent moldability is being developed. The plastic/ceramic composite material is manufactured by dispersing inorganic particles in a matrix made of plastic, and since it is made by dispersing inorganic particles in plastic, it is easy to mold and can be manufactured inexpensively.

For such a plastic/ceramic composite, it is very important to uniformly mix the inorganic particles with the plastic, because uniform mixing minimizes voids and improves the mechanical properties of the piezoelectric body.

On the other hand, inorganic oxides such as barium titanate, tellulium, zinc oxide, etc. have a high dielectric constant, but the size of single particles is small, so it is difficult to exist in the form of single particles. ), it is not well dispersed in the polymer matrix, the molding process is difficult and productivity is low, and it is difficult to form a thin film through electrospinning or solution process.

Therefore, there was a need to develop lipophilic piezoelectric nano-inorganic particles and their manufacturing technology in which these problems are solved.

Patent Registration No. 10-1974579

Therefore, it is an object of the present invention to improve the dispersibility of the piezoelectric inorganic nanoparticles in the PVDF-based polymer resin, which is a core-shell structure lipophilic piezoelectric organic-inorganic coated with a PVDF-based polymer on the surface of the piezoelectric inorganic nanoparticles. To provide composite nanoparticles.

Another object of the present invention is a nonsolvent-induced phase separation (NIPS) method using a difference in solubility index of a solvent so that an efficient process can be performed by increasing dispersibility with a polymer matrix through organicization of the surface of piezoelectric inorganic nanoparticles. It is to provide a method for producing piezoelectric organic-inorganic composite nanoparticles by which a PVDF-based polymer can be uniformly coated on the surface of the piezoelectric inorganic nanoparticles.

Another object of the present invention is to increase the dispersibility with the PVDF-based polymer resin by including the lipophilic piezoelectric organic-inorganic hybrid nanoparticles. To provide a PVDF-based polymer thin film containing piezoelectric organic-inorganic hybrid nanoparticles that can satisfy both malleability and excellent moldability and various piezoelectric application products including the same.

The object of the present invention is not limited to the above-mentioned object, and even if not explicitly mentioned, the object of the invention that can be recognized by a person of ordinary skill in the art from the description of the detailed description of the invention to be described later may also be included. .

In order to achieve the above object of the present invention, the present invention is piezoelectric inorganic nanoparticles; And a piezoelectric polymer coating layer formed on the surface of the piezoelectric inorganic nanoparticles; piezoelectric organic-inorganic hybrid nanoparticles comprising a.

In a preferred embodiment, the piezoelectric inorganic nanoparticles are at least one selected from the group consisting of BaTiO ₃ , PZT, PLZT, SBT, BST, and binary oxides of TeO, ZnO, MgO, and CdO.

In a preferred embodiment, the piezoelectric polymer is vinylidene-fluoride (VDF), trifluoroethylene (TrFE, trifluoroethylene), tetrafluoroethylene (TFE, tetrafluoroethylene), tetrafluoroethylene (TFE, tetrafluoroethylene) ), vinyl fluoride (VF, vinyl fluoride), perfluoromethyl vinyl ether (PEVE, perfluoro (methyl vinyl ether)), chlorotrifluoroethylene (CTFE, chlorotrifluoroethylene) at least two monomers selected from the group consisting of It is a PVDF-based polymer containing.

In a preferred embodiment, the piezoelectric inorganic nanoparticles have a particle size of 100 nm or less, and the polymer coating layer is formed to a thickness of 4 to 10 nm.

In a preferred embodiment, the polymer coating layer includes two or more coating films formed of different polymers.

In addition, the present invention comprises the steps of using an organic solvent 1 to prepare a dispersion solution 1 in which piezoelectric inorganic nanoparticles are dispersed and a dispersion solution 2 in which a PVDF-based polymer is dispersed; preparing a dispersion solution 3 in which the piezoelectric inorganic nanoparticles and the PVDF-based polymer are dispersed in the organic solvent 1 by mixing the dispersion solution 1 and the dispersion solution 2; obtaining a dispersion solution 4 containing the precursor piezoelectric organic-inorganic composite nanoparticles formed by treating the organic solvent 2, which is a non-solvent of the PVDF-based polymer, with the dispersion solution 3; obtaining a dispersion solution 5 containing piezoelectric organic-inorganic composite nanoparticles formed by evaporating and removing the organic solvent 1 from the dispersion solution 4; and separating the piezoelectric organic-inorganic composite nanoparticles from the dispersion solution 5; piezoelectric organic-inorganic hybrid nanoparticles comprising a method is provided.

In a preferred embodiment, the difference in solubility index between the organic solvent 1 and the organic solvent 2 is 5 or less.

In a preferred embodiment, the organic solvent 1 is DMF (N,N-dimethyl formamide), MEK (methyl ethyl ketone), NMP (N-Methyl-2-pyrrolidone), DME (dimethyl ether) and 1,4-Dioxane (1,4-Diethyleneoxide) is any one selected from the group consisting of, and the organic solvent 2 is an ethanol-based organic solvent.

