WO2016144043A1 - Conductive polymeric composite material and production method therefor - Google Patents

Abstract

The present invention relates to a conductive polymeric composite material. Specifically, it is possible to produce a conductive polymeric composite material with excellent conductivity, flexibility and biocompatibility by dispersing a conductive filer inside a polymeric compound comprising polydimethyl siloxane (PDMS) and a low-viscosity methyl-ended polydimethylsiloxane (MEP).

Description

Conductive Polymer Composites and Manufacturing Method Thereof

The present invention relates to a conductive polymer composite having excellent conductivity, flexibility and biocompatibility, and a method of manufacturing the same.

One of the silicone polymers, PDMS (Polydimethylsiloxane) is a polymer having excellent permeability to the air of a living body and having a flexibility similar to that of a living tissue, and is easily manufactured by a transparent soft lithography process. By implementing a micro electro mechanical system (MEMS) that extracts signals by forming electrodes directly connected to cells of a living body in PDMS, it is useful for monitoring the response signals of the living body or applying electrical stimuli. It is used.

Representative technology for this can be seen by the Republic of Korea Patent No. 864536 (hereinafter referred to as 'Patent Document 1') and Republic of Korea Patent No. 875711 (hereinafter referred to as 'Patent Document 2').

Patent Document 1 is a step of forming a polydimethylsiloxane substrate by spin coating a blend of a polydimethylsiloxane prepolymer and a curing agent in a mass ratio of 20: 1 to 5: 1 on a silicon wafer to form a polydimethylsiloxane substrate, the surface of the polydimethylsiloxane substrate Pre-treating, depositing a titanium layer and a gold layer on the surface of the pre-treated polydimetholylsiloxane sequentially and then patterning a microelectrode, forming a photoresist on the patterned microelectrode, and the photo Spin coating polydimethylsiloxane on top of the non-resist polydimethylsiloxane substrate, removing the photoresist formed on the patterned microelectrode, and then performing gold electroplating on the patterned gold layer. Packaging the microelectrode.

According to Patent Document 1, a method of packaging a polydimethylsiloxane microelectrode through a photolithography process and plating of an electrode part reduces costs, reduces a failure rate due to a relatively simple process, and pretreatment and deposition of a polydimethylsiloxane substrate. By optimizing the conditions there is an effect that can improve the adhesion of the metal micropattern.

In addition, Patent Document 2 relates to an electrode used for preparing an electrocardiogram or measuring a state of the body, and more particularly, to an electrode for an electrocardiogram using a PDMS layer using a PDMS that is non-irritating to a human body.

The patent document 2 does not cause any side effects on the skin even though the skin of the corresponding part of the body is in close contact with the protruding electrode, there is no need to use a separate conductive jelly, the ECG operation is easy, and the electrode Even if worn for a long time, it does not cause itching or inflammatory reaction of the skin, so it has a useful effect that can be used safely in patients with sensitive skin or various patients who need to wear the electrode for a long time. While it is effective to be used for such purposes as monitoring for a long time.

On the other hand, Patent Documents 1 and 2 are to be bonded to the PDMS after the electrode is formed on the PDMS layer, both of them are directly formed on the PDMS. Accordingly, when the electrode of the PDMS is in contact with the biological tissue, the air of the living body is transmitted through the PDMS, the molecular bond between the metal electrode and the PDMS is weakened, the use of it for some time is easily released and difficult to use has been exposed.

An object of the present invention is to provide a conductive polymer composite having excellent conductivity, flexibility and biocompatibility.

In addition, another object of the present invention to provide a method for producing the conductive polymer composite material.

The conductive polymer composite material of the present invention for achieving the above object may be a conductive filler dispersed in the polymer mixture including polydimethylsiloxane (PDMS) and low viscosity methyl ended polydimethylsiloxane (MEP).

The conductive polymer composite material may include 5 to 40 parts by weight of low viscosity methyl ended polydimethylsiloxane (MEP) and 0.5 to 20 parts by weight of the conductive filler based on 100 parts by weight of polydimethylsiloxane (PDMS).

The conductive filler and low viscosity methyl ended polydimethylsiloxane (MEP) may be mixed in a weight ratio of 1: 1 to 40.

The conductive filler may be at least one selected from the group consisting of carbon nanotubes, carbon black, metal fibers, conductive polymers, and graphene.

The low viscosity methyl ended polydimethylsiloxane (MEP) may have a viscosity of 50 to 1000 cSt.

