JP2009215424A - Electroconductive nano sized polymer particles and method for producing the conductive nano sized polymer particles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide conductive nano sized polymer particles that do not contain any surfactant, hence is excellent in conductivity, and to provide a method for producing the conductive nano sized polymer particles. <P>SOLUTION: The electroconductive nano sized polymer particle is useful as functional electronic materials or as electronic sensing materials because it a has an average particle diameter of 10-1,000 nm and does not include in the particle any surfactant that causes drop of conductivity, hence is excellent in conductivity, and the electroconductive nano sized polymer particle can be obtained easily and effectively by mixing a monomer having a π-conjugated double bond in a supercritical carbon dioxide together with an oxidizing agent and performing polymerization. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive polymer nanoparticle and a method for producing the conductive polymer nanoparticle. More specifically, the present invention relates to a conductive polymer nanoparticle that is excellent in conductivity and optimal as an electronic sensing material, and a method for producing the conductive polymer nanoparticle.

  A conductive polymer composed of a polymer of a monomer having a π-conjugated double bond represented by polythiophene (Pth), polypyrrole (PPy), polyaniline (PAn) and the like is an electronic sensing material (electronic functional material). ) Is expected to be applied. On the other hand, these conductive polymers have a problem that they are difficult to mold due to their low solubility in water and organic solvents due to their strong π-conjugated double bonds.

Therefore, it has been studied to synthesize and polymerize these conductive polymers in a fine particle state. For example, a co-solvent such as water or an organic solvent, a nonionic surfactant, an anionic surfactant, etc. Nano-sized conductive polymer fine particles (conductive polymer nano fine particles) composed of a polymer of monomers having a π-conjugated double bond by electropolymerization without using an oxidant and applying a surfactant as a dispersant Has been proposed (see, for example, Patent Document 1). In addition, a method for producing polypyrrole using carbon dioxide and ethanol in a supercritical state as a solvent, iron chloride (FeCl ₃ ) as an oxidant, and a surfactant has also been proposed (for example, Non-Patent Document 1). reference.)

JP 2003-1119080 A Tan et al., “Ionic Hydrocarbon Surfactants for Emulsification and Dispersion Polymerization in Supercritical CO2,” American Chemical Society, USA, 74, Macro71, United States, 74.

  However, when a surfactant is used in the polymerization, the surfactant remains in the resulting conductive polymer nanoparticles, whereas the presence of the surfactant causes a decrease in conductivity. It was not preferable.

  The present invention has been made in view of the above-described problems, and provides a conductive polymer nanoparticle that is excellent in conductivity without the presence of a surfactant and a method for producing the conductive polymer nanoparticle. It is in.

  In order to solve the above problem, the conductive polymer nanoparticle according to claim 1 of the present invention is a conductive polymer nanoparticle made of a polymer of a monomer having a π-conjugated double bond, The particle diameter is 10 to 1000 nm, and no surfactant is present.

  The conductive polymer nanoparticles according to claim 2 of the present invention are polythiophenes according to claim 1 described above.

  The method for producing conductive polymer nanoparticles according to claim 3 of the present invention is characterized in that a monomer having a π-conjugated double bond is mixed with supercritical carbon dioxide together with an oxidizing agent and polymerized. .

  The method for producing conductive polymer nanoparticles according to claim 4 of the present invention is characterized in that, in the above-described claim 3, the monomer having the π-conjugated double bond is thiophene or a thiophene derivative.

  The method for producing conductive polymer nanoparticles according to claim 5 of the present invention is characterized in that, in the above-described claim 3 or 4, the polymerization is terminated when the yield is 50 to 75%.

  The method for producing conductive polymer nanoparticles according to claim 6 of the present invention is characterized in that, in any of claims 3 to 5, the oxidizing agent is a hypervalent iodine compound.

  The conductive polymer nanoparticle according to claim 1 of the present invention has an average particle diameter of 10 to 1000 nm, the surfactant is not taken into the particle, and the conductivity is lowered by the surfactant. It has excellent conductivity and is useful as a functional electronic material or electronic sensing material. For example, anti-static materials, electrolytic capacitors, and polymer organic EL devices, including semiconductor materials, conductive paints, and anti-rust paints. , Secondary batteries, electromagnetic shielding materials, organic transistors, electrophotographic photoreceptors, organic semiconductor lasers, organic solar cells, capacitors, fuel cells, actuators, sensors, nanowires, intelligent materials, liquid crystalline organic semiconductors, etc. It can be used as a material for organic semiconductors and organic electronics.

