KR101477922B1 - Method for preparing piezo-electric material, piezo-electric material prepared by the same, and nanogenerator comprising the piezo-electric material - Google Patents

Abstract

The present invention relates to a method for preparing a piezo-electric material using a virus templet. Provided is a method for preparing a piezo-electric material which includes a step of mixing a barium precursor solution in a virus templet combined with an anion function on a surface; a step of mixing a titanium precursor solution in the mixed precursor solution; and a step of removing the virus templet by firing a material collected from the mixed solution.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a piezoelectric material using a virus-template, a piezoelectric material manufactured thereby, and a nano-generator including the same,

The present invention relates to a method for manufacturing a piezoelectric material using a virus-template, a piezoelectric material manufactured thereby, and a nano-generator including the same. More particularly, the present invention relates to a method for manufacturing a piezoelectric material using a virus- The present invention relates to a method for manufacturing a piezoelectric material using a virus-template capable of producing a piezoelectric material, a piezoelectric material produced thereby, and a nano-generator including the same.

BACKGROUND ART [0002] With the development of information communication, electric devices such as piezoelectric elements and solar cells have become necessary and large-capacity. A piezoelectric element produces power according to the pressure applied to the electric element.

A piezoelectric element means a device exhibiting a piezoelectric phenomenon. The piezoelectric element is also referred to as a piezoelectric element, and quartz, tourmaline, and rochelite have been used as piezoelectric elements since the early days. Recently, barium titanate (BaTiO ₃ , BTO), ammonium dihydrogen phosphate, Artificial crystals such as ethylene ethylenediamine are also excellent in piezoelectricity and can induce more excellent piezoelectric characteristics through doping.

Although BTO is considered to be highly utilizable because it has biocompatibility because it has no lead, the general method of synthesizing the fibrous kraft nanomaterial has the problem of using toxic organic solvent and alkoxide precursor. Furthermore, the resulting nanomaterial is contaminated by polymer residues or surfactants, which in turn has a negative impact on the original properties of the material.

Recently, as an alternative to the conventional art, a new synthesis method based on a biological template using a biological material as a template is disclosed, which can produce an inorganic structure having unique characteristics under normal temperature conditions. For example, DNA, viruses, and micro organisms can be used as templates to control material properties (e.g., composition, crystallinity, phase, morphology, etc.) and to make it environmentally friendly, Technology for use in the process is disclosed. In particular, viruses are used historically as programmable tools to self-assemble nano-sized inorganic structures, which use specific peptide-mediated interactions.

However, a flexible microgenerator having a bio-based stable network, that is, a flexible nano generator, has not yet been launched.

Accordingly, a problem to be solved by the present invention is to provide a piezoelectric material having a bio-based stable network and a nano generator based thereon.

According to an aspect of the present invention, there is provided a method of manufacturing a piezoelectric material using a virus-template, comprising: forming a complex by binding a piezoelectric material precursor solution to a virus-template; And synthesizing a piezoelectric material in the virus-template. The present invention also provides a method of manufacturing a piezoelectric material using the virus-template.

According to an embodiment of the present invention, there is provided a method of manufacturing a piezoelectric material using a virus-template, comprising: mixing a barium precursor solution with a virus template having an anionic functional group or a piezoelectric material-specific functional group bonded to its surface; And mixing the titanium precursor solution with the mixed precursor solution.

In one embodiment of the present invention, the method for manufacturing a piezoelectric material using the virus-template further comprises the step of removing the virus template by calcining the recovered material from the mixed solution.

In one embodiment of the present invention, the virus template is the E3-M13 virus.

In one embodiment of the present invention, the E3-M13 virus is a glutamate trimer bound to the N terminus of the pVIII protein of the M13 virus, respectively.

In one embodiment of the present invention, the anionic functional group is a carboxylate group.

In one embodiment of the present invention, the barium precursor solution and the titanium precursor solution are barium glycolate and titanium glycolate, respectively.