The viscosity of the polydimethylsiloxane (PDMS) may be 3000 to 7000 cSt.

The conductivity of the conductive polymer composite material may have a surface resistance of less than 100 Ω / sq.

The conductive polymer composite material may have a tensile strength of 1 to 5 MPa and a contact angle of 100 to 130 °.

The dispersion may be performed by sonication under isopropyl alcohol.

The conductive polymer composite material may further include a polydimethylsiloxane containing a metal catalyst and a curing agent.

In addition, the method for producing a conductive polymer composite material of the present invention for achieving the above another object comprises the steps of: (A) ultrasonically mixing a conductive filler and isopropyl alcohol; (B) sonicating by adding a low viscosity methyl ended polydimethylsiloxane (MEP) to the mixed mixture; (C) sonicating polydimethylsiloxane (PDMS-A) by adding the low viscosity methyl ended polydimethylsiloxane (MEP) to the mixture; (D) evaporating isopropyl alcohol contained in the sonicated mixture, followed by mixing by adding polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent; And (E) molding the mixture mixed in the step (D).

In the step (A), (B) and (C) it is possible to maintain the temperature of the mixture at 10 to 23 ℃ during the sonication.

In step (A), the conductive filler and isopropyl alcohol may be mixed in a weight ratio of 1:30 to 1000.

The temperature for evaporating the isopropyl alcohol in the step (D) may be 50 to 70 ℃.

The conductive polymer composite of the present invention can be used not only as an electrode (biosignal measuring electrode or electrical stimulation electrode), a biomaterial sensor in contact with the skin through high conductivity, flexibility and excellent biocompatibility, but also in the electrical circuit of the flexible device. It can be used as a conductor instead of a metal substrate.

1 is a view showing a process for manufacturing a conductive polymer composite material according to an embodiment of the present invention.

Figures 2a to 2d is a thermogravimetric analyzer (TGA, Figure 1), respectively, after mixing carbon nanotubes and isopropyl alcohol in one embodiment of the present invention before the ultrasonication reactant (gray line) and the reactant (black line) after sonication 2a), a differential scanning calorimeter (DSC, FIG. 2B), a Fourier transform infrared spectrometer (FT-IR, FIG. 2C) and a dispersion stability change meter (FIG. 2D).

Figures 3a to 3d is a thermogravimetric analyzer (TGA, Figure 3a), respectively, in one embodiment of the present invention after mixing up to the medium-weight polydimethylsiloxane solution before reacting the reactant (gray line) and the reactant (black line) after sonication ), A differential scanning calorimeter (DSC, FIG. 3B), a Fourier transform infrared spectrometer (FT-IR, FIG. 3C) and a dispersion stability change meter (FIG. 3D).

Figure 4 is a graph and photograph measured by a dispersion meter after reacting the reactants before and after sonication at room temperature for one week after sequentially mixing each material according to an embodiment of the present invention.

Figure 5 is a graph measuring the cell viability of the conductive polymer composite prepared according to one embodiment and comparative example of the present invention.

Figure 6 is a graph measuring the cytotoxicity of the conductive polymer composite prepared according to one embodiment and comparative example of the present invention.

7a to 7c is an infrared spectroscopy (FT-IR, Figure 7a), Raman spectroscopy (Fig. 7b) and X-ray diffraction analysis (XRD, Fig. It is a graph measured by 7c).

Figure 8a is a photograph taken with a high-resolution scanning electron microscope (HR-SEM) of the conductive polymer composite prepared in accordance with an embodiment of the present invention.

8B is a photograph taken with a transmission electron microscope (TEM) of a conductive polymer composite prepared according to an embodiment of the present invention.

Figure 9a is a graph measuring the conductivity of the conductive polymer composite prepared according to Examples 1 to 4.

Figure 9b is a graph measuring the tensile strength of the conductive polymer composites prepared according to Examples 1 to 4.

9C is a graph measuring a cycling test of a conductive polymer composite prepared according to an embodiment of the present invention.

10 is a flowchart illustrating a process of installing an electronic component in an electronic circuit manufactured using the conductive polymer composite material manufactured according to an embodiment of the present invention.

FIG. 11 is a photograph confirmed by supplying a current after bending the device manufactured in FIG. 10.

