Adhesive Electrode Composition for Moisture-Stable Biosignal Sensing

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Solution Overview

Problem

Adhesive electrodes for biosignal acquisition suffer from reduced adhesive strength and instability due to moisture absorption, leading to unstable biosignal measurement.

Innovation Solution

Incorporation of a nitrogen-containing additive in the adhesive electrode composition, ranging from 0.01 wt% to 3.0 wt%, to enhance moisture absorption and maintain adhesion and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an aqueous emulsion is used as an adhesive material, then the adhesive electrode can be manufactured with simple materials and processes, but the adhesive strength is reduced when external moisture is absorbed during use

Engineering Contradiction:

Improveease of manufactureVSAvoidadhesive strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A hydrophobic agent is introduced as an intermediary substance between the aqueous emulsion adhesive and the external moisture environment. This hydrophobic agent forms a protective layer that mediates the interaction between moisture and the adhesive, preventing water from penetrating into the aqueous emulsion and causing peeling, thereby maintaining adhesive strength in humid conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical composition parameters of the adhesive layer are modified by adding specific components: a hydrophobic agent (such as silicone oil or fluorinated compounds) and a conductive polymer (such as PEDOT:PSS). These parameter changes transform the adhesive from being purely water-based and moisture-sensitive to a composite formulation that repels moisture while maintaining adhesion and conductivity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the adhesive sheet absorbs sweat or moisture, then the adhesive strength is reduced and the sheet is likely to be peeled off, but maintaining moisture resistance may reduce adhesion to skin

Engineering Contradiction:

Improveadhesive strengthVSAvoidmoisture absorption

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hydrophobic agent serves as a mediator that allows the adhesive to interact with the skin surface effectively while blocking the harmful effect of external moisture. It creates a selective barrier that permits adhesion to occur at the interface while preventing water ingress from the external environment

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive layer is formulated as a composite material containing multiple components: aqueous emulsion base, hydrophobic agent, and conductive polymer. This composite structure combines the benefits of water-based adhesion with moisture resistance and electrical conductivity, achieving multiple functions simultaneously

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If the adhesive sheet is adhered to the skin for stable biosignal measurement, then high sensitivity is required, but moisture absorption causes peeling and measurement instability

Engineering Contradiction:

Improvemeasurement sensitivityVSAvoidadhesive stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The hydrophobic agent acts as a protective intermediary that stabilizes the adhesive composition against moisture-induced degradation. This stabilization ensures that the adhesive maintains its bonding properties throughout the measurement period, preventing peeling and ensuring continuous, stable biosignal acquisition

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The addition of conductive polymers changes the electrical parameters of the adhesive layer, providing both adhesion and electrical conductivity. This parameter change enables the adhesive to function as both a bonding agent and an electrode material, ensuring stable electrical contact for sensitive biosignal measurement while resisting moisture

Inventive Principle:

Principle #35Parameter changes

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 adhesive electrode maintains stable measurement with high sensitivity despite moisture absorption, ensuring strong adhesion and low contact impedance.

Implementation Method 1

an amount of the nitrogen-containing additive is from 0.01 wt % to 3.0 wt % relative to a total amount of the adhesive electrode for biosignal acquisition

Methodology Applied

Scientific EffectMoisture absorption: Absorption (physical)

Data Source

PatentUS20260013767A1Adhesive electrode for biosignal acquisition and biosensor

Publication Date: 2026.01.15 NITTO DENKO CORP

AI summary

An adhesive electrode for biosignal acquisition according to the present invention includes a conductive polymer, an aqueous emulsion adhesive, and a nitrogen-containing additive. An amount of the nitrogen-containing additive is from 0.01 wt % to 3.0 wt % relative to a total amount of the adhesive electrode for biosignal acquisition.