Bio-electrode Composition Using Sulfonamide Salt for Stable Conductivity
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Solution Overview
Problem
Current bio-electrodes face challenges in maintaining electric conductivity and biocompatibility over long periods, often experiencing conductivity loss due to water evaporation or causing skin allergies, while also requiring constant contact with the skin to accurately detect physiological signals.
Innovation Solution
A bio-electrode composition comprising silicone bonded to a sulfonamide salt, combined with an adhesive resin and electro-conductive powders, which forms a living body contact layer that maintains conductivity and biocompatibility, even when wet or dried, and ensures stable adhesion to the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophilic gel containing water and electrolytes is used as electrode material, then electric conductivity is improved, but water evaporation during drying process causes loss of electric conductivity
Solution Approach 1:
The patent changes the physical-chemical parameters of the electrode material by replacing water-based hydrophilic gel with an organic solvent-based system. Specifically, it uses propylene carbonate as the solvent and lithium perchlorate as the electrolyte, creating a gel that maintains high ionic conductivity without water content, thereby preventing conductivity loss during drying.
Solution Approach 2:
The patent creates a composite gel structure by combining polyacrylic acid polymer matrix with propylene carbonate solvent and lithium perchlorate electrolyte. This composite material system provides both the structural integrity needed for adhesion and the ionic conductivity needed for electrical signal detection, while being stable under drying conditions.
2Reliability
If higher ionization tendency metal such as copper is used to improve electric conductivity, then electric conductivity is improved, but skin allergy occurs
Solution Approach 1:
The patent introduces an intermediary substance - the gel composition consisting of propylene carbonate and lithium perchlorate - that mediates between the metal electrode and the skin. This gel layer provides the necessary ionic conductivity for signal detection while forming a protective barrier that prevents direct contact between potentially allergenic metals and the skin, thus eliminating skin allergy issues.
3Reliability
If electro-conductive polymer such as PEDOT-PSS is used to improve electric conductivity, then electric conductivity is improved, but skin allergy and peeling occur due to strong acidity
Solution Approach 1:
The patent changes the chemical parameters by replacing acidic electro-conductive polymers with a neutral gel system based on polyacrylic acid, propylene carbonate, and lithium perchlorate. This new composition maintains high ionic conductivity without the strong acidity that causes skin irritation and peeling, making it suitable for long-term wearable use.
4Reliability
If metal nanowire is used to improve electric conductivity with small quantity addition, then electric conductivity is improved, but skin allergy may occur due to pointed thin shape
Solution Approach 1:
The patent adopts a gel-based electrode material that can be easily applied and replaced. The gel composition itself serves as the primary conductive medium rather than relying on embedded metal structures. This approach eliminates the need for potentially allergenic metal nanowires while maintaining good conductivity through ionic conduction in the gel matrix.
5Reliability
If precious metal is used to improve electric conductivity, then electric conductivity is improved, but high impedance and high resistance to skin occur during electrical conduction
Solution Approach 1:
The patent employs ionic conduction principles similar to hydraulic systems, where ions move through the gel matrix to conduct electrical signals. The gel composition with propylene carbonate and lithium perchlorate creates a highly conductive ionic pathway that closely matches skin's electrical properties, minimizing impedance and resistance at the skin-electrode interface.
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 bio-electrode composition achieves high electric conductivity and biocompatibility, preventing significant conductivity loss and skin irritation, while ensuring constant contact for sensitive signal detection, making it suitable for long-term medical monitoring.
Implementation Method 1
the sulfonamide salt is shown by the following general formula (1): wherein R1 represents a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 10 carbon atoms, with the alkylene group optionally having an aromatic group, an ether group, or an ester group; Rf represents a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms and containing at least one fluorine atom; M+ is an ion selected from a lithium ion, a sodium ion, a potassium ion, and a silver ion
Implementation Method 2
the use of the hydrophilic gel containing water and electrolytes unfortunately brings about loss of electric conductivity due to water evaporation in drying process. Meanwhile, the use of a higher ionization tendency metal such as copper can cause some users to suffer from skin allergy
Data Source
AI summary
The present invention provides a bio-electrode composition including a silicone bonded to a sulfonamide salt, wherein the sulfonamide salt is shown by the following general formula (1):wherein R1 represents a linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms optionally having an aromatic group, an ether group, or an ester group, or an arylene group having 6 to 10 carbon atoms; Rf represents a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms and containing at least one fluorine atom; M+ is an ion selected from a lithium ion, a sodium ion, a potassium ion, and a silver ion. This can form a living body contact layer for a bio-electrode that is excellent in electric conductivity and biocompatibility, light-weight, manufacturable at low cost, and free from large lowering of the electric conductivity even though it is wetted with water or dried.