Patent Application
20140370297
This application claims the benefit of Korean Patent Application No. 10-2013-0069461, filed on Jun. 18, 2013, entitled “Conductive Polymer Composition and Conductive Film Using the Same”, which is hereby incorporated by reference in its entirety into this application.
1. Technical Field
The present invention relates to a conductive polymer composition and a conductive film using the same.
2. Description of the Related Art
A transparent electrode currently mainly used as a display is made of an indium-tin oxide (ITO), however, in the case in which the transparent electrode is made of ITO, excessive cost is required and a large area is difficult to be implemented. In particular, in the case in which the electrode having the large area is coated with ITO, change in a sheet resistance is large, which decreases brightness and light-emitting efficiency of the display. In addition, since a display market has expanded, indium, which is a main raw material of ITO, has been rapidly exhausted due to limited amount as a mineral. In order to resolve the above-described disadvantage of ITO, research into a transparent electrode formed by using a polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) polymer having excellent flexibility and prepared by a simple coating process has been actively conducted.
Meanwhile, in the case in which the transparent electrode is made of the polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) polymer, since the transparent electrode has a high sheet resistance at a level of 105 to 109 Ω/□, it is difficult to be used as a transparent electrode for a display. The high sheet resistance may be significantly decreased by adding dimethylsulfoxide (DMSO), ethyleneglycol, sorbitol, or the like, to a polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) solution. However, according to the above-described method, the high sheet resistance may be decreased, but since PEDOT/PSS is a typical water-soluble polymer, the sheet resistance is changed by moisture-absorption, and at the time of being applied to an electronic device for a display, a serious problem occurs such as reliability of wet load resistance. Therefore, a method solving the moisture-absorption property obtained by using the PEDOT/PSS polymer as a conductive material has been strongly demanded.
In the present invention, polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) is neutralized with lipid-soluble tertiary amine to solve the above-described problems, thereby completing the present invention.
Therefore, the present invention has been made in an effort to provide a conductive polymer composition including: polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with lipid-soluble tertiary amine; a binder; and a solvent.
In addition, the present invention has been made in an effort to provide a conductive film prepared by using the conductive polymer composition according to the present invention.
According to a preferred embodiment of the present invention, there is provided a conductive polymer composition including: polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with lipid-soluble tertiary amine; a binder; and a solvent.
A content of the polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with lipid-soluble tertiary amine may be 0.5 to 50 wt %, a content of the binder may be 0.5 to 30 wt %, and a content of the solvent may be 20 to 95 wt %, based on 100 parts by weight of the conductive polymer composition.
The lipid-soluble tertiary amine may be dicyclohexylmethylamine.
One molecule of the dicyclohexylmethylamine may be reacted with one sulfonic acid group of the polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS).
The polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with the lipid-soluble tertiary amine may have a hydrogen ion concentration (pH) of 2.5 to 3.5.
The hydrogen ion concentration (pH) may be 2.9 to 3.1.
The hydrogen ion concentration (pH) may be 3.0.
The binder may be at least one selected from a group consisting of alkylglycidylether(meta)acrylate, phenylglycidylether(meta)acrylate, (meta)acrylate, a polyfunctional(meta)acrylate, an epoxy-based binder, a urethane-based binder, an acryl-urethane copolymer, a carboxyl-based binder, and an amide-based binder, having 2 to 8 carbon atoms.
The solvent may be at least one selected from a group consisting of polyalcohol, dimethylsulfoxide, N,N-dimethylformamide, ethyleneglycol, polyethyleneglycol, meso-erythritol, aniline, acetone, methylethylketone, isopropylalcohol, butylalcohol, ethylalcohol, methylalcohol, dimethylacetamide, hexane, toluene, chloroform, cyclohexanone, distilled water, pyridine, methylnaphthalene, tetrahydro furan, dichlorobenzene, dimethylbenzene, trimethylbenzene, nitromethane, acrylonitrile, and water (H2O).
According to another preferred embodiment of the present invention, there is provided a conductive film including: a base member; and a transparent electrode formed by coating and drying the conductive polymer composition as described above on the base member.
The base member may be a single substrate selected from a group consisting of polycarbonate, polymethylmethacrylate, polyethyleneterephthalate, ethylenenaphthalate, polyethersulfone, a cyclic olefin polymer, a triacetylcellulose film, a polyvinylalcohol film, a polyimide film, polystyrene, biaxially oriented polystyrene, and a glass or a tempered glass, or a composite substrate manufactured by a combination thereof.
The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
The objects, features and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side” and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the prior art would obscure the gist of the present invention, the description thereof will be omitted.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
The above-described problems may be solved by using lipid-soluble tertiary amine according to the preferred embodiment of the present inventors.
Therefore, a conductive polymer composition according to the preferred embodiment of the present invention may contain polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with the lipid-soluble tertiary amine; a binder; and a solvent.