In a preferred embodiment, in the precursor piezoelectric organic-inorganic hybrid nanoparticles, the PVDF-based polymer dispersed in the organic solvent 1 is phase-separated into the piezoelectric inorganic nanoparticles by the organic solvent 2, so that the piezoelectric inorganic nanoparticles are the core and the It is formed in a core-shell structure with a coating layer formed by coating a phase-separated PVDF-based polymer on the surface as a shell.

In a preferred embodiment, the organic-inorganic hybrid nanoparticles are further added to the coating layer constituting the shell of the precursor piezoelectric organic-inorganic hybrid nanoparticles when the residual PVDF polymer remaining without phase separation in the organic solvent 1 evaporates the organic solvent 1 coated and formed.

In a preferred embodiment, the separating comprises centrifuging the dispersion solution 5; washing the piezoelectric organic-inorganic hybrid nanoparticles precipitated in the centrifugation step with organic solvent 2; and drying the washed piezoelectric organic-inorganic hybrid nanoparticles.

In a preferred embodiment, in the dispersion solution 3, the piezoelectric inorganic nanoparticles are included in an amount of 1 to 30% by weight.

In a preferred embodiment, the piezoelectric inorganic nanoparticles are at least one selected from the group consisting of BaTiO ₃ , PZT, PLZT, SBT, BST, and binary oxides of TeO, ZnO, MgO, and CdO, and the PVDF-based polymer is vinylidene. Fluoride (VDF, vinylidene- fluoride), trifluoroethylene (TrFE, trifluoroethylene), tetrafluoroethylene (TFE, tetrafluoroethylene), tetrafluoroethylene (TFE, tetrafluoro ethylene), vinyl fluoride (VF, vinyl fluoride) , Perfluoromethyl vinyl ether (PEVE, perfluoro (methyl vinyl ether)), chlorotrifluoroethylene (CTFE, chlorotrifluoroethylene) is a polymer containing two or more monomers selected from the group consisting of.

In addition, the present invention is characterized in that any one of the above-mentioned piezoelectric organic-inorganic hybrid nanoparticles or the piezoelectric organic-inorganic hybrid nanoparticles prepared by any one of the above-mentioned manufacturing methods are uniformly dispersed in a PVDF-based polymer resin solution. Provided is a PVDF-based polymer resin solution containing piezoelectric organic-inorganic hybrid nanoparticles.

In addition, the present invention is obtained by forming the above-mentioned piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer resin solution into a film, and thus has a structure in which the piezoelectric organic-inorganic hybrid nanoparticles are uniformly dispersed in a PVDF-based polymer matrix. It provides a PVDF-based polymer thin film containing piezoelectric organic-inorganic hybrid nanoparticles.

In addition, the present invention provides a piezoelectric application product comprising the above-described piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film.

In a preferred embodiment, the piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film is formed by stacking two or more layers.

In a preferred embodiment, the piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film is included to be positioned between the thin film made of PDMS or Eco-flex.

In a preferred embodiment, the piezoelectric application product is any one selected from the group consisting of a piezoelectric sensor, a piezoelectric generator, and a smart insole capable of self-generation.

The piezoelectric organic-inorganic hybrid nanoparticles of the present invention described above can improve the dispersibility poor in the PVDF-based polymer resin of the piezoelectric inorganic nanoparticles through the core-shell structure coated with the PVDF-based polymer on the surface of the piezoelectric inorganic nanoparticles. has lipophilicity.

In addition, according to the method for producing piezoelectric organic-inorganic composite nanoparticles of the present invention, PVDF-based polymers are uniform on the surface of piezoelectric inorganic nanoparticles through a nonsolvent-induced phase separation (NIPS) method using a difference in solubility index of a solvent. Therefore, it is possible to prepare piezoelectric organic-inorganic composite nanoparticles that can be efficiently processed by increasing the dispersibility with the polymer matrix through organicization of the surface of the piezoelectric inorganic nanoparticles.

In addition, the PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles of the present invention and various piezoelectric application products including the same can increase dispersibility with the PVDF-based polymer resin by including the lipophilic piezoelectric organic-inorganic hybrid nanoparticles. , by taking advantage of the high dielectric properties of piezoelectric inorganic nanoparticles and the moldability of PVDF polymers, both high dielectric properties and excellent moldability can be satisfied.