The present invention relates to a conductive polymer composite having excellent conductivity, flexibility and biocompatibility.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the conductive polymer composite of the present invention, the conductive filler is evenly dispersed without agglomeration inside the polymer mixture including polydimethylsiloxane (PDMS) and low viscosity methyl ended polydimethylsiloxane (MEP). Specifically, the low viscosity methyl ended polydimethylsiloxane (MEP) is formed to surround some or all of the conductive filler, the low viscosity methyl ended polydimethylsiloxane (PDMS) surrounding the conductive filler In conclusion, the conductive filler is evenly dispersed in the polymer mixture by dispersing in contact with (MEP).

The conductive filler is a material used to impart conductivity to the polymer composite material, specifically, at least one selected from the group consisting of carbon nanotubes, carbon black, metal fibers, conductive polymers and graphene. The metal fibers may include silver nanowires, copper nanowires, silver nanoparticles, silver flakes, and the like, and the conductive polymer may include polyethylene oxide (PEO). ), Polypyrrole (PPy), polyaniline (PANI), poly (3,4-ethylene dioxadiiophine) (PEDOT) and the like, but are not limited thereto.

The conductive filler tends to agglomerate strongly, which acts to minimize surface energy by forming bundles and agglomeration by van der Waals forces to minimize interfacial contact with the solvent.

In the present invention, in order to disperse the agglomerated conductive filler, a low viscosity methyl ended polydimethylsiloxane (MEP) is used to surround part or all of the conductive filler.

The content of the conductive filler is 0.5 to 20 parts by weight, preferably 4 to 12 parts by weight based on 100 parts by weight of the total polydimethylsiloxane (PDMS). If the content of the conductive filler is less than the lower limit, the desired conductivity may not be obtained. If the content of the conductive filler is greater than the upper limit, the amount of the conductive filler that is not dispersed and aggregated may increase, so that the conductivity may not be improved, and the curing reaction of the polymer may not be performed. You may not get the shape you want.

In addition, the low viscosity methyl ended polydimethylsiloxane (MEP) is formed to surround a part or the entire surface of the conductive filler to increase the dispersion of the conductive filler, the viscosity is 50 to 1000 cSt, preferably 100 to 350 cSt. If the viscosity of the low viscosity methyl ended polydimethylsiloxane (MEP) is less than the lower limit, the surface of the conductive filler may not be wrapped and the conductive filler may be difficult to disperse. If the upper limit is exceeded, the conductive filler may be difficult to disperse by contact with polydimethylsiloxane (PDMS).

The content of the low viscosity methyl ended polydimethylsiloxane (MEP) is 5 to 40 parts by weight, preferably 10 to 20 parts by weight based on 100 parts by weight of total polydimethylsiloxane (PDMS). If the content of low viscosity methyl ended polydimethylsiloxane (MEP) is less than the lower limit, the conductive filler may not be wrapped and it may be difficult to completely disperse the conductive filler into polydimethylsiloxane (PDMS), and if the upper limit is higher than polydimethyl The constituent ratio of the siloxane (PDMS) changes and prevents hardening so that it can be produced in the form of viscous mud rather than in a fixed form.

The conductive filler and low viscosity methyl ended polydimethylsiloxane (MEP) are mixed in a weight ratio of 1: 1 to 40, preferably in a weight ratio of 1: 2 to 5. If the content of low viscosity methyl ended polydimethylsiloxane (MEP) based on the conductive filler is lower than the lower limit, all the conductive fillers may not be wrapped, and if the upper limit is exceeded, the dispersion and conductivity of the conductive filler may be rather hindered. have.

In addition, the polydimethylsiloxane (PDMS) is a medium viscosity polydimethylsiloxane (PDMS-A), in contact with the low viscosity methyl ended polydimethylsiloxane (MEP) surrounding the conductive filler to contact the conductive filler polydimethylsiloxane (PDMS) -A) Evenly distributed into. When the polydimethylsiloxane (PDMS-A) is used directly without using the low viscosity methyl ended polydimethylsiloxane (MEP), the dispersibility of the conductive filler is lowered and the conductivity is lowered.

The viscosity of the polydimethylsiloxane (PDMS-A) is 3000 to 7000 cSt, preferably 3500 to 5500 cSt. If the viscosity of the polydimethylsiloxane (PDMS-A) is less than the lower limit, it may be difficult to contact with low viscosity methyl ended polydimethylsiloxane (MEP), and if the viscosity is higher than the upper limit, the hardened and flexible conductive polymer composite material Can't get it.