It is preferred that the conductive polymer composition contains 0.5 to 50 wt % of polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with lipid-soluble tertiary amine, 0.5 to 30 wt % of the binder, and 20 to 95 wt % of the solvent. In the case in which a weight ratio of PEDOT/PSS is less than 0.5%, the conductive polymer composition does not have conductivity, and in the case in which the weight ratio of PEDOT/PSS is more than 0.5%, there is a limitation in an added amount of the binder and the solvent to thereby deteriorate dispersibility of PEDOT/PSS. Meanwhile, in the case in which the added amount of the binder is less than 0.5 wt %, the processability of the conductive polymer composition is deteriorated, and in the case in which the added amount of the binder is more than 30 wt %, the conductive polymer composition does not have economical efficiency. In addition, in the case in which the added amount of the solvent is less than 20 wt %, the dispersibility and the processability of PEDOT/PSS are deteriorated, and in the case in which the added amount of the solvent is more than 95 wt %, there is a limitation in an added amount of PEDOT/PSS and the binder to thereby deteriorate conductivity and processability.
Meanwhile, examples of the binders used in the conductive polymer composition according to the preferred embodiment of the present invention may include alkylglycidylether(meta)acrylate, phenylglycidylether(meta)acrylate, (meta)acrylate, polyfunctional(meta)acrylate, an epoxy-based binder, a urethane-based binder, an acryl-urethane copolymer, a carboxyl-based binder, and an amide-based binder, having 2 to 8 carbon atoms, but the present invention is not limited thereto, and any binder may be used as long as the binder has compatibility with PEDOT/PPS.
In addition, examples of the solvent used in the conductive polymer composition according to the preferred embodiment of the present invention may include polyalcohol, dimethylsulfoxide, N,N-dimethylformamide, ethyleneglycol, polyethyleneglycol, meso-erythritol, aniline, acetone, methylethylketone, isopropylalcohol, butylalcohol, ethylalcohol, methylalcohol, dimethylacetamide, hexane, toluene, chloroform, cyclohexanone, distilled water, pyridine, methylnaphthalene, octamesylamine, tetrahydrofuran, dichlorobenzene, dimethylbenzene, trimethylbenzene, nitromethane, acrylonitrile, and water (H2O), but the present invention is not limited thereto, and any solvent may be used as long as the solvent has compatibility with PEDOT/PPS and the binder.
It is preferred that amine used in the preferred embodiment of the present invention is lipid-soluble tertiary amine. In particular, dicyclohexylmethylamine among the lipid-soluble tertiary amine deteriorates the moisture-absorption property of PEDOT/PSS and significantly maintains conductivity. One molecule of dicyclohexylmethylamine is reacted with one sulfonic acid group of polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS). That is, as described above, one molecule of PSS has several sulfonic groups, some of the sulfonic groups participate in combination with PEDOT and the remaining sulfonic groups are maintained in a state in which they are exposed while having the hydrophilic property. The sulfonic group which is exposed while having the hydrophilic property as described above is combined with one molecule of dicyclohexylmethylamine to thereby form a salt. Meanwhile, the degree of the salt formation is capable of being adjusted, and hydrogen ion concentration (pH) of polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) is determined by the number of sulfonic groups not combined with dicyclohexylmethylamine.
Meanwhile, the present inventors succeeded to find a critical section of the hydrogen ion concentration in which the moisture-absorption property may be the most effectively deteriorated and conductivity may be maintained through a number of experiments. That is, in the case in which the hydrogen ion concentration (pH) of polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS) neutralized with the lipid-soluble tertiary amine is 2.5 to 3.5, two effects, that are, the hydrophilic property deterioration and the conductive maintenance are maintained, in particular, it was evaluated that in the case in which the hydrogen ion concentration (pH) is 2.9 to 3.1, those effects were the most excellent.
In another preferred embodiment of the present invention, a conductive film may be fabricated by using the conductive polymer composition prepared according to the preferred embodiment of the present invention. The conductive film is fabricated by coating and drying the conductive polymer composition on a general base member. The base member may be made of a single substrate selected from a group consisting of polycarbonate (PC), polymethylmethacrylate (PMMA), polyethyleneterephthalate (PET), ethylenenaphthalate (PEN), polyether sulfone (PES), a cyclic olefin polymer (COC), a triacetylcellulose (TAC) film, a polyvinylalcohol (PVA) film, a polyimide (PI) film, polystyrene (PS), biaxially stretched polystyrene (K resin containing biaxially oriented PS; BOPS), glass or a tempered glass, or a composite substrate manufactured by a combination thereof. For example, the composite substrate indicates a substrate manufactured by using polymethylmethacrylate (PMMA) so as to have excellent hardness/transmittance which is an advantage thereof and using polycarbonate (PC) so as to supplement a vulnerable strength which is a disadvantage of PMMA. Here, PC may be the composite substrate manufactured by a combination such as PMMA/PC/PMMA, or the like, in which disadvantages of PMMA having excellent hardness/transmittance are supplemented.