  Since the conductive polymer nanoparticles according to claim 2 of the present invention are polythiophenes that are polymers of thiophene or its derivatives, they are excellent in conductivity, light weight, and plasticity, and are made of semiconductor materials, conductive paints, and rust prevention. Starting with paints, anti-static materials, electrolytic capacitors, polymer organic EL elements, secondary batteries, electromagnetic shielding materials, organic transistors, electrophotographic photoreceptors, organic semiconductor lasers, organic solar cells, capacitors, fuel cells, actuators, It is ideal for applications such as sensors, nanowires, intelligent materials, liquid crystalline organic semiconductors, or other organic semiconductors and organic electronics materials.

  In the method for producing a conductive polymer nanoparticle according to claim 3 of the present invention, a monomer having a π-conjugated double bond is mixed with supercritical carbon dioxide together with an oxidizing agent to be polymerized, Since a surfactant is not used in the polymerization, the surfactant is not present (residual) in the conductive polymer nanoparticles as a product, and thus nanoparticles having excellent conductivity can be provided. In addition, when conducting oxidative polymerization using an oxidizing agent, carbon dioxide in a supercritical state is used as a solvent, so that a spherical conductive polymer with a uniform average particle diameter is used as in the case of using a surfactant. Nanoparticles can be provided easily.

  The method for producing conductive polymer nanoparticles according to claim 4 of the present invention employs thiophene or a thiophene derivative as a monomer having a π-conjugated double bond, and therefore provides polythiophenes that enjoy the above-described effects. Can do.

  In the method for producing conductive polymer nanoparticles according to claim 5 of the present invention, the polymerization is terminated when the yield is 50 to 75%. Aggregation can be prevented, and a reaction product (conductive polymer nanoparticle) having a uniform average particle diameter can be obtained.

  The method for producing conductive polymer nanoparticles according to claim 6 of the present invention employs a hypervalent iodine compound as an oxidizing agent used in polymerization, and the compound is carbon dioxide in a supercritical state. It is optimal for the oxidant of the present invention and the polymerization proceeds efficiently.

  The present invention will be described below. The conductive polymer nanoparticle of the present invention comprises a polymer of a monomer having a π-conjugated double bond, has an average particle diameter of 10 to 1000 nm, and does not have a surfactant.

  The conductive polymer nanoparticle of the present invention is a polymer of a monomer having a π-conjugated double bond. Examples of monomers that can be used include thiophene, 3-alkylthiophene, 3-methoxythiophene, and 3-acetylthiophene. Thiophene derivatives such as 3-phenylthiophene and 3,4-ethylenedioxythiophene, pyrrole derivatives such as pyrrole, 3-alkylpyrrole, 3-methoxypyrrole, 3-acetylpyrrole, 3-phenylpyrrole, aniline, o-methyl Aniline derivatives such as aniline and m-methylaniline can be used. Examples of these polymers include polythiophene, poly (3-alkylthiophene), poly (3-methoxythiophene), poly (3-acetylthiophene), poly (3-phenylthiophene), and poly (3,4- Polythiophenes such as ethylenedioxythiophene), polypyrroles such as polypyrrole, poly (3-alkylpyrrole), poly (3-methoxypyrrole), poly (3-acetylpyrrole), poly (3-phenylpyrrole), polyaniline, Polyanilines such as poly (o-methylaniline) and poly (m-methylaniline) can be provided as conductive polymer nanoparticles.

In addition, since the conductive polymer nanoparticle of the present invention does not incorporate a surfactant into the fine particle as described above, it does not cause a decrease in conductivity due to the surfactant. Can be provided as a conductive polymer nanoparticle having a density of 10 ⁻⁶ to 10 ⁰ S / cm ⁻¹ .

Such a conductive polymer nanoparticle of the present invention having no surfactant and excellent conductivity is, for example, a supercritical carbon dioxide together with an oxidant and a monomer having a π-conjugated double bond. Can be obtained simply and efficiently. In such a production method, a surfactant is not used in the polymerization, so that the surfactant is not present (residual) in the conductive polymer nanoparticle as a product, and the conductivity is reduced due to the presence of a non-conjugated compound. In other words, the nanoparticle is excellent in conductivity with an electrical conductivity of 10 ⁻⁶ to 10 ⁰ S / cm ⁻¹ . In addition, since a co-solvent such as water or an organic solvent is not used, there is also an advantage that an environmentally harmonious synthesis process that does not emit volatile organic compounds (VOC) is obtained. In carrying out oxidative polymerization using an oxidant, carbon dioxide in a supercritical state is used as a solvent. Therefore, as in the case of using a surfactant, the average particle size is 10 to 1000 nm (preferably 20 to 500 nm) spherical conductive polymer nanoparticles can be obtained.