These technical effects of the present invention are not limited only to the range mentioned above, and even if not explicitly mentioned, the effect of the invention that can be recognized by those of ordinary skill in the art from the description of the specific content for the implementation of the invention to be described later is also of course included

1 is a sequence of nano-coating method with PVDF-TrFE of inorganic piezoelectric particles according to the present invention.
Figure 2 shows the cloud point through the ternary division between DMF, a goog-solvent, and Octanol, a non-solvent, of PVDF-TrFE.
3 shows FT-IR data of PVDF-TrFE, BaTiO ₃ (BTO), which are materials used for nano-coating, and FT-IR of BTO nano-coated with PVDF-TrFE.
4 is a TEM image before and after the piezoelectric inorganic nanoparticles are nano-coated with PVDF-TrFE.
Figure 5 shows the XRD pattern analysis of the nano-coated BTO and the nano-coated BTO is not progressed.
6 shows TGA data of PVDF-TrFE, BaTiO ₃ (BTO), which are materials used for nano-coating, and TGA data of BTO, nano-coated with PVDF-TrFE.
7 shows a piezoelectric nano-self-generator in which nano-coated BTO is dispersed in a PVDF-TrFE polymer matrix to form a film, copper electrodes are placed up and down, and then insulated with PDMS, a flexible material.
Figure 8 shows the piezoelectric data of a PVDF-TrFE film without BTO, a film made by mixing BTO without nano-coating in a PVDF-TrFE polymer matrix, and a film made by mixing BTO with nano-coating in a PVDF-TrFE polymer matrix comparison is shown.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the description of the invention is present, but one or more other It should be understood that it does not preclude the possibility of addition or presence of features or numbers, steps, operations, components, parts, or combinations thereof.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention. does not

In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description. In particular, when the terms "about", "substantially", etc. of degree are used, they may be construed as being used in a sense at or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented. .

In the case of a description of a temporal relationship, for example, if the temporal relationship is described as 'after', 'following', 'after', 'before', etc., 'immediately' or 'directly' This includes cases that are not continuous unless ' is used.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein, and like reference numerals indicate like elements in different forms.

The technical feature of the present invention is that the piezoelectric oil having lipophilicity can improve the dispersibility poor in the PVDF-based polymer resin of the piezoelectric inorganic nanoparticles through the core-shell structure coated with the PVDF-based polymer on the surface of the piezoelectric inorganic nanoparticles. -Piezoelectric organic-inorganic composite in which PVDF-based polymer can be uniformly coated on the surface of piezoelectric inorganic nanoparticles through nonsolvent-induced phase separation (NIPS) method using the difference in solubility index of inorganic composite nanoparticles and solvents Dispersibility with PVDF-based polymer resin can be increased by including nanoparticle manufacturing method and lipophilic piezoelectric organic-inorganic composite nanoparticles. There is a PVDF-based polymer thin film containing piezoelectric organic-inorganic hybrid nanoparticles that can satisfy both excellent moldability and piezoelectric application products.

That is, currently, lipophilic inorganic piezoelectric particles are being studied for various purposes and forms in the fields of electronic materials, optical materials, sensors, and composite hybrid materials. It is a composite made by mixing the high piezoelectric properties of inorganic nanoparticles with the advantages of moldability and ease of processing of polymer resins. Until now, it is mainly made by sequentially stacking piezoelectric inorganic nanoparticle layers and polymer layers, or piezoelectric inorganic nanoparticles. This is because there has been no attempt to coat the surface of the piezoelectric inorganic nanoparticles with a polymer, except that there is known a technique for producing it by adding and dispersing it to a molten polymer resin. On the other hand, in order to modify the surface of inorganic nanoparticles to be lipophilic, a method of chemically bonding the surface through a functional group of a monomolecular material, a surface modification method through adsorption using the electrostatic attraction of a functional group, a sol-gel (sol-gel) Although a method of surface modification through gel) reaction is known, in this case, when dispersed in the polymer matrix, the polymer matrix is dispersed and the inorganic nanoparticles are selectively dispersed depending on the functional group used to modify the surface. There is a problem that the materials that can be used are limited.

Therefore, the piezoelectric organic-inorganic hybrid nanoparticles of the present invention include piezoelectric inorganic nanoparticles; and a piezoelectric polymer coating layer formed on the surface of the piezoelectric inorganic nanoparticles.

Here, the piezoelectric inorganic nanoparticles are not limited as long as they are inorganic particles having piezoelectricity, but in one embodiment, BaTiO ₃ , PZT, PLZT, SBT, BST and one selected from the group consisting of binary oxides of TeO, ZnO, MgO, and CdO may be more than They are particularly difficult to use with current technology due to their small particle size and very poor dispersibility in PVDF-based polymer resins. .

The piezoelectric polymer is not limited as long as it is a polymer having piezoelectricity, but vinylidene fluoride (VDF, vinylidene-fluoride), trifluoroethylene (TrFE, trifluoroethylene), tetrafluoroethylene (TFE, tetrafluoroethylene), tetrafluoroethylene ( 2 selected from the group consisting of TFE, tetrafluoroethylene), vinyl fluoride (VF, vinyl fluoride), perfluoromethyl vinyl ether (PEVE, perfluoro(methyl vinyl ether)), and chlorotrifluoroethylene (CTFE, chlorotrifluoroethylene) It may be a PVDF-based polymer containing the above monomers.

In the piezoelectric organic-inorganic composite nanoparticles of the present invention, the piezoelectric inorganic nanoparticles may have a particle size of 100 nm or less, and the polymer coating layer may be formed to a thickness of 4 to 10 nm. When the polymer coating layer is formed to be less than 4 nm, there is a problem that the BTO particles are damaged and barium vacancies are generated when the TEM electron beam is applied. This is because there is a problem with the aggregation of BTO particles. If necessary, the polymer coating layer may be formed in a structure including two or more coating films formed of different polymers.