In one embodiment of the present invention, the barium glycolate is electrostatically bound to the carboxylate of the surface of the virus template to form a coordination bond.

In one embodiment of the present invention, the titanium glycolate electrostatically binds to the barium glycolate.

The present invention also provides the BTO piezoelectric material produced by the above-described method.

In one embodiment of the present invention, the piezoelectric material has a fibrous fibrous crystal structure.

In one embodiment of the present invention, the BTO piezoelectric material is anisotropic, and the BTO piezoelectric material structure follows the virus template structure.

The present invention also provides a flexible nano-generator including the BTO piezoelectric material as a piezoelectric layer manufactured by the above-described method.

In one embodiment of the present invention, the flexible nano generator includes: a lower flexible substrate; A lower electrode provided on the lower flexible substrate; A piezoelectric material layer provided on the lower electrode electrode and including the BTO piezoelectric material manufactured by the method described above; An upper electrode provided on the piezoelectric material layer; And an upper flexible substrate provided on the upper electrode.

In one embodiment of the present invention, the piezoelectric material layer is produced by mixing the BTO piezoelectric material prepared by the above-described method into a polymer.

According to the present invention, a piezoelectric self-assembling method can be used to produce a piezoelectric material having a high degree of dispersion and crystallinity, and the piezoelectric material can be used as an energy harvesting device. The BTO piezoelectric material according to the present invention is produced from a virus-intermetallic ion complex, which is due to the interaction between the metal-based ligand and the genetically engineered protein. The fabricated virus-based BTO-based flexible nano-generator can supply enough power to drive commercial devices alone without a separate energy source.

1 is a schematic diagram of an entire process for preparing a virus template BTO nanostructure according to an embodiment of the present invention.
FIG. 2 is a view illustrating a process for synthesizing the virus-template BTO nanostructure according to the present invention in detail.
Figure 3 is a diagram showing the piezoelectric voltage of a simplified virus-template BTO model inserted into a flexible matrix.
4 to 6 are diagrams showing the overall morphology and characterization results of a substance produced using a virus-template according to the present invention.
FIG. 7 shows the results of ATR-IR spectroscopy and XPS analysis of virus-metal ion complexes according to the present invention.
8 is a result of analysis of the intermediate phase and its components in the heat treatment process.
9 is a view for explaining a method of manufacturing a nano-generator according to an embodiment of the present invention and a method of recovering energy from physical deformation.
10 is a photograph showing the characteristics of the virus-template BTO nano-generator according to the present invention and its application results.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an item usage period control method and a server therefor according to embodiments of the present invention will be described with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention. Accordingly, equivalent inventions performing the same functions as the present invention are also within the scope of the present invention.

In order to solve the problems of the prior art described above, the inventor of the present invention has proposed a method of manufacturing a piezoelectric material using a virus-template having a charge of a positive ion or an anion on the surface thereof, Or Van der Waals attractive force to form a complex, and then the virus-template is removed by heat treatment or the like to produce a piezoelectric material.

Hereinafter, the piezoelectric material will be described as BTO, and the virus will be described as M13 virus. However, at least those skilled in the art can derive a piezoelectric material from the specification using various piezoelectric materials and viruses on the same principle. .

In one embodiment of the present invention, a high-capacity stable anisotropic BTO flexible nano-generator is prepared using the M13 virus (M13 bacteriophage ) as a template. The term virus-template in this specification means that the virus is used as a template.

The M13 virus used in the present invention is genetically engineered such that there is a glutamate trimer at the N-terminus of each pVIII protein. The virus is hereinafter referred to as 'E3-M13' and a BTO-based piezoelectric material is prepared using the virus as a template.

The present inventors have found that barium and titanium precursor ions are effectively bound to the E3 peptide of the virus through a metal ion-peptide bond reaction in the following experimental examples.

At this time, the fibrous form of M13 can play a very important role in inducing the formation of an evenly dispersed phase of anisotropic piezoelectric material, which is a very important factor in the production of effective piezoelectric devices. The interaction between the metal ion and the virus capsid protein, and thus the virus-metal ion complex formation, and thus the anisotropic BTO nanocrystal structure thus obtained, are analyzed in detail below.

