JP5509501B2 - Conductive polymer material and method for producing conductive polymer material - Google Patents

Description

  The present invention relates to a conductive polymer material having electrical conductivity and a method for producing a conductive polymer material, and more particularly to a conductive polymer material having elasticity and a method for producing a conductive polymer material.

  If the volume change of the polymer material can be controlled by electrical stimulation, it can be applied to flexible robots, soft actuators, and artificial muscles. Currently, conductive polymer actuators, ion conductive polymer actuators, elastomer polymer actuators, and the like are attracting attention as next-generation actuators that are compact, lightweight, flexible, and have no operation sound. Therefore, there is a need for an electrode having high conductivity and high elasticity that can follow the flexible movement of the actuator.

  In addition, in the field of organic printable electronics elements represented by electronic paper, organic solar cells, organic EL, and the like, development of flexible and flexible wiring and electrode materials that have elasticity is desired.

  As a polymer having conductivity, PEDOT / PSS (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonic acid)) is known. For example, Patent Document 1 discloses PEDOT / PSS. It describes the electrode structure of a capacitive switch using PSS as a transparent electrode.

  Non-Patent Document 1 describes a material made of single-walled carbon nanotube (SWNT), ionic liquid, elastic resin, etc. as a conductive material having elasticity.

JP 2007-52975 A

Tetsuo Nozawa = Nikkei Electronics, “Tetsuo Nozawa = Nikkei Electronics,“ The University of Tokyo develops wiring that uses carbon nanotubes ”, August 8, 2008, Tech-on, a site that supports engineers <Internet: http: // /techon.nikkeibp.co.jp/article/NEWS/20080807/156236/>

  However, PEDOT / PSS described in Patent Document 1 has no stretchability and low electrical conductivity. Moreover, although the substance described in Non-Patent Document 1 is stretchable, it has a low electrical conductivity and is a ternary substance. Therefore, the production method and production conditions are considered to be complicated.

  In view of such circumstances, the present invention intends to provide a conductive polymer material that has stretchability, high electrical conductivity, and can be easily manufactured, and a method for manufacturing the conductive polymer material.

  The conductive polymer material of the present invention comprises a arabitol addition step of adding arabitol to a colloidal solution of PEDOT / PSS, and a heat treatment step of drying and heating the solution obtained in the arabitol addition step The main feature is that it is manufactured by.

  Thereby, the conductive polymer material which has high electroconductivity and can be manufactured simply can be obtained.

  In addition, the conductive polymer material of the present invention is characterized in that, in the arabitol addition step, arabitol is added in an amount of 40 wt% to 90 wt% with respect to the solid component of the PEDOT / PSS.

  Thereby, a conductive polymer material having higher conductivity can be obtained.

  Furthermore, the conductive polymer material of the present invention is mainly characterized in that the heating temperature in the heat treatment step is in the range of 100 ° C to 200 ° C.

  Thereby, a conductive polymer material having higher conductivity can be obtained.

  Furthermore, the conductive polymer material of the present invention is mainly characterized in that the heating time in the heat treatment step is in the range of 1 hour to 5 hours.

  As a result, a highly stretchable conductive polymer material can be obtained.

  The method for producing a conductive polymer material of the present invention includes an arabitol addition step of adding arabitol to a colloidal solution of PEDOT / PSS, a heat treatment step of drying and heating the solution obtained in the arabitol addition step, The main feature is that

  Thereby, a conductive polymer material having high conductivity can be easily produced.

  Further, the method for producing a conductive polymer material of the present invention is characterized in that, in the arabitol addition step, arabitol is added in an amount of 40 wt% to 90 wt% with respect to the solid component of the PEDOT / PSS.

  Thereby, the electroconductive polymer material provided with higher electroconductivity can be manufactured.

  Furthermore, the method for producing a conductive polymer material of the present invention is mainly characterized in that the heating temperature in the heat treatment step is in the range of 100 ° C to 200 ° C.

  Thereby, the electroconductive polymer material provided with still higher electroconductivity can be manufactured.

  The main feature of the method for producing a conductive polymer material of the present invention is that the heating time in the heat treatment step is in the range of 1 hour to 5 hours.