Next, the method for producing piezoelectric organic-inorganic composite nanoparticles of the present invention comprises the steps of using an organic solvent 1 to prepare a dispersion solution 1 in which piezoelectric inorganic nanoparticles are dispersed and a dispersion solution 2 in which a PVDF-based polymer is dispersed; preparing a dispersion solution 3 in which the piezoelectric inorganic nanoparticles and the PVDF-based polymer are dispersed in the organic solvent 1 by mixing the dispersion solution 1 and the dispersion solution 2; obtaining a dispersion solution 4 containing the precursor piezoelectric organic-inorganic composite nanoparticles formed by treating the organic solvent 2, which is a non-solvent of the PVDF-based polymer, with the dispersion solution 3; obtaining a dispersion solution 5 containing piezoelectric organic-inorganic composite nanoparticles formed by evaporating and removing the organic solvent 1 from the dispersion solution 4; and separating the piezoelectric organic-inorganic composite nanoparticles from the dispersion solution 5.

Here, the difference in solubility index between the organic solvent 1 and the organic solvent 2 may be 5 or less. This difference in solubility index is because the polymer coating layer must be formed through a nonsolvent-induced phase separation (NIPS) method.

Therefore, organic solvent 1 is not limited as long as both piezoelectric inorganic nanoparticles and PVDF-based polymers can be dispersed, and the difference in solubility index with organic solvent 2 is 5 or less, but as an embodiment, DMF (N,N-dimethylformamide), It may be any one selected from the group consisting of MEK (methyl ethyl ketone), NMP (N-Methyl??2-pyrrolidone), DME (dimethyl ether) and 1,4-Dioxane (1,4-Diethyleneoxide), and organic Solvent 2 may be an ethanol-based organic solvent.

Dispersion in which the piezoelectric inorganic nanoparticles are dispersed by dissolving and/or dispersing the above-mentioned any one of the piezoelectric inorganic nanoparticles and the above-mentioned any one of the PVDF-based polymers in a certain amount, respectively, in any one of the above-mentioned organic solvent 1 Solution 1 and dispersion solution 2 in which the PVDF-based polymer is dispersed can be prepared. Here, the content of the piezoelectric inorganic nanoparticles included in the dispersion solution 1 may be determined such that the content of the piezoelectric inorganic nanoparticles in the dispersion solution 3 obtained by mixing the dispersion solution 1 and the dispersion solution 2 is 1 to 30% by weight. At this time, when the piezoelectric inorganic nanoparticles have a size of 100 nm or less, they are easily agglomerated with each other to form aggregation, so they are sufficiently dispersed using a sonicator in the selected organic solvent.

Dispersion solution 3 can be prepared by mixing dispersion solution 1 and dispersion solution 2, and since the solvents of dispersion solution 1 and dispersion solution 2 are the same, mix dispersion solution 1 and dispersion solution 2 and mix well to form piezoelectric inorganic nanoparticles A dispersion solution 3 in which the PVDF-based polymer is dispersed in the organic solvent 1 can be obtained.

The step of obtaining the dispersion solution 4 is performed by treating the organic solvent 2, which is a non-solvent of the PVDF-based polymer, with the dispersion solution 3, and the dispersion solution 4 may include the precursor piezoelectric organic-inorganic composite nanoparticles. That is, when the organic solvent 2 is added dropwise to the dispersion solution 3, the PVDF-based polymer dispersed in the organic solvent 1 is phase-separated into piezoelectric inorganic nanoparticles by the organic solvent 2, so that the piezoelectric inorganic nanoparticles are the core and the PVDF-based phase separated on the surface. This is because the precursor piezoelectric organic-inorganic composite nanoparticles can be obtained by forming a core-shell structure with the coating layer formed by coating the polymer as the shell.

More specifically, as an embodiment, when organic solvent 1 is selected as DMF, the difference in solubility index from organic solvent 1 is 5 or less, and organic solvent 2, which is a non-solvent of PVDF polymer, can select octanol, to obtain dispersion solution 4 To this end, when octanol is added dropwise to the dispersion solution 3, the PVDF-based polymer dispersed in DMF is phase-separated into piezoelectric inorganic nanoparticles to form a nano coating layer.

As shown in Fig. 2, since the outside of the ternary cloud point is a miscible region and the inside is an immiscible region, it is necessary to select the components of the immiscible region so that the PVDF-based polymer is precipitated. Therefore, when octanol is selected as organic solvent 2, the solubility parameter of DMF is 20.72 and the solubility parameter of octanol is 21.0, which is a difference of 5 or less, so DMF and octanol are mixed well, When octanol, the organic solvent 2, is added dropwise to the dispersion solution 3, which is a mixed polymer solution, the PVDF-based polymer dispersed in the DMF is phase-separated on the surface of the piezoelectric inorganic nanoparticles to form a nano coating.