  FIG. 1 is a state diagram of carbon dioxide. Carbon dioxide may be liquefied under temperature and pressure conditions above the triple point (−56.6 ° C., 0.52 MPa), but the temperature and pressure are critical (31.1 ° C., 7.38 MPa). Beyond that, it becomes a "supercritical fluid" that combines the characteristics of liquid and gas. In general, a fluid in a supercritical state has fast mass transfer and strong permeability, so that the dissolving power can be continuously changed. In particular, carbon dioxide in a supercritical state has a critical temperature of 31.1 ° C. and a critical pressure. The supercritical state can be achieved under relatively mild conditions such as 7.38 MPa. Also, supercritical carbon dioxide has no toxicity, is chemically inert, and high-purity carbon dioxide can be obtained at low cost. Therefore, using supercritical carbon dioxide as a solvent is safe and costly. It can be said that it is an excellent means in terms of the aspect.

  Carbon dioxide becomes a “non-aggregating high-pressure, high-density fluid” that does not liquefy even when compressed to a high density at temperatures exceeding the critical point. The intermolecular distance can be adjusted by pressure and temperature, the density can be changed from a dilute state to a place close to the liquid, and the solubility of the solute in the supercritical fluid can be changed. When a monomer having a π-conjugated double bond is polymerized, carbon dioxide in a supercritical state is used as a solvent, thereby causing a partial difference in solubility of the monomer due to density fluctuation. By stirring and mixing this in the reaction system, it is possible to create a fine reaction field, and without using a surfactant, a particulate (spherical) reaction is generated just as when using a surfactant. Product (conductive polymer nanoparticle) can be obtained.

  In addition, as described above, carbon dioxide becomes a “non-aggregating high-pressure, high-density fluid” that does not liquefy even when compressed to a high density at temperatures exceeding the critical point. By adjusting the density from a dilute state to a place close to a liquid, the solubility of the solute in the supercritical fluid can be changed. In the present invention, since the density of carbon dioxide in a supercritical state can be controlled, the average particle diameter of the generated conductive polymer nanoparticles is controlled using such density control of carbon dioxide. It becomes possible to do.

That is, the carbon dioxide in the supercritical state in the polymerization changes at about 0.5 to 1.0 g / cm ³ , and even in the present invention, it can be carried out in such a range of density, and the average particle size is Although it becomes possible to obtain conductive polymer nanoparticles in the range of 10 to 2000 nm, when the density of carbon dioxide is increased, the average particle diameter of the conductive polymer nanoparticles can be reduced. By setting it as 0.75-0.95 g / cm < ³ >, the average particle diameter of the electroconductive polymer nanoparticle obtained can be about 30-200 nm. By increasing the density of carbon dioxide, the monomer can be stably dispersed in the reaction system, and the average particle diameter of the conductive polymer nanoparticles that are the reaction product can be reduced.

  The density of carbon dioxide in the critical state is determined by the temperature and pressure of carbon dioxide. The temperature of carbon dioxide in the critical state may be a temperature equal to or higher than the critical point (31.1 ° C.), but the higher the temperature of carbon dioxide, the lower the density and the larger the average particle size. Further, the pressure of carbon dioxide in the critical state may be a pressure not lower than the critical point (7.38 MPa), but the higher the pressure, the higher the density and the smaller the average particle size. The temperature of the carbon dioxide in the supercritical state may be approximately 40 to 80 ° C., and the pressure may be approximately 15 to 25 MPa.

  In the method for producing conductive polymer nanoparticles of the present invention, the monomer having a π-conjugated double bond is not particularly limited as long as it is a monomer used for producing a conductive polymer. For example, polythiophene Thiophene derivatives such as thiophene, 3-alkylthiophene, 3-methoxythiophene, 3-acetylthiophene, 3-phenylthiophene and 3,4-ethylenedioxythiophene, and polypyrroles. For example, when producing pyrrole derivatives such as pyrrole, 3-alkylpyrrole, 3-methoxypyrrole, 3-acetylpyrrole, 3-phenylpyrrole, and polyanilines, aniline, o-methylaniline, m-methylaniline, etc. An aniline derivative or the like can be used. In the present invention, among these, thiophene derivatives such as thiophene and 3,4-ethylenedioxythiophene, pyrrole, and aniline are preferable.

  The concentration of the monomer may be determined depending on the type of polymer (conductive polymer nanoparticle) to be produced, conductivity, average particle size, etc., but is generally within the range of 1 to 1000 mM (0.001 to 1 M). It is preferable to select. In the present invention, the monomer concentration affects the conductive polymer nanoparticles that are the reaction product. Generally, the higher the monomer concentration, the more the average particle diameter of the conductive polymer nanoparticles is growing.

