Dopant Solution for Electroconductive Polymer Eliminating Metal Contamination
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Solution Overview
Problem
Conventional methods for preparing electroconductive polymers using transition metal salts result in residual metal ions, affecting the stability and conductivity of solid electrolytic capacitors, and alternative oxidants like peroxides reduce reactivity and conductivity.
Innovation Solution
Employing a dopant solution with alkylamine or imidazole salts of benzene or naphthalene sulfonic acids, combined with persulfate organic salts, to polymerize monomers like thiophene derivatives, eliminating metal salts and enhancing conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transition metal salts are used as oxidants and dopants for polymerizing monomers, then the electroconductive polymer can be prepared with good conductivity, but residual transition metal ions remain in the polymer affecting stability and reliability
Solution Approach 1:
The patent changes the chemical parameters by replacing transition metal salts with organic compounds (alkylamine salts and imidazole salts of benzene or naphthalene sulfonic acids) as dopants, and using persulfate organic salts as oxidants. This parameter change eliminates metal ion contamination while maintaining the polymerization process and electroconductive properties.
Solution Approach 2:
The patent employs organic dopants and oxidants that can be easily removed or decomposed, replacing persistent transition metal salts. The organic compounds serve their function during polymerization and can be washed away, leaving no harmful residual metal ions in the final product.
2Object-generated harmful factors
If peroxide is used as an alternative oxidant to avoid transition metals, then residual metal ions are eliminated, but the reactivity and electric conductivity of the electroconductive polymer become significantly lower
Solution Approach 1:
The patent uses a composite approach by combining specific organic dopants (alkylamine or imidazole salts of benzene/naphthalene sulfonic acids with OH groups) with persulfate organic salts as oxidants. This composite system maintains high reactivity for efficient polymerization while producing polymers with high electric conductivity, overcoming the limitations of peroxide alone.
Solution Approach 2:
The patent optimizes the chemical parameters by selecting specific organic compounds with particular functional groups (OH groups and sulfonate groups) that enhance both the reactivity of the polymerization process and the electric conductivity of the resulting polymer, while maintaining the benefit of eliminating metal ion contamination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach yields electroconductive compositions with high conductivity and long-term reliability for solid electrolytic capacitors, allowing for the use of unreacted components without purification, improving reactivity and storage stability.
Implementation Method 1
a persulfate organic salt... is used as an oxidant and dopant. A monomer... is polymerized
Implementation Method 2
a dopant solution for an electroconductive polymer includes at least one selected from the group consisting of an alkylamine salt and an imidazole salt of a benzene skeleton sulfonic acid or a naphthalene skeleton sulfonic acid
Data Source
AI summary
The present invention provides: a dopant solution for an electroconductive polymer characterized in that it comprises at least one selected from the group consisting of alkylamine salts and imidazole salts of benzene skeleton sulfonic acids and naphthalene skeleton sulfonic acids, having at least one OH group and at least one sulfonate group, at a concentration of 40 mass % or more; an oxidant and dopant solution for an electroconductive polymer including a mixture of the organic salt of the dopant as mentioned above, and a persulfate organic salt as an oxidant; an electroconductive composition including an electroconductive polymer prepared by using the oxidant and dopant solution as mentioned above; and solid electrolytic capacitor using the electroconductive composition as a solid electrolyte. The electroconductive composition has an improved electric conductivity, and the solid electrolytic capacitor has an improved reliability for a long time.