Bio-electrode Composition Using Sulfonimide Salt for Stable Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current bio-electrodes for wearable devices face challenges in maintaining electric conductivity and biocompatibility over time, often experiencing conductivity loss due to water evaporation or causing skin allergies, and fail to efficiently convert ion concentration changes into electric signals.
Innovation Solution
A bio-electrode composition comprising silsesquioxane bonded to a sulfonimide salt, combined with an adhesive resin and electro-conductive powders, which forms a stable living body contact layer that maintains conductivity and biocompatibility, even when wet or dried, and prevents skin irritation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophilic gel containing water and electrolytes is used as electrode, then electric conductivity is improved, but water evaporation during drying process causes loss of electric conductivity
Solution Approach 1:
The patent replaces water-based hydrophilic gel with an organic solvent-based system (isopropyl alcohol, ethyl acetate, or ethyl lactate) that does not evaporate as readily. This parameter change in the solvent type maintains electric conductivity while preventing the conductivity loss caused by water evaporation during the drying process.
Solution Approach 2:
The patent uses conventional, inexpensive organic solvents (isopropyl alcohol, ethyl acetate, ethyl lactate) that are readily available and easy to handle. These solvents provide the necessary electric conductivity during use and can be completely evaporated during drying without leaving harmful residues, making the electrode disposable and cost-effective.
2Reliability
If higher ionization tendency metal such as copper is used, then electric conductivity is improved, but skin allergy occurs in some users
Solution Approach 1:
The patent introduces an organic solvent-based electroconductive paste as an intermediary layer between the metal electrode and the skin. This paste contains organic solvents (isopropyl alcohol, ethyl acetate, or ethyl lactate) that provide ionic conductivity without causing skin allergy, mediating between the conductive metal and the sensitive skin to eliminate the harmful allergic reaction while maintaining electric conductivity.
3Reliability
If electro-conductive polymer such as PEDOT-PSS is used, then electric conductivity is improved, but skin allergy and peeling occur during washing
Solution Approach 1:
The patent replaces expensive electro-conductive polymers like PEDOT-PSS with a simple organic solvent-based paste formulation using conventional solvents (isopropyl alcohol, ethyl acetate, ethyl lactate) and inexpensive conductive materials. This disposable paste approach eliminates the adhesion and peeling problems of polymers while providing adequate conductivity for single-use or short-term electrodes.
Solution Approach 2:
The patent changes the binding mechanism from polymer adhesion to solvent evaporation-based fixation. The organic solvent-based paste is applied and then dried, allowing the solvent to evaporate and leave behind a conductive residue that adheres to the skin through evaporation rather than polymer bonding, eliminating peeling during washing.
4Reliability
If metal nanowire is used, then electric conductivity is improved, but skin allergy may occur due to pointed thin material shape
Solution Approach 1:
The patent changes the physical form of conductive materials from solid metal nanowires to a liquid/paste formulation containing organic solvents and fine conductive particles. This parameter change in material state and morphology eliminates the pointed sharp edges of nanowires that cause skin irritation, while maintaining high surface area and electric conductivity through the dispersed particulate form in the organic solvent matrix.
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 ensures high sensitivity and stability in detecting electric signals from the skin with constant contact, preventing conductivity loss and skin irritation, while being lightweight and cost-effective.
Implementation Method 1
The hydrophilic gel, containing sodium, potassium, and calcium electrolytes in a hydrophilic polymer containing water, detects changes in ion concentration from the skin to convert the data into electricity
Implementation Method 2
the use of a battery containing an ionic liquid has been examined... the ionic liquid is thermally and chemically stable, and the electric conductivity is excellent
Implementation Method 3
the use of the hydrophilic gel containing water and electrolytes unfortunately brings about loss of electric conductivity due to water evaporation in drying process
Implementation Method 4
the bio-electrode is required to be in constant contact with the skin... preferably by use of adhesive biomedical electrodes
Data Source
AI summary
The present invention provides a bio-electrode composition including a silsesquioxane bonded to a sulfonimide salt, wherein the sulfonimide 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 that may have 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 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.