1 is a schematic diagram of an entire process for preparing a virus template BTO nanostructure according to an embodiment of the present invention.

Referring to FIG. 1, virus-metal ion complexes were prepared by culturing the genetically modified M13 virus in a ligand solution, and a highly purified and well dispersed nanostructure was obtained by calcination.

Example 1

Manipulation of pVIII of M13 virus

To insert three glutamates (hereinafter denoted as E3) in pVIII, the M13KE phage vector was modified with site-directed mutagenesis. The PstI site that was already present at position 6250 was removed by substituting A for T. [ The specific site of the restriction enzyme for DNA insertion with pVIII was generated with the mutagenesis enzyme. In addition, PstI and BamHI positions were added by replacing T with A at position 1372 and C at position 1381, respectively. The sequence of E3 was synthesized as follows.

Forward, 5 ㅄ - [phos] GAA GAG GAA-3 ㅄ and Reverse, 5 ㅄ - [phos] GAT CTT CCT CTT CTG CA-3 ㅄ.

The annealed DNA fragment was ligated to the pVIII-modified M13KE phage vector and transferred to XL-1 blue competent cells.

The M13 phage engineered to express E3 on the pVIII surface was amplified using DNA sequencing and ER2738 growth medium.

Virus - Template Flexible BTO Device Manufacturing

FIG. 2 is a view illustrating a process for synthesizing the virus-template BTO nanostructure according to the present invention in detail.

Referring to FIG. 2, the Major Coat Protein of pVIII strongly binds to and binds to the positively charged metal ion precursor. As shown in FIG. 3, the surface of the virus template according to the present invention and the genetically- (Anionic functional groups, carboxylates) associated with the anion.

To a metal ion complex to produce a (Virus-metal ionic complex), barium glycolate solution of 200mM 10 ¹³ pfu · mL ^{- -} also the virus shown in Figure 2 and by incubation at room temperature for the first two hours with E3-M13 virus , Then 200 mM of titanium glycollate was added to the virus solution. At this time, the titanium precursor solution was added at a temperature of 80 ° C. at a pH≥10 to promote the concentration and diffusion of the two types of glycolate precursor solution. The titanium glycolate chelate [Ti ^IV (OCH ₂ CH ₂ O) ₃ ] ^2- is electrostatically charged with E3-M13, which is electrically charged with an extremely strong negative ion charge, because of being charged with anions, it is very important to add the above sequential order.

That is, the barium glycolate chelate [Ba ^II (HOCH ₂ CH ₂ OH) ₄ (OH ₂ )] ²⁺ has a cationic charge and thus avoids such electrostatic repulsion, Can be electrostatically coupled first.

Barium glycolate, which is electrostatically bound to the virus, is then easily bound to titanium glycolate by electrostatic action and hydrogen bonding.

If the two precursors are added together at the same time, the titanium glycolate is easily self-polymerized to form a very large precipitate aggregate, and barium glycolate is present only in the form of the dissolved ligand.

Also, in the BTO-based nano-generator according to the present invention, the heat treatment process as the calcination process is a process necessary for forming the perovskite crystal structure because of the high crystal energy of the BTO. In one embodiment of the present invention, the calcination process was conducted at 600 to 1000 degrees Celsius for 2 hours. However, if necessary, the temperature and time can be freely selected, and further, the calcination process for removing the template can be omitted.

The virus-template according to an embodiment of the present invention is removed in the subsequent calcination process, but the anisotropic fibrous BTO nanostructure remains highly crystalline (see FIG. 5). If a single incubation step is used, the remaining material after calcination will be only materials such as BaTi ₄ O ₉ and BaTi ₂ O ₅ , which are spun with titanium.

analysis

Figure 3 is a diagram showing the piezoelectric voltage of a simplified virus-template BTO model inserted into a flexible matrix.

