KR102548447B1 - Piezoelectric paint composition for energy harvesting and manufacturing method thereof - Google Patents

Abstract

The piezoelectric paint according to the present invention includes a fluorine-based polymer, graphene oxide surface-modified with an alcohol surface modifier, and a solvent, wherein the alcohol surface modifier includes a fluorine-based alcohol, and the surface-modified graphene oxide is compared to the fluorine-based polymer It is characterized in that it contains 0.0005 to 0.002% by weight.

Description

Piezoelectric paint composition for energy harvesting and manufacturing method thereof

The present invention relates to a piezoelectric paint for energy harvesting and a manufacturing method thereof.

Energy harvesting refers to a technology that converts energy generated from natural energy sources such as sunlight, vibration, heat, and wind power into electrical energy and harvests the energy.

Among them, the piezoelectric-based energy harvester proposed based on the piezoelectric effect converts mechanical energy such as vibration, bending, and load generated by minute movements into electrical energy even in the absence of conventional renewable energy sources such as wind and sun. As a technology that can be converted into energy, it is attracting attention as a next-generation energy production technology.

In particular, when a piezoelectric-based energy harvester is installed on a road, there is an advantage in securing a stable energy source, and related research is being actively conducted.

However, in the case of a conventional piezoelectric-based energy harvester, after manufacturing the device, it is possible to install it by removing and burying the asphalt surface of the existing road, and there is a problem in that a lot of time and money are consumed in this process.

In addition, when a piezoelectric layer is formed by applying a composition containing a conventional piezoelectric material, there is a limitation in that a significant level of piezoelectric performance is obtained only when a film is formed by applying the composition and then additionally subjected to a process such as corona poling treatment. However, this corona polling process is extremely difficult to process on a large area, and requires peripheral facilities, so there is a limitation that the process cannot be performed on structures such as roads.

Accordingly, it is necessary to develop a piezoelectric paint capable of energy harvesting in a simple way without requiring corona poling.

US Patent Publication No. 9583693 Republic of Korea Patent Publication No. 10-2017-0026078

An object of the present invention is to provide a piezoelectric paint capable of energy harvesting in a simple manner.

Another object of the present invention is to provide a piezoelectric paint capable of energy harvesting by applying the piezoelectric paint without a construction process that damages an existing road.

Another object of the present invention is to provide a piezoelectric paint having excellent energy harvesting efficiency.

The piezoelectric paint according to the present invention includes a fluorine-based polymer, graphene oxide surface-modified with an alcohol surface modifier, and a solvent,

The alcohol surface modifier includes a fluorine-based alcohol,

The surface-modified graphene oxide is characterized in that it contains 0.0005 to 0.002% by weight compared to the fluorine-based polymer.

In the piezoelectric paint according to an embodiment of the present invention, the fluorine-based polymer may include a vinylidene fluoride functional group.

In the piezoelectric paint according to an embodiment of the present invention, the fluorine-based polymer may be a polyvinylidene-trifluoroethylene copolymer.

In the piezoelectric paint according to an embodiment of the present invention, the polyvinylidene-trifluoroethylene copolymer may contain 10 to 40 mol% of a trifluoroethylene functional group.

In the piezoelectric paint according to an embodiment of the present invention, the solvent includes one or two or more selected from methyl ethyl ketone, dimethylformamide, dimethylacetamide, triethyl phosphate, and N-methyl-2-pyrrolidone. can be characterized.

In the piezoelectric paint according to an embodiment of the present invention, the fluorine-based alcohol may include a -CF ₃ functional group at an end.

In the piezoelectric paint according to an embodiment of the present invention, the fluorine-based alcohol may have a molecular weight of 250 g/mol or less.

In the piezoelectric paint according to an embodiment of the present invention, the piezoelectric paint may include 10 to 30 parts by weight of a fluorine-based polymer based on 100 parts by weight of a solvent.

The present invention also provides a method for preparing a piezoelectric paint composition, which includes a first step of preparing modified graphene oxide by mixing graphene oxide and an alcohol modifier; and

A second step of injecting the graphene oxide into a fluorine-based polymer and then mixing a solvent;

The alcohol modifier includes a fluorine-based alcohol.

In the method for preparing a piezoelectric paint composition according to an embodiment of the present invention, the alcohol modifier may include 25 to 55% by volume of a fluorine-based alcohol.

