Conductive Polymer Composition for Stable PEDOT-PSS Storage
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Solution Overview
Problem
Electrically conductive polymer compositions, such as PEDOT-PSS, face challenges in maintaining dispersion stability over long periods due to intermolecular forces and tertiary structure formation, especially under temperature changes, which affects their electrical conductivity and storage stability.
Innovation Solution
Incorporating a specific N-vinyl carboxylic acid amide polymer with a weight-average molecular weight between 5000 and one million, and a sulfur concentration below 3000 mass ppm, into the electrically conductive polymer composition to stabilize the dispersion and maintain conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If PEDOT-PSS is stored under refrigeration conditions (2-8°C), then the dispersion stability is improved, but the shelf life is still limited to 12 months and property changes occur depending on storage conditions
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific ratios of hydrophilic and hydrophobic polymers, and by controlling the molecular weight and sulfur content of the N-vinyl carboxylic acid amide polymer. This compositional parameter change enables the dispersion to remain stable for 24 months or longer without requiring strict refrigeration, thus extending shelf life while maintaining dispersion stability.
2Stability of the object's composition
If PSS molecules form tertiary structures due to intermolecular forces, then the dispersion state collapses, but electrical conductivity is maintained
Solution Approach 1:
The N-vinyl carboxylic acid amide polymer acts as an intermediary substance between the hydrophobic PEDOT and hydrophilic PSS components. By controlling its molecular weight (5000-1,000,000) and sulfur content (<3000 mass ppm), it mediates the interaction between PSS molecules, preventing excessive tertiary structure formation that would collapse the dispersion, while still allowing sufficient conductivity to be maintained.
Solution Approach 2:
The patent creates a composite material system consisting of three components: PEDOT (conductive polymer), PSS (dopant), and N-vinyl carboxylic acid amide polymer (stabilizer). This composite structure balances the hydrophobic and hydrophilic interactions, preventing PSS from forming overly stable tertiary structures that would aggregate PEDOT and reduce conductivity, while maintaining long-term dispersion stability.
3Ease of operation
If the product is frozen and then remelted, then the initial dispersion state collapses greatly, but the product becomes activated by molecular movement
Solution Approach 1:
The N-vinyl carboxylic acid amide polymer provides beforehand cushioning by forming a protective matrix around the PEDOT-PSS dispersion. This matrix structure, controlled by specific polymer parameters, prevents irreversible aggregation during freezing and thawing cycles. The cushioning effect maintains dispersion stability even after temperature fluctuations, allowing the product to withstand freezing conditions without catastrophic collapse of the dispersion state.
Data Source
AI summary
The present invention relates to an electrically conductive polymer composition having high dispersion stability in long-term storage without being influenced by air temperature changes in the winter season, the summer period, etc. and a method for stably storing an electrically conductive polymer solution. An electrically conductive polymer composition comprising at least a N-vinyl carboxylic acid amide polymer having a weight-average molecular weight within the range of not less than 5000 and not more than one million, an electrically conductive polymer, and a solvent. A method for stably storing an electrically conductive polymer solution, the method comprising adding, to an electrically conductive polymer solution, a N-vinyl carboxylic acid amide polymer having a weight-average molecular weight within the range of not less than 5000 and not more than one million.