Referring to FIG. 3, it can be seen that the tangential structure of the anisotropic virus-template BTO nanostructure prepared according to the present invention is very important for energy harvesting of the nano-generator.

In Fig. 3, the piezoelectric voltage distribution of the anisotropic BTO nanostructure was shown as a color for tensile stress on the X axis. According to the finite element analysis (FEA), it was found that the virus-template fibrous BTO nanostructures can generate electrical energy from mechanical vibration much better than BTO nanoparticles.

Results of the overall morphology and characterization of the material generated using the virus-template according to the present invention are set forth in Figures 4-6.

Fig. 4 is a TEM image of E3-M13, a virus of capsid-bearing capsid by uranyl acetate.

Referring to FIG. 4, a fibrous structure with a well-mixed diameter of about 7 nm can be seen.

In the inset image of FIG. 4, the zeta-potential analysis of the E3-M13 virus and the wild type M13 (M13KE) is the result of Tris buffer solution Tris analysis.

Referring to the inset image of FIG. 4, it can be seen that E3-M13 has more negative charge than M13KE.

Also, referring to FIG. 5, it can be seen that, after the glycolate calcination step to coagulate the metal ligand on the virus surface, the resulting structure diameter increased to about 20 nm level, but the percolate type virus structure was well maintained. Some crystalline structures of the amorphous matrix of viruses were observed by hydrolysis of titanium glycolate, which can be seen from the HRTEM image analysis results embedded in FIG.

These crystal structures are judged to be small-sized TiO ₂ regions as a result of selected-area electron diffraction (SAED) analysis, but the overall XRD pattern of the virus template intermediate does not show any peaks because most of the complexes are glycolate / - based amorphous regions.

Referring to FIG. 6, it can be seen that, after the calcination process, the final varnish-template BTO nanostructure having a well-dispersed morphology and an anisotropic shape has a width of 50 to 100 nm according to the heat treatment. The particle size of the nanocrystals is sufficient to form a tetragonal phase, which is very important for the piezoelectric properties in which the material according to the invention is used. The insert image of Figure 6 clearly shows the cubic structure of the perovskite obtained after the calcination process.

The M13 virus expressing tremeric or tetrameric glutamate is very useful as a template for metal oxide synthesis. However, a more accurate analysis of the chemical properties of the virus-metal ion complexes was conducted below.

FIG. 7 shows the results of ATR-IR spectroscopy and XPS analysis of virus-metal ion complexes according to the present invention.

Referring to FIG. 7, it can be seen that the two oxygen atoms in the carboxylic acid of glutamate contribute to the chelate of the central metal because the carboxylate of the glutamate expressed in accordance with the present invention has a higher electrical density than the hydroxyl group It is because it has.

The metal-oxygen coordination of the chelate can be seen from multiple peaks of less than 670 cm-1, where the stretching vibration of the Ti-O bond was observed in the virus-metal ion complex as well as the final virus-template BTO in the calcined form. Since the chelation according to the present invention is made by the carbon atoms around the metal element, the result of the O1s XPS analysis is important for understanding the chemical state in the bonding structure of the complex compound. In a broad spectrum, oxygen-metal chelate bonds can be observed at binding energies (530.8 eV) lower than CO bond energies (531.0 eV). Furthermore, a clear envelope characteristic of the metal oxide at lower energy (529.5 eV) was observed, which is consistent with the crystalline and amorphous TiO ₂ observed as a result of HRTEM and SAED from virus-metal ion complexes.

8 is a result of analysis of the intermediate phase and its components in the heat treatment process.

Referring to FIG. 8, the results of TG (Thermogravimetry) and DSC (differential scanning calorimetry) analysis show that water evaporation and M13 combustion occur at 100 to 200 degrees Celsius and 200 to 400 degrees Celsius, respectively. Although the carbon source of the glycolate burned after 400 degrees Celsius, there was a wide endothermic region due to the annealing and diffusion of the two metal elements (see FIG. 8A). In the case of combustion at 600 to 900 degrees Celsius, various titanium-rich compositions or phases were produced by insufficient heat treatment. A Raman shift band of the final virus-template BTO nanostructure corresponding to the general resultant shape of tetragonal perbroscite BTO was revealed (see FIG. 8B). In particular, the cubic phase represents the B1 and E modes at 307 cn-1 and shows the high-frequency horizontal optic mode at 715 cm-1, which is experimental evidence for cubic to cubic deformation. The XRD pattern also defines the P3mm crystal structure of BTO, which can be confirmed through the inset image of FIG. 10b.