The method for preparing a piezoelectric paint composition according to an embodiment of the present invention may further include adding an acid during the reforming reaction in the first step.

The piezoelectric paint according to the present invention includes a fluorine-based polymer, graphene oxide surface-modified with an alcohol surface modifier, and a solvent, wherein the alcohol surface modifier includes a fluorine-based alcohol, and the surface-modified graphene oxide is compared to the fluorine-based polymer There is an advantage in that energy harvesting is possible only by application of paint, including 0.0005 to 0.002% by weight, and there is an advantage in that construction can be performed quickly without damaging existing roads when constructing on roads.

1 illustrates FT-IR measurement results of surface-modified graphene oxide in a piezoelectric paint composition according to an embodiment of the present invention.
2 and 3 show the surface observed with a scanning electron microscope (SEM) after applying the coating composition prepared by the embodiment of the present invention.

Advantages and characteristics of the embodiments of the present invention, and methods for achieving them will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the embodiment of the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

The piezoelectric paint according to the present invention includes a fluorine-based polymer, graphene oxide surface-modified with an alcohol surface modifier, and a solvent,

The alcohol surface modifier includes a fluorine-based alcohol,

The surface-modified graphene oxide is characterized in that it contains 0.0005 to 0.002% by weight compared to the fluorine-based polymer.

The piezoelectric paint according to the present invention has the advantage of being able to manufacture a piezoelectric element by a simple method of applying the paint, and when applying to a road, it has the advantage of enabling energy harvesting by applying the paint without damaging the existing road.

Preferably, the surface-modified graphene oxide may be included in an amount of 0.0007 to 0.0015% by weight compared to the fluorine-based polymer, and a large number of graphene oxide is included in this range to prevent problems affecting the piezoelectric network and to sufficiently improve piezoelectric performance. There are advantages to being effective.

The piezoelectric paint according to the present invention includes graphene oxide surface-modified with an alcohol surface modifier containing fluorine-based alcohol, thereby significantly increasing the dispersibility of graphene oxide and uniformly dispersing in the coating film. Accordingly, graphene oxide There is an advantage in that the piezoelectric efficiency is increased according to the addition and the output voltage is increased.

Specifically, the fluorine-based alcohol may use an alcohol containing a -CF ₃ group at the terminal, and preferably, the fluorine-based alcohol may have a molecular weight of 250 g/mol or less. As a specific example, the fluorine-based alcohol is 4,4,5,5,5-pentafluoro-1-pentanol, 2,2,3,3,4,4,4-heptafluoro-1-butanol, nona It may contain one or two or more selected from fluoro-tert-butyl alcohol and 1,1,1,3,3,3-hexafluoro-2-propanol.

The alcohol surface modifier may include a fluorine-based alcohol and a low molecular weight alcohol, and the low molecular weight alcohol may specifically include one or two or more selected from methanol, ethanol, and isopropanol.

The alcohol surface modifier may include 25 to 55% by volume, preferably 30 to 45% by volume of the fluorine-based alcohol, and may include the balance of low molecular weight alcohol, and by including the fluorine-based alcohol in the above-described range, the piezoelectric paint The resulting coating film exhibits high lead efficiency and excellent mechanical strength at the same time.

Preferably, a polymer containing a vinylidene fluoride functional group may be used as the fluorine-based polymer, and more preferably, the fluorine-based polymer may be a polyvinylidene-trifluoroethylene copolymer.

As a specific example, the polyvinylidene-trifluoroethylene copolymer may include 10 to 40 mol% of the trifluoroethylene functional group, preferably 15 to 35 mol%, and within this range, the surface-modified graphene oxide and It is possible to maximize compatibility and secure high piezoelectric efficiency.

The piezoelectric paint may include 10 to 30 parts by weight, preferably 12 to 20 parts by weight, and more preferably 13 to 19 parts by weight of a fluorine-based polymer based on 100 parts by weight of the solvent, and when a small amount of the fluorine-based polymer is included, a sufficient coating thickness and It may be difficult to secure the piezoelectric effect, and when a large amount of fluorine-based polymer is included, workability is reduced and it is difficult to form a uniform thickness coating film.

The solvent may use an organic solvent capable of dissolving the fluorine-based polymer, preferably the solvent is selected from methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, triethyl phosphate and N-methyl-2-pyrrolidone One or more of them may be used.