  The oxidant that can be used is only required to be soluble in carbon dioxide in a supercritical state, and a so-called “hypervalent iodine compound” can be used as an oxidant. Examples of the hyperatomized iodine compound include (perfluoro-n-octyl) phenyliodonium trifluoromethanesulfonate, (perfluorohexyl) phenyliodonium trifluoromethanesulfonate, (perfluoroisopropyl) phenyliodonium trifluoromethanesulfonate, and (perfluoropropyl). Phenyliodonium trifluoromethanesulfonate, iodomesitylene diacetate, phenyl [2- (trimethylsilyl) phenyl] iodonium trifluoromethanesulfonate, [bis (trifluoroacetoxy) iodo] benzene, [bis (trifluoroacetoxy) iodo] pentafluoro An oxidizing agent such as benzene may be mentioned. One type of these oxidizing agents may be used alone, or two or more types may be used in combination.

Such a superatomized iodine compound is represented by the following formula (I) or the following formula (II). Here, in Formula (I) or Formula (II), R ₁ is H, CH ₃ or F, R ₂ is phenyl, alkyl, perfluoroalkyl, A is alkyl sulfonic acid, perfluoroalkyl sulfonic acid, Anions such as tetrafluoroborate, R ₂ ′, R ₃ ′ are one or two of alkyl sulfonic acid, perfluoro sulfonic acid, alkyl ester, perfluoro ester, one of which is one of the other , Alkyl, perfluoroalkyl, or phenyl.

In addition to being soluble in carbon dioxide in the supercritical state, these hypervalent iodine compounds exhibit reactivity equivalent to that of a metal oxidant even though the compound does not contain a metal element, Since it also waits for the property as a doping agent, it is preferable as an oxidizing agent used in the production method of the present invention. Further, these hypervalent iodine compounds contain a fluorine group, so that they have high affinity with carbon dioxide in a supercritical state and become soluble. On the other hand, in the case of an oxidant containing a transition metal such as iron chloride (FeCl ₂ ), it becomes insoluble in carbon dioxide in a supercritical state, and as a result, an organic solvent must be added. Therefore, it is used in the production method of the present invention. It is not preferable as an oxidizing agent.

  The concentration of the oxidizing agent to be used may be determined according to the type and concentration of the monomer, the type of the oxidizing agent to be used, etc., and is generally 1 to 1000 mM (0.001 to 1 M) (or to the monomer 1M). About 0.05 to 0.5M).

  The oxidative polymerization using the oxidant is performed by mixing an oxidant, a monomer having a π-conjugated double bond, and a supercritical carbon dioxide serving as a solvent, but is preferably performed in a stirred state. Stirring can be performed using known stirring means such as a magnetic stirrer, homogenizer, and stirrer, and the stirring speed can be, for example, 100 to 1000 rpm.

  The polymerization time may be appropriately determined depending on the type, concentration, amount, and the like of the monomer used, but it may be approximately 30 minutes or more, and preferably 30 to 120 minutes. If the polymerization is excessively advanced, particles may aggregate due to a reaction between polymer chains, and conductive polymer nanoparticles having a uniform average particle diameter may not be obtained. When the polymerization is terminated at a rate of 50 to 75% (the polymerization time is approximately 40 to 80 minutes), aggregation of the particles can be prevented, and a reaction product having a uniform average particle diameter (conductivity) Polymer nanoparticle) can be obtained.

  In addition to the essential components such as the monomer, oxidant, and carbon dioxide in the supercritical state, various additives are added to the reaction system as needed within a range that does not interfere with the purpose and effect of the present invention. can do. A conventionally well-known thing can be used as an additive, For example, organic solvents, such as methanol, ethanol, and acetonitrile, are mentioned.

  FIG. 2 is a schematic view showing an embodiment of a production apparatus for carrying out the method for producing conductive polymer nanoparticles according to the present invention. In the manufacturing apparatus 1 shown in FIG. 2, the high-pressure cell 10 introduces raw materials to perform a polymerization reaction, and a heater 11 (ribbon heater) for heating the high-pressure cell 10 is provided around the high-pressure cell 10. In addition, a stirrer 13 for stirring is placed inside the high-pressure cell 10. The temperature and pressure of the high-pressure cell 10 can be confirmed by the thermocouple 14 and the pressure gauge 15 installed. The high-pressure cell 10 can confirm the internal state of the high-pressure cell 10 from the outside through the observation window 17 made of sapphire glass.

  Carbon dioxide used as a solvent for the polymerization is stored in a carbon dioxide cylinder 21 and is introduced into the high pressure cell 10 through the path A in FIG. Further, the monomer having a π-conjugated double bond as a raw material is charged into the path B in the production apparatus 1 of FIG. 2 and is press-fitted into the high-pressure cell 10 by carbon dioxide. The heater 12 (ribbon heater) heats the passing carbon dioxide. The pressure in the reaction system including the inside of the high-pressure cell 10 is adjusted by driving the pump 22, and the pressure in the system is measured by the pressure gauge 16. Further, a valve V is disposed in the path and in the high-pressure cell 10.