The complete crystallinity of the virus-template BTO according to the present invention can be confirmed by HRTEM and SAED, which can be seen in Figures 8c-i and ii. The large grain boundaries with the existing grain boundaries are shown in Figures 8c-iii, indicating that the virus-templated BTO nanostructures synthesized according to the present invention were derived from virus-metal ion complexes and were not derived from agglomerates of BTO particles Prove it.

Piezoelectric reaction analysis was performed to confirm the polarity switching behavior in the virus-template BTO region obtained according to the present invention. Referring to FIG. 8D, the abrupt hysteresis loop is the result of the observed piezoelectric behavior after turning off the electric field. The phase history exhibits perfect polarity tunability, which is shown in the inset image of Figure 8d.

To obtain energy using a piezo-electric virus-template BTO, a nano-generator based on a piezoelectric material has to be fabricated, which is shown in Figure 9a.

Referring to FIG. 9A, a BTO piezoelectric layer is prepared by mixing a virus-template BTO nanostructure subjected to stirring and filtration with polydimethylsiloxane (PDMS). Subsequently, the indium-tin oxide (ITO) -coated polyethylene terephthalate (PET) substrate is covered with a PDMS insulating layer to prevent breakdown of the device. Next, the virus-template BTO-based piezoelectric layer prepared according to the present invention is spin-coated on a PDMS coated flexible substrate. As an upper electrode, an ITO laminated PET thin film substrate (~50 mu m) was laminated on the substrate.

Figure 9 (a) is a photograph of a virus-template BTO nano-generator produced according to the present invention. Referring to FIG. 9A, the virus-template BTO nano-generator produced according to the present invention has soft and flexible characteristics. Also due to the anisotropic structure of M13, percolate nanostructures are well dispersed in a soft flexible matrix without the use of any special dispersants, as shown in Figures 9a-v.

9B is a graph showing the results of measurement of the output performance of the virus-template BTO nano-generator in periodic bending / unfolding operation.

Referring to FIG. 9B, the short-circuit current and open-circuit voltage measured from the virus-template BTO nano-generator (effective area 2.5 x 2.5 cm ² ) according to the present invention were ~ 300 nA and ~ 6 V, respectively. The output current and the voltage were measured in order to confirm the electric signal produced by the nano-generator manufactured according to the present invention. The polarity of the electrical signal at the forward connection was reversed when the connector was reversed (Figs. 9b i and ii). These electric powers are higher than those of the previous nano generators using BTO nanoparticles in combination with carbon nanotubes, which is considered to be due to the improvement in the dispersibility due to anisotropy of the anisotropic M13 template structure.

9C is a view for explaining the energy conversion mechanism of the nano generator element according to the present invention.

Referring to FIG. 9C, during the poling process, the electric dipole direction in the virus-template BTO piezoelectric region according to the present invention is aligned parallel to the external electric field. When the nano-generator according to the present invention undergoes mechanical deformation, the piezoelectric voltage is induced in the upper and lower electrodes due to polar stress. The voltage induces a free electron flow that neutralizes the electric field generated by the dipole. Since the virus-template BTO piezoelectric layer and the insulating PMS are insulators, the current flows only through the external circuit, so that no charge leakage occurs during the periodic measurement process. In the static pressure state, the built-in voltage disappears because the piezoelectric voltage is balanced by the free charge accumulated at both electrodes. However, when the pressure disappears, the voltage disappears, and a built-in built-in voltage in the opposite direction, which is formed by the free charges accumulated at both ends of the external circuit, is formed. Free electrons flow in the opposite direction, and then the current becomes zero.