  As a result, a highly stretchable conductive polymer material can be obtained.

  According to the conductive polymer material and the method for producing a conductive polymer material of the present invention, a conductive polymer material having high electrical conductivity can be easily produced.

It is a conceptual diagram of the structure of the conductive polymer material of this invention. It is the graph which showed the relationship between the kind and quantity of sugar alcohol to add, and electrical conductivity. It is a figure which shows the tension test result of the PEDOT / PSS polymer film which added arabitol as sugar alcohol. It is a figure which shows the tension test result of the PEDOT / PSS polymer film which added sorbitol as sugar alcohol. It is a figure which shows the tension test result of the PEDOT / PSS polymer film which added xylitol as sugar alcohol. It is a figure which shows the tension test result of the PEDOT / PSS polymer film which added glycerol as sugar alcohol. It is a figure which shows the electrical conductivity and cutting elongation of a PEDOT / PSS polymer film when sugar alcohol is added 80%. It is a graph which shows the relationship between heat processing temperature, the amount of arabitol addition, and electrical conductivity. It is a graph which shows the relationship between heat processing temperature and time, and electrical conductivity. 4 is a graph showing stress strain curves before and after heat treatment of a polymer film containing 60% arabitol.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the present specification, when the numerical range is expressed using “˜”, the upper and lower numerical values indicated by “˜” are also included in the numerical range.

<Configuration of conductive polymer material>
The conductive polymer material of the present invention mainly comprises poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonic acid) (PEDOT / PSS), which is a conductive polymer, and sugar alcohol. Consists of including.

The conductive polymer material of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of the structure of the conductive polymer material of the present invention. The PEDOT / PSS constituting the conductive polymer material of the present invention (hereinafter, the conductive polymer material of the present invention may be referred to as the polymer film of the present invention or simply the polymer film) is a raw material stage. Then, it is a colloidal solution, and is dispersed in water (H ₂ O) as a dispersion medium as colloidal particles.

  The polymer film of the present invention can be obtained by adding a sugar alcohol aqueous solution to the PEDOT / PSS colloidal solution, mixing, drying, and heating.

  FIG. 1A is a diagram conceptually showing the structure of the polymer film of the present invention. As shown in this figure, the PEDOT / PSS particles 10 are considered to be bonded to each other by hydrogen bonds. The sugar alcohol 20 exists between the PEDOT / PSS particles 10 and prevents the binding of the PEDOT / PSS particles 10. Thereby, it is considered that the hydrogen bonds between the polymer films are broken and the polymer film is easily stretched.

  FIG. 1B is a diagram conceptually showing the configuration of the PEDOT / PSS particles 10. As shown in this figure, PSS (poly (4-styrene sulfonic acid)) 30 is a string-like polymer having a molecular weight of 10,000 or more. PEDOT (poly (3,4-ethylenedioxythiophene)) 40 is a polymer or oligomer having a considerably lower molecular weight than PSS30, and is bound to PSS30.

  FIG. 1C is a diagram showing a structural formula of PEDOT 40, and FIG. 1D is a diagram showing a structural formula of PSS 30.

<Method for producing conductive polymer material and evaluation>
Next, the manufacturing method of the conductive polymer material of the present invention and the characteristic evaluation of the manufactured polymer film will be described.

(Method for producing conductive polymer material)
A sugar alcohol aqueous solution was added to and mixed with a colloidal solution of PEDOT / PSS (CLEVIOS PH1000, CLEVIOS P AG manufactured by HCStarck). Next, 0.01 wt% of dodecylbenzenesulfonic acid (soft type) (manufactured by Tokyo Chemical Industry Co., Ltd.) was mixed with this mixed solution and stirred well, then weighed into a Teflon petri dish (diameter 105 mm), The film was dried at 50 ° C. for 8 hours, and further heat-treated in air while changing the temperature and time to prepare a cast film. Here, the heat treatment can be performed in vacuum instead of in air, but better characteristics were obtained when performed in air. The heat treatment can be performed not in air but in an inert gas or other gas.