The step of obtaining the dispersion solution 5 may be performed to include the piezoelectric organic-inorganic composite nanoparticles formed by evaporating and removing the organic solvent 1 from the dispersion solution 4. The piezoelectric organic-inorganic hybrid nanoparticles may be further coated on the coating layer constituting the shell of the precursor piezoelectric organic-inorganic hybrid nanoparticles when the residual PVDF polymer remaining without phase separation in the organic solvent 1 evaporates the organic solvent 1. As an embodiment, if the organic solvents 1 and 2 are DMF and octanol, respectively, as described above, their boiling points are 153°C and 195°C, respectively. DMF can be removed by evaporation. At this time, PVDF-based polymer remaining in DMF without nonsolvent phase separation is coated on the surface of piezoelectric inorganic nanoparticles as DMF evaporates to form piezoelectric organic-inorganic hybrid nanoparticles.

Separating the piezoelectric organic-inorganic hybrid nanoparticles from the dispersion solution 5 includes centrifuging the dispersion solution 5; washing the piezoelectric organic-inorganic hybrid nanoparticles precipitated in the centrifugation step with organic solvent 3 (ethanol); and drying the washed piezoelectric organic-inorganic hybrid nanoparticles. As described above, washing and drying using a solvent belonging to organic solvent 3 having a low boiling point was more preferable for forming the nano-coating film.

Next, the PVDF-based polymer resin solution containing the piezoelectric organic-inorganic hybrid nanoparticles of the present invention is one in which any one of the above-described piezoelectric organic-inorganic hybrid nanoparticles is uniformly dispersed in the PVDF-based polymer resin solution, and as described above, the piezoelectric Since organic-inorganic hybrid nanoparticles have lipophilic properties, they can be easily obtained by simply adding piezoelectric organic-inorganic hybrid nanoparticles to a PVDF-based resin solution obtained by dissolving a PVDF-based polymer in a specific solvent and stirring.

Next, since the PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles of the present invention is obtained by forming a film of the above-described PVDF-based polymer resin solution containing the piezoelectric organic-inorganic hybrid nanoparticles, the piezoelectric organic-inorganic hybrid in the PVDF-based polymer matrix It has a structure in which nanoparticles are uniformly dispersed. Here, any known method may be used for film forming, and as an embodiment, solvent casting or electrospinning may be used.

Next, the piezoelectric application product of the present invention includes the above-described PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles, and the PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles can be formed by stacking two or more layers. In addition, a PVDF-based polymer thin film containing piezoelectric organic-inorganic hybrid nanoparticles may be included to be positioned between the thin films made of PDMS (Poly Dimethyl Siloxane) or Eco-flex (Smooth-On Inc., USA).

As an embodiment of the piezoelectric application product of the present invention, it may be any one selected from the group consisting of a piezoelectric sensor, a piezoelectric generator, and a smart insole capable of self-generation. That is, the PVDF-based polymer thin film containing piezoelectric organic-inorganic composite nanoparticles of the present invention can be applied as a piezoelectric sensor, a piezoelectric generator, and a smart insole capable of self-generation by itself or in combination with other elements. .

Example 1

Through the process as shown in Figure 1, piezoelectric organic-inorganic hybrid nanoparticles 1 were prepared as follows.

1. Dispersion solution 1 (101) and dispersion solution 2 (102) preparation steps

Dispersion solution 1 was prepared by dispersing 1 g of barium titanate (IV) (BaTiO ₃ , average particle size less than 100 nm; BTO) in 60 g of N,N-Dimethyl Formamide (DMF) for 4 hours using sonicators. Dispersion solution 2 was prepared by stirring 0.5 g of P(VDF-TrFE) in 6.7 g of N,N-Dimethyl Formamide (DMF) at 60°C and 400 rpm.

2. Dispersion solution 3 to dispersion solution 5 and piezoelectric organic-inorganic hybrid nanoparticle manufacturing step (103)

After mixing the dispersion solution 1 and the dispersion solution 2, the dispersion solution 3 was prepared by stirring at 60°C and 400 rpm for 24 h. Thereafter, 66.7 g of 1-Octanol was added dropwise to the stirring dispersion solution 3 with a burette, and after the dropping was completed, the dispersion solution 4 was prepared by stirring for 24 h. Dispersion solution 4 was treated at 175℃ and 400rpm, and N,N-Dimethyl Formamide (DMF) was evaporated to obtain dispersion solution 5. (Boiling point of N,N-Dimethyl Formamide: 153℃ Boiling point of 1-Octanol: 195℃) Dispersion solution 5 was centrifuged at 3000rpm for 10min to separate precipitated piezoelectric organic-inorganic hybrid nanoparticles 1, and piezoelectric organic-inorganic hybrid nanoparticles 1 were washed three times with ethyl alcohol and then reduced pressure to remove ethyl alcohol and residual 1- Octanol was removed and dried to prepare piezoelectric organic-inorganic hybrid nanoparticles 1 (BTO/PVDF-TrFE coat powder).

Example 2

Piezoelectric organic-inorganic composite nanoparticles 2 were prepared in the same manner as in Example 1, except that Tellurium (average particle size 100 nm) particles were used instead of Barium titanate particles (BTO) as piezoelectric nano-inorganic particles.