The conductive polymer composite material of the present invention has excellent conductivity because the conductivity is surface resistance of 100 Ω / sq or less, preferably 1 to 30 Ω / sq; Specifically, when the content of the conductive filler is 10 parts by weight or more, the conductivity is 1 Ω / sq or less. The surface resistance value is a measure of the resistance to the conductive material, and the lower the value of the surface resistance, the better the conductivity.

In addition, the conductive polymer composite material of the present invention is not easily deformed because the tensile strength is 1 to 5 MPa; The contact angle is 100 to 130 °, and the biocompatibility is excellent.

In addition, polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent may be further added to obtain a more flexible composite material while providing high strength.

In addition, the present invention provides a method for producing a conductive polymer composite material with reference to FIG.

Method for producing a conductive polymer composite material of the present invention comprises the steps of (A) ultrasonically mixing a conductive filler and isopropyl alcohol; (B) sonicating by adding a low viscosity methyl ended polydimethylsiloxane (MEP) to the mixed mixture; (C) sonicating by adding a medium viscosity polydimethylsiloxane (PDMS-A) to the mixture to which the low viscosity methyl ended polydimethylsiloxane (MEP) is added; (D) evaporating the solvent of the sonicated mixture and then mixing by adding polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing compound; And (E) molding the mixture mixed in the step (D).

First, in step (A), the conductive filler and isopropyl alcohol are mixed and treated with ultrasonic waves for 10 to 60 minutes (FIGS. 1A to 1C).

In order to disperse the aggregated conductive filler, the aggregated conductive filler is mixed with isopropyl alcohol and then ultrasonicated to disperse the conductive filler.

Since the solvent to be mixed with the conductive filler should be evaporated without leaving air for excellent conductivity when evaporating the solvent later, it is preferable to use high purity (99.9% or more) isopropyl alcohol. Specifically, the isopropyl alcohol has a stable structure composed of three carbons and one oxygen, so that the hydrophobic part easily contacts the surface of the conductive filler, and the hydrophilic part has a hydrophilic group having a hydroxyl group or the like. It is also easy to contact the PDMS of the part. In addition, the conductive filler and PDMS partially dispersed and dissolved in isopropyl alcohol, respectively, are evenly dispersed in the PDMS through ultrasonic waves.

When hexane or chloroform is used instead of the isopropyl alcohol, the boiling point is low and the volatility is high, so that a large amount of air is evaporated while leaving a large amount of air in the polymer, so that an empty space is formed between the conductive fillers, thereby degrading conductivity. In addition, in the case of using methyl alcohol or ethyl alcohol, since the hydrophobic part has less hydrophobic parts, the dispersibility of the conductive filler is low, and the solubility of polydimethylsiloxane and low viscosity methyl ended polydimethylsiloxane is low, so that the conductive filler is evenly distributed even if ultrasonic treatment is performed. It is not distributed.

The sonication destroys van der Waals forces between the mutual surfaces of the aggregated bundles of conductive fillers by the application of physical forces and separates the conductive fillers into a single conductive filler. In the present invention, in the ultrasonic treatment method, the ultrasonic treatment should be performed while maintaining the temperature at room temperature, preferably 10 to 23, within a time of 10 to 60 minutes by a bath ultrasonic method to minimize the damage of the conductive filler and to stabilize the dispersion. .

The ultrasonic wave may obtain a stable dispersion in which the conductive filler is evenly dispersed by using ultrasonic waves whose spatial peak pulse average intensity (ISPAA) varies between about 50 and 1,000 mW / cm 2 in a frequency range of about 40 to 5,000 kHz.

In addition, when using a solvent other than isopropyl alcohol as the solvent and a method other than the ultrasonic method as a physical method, since the conductive filler cannot be completely separated and dispersed in the solvent, the isopropyl alcohol and the ultrasonic treatment may be used. It is preferable to carry out together.

The conductive filler and isopropyl alcohol are mixed in a weight ratio of 1:30 to 1000, preferably in a weight ratio of 1:40 to 600. When the weight ratio of isopropyl alcohol based on the conductive filler is out of the above range, not only the aggregated conductive filler is separated but also the separated conductive filler may not be stably dispersed in isopropyl alcohol.

Next, in step (B), a low-viscosity methyl ended polydimethylsiloxane (MEP) is added to the mixture mixed in step (A) and then ultrasonicated (FIG. 1D).

The low viscosity methyl ended polydimethylsiloxane (MEP) comes into contact with the hydrophobic portion of isopropyl alcohol and wraps the dispersed conductive filler by sonication.