  Here, the reason for mixing dodecylbenzenesulfonic acid is that the mixed solution spreads on the Teflon (registered trademark) petri dish with good wettability by mixing dodecylbenzenesulfonic acid. When dodecylbenzene sulfonic acid is not mixed, the teflon (registered trademark) petri dish has poor wettability, so the contact angle between the mixed solution and the teflon (registered trademark) petri dish increases, and the mixed solution does not move on the teflon (registered trademark) petri dish. Phenomenon occurs that does not spread well.

(Conductive polymer material evaluation method)
The film thickness of the produced polymer film was measured using a digital micrometer (MDC-25NJ, manufactured by Mitutoyo Corporation).

  The electrical conductivity (electrical conductivity) of the produced polymer film was measured using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical). Specifically, a four-probe probe (PSP, manufactured by Mitsubishi Chemical) fixed to the stand with a crank is connected to a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical), and the polymer film is lifted using a lab jack. Measurements were made by pressing against a 4-probe probe.

  At this time, the RCF value was corrected by flowing the shape (film thickness, diameter, measurement coordinates) of the polymer film to the resistivity meter in advance, and the resistance value and the conductivity were calculated.

  The tensile test of the polymer film was performed using a tensile tester (EZ-TEST, manufactured by Shimadzu Corporation). First, the polymer film was cut by pressing the blade of the cutter knife directly against the cut edge and hitting it with a hammer from above so that no cracks were generated.

  The cut polymer film was affixed to a backing paper with a distance of 20 mm between chucks of a tensile tester, and both sides were fixed with cellophane tape. The film thickness of the polymer film affixed to the mount was measured with a micrometer (MDC-25MJ, manufactured by Mitutoyo), and the width was measured with a cassette meter (TM, manufactured by Mitutoyo).

  The polymer film was attached to a calibrated chuck of a tensile tester, and the center of the mount was cut with scissors. The test conditions were input to a tensile testing machine, zero-point alignment was performed with a slight load on the load cell (film tension), and a tensile test was performed under the following conditions. During the tensile test, temperature and relative humidity were measured with a digital thermo-hygrometer (CTH-1000, manufactured by CUSTOM).

Sample width: 2mm
Chuck interval: 20mm
Strain rate: 10% / min
Sampling time: 0.05sec
Strain gauge: 500N
The Young's modulus, cutting strength and cutting elongation of the film were determined by analysis using analysis software (Trapezium 2) on a PC.

Evaluation 1: (Evaluation of changes in physical properties depending on the type of sugar alcohol added)
A polymer film was prepared and evaluated by the polymer film production method and the evaluation method described above. In this evaluation, changes in physical properties depending on the type of sugar alcohol added were measured.

  Specifically, arabitol, glycerol, xylitol, and sorbitol are used as sugar alcohols to be added to PEDOT / PSS (using CLEVIOS P AG made by HCStarck). % Polymer film was prepared and the electrical conductivity and tensile properties were measured. The heat treatment temperature at this time was 120 ° C. for 1 hour. The measurement results are shown in FIGS.

Evaluation 1- (1): Conductivity measurement results for each type of sugar alcohol FIG. 2 is a graph showing the relationship between the type and amount of sugar alcohol added and the conductivity. As shown in FIG. 2, it was found that the conductivity increased rapidly by adding 40% or more of arabitol, glycerol, xylitol, and sorbitol, and reached a maximum at 80%. This is presumably because the inter-particle carrier movement was promoted by the removal of the insulating PSS present on the surface of the PEDOT / PSS colloid.

  Moreover, as shown in FIG. 2, as the sugar alcohol to be added, the one using arabitol had the highest conductivity. The amount of sugar alcohol to be added is preferably 40% to 90% of the range where the conductivity is increased, and more preferably 60% to 80% of the range where the conductivity is increased. And 80% at which the conductivity is maximized is most preferable.

Evaluation 1- (2): Tensile Characteristic Measurement Results FIGS. 3 to 6 are diagrams showing the tensile test results of PEDOT / PSS polymer films to which arabitol, sorbitol, xylitol, and glycerol are added as sugar alcohols, respectively. 3 to 6, the upper left graph shows the relationship between tensile stress and elongation for each sugar alcohol addition amount, and the lower left graph shows the relationship between the sugar alcohol addition amount and the tensile strength. The graph on the upper right shows the relationship between the added amount of sugar alcohol and Young's modulus, and the graph on the lower right shows the relationship between the added amount of sugar alcohol and the cutting elongation.