Example 3

Piezoelectric organic-inorganic composite nanoparticles 3 were prepared in the same manner as in Example 1, except that zinc oxide (average particle size 100 nm or less) particles were used instead of barium titanate particles (BTO) as piezoelectric nano-inorganic particles.

Example 4

Piezoelectric organic-inorganic composite nanoparticles 1 obtained in Example 1 were stirred for 2 hours at 300 RPM at 90° C. in a solution prepared by dispersing P(VDF-TrFE) in organic solvent 1 for 2 hours to contain piezoelectric organic-inorganic composite nanoparticles A PVDF-based polymer resin solution was prepared.

Example 5

Using the PVDF-based polymer resin solution containing the piezoelectric organic-inorganic hybrid nanoparticles obtained in Example 4, the doctor blade was set at 100 μm intervals, and the above-mentioned PVDF-based polymer resin solution containing the piezoelectric organic-inorganic composite nanoparticles was used by solvent-casting method. was formed into a film on a glass plate at a constant thickness, annealed at 150°C for 2 hours, the temperature was reduced by 0.2°C per minute for 10 hours, and the film was dried to 30°C. PVDF containing piezoelectric organic-inorganic hybrid nanoparticles A polymer-based thin film (BTO/PVDF-TrFE coating film) was prepared.

Example 6

Using the piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film (BTO/PVDF-TrFE coating film) obtained in Example 5, a piezoelectric nano-self-generator having the structure shown in FIG. 7 was manufactured.

Comparative Example 1

A PVDF-TrFE film was prepared in the same manner as in Example 5, except that a PVDF-TrFE polymer resin solution was used instead of a PVDF-based polymer resin solution containing piezoelectric organic-inorganic hybrid nanoparticles.

Comparative Example 2

BTO/PVDF-TrFE non-coating was performed in the same manner as in Example 5, except that a PVDF-TrFE polymer resin solution containing only BTO, a piezoelectric inorganic particle, was used instead of a PVDF-based polymer resin solution containing piezoelectric organic-inorganic hybrid nanoparticles. Film was prepared.

Comparative Example 3

Comparative Example piezoelectric nano self-generator in the same manner as in Example 6, except that a BTO/PVDF-TrFE non-coating film was used instead of a PVDF-based polymer thin film containing piezoelectric organic-inorganic hybrid nanoparticles (BTO/PVDF-TrFE coating film) 2 was prepared.

Comparative Example 4

A piezoelectric nano self-generator 1 of Comparative Example was prepared in the same manner as in Example 6 except that a PVDF-TrFE film, not a PVDF-based polymer thin film (BTO/PVDF-TrFE coating film) containing piezoelectric organic-inorganic hybrid nanoparticles was used.

Experimental Example 1

PVDF-TrFE, BaTiO ₃ (BTO) and piezoelectric organic-inorganic hybrid nanoparticles 1 (BTO/PVDF-TrFE coating powder) used to obtain piezoelectric organic-inorganic hybrid nanoparticles 1 in Example 1 were subjected to FT-IR Spectroscopy. The measured peak was analyzed using and the results are shown in FIG. 3 .

The FT-IR data shown in Figure 3 shows the β-phase (840, 1280 and 1431 cm ^-1 ) peaks involved in the piezoelectric output of PVDF-TrFE and the vibrational peaks (540, 860, 1421 cm ^-1 ) of BTO. 3 and in the case of BTO nano-coated with PVDF-TrFE, 840, 1280, and 1431 cm ^-1 peaks, the β-phase peaks of PVDF-TrFE, which were not seen in BTO before surface modification, were clearly displayed. 540, 1280 and 1421 cm ^-1 were also confirmed, and the observation of the PVDF-TrFE peak, which did not appear in BTO before surface modification, shows that the polymer layer is well coated and stably maintained even after nano-coating.

Experimental Example 2

The BaTiO ₃ (BTO) used in Example 1 and the finally obtained piezoelectric organic-inorganic hybrid nanoparticles 1 were observed by TEM, and a photograph of the result is shown in FIG. 4 . The left is a photograph of BaTiO ₃ (BTO), and the right is a photograph of the piezoelectric organic-inorganic hybrid nanoparticles 1.

From FIG. 4, it can be observed that the polymer coating layer is uniformly formed on the surface of the BTO with a thickness of 4.157 nm.

Experimental Example 3

The XRD patterns of BaTiO ₃ (BTO) used in Example 1 and finally obtained piezoelectric organic-inorganic hybrid nanoparticles 1 were analyzed, and the result graph is shown in FIG. 5 .

From FIG. 5, the diffraction peaks [(100), (110), (111), (200), (210) in the tetragonal phase of BTO observed the crystal structure of BTO@PVDF-TrFE and BTO nanoparticles using the XRD pattern. , (211), (220), (222), (103)], and even after the nano-coating process, the diffraction peak indicating the crystallinity of the BTO@PVDF-TrFE nanoparticles is the diffraction peak of the bare BTO. It was confirmed that the nano-coating process did not damage the crystallinity of BTO.