The ultrasonic treatment performed in step (B) is performed under the same conditions as in step (A), but is performed for 5 to 20 minutes, preferably 10 to 15 minutes. If the sonication time is less than the lower limit, the low viscosity methyl ended polydimethylsiloxane (MEP) cannot wrap the conductive filler, and if it exceeds the upper limit, the methyl ended polydimethylsiloxane (MEP) rather prevents the conductive filler from covering the conductive filler. can do.

Next, in step (C), the mixture prepared in step (B) is subjected to sonication by adding a medium viscosity polydimethylsiloxane (PDMS-A) (FIG. 1E).

The medium viscosity polydimethylsiloxane (PDMS-A) is a more stable dispersion by evenly dispersing the conductive filler in solution in contact with isopropyl alcohol and low viscosity methyl ended polydimethylsiloxane (MEP) surrounding the conductive filler due to sonication. Can be obtained.

The ultrasonic treatment performed in step (C) is performed under the same conditions as in step (A), but is performed for 5 to 20 minutes, preferably 10 to 15 minutes. If the sonication time is less than the lower limit, it may be difficult to contact the low viscosity methyl ended polydimethylsiloxane (MEP), and if the upper limit is exceeded, the conductive filler may be damaged.

Next, in step (D), isopropyl alcohol contained in the mixture prepared in step (C) is evaporated, and then polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent is added and mixed (FIG. 1f and FIG. 1g).

The temperature at which the isopropyl alcohol is evaporated is 50 to 70 ° C., preferably 50 to 60 ° C., so that no empty space is formed between the conductive filler and the polymers (PDMS and MEP), and 3 to 12 (overnight) hours under the temperature. Is performed. The evaporation must be performed under the above temperature so that the polymer can be filled in place while the isopropyl alcohol is evaporated.

If the evaporation temperature and the evaporation time is less than the lower limit, isopropyl alcohol may not be completely evaporated. If the evaporation temperature is higher than the upper limit, an empty space may exist between the conductive filler and the polymer, thereby deteriorating physical properties.

When the isopropyl alcohol is evaporated, it becomes flexible. In this case, polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent is added and mixed to obtain a more flexible composite material with excellent strength.

The metal of the polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent may be platinum, but it cannot be used as a curing catalyst when other metals such as gold or silver are used. Preferably, polydimethylsiloxane (SiH-PDMS) containing a SiH compound may be further added to the polydimethylsiloxane (PDMS-B) containing the metal catalyst and curing agent, wherein the polysiloxane and Si-H containing a vinyl group are added. As a result of the addition reaction of the polysiloxane having a bond, the siloxane is crosslinked. By-products are not generated by the platinum compound used as a catalyst.

The polydimethylsiloxane (PDMS-B) containing the metal catalyst and the curing agent has a weight ratio of 1: 2-20 of the polydimethylsiloxane (PDMS-B) and the polydimethylsiloxane (PDMS-A) containing the metal catalyst and the curing agent. To be mixed. If the content of polydimethylsiloxane (PDMS-A) is less than the lower limit based on polydimethylsiloxane (PDMS-B) containing a metal catalyst and a curing agent, the curing reaction will not proceed, and if the upper limit is higher than It will not be able to cure to make the composite material flexible.

Next, in the step (E), the mixture mixed in the step (D) is injected into a molding die and cured at 70 to 100 ° C. for 1 to 12 hours to prepare a conductive polymer composite material.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Example 1 CNT 1 part

0.045 g of multiwall carbon nanotubes were mixed with 25 g of isopropyl alcohol (99.9%), sonicated for 30 minutes until a homogeneous solution, and then a low viscosity methyl ended polydimethylsiloxane solution ( 0.5 g of MEP, Dow Corning, 100 cSt, total PDMS (10% concentration of MEP solution compared to PDMS-A + PDMS-B) is mixed and sonicated for 10 minutes. Then add 4.5 g of a medium viscosity polydimethylsiloxane solution (PDMS-A, Sylgard 184 A, Dow Corning, 3500 cSt, 90% PDMS-A solution relative to the total PDMS) and then add the reaction mixture to a homogeneous solution. The reaction mixture is sonicated for about 10 minutes and the solvent of the reaction mixture is evaporated at about 55 ° C. for 6 hours. Then a polydimethylsiloxane solution (PDMA-B, Sylgard 184 B, Dow Corning, 100 cst, 1: 10 weight ratio (PDMA-B: total PDMS)) containing 0.5 g of platinum catalyst was added to the reaction mixture, After mixing evenly, the prepared mold was filled and thermally cured at 100 ° C. for 1 hour to prepare a molded conductive polymer composite material.

