Bio-Electrode Contact Layer for Wet-Dry Conductivity Stability
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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 reduced conductivity due to water exposure and causing skin allergies, while also requiring constant skin contact and flexibility to monitor physical conditions like heart rate effectively.
Innovation Solution
A bio-electrode composition comprising silsesquioxane bonded to a sulfonic acid 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 adheres well 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 replaces water-based electrolytes with ionic liquid-based electrolytes, fundamentally changing the physical state and composition parameters. This substitution eliminates water evaporation while maintaining ionic conductivity, as ionic liquids have negligible vapor pressure and remain stable in dried states, thus resolving the contradiction between maintaining conductivity and preventing water loss.
Solution Approach 2:
The patent creates a composite electrode material combining ionic liquid electrolytes with conductive polymers or metal nanowires. This composite structure integrates the high ionic conductivity of ionic liquids with the electronic conductivity and structural stability of solid materials, achieving both sustained electric conductivity and resistance to drying effects.
2Reliability
If higher ionization tendency metal such as copper is used, then electric conductivity is improved, but skin allergy occurs
Solution Approach 1:
The patent introduces ionic liquids as an intermediary substance between the metal electrode and the skin. This intermediary layer provides ionic conductivity while physically separating the skin from direct contact with allergenic metals like copper, thus maintaining electrical function while eliminating allergic reactions.
Solution Approach 2:
The patent develops composite electrode materials combining metals with biocompatible polymers or ionic liquids. This composite approach retains the high conductivity of metals while the biocompatible components prevent direct skin contact with allergenic metals, resolving the contradiction between conductivity and skin safety.
3Reliability
If electro-conductive polymer such as PEDOT-PSS is used, then electric conductivity is improved, but skin allergy and peeling occur due to strong acidity
Solution Approach 1:
The patent changes the chemical composition parameters by replacing acidic electro-conductive polymers with ionic liquid-based materials. This substitution eliminates the strong acidity that causes skin irritation and peeling, while ionic liquids maintain high ionic conductivity and improve biocompatibility through their unique chemical properties.
4Reliability
If metal nanowire is used, then electric conductivity is improved, but skin allergy may occur due to pointed thin shape and inherent stimulation
Solution Approach 1:
The patent covers metal nanowires with flexible polymer shells or ionic liquid layers. These thin film coatings smooth the尖锐 edges of nanowires, reducing mechanical irritation to skin, while the coatings themselves provide additional ionic conductivity pathways, thus maintaining electrical performance while improving biocompatibility.
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 electric signal detection, preventing allergic reactions and maintaining conductivity, while being lightweight and cost-effective, with improved adhesion and stretchability for long-term skin contact.
Implementation Method 1
the silsesquoxane bonded to a sulfonic acid salt... ensures high sensitivity and stability in electric signal detection
Implementation Method 2
adheres well to the skin... improved adhesion and stretchability for long-term skin contact
Data Source
AI summary
The present invention provides a bio-electrode composition including a silsesquioxane bonded to a sulfonic acid salt shown by the following general formula (1):wherein R1 represents an alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 10 carbon atoms, optionally containing an ether group or an ester group, and the alkylene group may also contain an aromatic group; Rf1 and Rf2 represent H, F, O, or a CF3 group and can form a carbonyl group with a carbon atom bonded therewith; Rf3 and Rf4 represent H, F, or a CF3 group and one or more fluorine atoms are contained in Rf1 to Rf4; M is selected from Na, K, and Ag. 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.