The present invention also provides a method for preparing a piezoelectric paint composition, which includes a first step of preparing modified graphene oxide by mixing graphene oxide and an alcohol modifier; and

A second step of injecting the graphene oxide into a fluorine-based polymer and then mixing a solvent;

The alcohol modifier is characterized in that it comprises a fluorine-based alcohol.

The method for manufacturing a piezoelectric paint composition according to the present invention can produce a piezoelectric paint including the above steps, and has an advantage of exhibiting a piezoelectric effect by simply applying the prepared piezoelectric paint.

The first step may be a step of reforming by adding 1 to 7 g of graphene oxide per 1 L of the alcohol modifier, preferably 20 to 50 ml of an aqueous acid solution per 1 L of the alcohol modifier, and the aqueous acid solution has a concentration It can be used that is 30% by weight or more. In addition, the graphene oxide may be prepared through a conventional Hummer's method, etc., but the present invention is not limited thereto.

The present invention also includes an energy harvesting device made of the piezoelectric paint. The energy harvesting device may include a coating film formed of a piezoelectric paint; And it may include an electrode formed on one side or both sides of the coating film. At this time, the electrode is for transferring the power generated by the piezoelectric effect in the coating film to a device requiring power or a power storage device, and can be largely classified into a thin film electrode and an electrode coating film formed of a coating composition for electrodes.

The thin-film electrode can be used without limitation when it is commonly used in the art, and specifically, a thin film containing one or two or more selected from gold, silver, platinum, copper, and aluminum may be used.

An electrode coating film formed from the coating composition for an electrode may be formed by applying a coating composition containing a conductive filler and a polymer binder. In this case, the conductive filler may include one or more carbon-based fillers selected from carbon nanotubes, graphene, graphene oxide, and reduced graphene oxide, or metal fillers selected from gold, silver, platinum, copper, and aluminum. .

In addition, the polymeric binder can be used without limitation in the case of a commonly used binder, preferably an acrylic-urethane copolymer, but the present invention is not limited thereto.

In addition, when using a thin-film electrode, an adhesive layer for bonding may be further included between the thin-film electrode and a coating film formed by curing the piezoelectric paint, and this adhesive layer also includes the above-described carbon-based filler or metal filler to secure conductivity, , piezoelectric coating films and thin film electrodes can be used without limitation.

Hereinafter, the present invention will be specifically described by Examples and Comparative Examples. The following examples are only for helping understanding of the present invention, and the scope of the present invention is not limited by the following examples.

[Production Example 1]

1. Preparation of surface-modified graphene oxide

3 g of graphene oxide particles were dispersed in 1 L of an alcohol modifier, and ultrasonic waves were applied for 90 minutes to disperse them. Then, 35 ml of concentrated hydrochloric acid aqueous solution having a concentration of 35% by weight was mixed and stirred at 55 ° C. for 3 hours to perform a modification reaction. . Thereafter, sodium bicarbonate was added until the pH reached 6.5 to 7, and the solid content was separated and completely dried at room temperature to prepare modified graphene oxide.

At this time, as the alcohol modifier, a mixture of methanol and fluorine-based alcohol in a volume ratio of 6:4 was used, and the fluorine-based alcohol was 4,4,5,5,5-pentafluoro-1-pentanol (4,4,5,5 ,5-Pentafluoro-1-pentanol) was used.

2. Manufacture of piezoelectric paint

The prepared surface-modified graphene oxide was added to 85 g of a methylethyl ketone solvent, and ultrasonic waves were irradiated to disperse the graphene oxide. Thereafter, 15 g of a fluorine-based resin was added and stirred to prepare a piezoelectric paint. At this time, the fluorine-based resin was a vinylidene fluoride/trifluoroethylene copolymer (P(VDF-co-TrFE), and a resin having a VDF/TrFE molar ratio of 70/30 was used, and the surface-modified graphene oxide was the fluorine-based resin. It was added so that it was 0.001% by weight compared to

3. Manufacture of energy harvesting device

A platinum electrode was prepared as a lower electrode, a conductive adhesive was applied to the prepared platinum electrode, and a piezoelectric paint was applied thereto, followed by complete drying. Thereafter, the conductive adhesive was applied once again, and the upper platinum electrode was bonded and completely dried to manufacture an energy harvesting device.

At this time, the conductive adhesive was prepared by dissolving polyaniline in a NMP (N-methyl-2-pyrrolidone) solvent at a concentration of 10% by weight and mixing 80 parts by weight of platinum nanoparticles with 100 parts by weight of polyaniline.