Example 2 CNT 2 parts by weight

In the same manner as in Example 1, but using a multi-walled carbon nanotube 0.09 g to prepare a conductive polymer composite material.

Example 3 4 parts by weight of CNT

In the same manner as in Example 1, using a multi-walled carbon nanotubes 0.18 g to prepare a conductive polymer composite material.

Example 4 8 parts by weight of CNT

In the same manner as in Example 1, using a 0.36 g multi-walled carbon nanotubes to prepare a conductive polymer composite material.

Comparative Example 1.CNT Omitted

A polymer composite material was prepared in the same manner as in Example 1, without using carbon nanotubes.

Comparative Example 2. PDMS Only

5 g of medium viscosity polydimethylsiloxane (Sylgard 184 base, PDMS-A from Dow Corning) is mixed with 25 g of isopropyl alcohol to sonicate the reaction mixture for about 10 minutes until a homogeneous solution is obtained and the solvent of the reaction mixture. Is evaporated at about 55 ° C. for 6 hours. Thereafter, 0.5 g of a polydimethylsiloxane solution containing platinum compound (Dow Corning Sylgard 184 curing agent, PDMS-B) was added to the reaction mixture, mixed evenly, filled into the prepared mold, and heated at 100 ° C. for 1 hour. Cured and molded to prepare a conductive polymer composite material.

Comparative Example 3.

In the same manner as in Example 1, a conductive polymer composite material was prepared without using a low viscosity methyl ended polydimethylsiloxane solution (MEP).

<Test Example>

In Comparative Example 3, CNT and the medium viscosity polydimethylsiloxane were not mixed, so that the conductive polymer composite material could not be manufactured.

Test Example 1. Measurement of contact angle, tensile strength and conductivity

1-1. Measurement of contact angle (°): It is the value measured by dropping a droplet such as water on the sample surface and measuring the angle between the stationary droplet and the surface (static contact angle). In general, the test is performed by dropping water droplets. The higher the surface tension of the solid surface, the better the wettability and the smaller the contact angle, and the smaller the contact angle means the higher the hydrophilicity, the better the wettability and the better adhesion. (ASTM D 5946).

1-2. Tensile strength (MPa) measurement: Test the test material by cutting it into the specified test piece, then fastening both ends of the test piece to the tester, and slowly pulling the test piece in the axial direction of the test piece until the strain and the corresponding load are measured. Tensile strength against deformation of the material was measured (ASTM D412 test).

1-3. Conductivity (Ω / sq) measurement: Apply the current to the sample from the current source and measure the potential difference using a Nanovoltmeter. With the 4-probe method, two probes are used to flow the current and the other two probes Used to measure Obtain V (voltage) / I (current) = ohm from the applied current and the measured voltage, and apply the correction factor (Correctioin Factor) to calculate the surface resistance in ohm / sq. Ohm X C.F = ohm / sq

Table 1 division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Contact angle (°) 103.1 ± 1.51 103.0 ± 2.89 108.2 ± 4.13 107.9 ± 1.57 98.60 ± 3.29 102.2 ± 1.32 Tensile Strength (MPa) 2.47 ± 0.06 2.55 ± 0.12 2.90 ± 0.08 3.21 ± 0.16 1.80 ± 0.05 1.71 ± 0.17 Conductivity (Ω / sq) 5225 ± 1755 212.3 ± 30.92 23.67 ± 1.07 8.72 ± 1.48 > 10 ¹² > 10 ¹⁴

As shown in Table 1, the conductive polymer composites prepared according to Examples 1 to 4 of the present invention was confirmed that the contact angle, tensile strength and conductivity are superior to Comparative Examples 1 and 2, Comparative Examples 1 and 2 The conductivity was not measured.

Test Example 2 Measurement of Dispersion Stability

Figures 2a to 2d is a thermogravimetric analyzer (TGA, Figure 2a), respectively, after mixing the carbon nanotubes and isopropyl alcohol in Example 3 and before the ultrasonication reactant (gray line) and the reactant (black line) after sonication, It is a graph measured with a differential scanning calorimeter (DSC, Fig. 2b), a Fourier transform infrared spectrometer (FT-IR, Fig. 2c) and a dispersion stability change meter (Fig. 2d).

As shown in FIG. 2, the reactants before the sonication (gray line) and the reactants after the sonication (black line) are dispersions in completely different states, and the dispersions are stabilized after the sonication.