Hereinafter, although the constitution and effects of the present invention have been specifically disclosed by the specific examples of the present invention, it will be appreciated that the following preferred examples are merely described for illustrative purposes, and the present invention is not limited thereto.
A conductive polymer composition of Example 1 was prepared by slowly dropping dicyclohexylmethylamine into a binder alkylglycidylether(meta)acrylate and PEDOT/PSS aqueous dispersion 5305 AGFA Company, followed by stirring and neutralization up to pH 3.0.
A conductive polymer composition of Example 2 was prepared by neutralization up to pH 2.9 under the same condition as Example 1.
A conductive polymer composition of Example 3 was prepared by neutralization up to pH 3.1 under the same condition as Example 1.
A conductive polymer composition of Example 4 was prepared by neutralization up to pH 2.5 under the same condition as Example 1.
A conductive polymer composition of Example 5 was prepared by neutralization up to pH 2.6 under the same condition as Example 1.
A conductive polymer composition of Example 6 was prepared by neutralization up to pH 2.7 under the same condition as Example 1.
A conductive polymer composition of Example 7 was prepared by neutralization up to pH 2.8 under the same condition as Example 1.
A conductive polymer composition of Example 8 was prepared by neutralization up to pH 3.2 under the same condition as Example 1.
A conductive polymer composition of Example 9 was prepared by neutralization up to pH 3.3 under the same condition as Example 1.
A conductive polymer composition of Example 10 was prepared by neutralization up to pH 3.4 under the same condition as Example 1.
A conductive polymer composition of Example 11 was prepared by neutralization up to pH 3.5 under the same condition as Example 1.
A conductive polymer composition of Comparative Example 1 was prepared by neutralization up to pH 2.0 to 2.4, and 3.6 to 3.9 under the same condition as Example 1.
Example 1 in Fabricating Conductive Film
A conductive film of Example 1 was obtained by applying the conductive polymer composition prepared by each Examples 1 to 11 on a polyethyleneterephthalate (PET) film using a bar coater and drying for 1 min at 100° C.
Comparative Example 1 in Fabricating Conductive Film
A conductive film of Comparative Example 1 was obtained by applying the conductive polymer composition prepared by Comparative Example 1 on the polyethyleneterephthalate (PET) film using a bar coater and drying for 1 min at 100° C.
The following Table 1 shows results obtained by measuring moisture-absorption degree and electrical conductivity using the sample fabricated by Example 1 and the sample fabricated by Comparative Example 1 in fabricating the conductive film. The moisture-absorption degree was obtained by putting the samples into a chamber having relative humidity of 85%, being exposed by moisture for 2 hours, and measuring an increase rate in weight of each sample, and the electrical conductivity was tested by using a silver paste electrode and measuring each sheet resistance.
It may be appreciated from Table 1 above that after the hydrogen ion concentration of PEDOT/PSS reached to 2.5 or more, the moisture-absorption degree thereof was rapidly decreased, and in particular, after the hydrogen ion concentration thereof reached to 2.9 or more, the moisture-absorption degree was significantly decreased. In addition, it may be appreciated from the measurement results of the sheet resistance that there was no increase in the sheet resistance up to pH 3.1, but the sheet resistance increased from pH of 3.2, and in particular, rapidly increased from pH 3.6. Therefore, it may be appreciated from those experimental results that in the case in which PEDOT/PSS is neutralized with dicyclohexylamine, when it is titrated so that the hydrogen ion concentration has a preferred range of 2.5 to 3.5, and more preferably, 2.9 to 3.1, the moisture-absorption property may be deteriorated and electrical conductivity may be maintained. In particular, it may be appreciated from the data above that as the hydrogen ion concentration of PEDOT/PSS was close to 3.0, two effects, that is, the moisture-absorption property deterioration and conductivity maintenance were easily obtained.
It may be appreciated from Table 2 above that in region {circle around (1)}, water-dispersibility was significantly excellent to have excellent processibility but the moisture-absorption degree was significantly high. Meanwhile, it may be appreciated that in region {circle around (3)}, the moisture-absorption degree was significantly decreased, but water-dispersibility was significantly decreased. However, it may be appreciated that in region ®, the moisture-absorption degree was decreased and water-dispersibility was favorably maintained.
Meanwhile,
As set forth above, with the conductive polymer composition and the conductive film using the same according to the preferred embodiment of the present invention, the lipid-soluble tertiary amine is used to neutralize polyethylenedioxythiophene/polystyrenesulfonate (PEDOT/PSS), thereby solving the moisture-absorption property caused by PEDOT/PSS according to the prior art, and solving the change in conductivity according to the moisture-absorption.
Although the embodiments of the present invention have been disclosed for illustrative purposes, it will be appreciated that the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention.
Accordingly, any and all modifications, variations or equivalent arrangements should be considered to be within the scope of the invention, and the detailed scope of the invention will be disclosed by the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0069461 | Jun 2013 | KR | national |