  From FIG. 3, the Young's modulus (shown in the upper right graph of FIG. 3) and the tensile strength (shown in the lower left graph of FIG. 3) decrease with the amount of arabitol added, and the cut elongation (shown in the lower right graph of FIG. 3). From this, it was found that the polymer film was softer and easier to stretch.

  Further, by adding 80% arabitol as shown in FIG. 2, the conductivity is improved from 1.5 S / cm to 131 S / cm (87 times), and the elongation at break is 3% as shown in FIG. It became clear that it improved to 21% (7 times). Sorbitol (FIG. 4) and xylitol (FIG. 5) showed the same tendency, but glycerol (FIG. 6) showed almost no plastic effect.

  Thus, it was found that the conductivity and mechanical properties of the PEDOT / PSS polymer film vary greatly depending on the type and amount of sugar alcohol. Further, in order to study the special characteristics of sugar alcohol, a polymer film to which 80% of maltitol, propylene glycol, erythritol, sucrose, and mannitol was added was prepared and evaluated by the above method. FIG. 7 shows the results obtained.

  FIG. 7 is a diagram showing the electrical conductivity and breaking elongation of a PEDOT / PSS polymer film when 80% of sugar alcohol is added. As shown in this figure, propylene glycol and maltitol slightly improved conductivity, but erythritol, sucrose, and mannitol decreased.

  With maltitol and erythritol, sugar alcohol and PEDOT / PSS separated and precipitated during the drying process during film formation, and no improvement in stretchability of the film was observed. From the above evaluation results, it was found that arabitol is most suitable as an additive for improving the conductivity and stretchability of PEDOT / PSS.

  Accordingly, the polymer film of the present invention has a conductivity higher than 57 S / cm of the carbon nanotube / ionic liquid / fluorine polymer composite material known as a stretchable electrode described in Non-Patent Document 1. It has a conductivity more than twice as high, and the manufacturing method is very simple and convenient.

Evaluation 2: (Detailed evaluation of changes in physical properties when arabitol is used as a sugar alcohol)
Using arabitol as a sugar alcohol, a polymer film was produced and evaluated by the polymer film production method and evaluation method described above.

  Specifically, a polymer film was prepared by adding arabitol to PEDOT / PSS (using CLEVIOS PH1000 manufactured by HCStarck) in a predetermined amount (wt%) with respect to the solid component of PEDOT / PSS, and the conductivity and tensile properties. Was measured. The measurement results are shown in FIGS.

Evaluation 2- (1): Conductivity measurement for each heat treatment temperature and heat treatment time Polymer films using arabitol as sugar alcohol and 0-80 wt% arabitol added to PEDOT / PSS solid components at various temperatures FIG. 8 shows changes in electrical conductivity when heat-treated in air for 1 hour. FIG. 8 is a graph showing the relationship between the heat treatment temperature and the amount of arabitol added and the electrical conductivity.

  As shown in FIG. 8, the conductivity increases rapidly at a heat treatment temperature of 100 ° C. or higher, reaching a maximum of 341 S / cm at an arabitol of 60% and a heat treatment temperature of 140 ° C. However, heat treatment at 140 ° C. or higher showed a tendency for the film to become hard and the stretchability to decrease. This is presumably because arabitol, which also functions as a plasticizer, was detached from the film.

  Next, the heat treatment time was evaluated. The addition amount of arabitol was 60 wt%, the heat treatment temperature was 50 ° C. to 140 ° C., the polymer film was produced by changing the heat treatment time, and the conductivity was measured. The measurement results are shown in FIG. FIG. 9 is a graph showing the relationship between the heat treatment temperature and time and conductivity.

  As shown in FIG. 9, when the heat treatment temperature was 50 ° C. or 80 ° C., the conductivity was not improved even when the heat treatment time was extended, but when the temperature was 100 ° C. or more, the conductivity increased rapidly. It was. At a heat treatment temperature of 140 ° C., the polymer film became hard even after one hour of heat treatment.