Figures 3a to 3d is a thermogravimetric analyzer (TGA, Figure 3a), the time difference between the reactant (gray line) and the ultrasonic wave reactant (gray line) and the ultrasonic wave reactant after mixing to the medium-weight polydimethylsiloxane solution in Example 3, respectively It is a graph measured with a scanning calorimeter (DSC, FIG. 3B), a Fourier transform infrared spectrometer (FT-IR, FIG. 3C) and a dispersion stability change meter (FIG. 3D).

As shown in FIG. 3, it was confirmed that the reactants before the sonication (gray line) and the reactants after the sonication (black line) are dispersions in completely different states. It was also confirmed that after the sonication the reactants became more stable.

Figure 4 is a graph and photograph measured by a dispersion meter after reacting the reactants before and after sonication at room temperature for one week after sequentially mixing each material according to Example 3.

As shown in FIG. 4, the reactants before the sonication and the reactants after the sonication are dispersions in completely different states, and the dispersions are stabilized after the sonication.

Test Example 3. Measurement of Cell Viability

5 is a graph measuring the cell viability of the conductive polymer composite prepared according to Example 3, Comparative Example 1 and Comparative Example 2 of the present invention.

Human primary keratinocyte (thermo Fisher) HaCaT cells (5,000 cells per 96 wells used) on 5 mm round specimens prepared using the conductive polymer composites of Example 3, Comparative Example 1 and Comparative Example 2 Was incubated for 60 hours. Cell viability of HaCaT cells exposed to these conditions was measured by Cell Counting Kit-8 (CCK-8, Dojindo).

The cell viability for each material was similar without changing statistical values, and similar to PDMS (Comparative Example 2) reported to have excellent biocompatibility as shown in FIG. It was confirmed that also excellent cell compatibility.

Test Example 4. Measurement of Cytotoxicity

Figure 6 is a graph measuring the cytotoxicity of the conductive polymer composite prepared according to Example 3, Comparative Example 1 and Comparative Example 2 of the present invention.

The effluent of the 5 mm round specimens prepared using the conductive polymer composites of Examples 3, Comparative Examples 1 and 2 was subjected to 10% FBS (fetal bovine serum), 100 U / ml penicillin and 100 mg / ml streptomycin. The culture was collected by incubating for 3 days at 37 ° C. in 80% humid conditions (5% CO 2 atmosphere) in DMEM (Dulbeccos modified Eagles medium) containing. The solution was added to human primary keratinocytes (thermo Fisher's) HaCaT cells (5,000 cells per 96 wells used) and incubated for 60 hours, and the cytotoxicity rate of the effluent was measured by Cell Counting Kit-8. It was.

The cytotoxicity rate by the effluent of each material was similar without changing the statistical value, and as shown in Figure 6 similar to the PDMS (Comparative Example 2) reported to be excellent biocompatibility of Example 3 The conductive polymer composite also showed no cytotoxicity.

Test Example 5.

7a to 7c are infrared spectroscopy (FT-IR, 7a), Raman spectroscopy (FIG. 7b) and X-ray diffraction analysis (XRD, 7c) of the polymer composite material prepared according to Example 3 and Comparative Example 1 It is a graph measured by.

As shown in FIG. 7, it was confirmed that the polymer composite material prepared according to Example 3 and Comparative Example 1 was a polymer composite material having completely different properties.

Test Example 6 Surface Property Measurement

Figure 8a is a photograph taken with a high-resolution scanning electron microscope (HR-SEM) of the conductive polymer composite material of Example 3, Figure 8b is a photograph taken with a transmission electron microscope (TEM) of the conductive polymer composite material of Example 3 to be.

As shown in FIG. 8A, not only the carbon nanotubes are uniformly dispersed and fixed in the polymer, but also the carbon nanotubes are in good contact with each other.

In addition, as shown in Figure 8b, it was confirmed that the carbon nanotubes are dispersed in a single strand in the polymer.

Therefore, it was confirmed again that the conductive polymer composite material of the present invention was a material having excellent conductivity.

Test Example 7 Measurement of Conductivity, Tensile Strength and Elasticity

9A is a graph measuring conductivity of the conductive polymer composites prepared according to Examples 1 to 4, and FIG. 9B is a graph measuring tensile strength of the conductive polymer composites prepared according to Examples 1 to 4. 9c is a graph measuring a cycling test of the conductive polymer composites prepared according to Examples 1 to 4. FIG.