  With reference to FIG. 3, an embodiment of the method for producing the conductive polymer nanoparticles of the present invention will be described. FIG. 3 is a view showing a flowchart of the method for producing conductive polymer nanoparticles of the present invention. First, an oxidizing agent is introduced into the high-pressure cell 10 (S1), and the high-pressure cell 10 is brought into a sealed state to a temperature above the critical point (for example, 40 to 80 ° C.) (S2). Next, after introducing carbon dioxide from the carbon dioxide cylinder 21 through the path A into the cell (S3), the high pressure cell 10 is brought to a supercritical state with a pressure higher than the critical point (for example, 15 to 25 MPa) ( S4), stirring for a while. At this time, the system may be left for a while (about 30 to 120 minutes) in order to stabilize the system.

  After charging a monomer having a π-conjugated double bond in the path B and introducing the monomer into the high pressure cell 10 in which the oxidant and carbon dioxide in a supercritical state are mixed into the high pressure cell 10 from the path B (S5 ), And further stirred and mixed to proceed the polymerization (S6). After completion of the polymerization, the inside of the high-pressure cell 10 is decompressed (S7), and conductive polymer nanoparticles can be obtained.

  The obtained conductive polymer nanoparticles are preferably purified by centrifuging and centrifuging with alcohols such as methanol, ethanol, propanol and butanol after decompression (S8). The purified conductive polymer nanoparticles can be re-dispersed in a solvent such as methanol, ethanol, propanol, or butanol, so that a dispersion solution of these solvents (conductive polymer nanoparticles) Dispersion solution).

  Since the conductive polymer nanoparticle of the present invention has excellent conductivity without the presence of a surfactant, it is useful as a functional electronic material or an electronic sensing material, for example, a semiconductor material, a conductive paint, Including anti-corrosion paints, anti-static materials, electrolytic capacitors, polymer organic EL elements, secondary batteries, electromagnetic shielding materials, organic transistors, electrophotographic photoreceptors, organic semiconductor lasers, organic solar cells, capacitors, fuel cells, It can be used as actuators, sensors, nanowires, intelligent materials, liquid crystalline organic semiconductors, or other organic semiconductors, organic electronics materials, and the like.

  In addition, since the conductive polymer nanoparticle of the present invention can be dispersed in an organic solvent and has good dispersion stability, the conductive polymer nanoparticle can be used as an alcohol such as methanol, ethanol, propanol, or dimethyl Organic formamides such as formamide and diethylformamide, organic sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide, acetates such as methyl acetate and ethyl acetate, ketones such as acetone and diethyl ketone, furans such as tetrahydrofuran and 2-methyltetrahydrofuran It is dispersed in an organic solvent such as a coating, coated on a predetermined substrate using a known film forming means such as a casting method, a dip method, a spin coating method, an applicator method, an ink jet method, and dried to be conductive. A thin film made of polymer nanoparticles is It can be easily formed thereon.

  In addition, you may make it use the conductive polymer nanoparticle of this invention as what is called a core-shell type composite particle. The conductive polymer nanoparticle can be applied to both the core part and the shell part of the core-shell type composite particle, for example, a noble metal such as gold, silver or platinum, a carbon, a complex such as porphyrin or phthalocyanine. , Tetraphenylbenzidines, aromatic amines, styrylbenzenes and other monomers and oligomers as core parts and conductive polymer nanoparticles as shell parts, and composite polymer nanoparticles and conductive polymer nanoparticles as core parts Further, it can be used as a composite particle to which another π-conjugated polymer, an organic compound such as porphyrin, phthalocyanine or the like is applied as a shell part. Moreover, it can also be used as a composite material in which conductive polymer nanoparticles are doped with iodine, a low molecular anion, an anionic oligomer, an anionic polymer, or the like.

The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and has the configuration of the present invention and can achieve the objects and effects. It goes without saying that modifications and improvements within the scope are included in the content of the present invention. Further, the specific structure, shape, and the like in carrying out the present invention are not problematic as other structures, shapes, and the like as long as the objects and effects of the present invention can be achieved. The present invention is not limited to the above-described embodiments, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

For example, in the above-described embodiment, the example of using the manufacturing apparatus 1 shown in FIG. 2 has been described as the method for manufacturing the conductive polymer nanoparticle. However, as the method for manufacturing the conductive polymer nanoparticle, However, the present invention is not limited to this, and there is no problem even if the manufacturing method is performed using a manufacturing apparatus having another configuration.
In addition, the specific structure, shape, and the like when implementing the present invention may be other structures as long as the object of the present invention can be achieved.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this Example at all.