Experimental Example 4

PVDF-TrFE, BaTiO ₃ (BTO) and piezoelectric organic-inorganic hybrid nanoparticle 1 (BTO/PVDF-TrFE coat powder) used to obtain piezoelectric organic-inorganic hybrid nanoparticles 1 in Example 1 were analyzed by thermogravimetric analysis. Analysis, TGA) was used to investigate the TGA data, and a graph of the results is shown in FIG. 6 .

From Figure 6 to 800 ℃, PVDF-TrFE, BTO, and nanoparticle 1 (BTO / PVDF-TrFE coating powder) weight loss was confirmed whether the nano coating was well, PVDF-TrFE about 90% loss and BTO about 3% was lost, and it was confirmed that about 26% of Nanoparticle 1 was lost, indicating that the nano-coating was good.

Experimental Example 5

Obtained in Example 5. PVDF-based polymer thin film containing piezoelectric organic-inorganic composite nanoparticles (BTO/PVDF-TrFE coat Film), PVDF-TrFE Film and BTO/PVDF-TrFE non- obtained in Comparative Examples 1 and 2, respectively In order to measure the piezoelectricity of the nano-piezoelectric generators each made of a coating film, self-manufactured compression/releasing of the piezoelectric nano-self-generators obtained in Example 6 and Comparative Pre-piezoelectric nano-self-generators 1 and 2 obtained in Comparative Examples 3 and 4 The piezoelectric data was measured by applying a strain to the nano piezoelectric generator with a constant pressure force and the same frequency with a machine, and the results are shown in FIG. 8 .

From FIG. 8, the nano piezoelectric generator made of PVDF-based polymer thin film (BTO/PVDF-TrFE coating film) containing piezoelectric organic-inorganic hybrid nanoparticles obtained in Example 5 was PVDF-TrFE obtained in Comparative Example 1 and Comparative Example 2, respectively. The output voltage was about 4.5 times and 1.9 times higher than that of the nano piezoelectric generator made of film and BTO/PVDF-TrFE non-coating film, respectively.

From the above experimental results, it can be seen that according to the present invention, a piezoelectric thin film and a piezoelectric nano self-generator with higher performance can be manufactured by increasing the dispersibility of inorganic piezoelectric nanoparticles through nano-coating.

Therefore, the piezoelectric organic-inorganic hybrid nanoparticles of the present invention have remarkably improved dispersibility in PVDF-based polymer resin solutions by securing lipophilicity. will be able

Although the present invention has been illustrated and described with reference to preferred embodiments as described above, it is not limited to the above-described embodiments, and those of ordinary skill in the art to which the present invention pertains within the scope not departing from the spirit of the present invention Various changes and modifications will be possible.

Claims (19)