As shown in Figure 9, it was confirmed that the conductive polymer composites of Examples 1 to 4 have high electrical, mechanical and elasticity.

Flexible circuit manufacturing

Example 5 Flexible Circuit

After designing an electric circuit by pouring SU-8 on the silicon wafer, UV irradiation was carried out to form a mold with a protruding shape of the electric circuit, and then PDMS was poured into the mold to cure, thereby obtaining a size of about 5x10 cm (thickness 1 to 2). mm) of electrical circuits were formed.

Next, after filling the conductive polymer composite material of Example 1 in the formed electric circuit and inserting a suitable electronic device and cured at 60 ℃, the device manufactured by installing the electronic component in the electronic circuit manufactured using Example 1 Was prepared (FIG. 10).

Test Example 8 Current Flow Measurement

FIG. 10 is a flowchart illustrating a process of installing an electronic component in an electronic circuit manufactured by using the third embodiment of the present invention, and FIG. 11 illustrates a bending of the device manufactured in FIG. 10 (bending test). This is a picture confirmed by supplying a current.

As shown in FIG. 11, after bending the device manufactured using Example 3 and flowing a current, the number '7' is lit, so the electronic circuit manufactured using the composite material increases. Even if it is bent, folded or bent, it is confirmed that electricity is present.

In addition, it was confirmed that electricity flows in all directions, not in one direction.

The conductive polymer composite material of the present invention can be used not only as a biosignal measuring electrode, an electrical stimulation electrode and a biomaterial sensor, but also as a conductor instead of a metal substrate in an electrical circuit of a flexible device.

Claims (14)

A conductive polymer composite material comprising a conductive filler dispersed in a polymer mixture including polydimethylsiloxane (PDMS) and low viscosity methyl ended polydimethylsiloxane (MEP). The method of claim 1, wherein the conductive polymer composite material comprises 5 to 40 parts by weight of low viscosity methyl ended polydimethylsiloxane (MEP) and 0.5 to 20 parts by weight of the conductive filler based on 100 parts by weight of polydimethylsiloxane (PDMS) Conductive polymer composite material. The conductive polymer composite material according to claim 1, wherein the conductive filler and the low viscosity methyl ended polydimethylsiloxane (MEP) are mixed in a weight ratio of 1: 1 to 40. The conductive polymer composite material of claim 1, wherein the conductive filler is at least one selected from the group consisting of carbon nanotubes, carbon black, metal fibers, conductive polymers, and graphene. The conductive polymer composite material according to claim 1, wherein the viscosity of the low viscosity methyl ended polydimethylsiloxane (MEP) is 50 to 1000 cSt. The conductive polymer composite material according to claim 1, wherein the polydimethylsiloxane (PDMS) has a viscosity of 3000 to 7000 cSt. The conductive polymer composite material of claim 1, wherein the conductive polymer composite has a surface resistance of 100 Ω / sq or less. The conductive polymer composite material of claim 1, wherein the conductive polymer composite material has a tensile strength of 1 to 5 MPa and a contact angle of 100 to 130 °. The conductive polymer composite material according to claim 1, wherein the dispersion is performed by sonication under isopropyl alcohol. The conductive polymer composite material of claim 1, wherein the conductive polymer composite material further comprises a polydimethylsiloxane containing a metal catalyst and a curing agent. (A) mixing and sonicating the conductive filler and isopropyl alcohol; (B) sonicating by adding a low viscosity methyl ended polydimethylsiloxane (MEP) to the mixed mixture; (C) adding polydimethylsiloxane (PDMS) to the mixture containing the low viscosity methyl ended polydimethylsiloxane (MEP) to sonicate; (D) evaporating isopropyl alcohol contained in the sonicated mixture, followed by mixing by adding polydimethylsiloxane (PDMS) containing a metal catalyst and a curing agent; And (E) forming the mixture mixed in the step (D); manufacturing method of a conductive polymer composite material comprising a. The method of claim 1, wherein the temperature of the mixture during the ultrasonic treatment in the steps (A), (B) and (C) is maintained at 10 to 23 ℃. The method of claim 1, wherein the conductive filler and isopropyl alcohol in the step (A) is a method for producing a conductive polymer composite material, characterized in that mixed in a weight ratio of 1: 30 to 1000. The method of claim 1, wherein the temperature for evaporating isopropyl alcohol in the step (D) is 50 to 70 ℃ manufacturing method of the conductive polymer composite material.

Images