[Example 1]
Polymerization of poly (3,4-ethylenedioxythiophene) (EDOT):
Polymerization of poly (3,4-ethylenedioxythiophene) was performed using the production apparatus 1 shown in FIG. It is a hypervalent iodine compound having a fluorine group as an oxidizing agent (polymerization initiator) in a high pressure cell 10 (capacity: 50 cm ³ ) made of SUS316 with an observation window 17 and is soluble in carbon dioxide in a supercritical state. [Bis (trifluoroacetoxy) iodo] benzene (BTI) (concentration: 0.05M) was introduced, the high-pressure cell 10 was sealed, and then carbon dioxide (CO ₂ ) was introduced from path A while stirring with a stirrer 13. Then, the pressure was increased to 20 MPa, the temperature was increased to 40 ° C., carbon dioxide was brought into a supercritical state, and the mixture was left for 30 minutes to stabilize the system.

Next, 3,4-ethylenedioxythiophene (EDOT) (concentration: 0.05 M), which is a monomer having a π-conjugated double bond, is charged into the pipe of the path B, and the path is switched by the valve V, and the differential pressure is changed. Was used to press-fit the monomer into the high-pressure cell 10 and stirred and mixed. Polymerization is carried out with a reaction time of 60 minutes, with the time when 3,4-ethylenedioxythiophene is introduced into the high-pressure cell 10 as the polymerization start time, and the polymer is poly (3,4-ethylenedioxythiophene) (PEDOT). ) In addition, surfactant was not present in the obtained polymer. In addition, [bis (trifluoroacetoxy) iodo] benzene (BTI) used as an oxidizing agent becomes CF ₃ COO ⁻ after the reaction, is taken into poly (3,4-ethylenedioxythiophene) (PEDOT), and is doped. Acts as part of the material.

  The obtained poly (3,4-ethylenedioxythiophene) (PEDOT) was recovered by reducing the pressure, washed with ethanol by centrifugation (rotation speed: 15000 rpm), purified, and then subjected to dynamic light scattering (Dynamic Light Scattering). : DLS) average particle size measurement, and scanning electron microscope (Scanning Electron Microscope: SEM) particle shape observation.

Note that poly (3,4-ethylenedioxythiophene) recovered by centrifugation could be redispersed in methanol by sonication. Moreover, as a result of measuring the electrical conductivity of the obtained poly (3,4-ethylenedioxythiophene) by a four-terminal method with a resistivity meter using iodine as a doping material, it was about 3.3 × 10 ^−2. S / cm.

The conditions described above (supercritical carbon dioxide temperature 40 ° C., pressure 20 MPa, oxidant concentration 0.05 M, monomer concentration 0.05 M, polymerization time 60 minutes, pressure 20 MPa, carbon dioxide density. the measurement results in the polymerization poly (3,4-ethylenedioxythiophene) (PEDOT) dynamic light scattering of fine particles in the 0.84g / cm ³⁾ (DLS) shown in FIG. As shown in FIG. 4, the average particle diameter (average primary particle diameter) of the obtained poly (3,4-ethylenedioxythiophene) fine particles was about 100 nm. As described above, the average particle diameter (average primary particle diameter) of the conductive polymer nanoparticles according to the present invention may be a value measured using, for example, DLS.

  FIG. 5 is a view showing a morphological photograph of the poly (3,4-ethylenedioxythiophene) (PEDOT) fine particles obtained in Example 1 by a scanning electron microscope (SEM). As shown in FIG. 5, it was revealed that the obtained poly (3,4-ethylenedioxythiophene) fine particles were spherical fine particles having a uniform particle diameter (average particle diameter). This is because, when carbon dioxide in a supercritical state is used as a solvent, a partial difference occurs in the solubility of 3,4-ethylenedioxythiophene due to density fluctuations. A reaction field can be created, and it is considered that a particulate product was obtained as in the case of using a surfactant.

  Next, the control of the average particle size according to the polymerization conditions was examined. Specifically, the average particle of poly (3,4-ethylenedioxythiophene) when the temperature is constant (40 ° C.) and the density is changed by adjusting the pressure under the conditions of Example 1 described above. The effect on the diameter was confirmed.

  FIG. 6 is a graph showing the relationship between the density of carbon dioxide at a constant temperature (40 ° C.) and the average particle diameter of the obtained polyethylenedioxythiophene (conditions for carbon dioxide are shown in Table 1). As shown in FIG. 6, the size of the poly (3,4-ethylenedioxythiophene) fine particles depends on the density of carbon dioxide in a supercritical state, and the higher the density, the more poly (3,4-ethylenedioxyphene) obtained. It was confirmed that the average particle size of (thiophene) was reduced. The reason for this is considered to be that poly (3,4-ethylenedioxythiophene) fine particles are stably dispersed by increasing the density of carbon dioxide.