[Production Example 2]

It was prepared in the same way as in Preparation Example 1, but mixed so that the content of graphene oxide was 0.002% by weight compared to the fluorine-based resin, and then a piezoelectric paint and an energy harvesting device were prepared using this.

[Comparative Example 1]

Piezoelectric paint was prepared by mixing 15% by weight of vinylidene fluoride/trifluoroethylene copolymer (P(VDF-co-TrFE), VDF/TrFE = 70/30 molar ratio, hereinafter referred to as resin) in methyl ethyl ketone solvent And, an energy harvesting device was also manufactured in the same manner as in Preparation Example 1 using the manufactured piezoelectric paint.

[Comparative Example 2]

It was prepared in the same manner as in Example 1, but mixed without any treatment to graphene oxide to prepare a piezoelectric paint and an energy harvesting device.

Check the surface of the piezoelectric layer

The piezoelectric layer prepared in Preparation Example 1 was observed with a scanning electron microscope (SEM), and the piezoelectric layer prepared in FIG. 2 and Preparation Example 2 was observed with an SEM, and the results are shown in FIG. 3 . Comparing Figures 2 and 3, it can be seen that a uniform layer is formed as a whole in the case of Figure 2, but it can be seen that cracks in the coating film have occurred in Figure 3 in a dark color.

Piezoelectric Characteristics Analysis

The d33 value of Preparation Example and Comparative Example was measured using a piezometer, and the output voltage obtained by applying a pressure of 50 N per cm 2 was measured, and the results are shown in Table 1 below.

Sample d33 Output voltage (V) Preparation Example 1 1.37 2.71 Preparation Example 2 0.93 2.30 Comparative Example 1 0.31 0.28 Comparative Example 2 0.34 1.96

Referring to Table 1, in the case of Comparative Example 1 not including graphene oxide at all, it can be seen that the d33 value and the lowest output voltage. In the case of Comparative Example 2 including graphene oxide without any treatment, it can be seen that the d33 value slightly increased and the output voltage significantly increased compared to Comparative Example 1. In addition, in the case of Preparation Examples 1 and 2 surface-modified with fluorine-based alcohol, it can be confirmed that they exhibit high d33 values and output voltages compared to Comparative Examples 1 and 2, and among them, the d33 value and output voltage of Preparation Example 1 are the highest one can be found.

Claims (11)

It includes a fluorine-based polymer, graphene oxide surface-modified with an alcohol surface modifier, and a solvent,
The alcohol surface modifier includes a fluorine-based alcohol,
The surface-modified graphene oxide is contained in an amount of 0.0005 to 0.002% by weight compared to the fluorine-based polymer,
The fluorine-based alcohol is a piezoelectric paint, characterized in that it comprises a -CF ₃ functional group at the terminal.
According to claim 1,
The fluorine-based polymer is a piezoelectric paint, characterized in that it contains a vinylidene fluoride functional group.
According to claim 2,
The fluorine-based polymer is a piezoelectric paint, characterized in that polyvinylidene-trifluoroethylene copolymer.
According to claim 3,
The polyvinylidene-trifluoroethylene copolymer is a piezoelectric paint, characterized in that it contains 10 to 40 mol% of the trifluoroethylene functional group.
According to claim 1,
The piezoelectric paint, characterized in that the solvent comprises one or two or more selected from methyl ethyl ketone, dimethylformamide, dimethylacetamide, triethyl phosphate and N-methyl-2-pyrrolidone.
delete According to claim 1,
The fluorine-based alcohol is a piezoelectric paint, characterized in that the molecular weight is 250 g / mol or less.
According to claim 1,
The piezoelectric paint is a piezoelectric paint, characterized in that it comprises a fluorine-based polymer of 10 to 30 parts by weight relative to 100 parts by weight of the solvent.
A first step of preparing modified graphene oxide by mixing graphene oxide and an alcohol modifier; and
A second step of injecting the graphene oxide into a fluorine-based polymer and then mixing a solvent;
The method for producing a piezoelectric paint composition, characterized in that the alcohol modifier contains 25 to 55% by volume of fluorine-based alcohol.
delete According to claim 9,
The method for producing a piezoelectric paint composition, characterized in that it further comprises the step of introducing an acid during the reforming reaction of the first step.

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