piezoelectric inorganic nanoparticles; and
It includes; a piezoelectric polymer coating layer formed on the surface of the piezoelectric inorganic nanoparticles;
In the piezoelectric polymer coating layer, the piezoelectric polymer dispersed in organic solvent 1 without a separate functional group layer connecting the piezoelectric inorganic nanoparticles and the piezoelectric polymer coating layer is phase-separated into the piezoelectric inorganic nanoparticles by the organic solvent 2. Piezoelectric organic-inorganic hybrid nanoparticles, characterized in that the difference in solubility index between the organic solvent 1 and the organic solvent 2 is 5 or less.
The method of claim 1,
The piezoelectric inorganic nanoparticles are piezoelectric organic-inorganic hybrid nanoparticles, characterized in that at least one selected from the group consisting of BaTiO ₃ , PZT, PLZT, SBT, BST, and binary oxides of TeO, ZnO, MgO, and CdO.
The method of claim 1,
The piezoelectric polymer is vinylidene fluoride (VDF, vinylidene-fluoride), trifluoroethylene (TrFE, trifluoroethylene), tetrafluoroethylene (TFE, tetrafluoroethylene), vinyl fluoride (VF, vinyl fluoride), perfluoromethyl Piezoelectric organic-inorganic hybrid nano, characterized in that it is a PVDF-based polymer comprising two or more monomers selected from the group consisting of vinyl ether (PEVE, perfluoro (methyl vinyl ether)) and chlorotrifluoroethylene (CTFE, chlorotrifluoroethylene) particle.
The method of claim 1,
The piezoelectric inorganic nanoparticles have a particle size of 100 nm or less, and the piezoelectric polymer coating layer is formed to a thickness of 4 to 10 nm. Piezoelectric organic-inorganic hybrid nanoparticles.
The method of claim 1,
The piezoelectric polymer coating layer is piezoelectric organic-inorganic hybrid nanoparticles, characterized in that it comprises two or more coating films formed of different polymers.
using an organic solvent 1 to prepare a dispersion solution 1 in which piezoelectric inorganic nanoparticles are dispersed and a dispersion solution 2 in which a PVDF-based polymer is dispersed;
preparing a dispersion solution 3 in which the piezoelectric inorganic nanoparticles and the PVDF-based polymer are dispersed in the organic solvent 1 by mixing the dispersion solution 1 and the dispersion solution 2;
obtaining a dispersion solution 4 containing the precursor piezoelectric organic-inorganic composite nanoparticles formed by dropping and stirring the organic solvent 2, which is a non-solvent of the PVDF-based polymer, into the dispersion solution 3;
obtaining a dispersion solution 5 containing piezoelectric organic-inorganic composite nanoparticles formed by evaporating and removing the organic solvent 1 from the dispersion solution 4; and
Separating the piezoelectric organic-inorganic composite nanoparticles from the dispersion solution 5; piezoelectric organic-inorganic hybrid nanoparticle manufacturing method comprising a.
7. The method of claim 6,
Piezoelectric organic-inorganic hybrid nanoparticle manufacturing method, characterized in that the organic solvent 1 and the organic solvent 2 have a solubility index difference of 5 or less.
8. The method of claim 7,
The organic solvent 1 is DMF (N,N-dimethylformamide), MEK (methyl ethyl ketone), NMP (N-Methyl-2-pyrrolidone), DME (dimethyl ether) and 1,4-Dioxane (1,4-Diethyleneoxide) Any one selected from the group consisting of
The organic solvent 2 is a piezoelectric organic-inorganic hybrid nanoparticle manufacturing method, characterized in that the ethanol-based organic solvent.
7. The method of claim 6,
The precursor piezoelectric organic-inorganic hybrid nanoparticles are PVDF-based polymers dispersed in the organic solvent 1 are phase-separated into piezoelectric inorganic nanoparticles by the organic solvent 2, so that the piezoelectric inorganic nanoparticles are the core and phase-separated PVDF-based nanoparticles on the surface A piezoelectric organic-inorganic hybrid nanoparticle manufacturing method, characterized in that it is formed in a core-shell structure having a coating layer formed by coating a polymer as a shell.
7. The method of claim 6,
The organic-inorganic hybrid nanoparticles are further coated on the coating layer constituting the shell of the precursor piezoelectric organic-inorganic hybrid nanoparticles when the residual PVDF polymer remaining without phase separation in the organic solvent 1 evaporates the organic solvent 1. A piezoelectric organic-inorganic hybrid nanoparticle manufacturing method.
7. The method of claim 6,
The separating may include centrifuging the dispersion solution 5; washing the piezoelectric organic-inorganic hybrid nanoparticles precipitated in the centrifugation step with organic solvent 2; and drying the washed piezoelectric organic-inorganic hybrid nanoparticles.
7. The method of claim 6,
In the dispersion solution 3, the piezoelectric inorganic nanoparticles are included in an amount of 1 to 30% by weight, piezoelectric organic-inorganic hybrid nanoparticle manufacturing method.
7. The method of claim 6,
The piezoelectric inorganic nanoparticles are at least one selected from the group consisting of BaTiO ₃ , PZT, PLZT, SBT, BST, and binary oxides of TeO, ZnO, MgO, and CdO,
The PVDF-based polymer is vinylidene fluoride (VDF, vinylidene- fluoride), trifluoroethylene (TrFE, trifluoroethylene), tetrafluoroethylene (TFE, tetrafluoro ethylene), vinyl fluoride (VF, vinyl fluoride), perfluoro Piezoelectric organic-inorganic hybrid nano, characterized in that it is a polymer containing two or more monomers selected from the group consisting of methyl vinyl ether (PEVE, perfluoro (methyl vinyl ether)) and chlorotrifluoroethylene (CTFE, chlorotrifluoroethylene) Particle manufacturing method.
The piezoelectric organic-inorganic hybrid nanoparticles of any one of claims 1 to 5 or the piezoelectric organic-inorganic hybrid nanoparticles prepared by the method of any one of claims 6 to 13 are uniform in the PVDF-based polymer resin solution. A PVDF-based polymer resin solution containing piezoelectric organic-inorganic hybrid nanoparticles, characterized in that it is dispersed.
The piezoelectric oil, characterized in that it has a structure in which the piezoelectric organic-inorganic hybrid nanoparticles are uniformly dispersed in a PVDF-based polymer matrix because it is obtained by forming the PVDF-based polymer resin solution containing the piezoelectric organic-inorganic hybrid nanoparticles of claim 14 into a film - PVDF-based polymer thin film containing inorganic hybrid nanoparticles.
The piezoelectric application product comprising the PVDF-based polymer thin film containing the piezoelectric organic-inorganic hybrid nanoparticles of claim 15.
17. The method of claim 16,
The piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film is a piezoelectric application product, characterized in that it is formed by stacking two or more layers.
17. The method of claim 16,
The piezoelectric organic-inorganic hybrid nanoparticle-containing PVDF-based polymer thin film is a piezoelectric application product, characterized in that it is included between the PDMS or Eco-flex thin films.
17. The method of claim 16,
The piezoelectric application product is a piezoelectric application product, characterized in that any one selected from the group consisting of a piezoelectric sensor, a piezoelectric generator, and a smart insole capable of self-generation.

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