Bio-electrode Composition Using Fluorosulfonic Acid Salt
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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 detect ion concentration changes from the skin.
Innovation Solution
A bio-electrode composition comprising silicone bonded to a fluorosulfonic acid salt, which forms a living body contact layer that is both electrically conductive and biocompatible, using a fluorosulfonic acid salt with specific chemical structures and an adhesive resin to prevent elution and enhance adhesion, along with carbon or metal powders for improved conductivity.
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 replaces water-based electrolytes with ionic liquid-based electrolytes, changing the physical and chemical parameters of the electrode composition. This substitution eliminates water evaporation while maintaining ionic conductivity, as ionic liquids have negligible vapor pressure and remain stable during drying processes.
Solution Approach 2:
The patent creates a composite electrode material combining hydrophilic polymer, ionic liquid, and electrolyte salts. This composite structure integrates the water-absorbing capability of hydrophilic polymers with the non-volatile ionic conductivity of ionic liquids, achieving both stable conductivity and resistance to water loss.
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 ionic liquid as an intermediary substance between the metal electrode and the skin. This intermediary layer provides ionic conductivity while preventing direct contact between potentially allergenic metals and the skin, thus eliminating skin allergy reactions while maintaining electrical function.
Solution Approach 2:
The patent changes the conduction mechanism from electronic conduction (metals) to ionic conduction (ionic liquid). This parameter change allows the use of non-allergenic materials that conduct electricity through ion movement rather than electron flow, eliminating skin irritation while maintaining conductivity.
3Reliability
If electro-conductive polymer such as PEDOT-PSS is used to improve electric conductivity, then electric conductivity is improved, but skin allergy occurs due to strong acidity and peeling during washing
Solution Approach 1:
The patent replaces acidic electro-conductive polymers with neutral ionic liquid-based electrolytes. This parameter change in chemical composition eliminates the strong acidity that causes skin allergy and improves biocompatibility while maintaining ionic conductivity through the ionic liquid medium.
Solution Approach 2:
The patent creates a composite system where ionic liquid serves as both the electrolyte and the bonding matrix. This composite structure provides stable adhesion to skin and fabric substrates, preventing peeling during washing while maintaining continuous ionic conductivity, unlike polymer-based electrodes that peel and lose conductivity.
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 material shape
Solution Approach 1:
The patent uses ionic liquid as an intermediary that eliminates the need for metal nanowires. The ionic liquid provides ionic conductivity through dissolved electrolyte salts, replacing the electronic conduction pathway of metal nanowires with an ionic conduction mechanism that uses non-allergenic materials.
Solution Approach 2:
The patent substitutes the mechanical structure of metal nanowires with a molecular-level ionic liquid solution. Instead of relying on the physical arrangement and contact of nanoscale metal structures, the system uses mobile ions dissolved in ionic liquid to conduct electricity, eliminating mechanical sharp edges that could cause skin irritation.
5Reliability
If precious metal is used to improve electric conductivity, then electric conductivity is improved, but high impedance and high resistance to skin occurs during electrical conduction
Solution Approach 1:
The patent replaces electronic conduction (precious metals) with ionic conduction (ionic liquid with electrolyte salts). This substitution changes the conduction mechanism to match the ionic nature of skin surface potentials, reducing impedance and improving the ease of detecting biological signals.
Solution Approach 2:
The patent changes the electrical conduction parameter from electronic to ionic. This parameter change aligns the electrode's conduction mechanism with the ionic composition of skin secretions, reducing interfacial impedance and improving signal detection sensitivity for electrocardiogram measurements.
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 maintains high electric conductivity and biocompatibility, even when wet or dried, and provides stable long-term adhesion to the skin, enabling sensitive detection of electric signals with reduced risk of skin irritation.
Implementation Method 1
M+ is an ion selected from a sodium ion, a potassium ion, and a silver ion
Implementation Method 2
an adhesive resin to prevent elution and enhance adhesion
Data Source
AI summary
The present invention provides a bio-electrode composition including a silicone bonded to a fluorosulfonic acid salt, wherein the fluorosulfonic acid salt is shown by the following general formula (1):wherein R1 represents an alkylene groups with 1 to 20 carbon atoms or an arylene groups with 6 to 10 carbon atoms; Rf1 and Rf2 each represent a hydrogen atom, a fluorine atom, an oxygen atom, or a trifluoromethyl group; Rf3 and Rf4 each represent a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that one or more fluorine atoms are contained in Rf1 to Rf4; M is selected from sodium, potassium, and silver. 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.