(Conditions for carbon dioxide)

[Example 2]
Polymerization of polypyrrole (PPy):
Similar to the method shown in Example 1, except that pyrrole (Py) is used as the monomer instead of 3,4-ethylenedioxythiophene (EDOT), and the concentration of the oxidizing agent is changed from 0.05M to 0.005M. Using this method, polypyrrole (PPy), which is a polymer, was produced. In addition, surfactant was not present in the obtained polymer.

The obtained polypyrrole was observed for particle shape by a scanning electron microscope (SEM). FIG. 7 is a view showing a morphological photograph of polypyrrole (PPy) fine particles obtained in Example 2 by a scanning electron microscope (SEM). As shown in FIG. 7, it was confirmed that polypyrrole fine particles having a comparatively nano-order size were obtained as in the case of poly (3,4-ethylenedioxythiophene) (PEDOT) in Example 1. The shape of the fine particles was spherical. In addition, as a result of measuring the electrical conductivity of the obtained polypyrrole (PPy) by the four-terminal method in the same manner as in Example 1, it was about 2.1 × 10 ⁻¹ S / cm.

  Next, the change of the average particle diameter with respect to polymerization time was confirmed. Specifically, the average particles of polypyrrole when the polymerization time is 30 minutes, 60 minutes (the above-mentioned conditions), 180 minutes, and 360 minutes under the conditions of Example 2 described above (common to the conditions of Example 1). The change in diameter was confirmed.

  FIG. 8 is a view showing a morphological photograph of polypyrrole (PPy) fine particles obtained with a polymerization time of 60 minutes by a scanning electron microscope (SEM), and FIG. 9 is a view of polypyrrole (PPy) obtained with a polymerization time of 180 minutes. FIG. 10 is a view showing a morphological photograph of fine particles by a scanning electron microscope (SEM). FIG. 10 shows a morphological photograph of polypyrrole (PPy) fine particles obtained with a polymerization time of 360 minutes by a scanning electron microscope (SEM). FIG. As shown in FIGS. 8 to 10, it was confirmed that the primary particle diameter increased with the lapse of the polymerization time, and the particles became larger due to aggregation of the particles.

FIG. 11 is a graph showing the relationship (time-dependent change) between the polymerization time and the yield (the temperature of carbon dioxide is 40 ° C., the pressure is 20 MPa, and the density is 0.84 g / cm ³ ). As shown in FIG. 11, when the polymerization time was 30 minutes, the yield reached about 50%, and it was confirmed that the reaction proceeded rapidly at the initial stage of the polymerization. From these results, it is considered that the optimum reaction time is about 60 minutes in this example.

  Further, as in Example 1, the control of the average particle diameter by the polymerization conditions was examined. Specifically, in the condition of the above-described Example 2 (common with Example 1), the temperature is kept constant (40 ° C.), and the pressure is adjusted to change the density. The effect was confirmed.

  FIG. 12 is a graph showing the relationship between the density of carbon dioxide at a constant temperature (40 ° C.) and the average particle diameter of the obtained polypyrrole (PPy) (the conditions for carbon dioxide are shown in Table 2). As shown in FIG. 12, as in the case of poly (3,4-ethylenedioxythiophene) in Example 1, the size of the polypyrrole fine particles depends on the density of carbon dioxide in the supercritical state, and the higher the density, the more obtained. It was confirmed that the average particle size of the resulting polypyrrole was small.

(Conditions for carbon dioxide)

  In addition, in the conditions of Example 2 (common to Example 1), the change in average particle diameter was confirmed when the pressure was constant (20 MPa) and the polymerization temperature was changed from 40 ° C. to 50 ° C. and 80 ° C. (of carbon dioxide The conditions are shown in Table 3.) FIG. 13 is a graph showing the relationship between the polymerization temperature and the average particle size of polypyrrole. As shown in FIG. 13, it was confirmed that the average particle diameter of the obtained polypyrrole increases as the polymerization temperature increases, that is, as the density of carbon dioxide in the supercritical state decreases.

(Conditions for carbon dioxide)

  The average particle diameter of the resulting polypyrrole (PPy) when the concentration of the used monomer pyrrole (Py) and the oxidizing agent [bis (trifluoroacetoxy) iodo] benzene (BTI) are varied Confirmed the impact on Specifically, the concentration of polypyrrole when the concentration of pyrrole is 0.05M, 0.1M, 0.25M, and [bis (trifluoroacetoxy) iodo] benzene is 0.0025M, 0.005M, 0.01M. The change of the average particle diameter was confirmed.

