Sulfonated Thiophene Monomers for Self-Doped Conductive Layers
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Solution Overview
Problem
Existing π-conjugated polymer compositions, such as PEDOT/PSS-dispersions, suffer from high inert material content, large particle sizes, and limited solids content, which hinder effective penetration into porous electrodes and result in suboptimal electrical conductivity in solid electrolyte capacitors.
Innovation Solution
Development of functionalized thiophene monomers with specific structures and minimal unsaturated organic sulfonic acids, combined with optimized polymerization processes, to produce conductive layers with enhanced electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PEDOT/PSS-dispersions are used as solid electrolytes, then the capacitors can be manufactured with conductive polymer layers, but the electrical conductivity is limited due to high inert material content (PSS) and large particle sizes
Solution Approach 1:
The invention extracts and removes the inert PSS component from the conductive polymer system. By using self-doped polythiophenes that do not require external counter-ions like PSS, the harmful inert material is completely eliminated, achieving both high conductivity and low inert content simultaneously
Solution Approach 2:
The invention changes the chemical structure parameters of the polythiophene by introducing sulfonate groups directly onto the polymer backbone. This structural modification enables self-doping, transforming the material from requiring external counter-ions to being inherently conductive, thus improving electrical conductivity while reducing inert material
2Volume of moving object
If PEDOT/PSS-dispersions are used, then the solid electrolyte can be applied to porous electrodes, but the large particle sizes prevent effective penetration into smaller pores
Solution Approach 1:
The invention changes the physical parameter of particle size by using a molecular-level self-doped polymer system instead of aggregated PEDOT/PSS particles. The self-doped polythiophenes form much smaller, more uniform structures that can penetrate into smaller pores of porous electrodes effectively
3Quantity of substance
If PEDOT/PSS-dispersions are used, then the solid electrolyte can be formed with typical solids content, but the maximum solids content is limited to about 3 wt. %
Solution Approach 1:
The invention changes the concentration parameter by eliminating the solvent and counter-ion requirements. Self-doped polythiophenes can be processed as neat polymers or in minimal solvent systems, enabling solids content to exceed 3 wt. % significantly, which directly improves electrical conductivity by reducing the volume fraction of non-conductive components
4Reliability
If sulfonate groups are introduced to create self-doped polythiophenes, then counter-ions like PSS are no longer required, but the manufacturing process becomes more complex
Solution Approach 1:
The invention applies preliminary action by pre-introducing sulfonate groups onto the thiophene monomer units before polymerization. This pre-functionalization ensures that the polymer automatically possesses self-doping capability upon formation, eliminating the need for subsequent counter-ion addition or complex post-processing steps
Solution Approach 2:
The invention merges the doping function and polymer structure into a single integrated system. The sulfonate groups are incorporated directly into the polythiophene backbone, combining the conductive polymer and dopant into one material, which simplifies the overall manufacturing process despite the initial structural complexity
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 resulting conductive layers exhibit significantly improved electrical conductivity, suitable for applications in solid electrolyte capacitors and other electronic devices.
Implementation Method 1
oxidative polymerization of the corresponding monomer 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid and 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid
Data Source
AI summary
A monomer composition comprising at least one functionalized thiophene monomer having the structure (I), wherein X1 and X2 represent independently from each other O or S; X3 represents —CH2—O— with the carbon atom bonded to R1 or represents —O—; R1 represents a trivalent organic group; R2 represents a divalent organic group; M1 represents a monovalent cation; wherein the monomer composition is essentially free of unsaturated organic sulfonic acids having the structure (II), wherein R3 represents a divalent organic group; M2 represents a monovalent cation; or wherein the monomer composition comprises unsaturated organic sulfonic acids having the structure (II) in such a maximum amount that the molar ratio of the total amount of unsaturated organic sulfonic acids having the structure (II) to the total amount of functionalized thiophene monomers having structure (I) is 1:32 or less.