10 is a photograph showing the characteristics of the virus-template BTO nano-generator according to the present invention and its application results.

The output performance of the virus-template BTO nano-generator depends on the degree of pressure, since the piezoelectric charge remains constant at the same level of pressure. At constant pressure, a rapid pressure application rate leads to a higher output voltage (see FIG. 10A). Similarly, the output increases with the curvature bending even at the same speed, because deformation of the piezoelectric layer generates a larger built-in voltage in the circuit (see FIG. 10B).

The stability of the virus-template BTO-based nano-generator was measured through cycle testing.

Figures 10c and d are the cycle test results of the virus-template BTO-based nano-generator according to the present invention.

Referring to Figures 10c and d, the nanosgenerator according to the present invention showed stable characteristics without any special deterioration phenomenon under a fast cycle (3.5 Hz) for 21,000 cycles. The voltage and current measured during the test were similar to those initially measured. The above results show that the BTO piezoelectric material prepared using the virus as a template according to the present invention exhibits very stable characteristics even in a nano generator and is suitable as an energy harvest material.

The virus-template BTO-based flexible nano-generator manufactured according to the present invention can supply enough power to drive commercial devices alone without a separate energy source. 10E is a photograph showing a case where the LED is driven by the nano generator according to the present invention. Also, FIG. 10F is a photograph showing a case where the LCD is completely driven by the nano-generator manufactured according to the present invention.

As described above, the present inventors have produced a fibrous kite piezoelectric material having high dispersion and crystallinity at the same time by using a biological self-assembly method, and the piezoelectric material can be used as an energy harvesting element. The BTO piezoelectric material according to the present invention is produced from a virus-intermetallic ion complex, which is due to the interaction between the metal-based ligand and the genetically engineered protein.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is concerned. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

Claims (15)

Binding the E3-M13 virus-template to the piezoelectric material precursor solution to form a complex; And
And a step of synthesizing a piezoelectric material in the virus-template. The method of claim 1, wherein the method comprises:
Mixing a barium precursor solution with a virus template having an anionic functional group or a piezoelectric substance-specific functional group bonded to its surface; And
And mixing the titanium precursor solution with the mixed precursor solution to form a piezoelectric material. 3. The method of claim 2,
The method for manufacturing a piezoelectric material using the virus-template further comprises a step of removing the virus template by calcining the recovered material from the mixed solution. delete The method according to claim 1,
Wherein the E3-M13 virus is characterized in that glutamate trimer is bound to the N terminus of the pVIII protein of the M13 virus, respectively. 3. The method of claim 2,
Wherein the anionic functional group is a carboxylate group. 3. The method of claim 2,
Wherein the barium precursor solution and the titanium precursor solution are barium glycolate and titanium glycolate, respectively. 8. The method of claim 7,
Wherein the barium glycolate electrostatically binds carboxylate on the surface of the virus template to form a coordination bond. 9. The method of claim 8,
Wherein the titanium glycolate is electrostatically bound to the barium glycolate. A BTO piezoelectric material produced by the method according to any one of claims 1 to 3 and 5 to 9,
Wherein the BTO piezoelectric material has an anisotropic fiber shape and the BTO piezoelectric material structure conforms to an E3-M13 virus-template structure. 11. The method of claim 10,
Wherein the piezoelectric material forms a fibrous crystal structure of fibrous material. delete A flexible nano-generator comprising the BTO piezoelectric material according to claim 10 as a piezoelectric layer. 14. The method of claim 13,
The flexible nano-
A lower flexible substrate;
A lower electrode provided on the lower flexible substrate;
A piezoelectric material layer provided on the lower electrode electrode and including the BTO piezoelectric material;
An upper electrode provided on the piezoelectric material layer; And
And an upper flexible substrate provided on the upper electrode. 15. The method of claim 14,
Wherein the piezoelectric material layer is manufactured by mixing the BTO piezoelectric material with a polymer.

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