  8 and 9, the heat treatment temperature is preferably 100 ° C. to 200 ° C., which can improve the conductivity. Further, the heat treatment temperature is more preferably from 100 ° C. to 140 ° C. Thereby, not only can the conductivity be improved, but also the curing of the polymer film can be prevented. The most preferable heat treatment temperature was 120 ° C., which allowed both improvement in conductivity and stretchability to be kept high.

  As for the heat treatment time, as shown in FIG. 9, heating for 1 hour or more is preferable. This is because the conductivity rapidly increases when heated for 1 hour or longer. The heat treatment time is more preferably 1 hour to 5 hours. This is because the polymer film cures considerably when heated for more than 5 hours. Furthermore, the heat treatment time is more preferably 1 hour to 3 hours. This is because the curing of the polymer film could be suppressed considerably by setting the heating time to within 3 hours. The most preferred heat treatment time is 2 hours. Thereby, a polymer film having high conductivity and high stretchability can be obtained.

Evaluation 2- (2): Measurement of mechanical properties of polymer film with arabitol The molecular film was heat-treated in air at 120 ° C. for 2 hours to prepare a polymer film. This polymer film was subjected to a tensile test and data analysis before and after the heat treatment. A tensile test and data analysis were also performed on a PEDOT / PSS (using CLEVIOS PH1000 manufactured by HCStarck) polymer film to which arabitol was not added. FIG. 10 shows the obtained stress strain curve. FIG. 10 is a graph showing stress-strain curves before and after heat treatment of a polymer film containing 60% arabitol.

  In FIG. 10, the curve labeled PH1000 indicates a PEDOT / PSS (CLEVIOS PH1000 manufactured by HCStarck) polymer film without added arabitol, and the curve labeled PH1000 + 60% arabitol (before heat treatment) Before the heat treatment of the polymer film added with 60% by weight of arabitol, the curve indicated as PH1000 + 60% arabitol (after heat treatment) indicates after the heat treatment of the polymer film to which 60% by weight of arabitol was added.

  As shown in FIG. 10, the polymer film to which 60% by weight of arabitol was added (before heat treatment) was compared with the polymer film to which arabitol was not added, Young's modulus (curve slope), strength (Y axis). The elongation at break (X-axis) was low, and no improvement in mechanical properties was observed.

  On the other hand, by performing heat treatment at 120 ° C. for 2 hours, the Young's modulus decreased and the elongation at break increased greatly, so it can be said that this heat treatment made the film softer and easier to deform. The cutting elongation at this time was 23%, which was found to reach 2.5 times that of the PEDOT / PSS polymer film to which no arabitol was added. From the obtained results, it was revealed that a PEDOT / PSS polymer film having high conductivity and high stretchability can be produced by adjusting the combination of sugar alcohol addition and heat treatment.

  PEDOT / PSS particles ... 10, sugar alcohol ... 20, PSS ... 30, PEDOT ... 40

Claims (8)

An arabitol addition step of adding arabitol to the colloidal solution of PEDOT / PSS;
A heat treatment step of drying and heating the solution obtained in the arabitol addition step;
A conductive polymer material produced by a production method comprising: In the arabitol addition step, arabitol is added in an amount of 40 wt% to 90 wt% with respect to the solid component of the PEDOT / PSS.
The conductive polymer material according to claim 1. The heating temperature in the heat treatment step is in the range of 100 ° C to 200 ° C.
The conductive polymer material according to claim 1 or 2. The heating time in the heat treatment step is in the range of 1 hour to 5 hours.
The conductive polymer material according to claim 1. An arabitol addition step of adding arabitol to the colloidal solution of PEDOT / PSS;
A heat treatment step of drying and heating the solution obtained in the arabitol addition step;
A method for producing a conductive polymer material comprising: In the arabitol addition step, arabitol is added in an amount of 40 wt% to 90 wt% with respect to the solid component of the PEDOT / PSS.
The method for producing a conductive polymer material according to claim 5. The heating temperature in the heat treatment step is in the range of 100 ° C to 200 ° C.
The manufacturing method of the conductive polymer material of Claim 5 or 6. The heating time in the heat treatment step is in the range of 1 hour to 5 hours.
The manufacturing method of the conductive polymer material as described in any one of Claims 5-7.

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