FIG. 14 is a graph showing the relationship between the concentration of pyrrole and [bis (trifluoroacetoxy) iodo] benzene and the average particle size of polypyrrole (PPy) (the temperature of carbon dioxide is 40 ° C., the pressure is 20 MPa, the density 0.84 g / cm ³ ). As shown in FIG. 14, it was confirmed that there was almost no influence on the average particle diameter even when the concentration of [bis (trifluoroacetoxy) iodo] benzene as an oxidizing agent was changed. On the other hand, when the pyrrole concentration as the monomer was increased, the average particle size was increased accordingly.

[Example 3]
Polymerization of poly (3-acetylthiophene):
Poly (3- (3)), which is a polymer, was used in the same manner as in Example 1 except that 3-acetylthiophene was used instead of 3,4-ethylenedioxythiophene (EDOT) as the monomer. Acetylthiophene) was prepared. In addition, surfactant was not present in the obtained polymer. It was 4.0 * 10 ^<-2 > S / cm as a result of measuring the electrical conductivity of the obtained poly (3-acetylthiophene) by the 4-terminal method similarly to Example 1. FIG.

[Example 4]
Polymerization of poly (3-acetylpyrrole):
Poly (3- (3)), which is a polymer, was used in the same manner as in Example 1 except that 3-acetylpyrrole was used in place of 3,4-ethylenedioxythiophene (EDOT) as the monomer. Acetylpyrrole) was produced. In addition, surfactant was not present in the obtained polymer. It was 5.0 * 10 ^<-2 > S / cm as a result of measuring the electrical conductivity of the obtained poly (3-acetylpyrrole) by the 4-terminal method similarly to Example 1. FIG.

  The present invention can be advantageously used as conductive polymer nanoparticles applied as an electronic functional material or the like.

It is a phase diagram of carbon dioxide. It is the schematic which showed the one aspect | mode of the manufacturing apparatus which enforces the manufacturing method of the conductive polymer nanoparticle of this invention. It is the figure which showed the flowchart of the manufacturing method of the conductive polymer nanoparticle of this invention. FIG. 3 is a diagram showing measurement results in dynamic light scattering (DLS) of poly (3,4-ethylenedioxythiophene) (PEDOT) fine particles obtained in Example 1. It is the figure which showed the form photograph by the scanning electron microscope (SEM) of the poly (3,4-ethylene dioxythiophene) (PEDOT) microparticles | fine-particles obtained in Example 1. FIG. It is the figure which showed the relationship between the density of a carbon dioxide, and the average particle diameter of poly (3,4-ethylene dioxythiophene) (PEDOT). It is the figure which showed the form photograph by the scanning electron microscope (SEM) of the polypyrrole (PPy) microparticles | fine-particles obtained in Example 2. FIG. It is the figure which showed the form photograph by the scanning electron microscope (SEM) of the polypyrrole (PPy) microparticles | fine-particles obtained by superposing | polymerizing time for 60 minutes. It is the figure which showed the form photograph by the scanning electron microscope (SEM) of the polypyrrole (PPy) microparticles | fine-particles obtained by making polymerization time into 180 minutes. It is the figure which showed the form photograph by the scanning electron microscope (SEM) of the polypyrrole (PPy) microparticles | fine-particles obtained by making polymerization time into 360 minutes. It is the figure which showed the relationship between superposition | polymerization time and a yield. It is the figure which showed the relationship between the density of a carbon dioxide, and the average particle diameter of polypyrrole (PPy). It is the figure which showed the relationship between superposition | polymerization temperature and the average particle diameter of polypyrrole (PPy). It is the figure which showed the relationship between the density | concentration of pyrrole and [bis (trifluoroacetoxy) iodo] benzene, and the average particle diameter of polypyrrole (PPy).

Explanation of symbols

1 Manufacturing Equipment 10 High Pressure Cell 11, 12 Heater (Ribbon Heater)
13 Stirrer 14 Thermocouple 15, 16 Pressure gauge 17 Observation window 21 Carbon dioxide cylinder 22 Pump V valve

Claims (6)

Conductive polymer nanoparticles comprising a polymer of monomers having a π-conjugated double bond,
Conductive polymer nanoparticles having an average particle diameter of 10 to 1000 nm and no surfactant.   The conductive polymer nanoparticle according to claim 1, which is a polythiophene.   A method for producing conductive polymer nanoparticles, wherein a monomer having a π-conjugated double bond is mixed with an oxidizing agent and carbon dioxide in a supercritical state and polymerized.   The method for producing conductive polymer nanoparticles according to claim 3, wherein the monomer having a π-conjugated double bond is thiophene or a thiophene derivative.   The method for producing conductive polymer nanoparticles according to claim 3 or 4, wherein the polymerization is terminated when the yield is 50 to 75%. 6. The method for producing conductive polymer nanoparticles according to claim 3, wherein the oxidizing agent is a hypervalent iodine compound.