Sulfonated Cellulose-Doped Polyaniline Humidity Sensor

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Solution Overview

Problem

Existing humidity sensors lack stability and mechanical robustness, particularly in chemiresistive types, which affects their performance in monitoring relative humidity effectively.

Innovation Solution

The development of conductive polyaniline nanofibers doped with sulfonated cellulose or starch derivatives, combined with Kollidon SR, forms a nanocomposite sensing layer that enhances mechanical stability and sensitivity, using techniques like electrospinning and solid-state doping to create a durable and responsive humidity sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thin films are used as sensing layers, then the device complexity is low, but the mechanical stability and sensitivity are insufficient

Engineering Contradiction:

Improvemechanical stabilityVSAvoidsensing layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite materials by combining conductive polyaniline nanofibers with sulfonated cellulose or starch derivatives to form a nanocomposite sensing layer. This composite structure integrates the high conductivity and sensitivity of polyaniline nanofibers with the mechanical stability and hydrophilicity of sulfonated cellulose/starch, thereby simultaneously improving mechanical stability and sensing performance while maintaining a relatively simple device structure.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes porous materials by incorporating nanocellulose or starch derivatives with inherent porous structures into the sensing layer. These porous materials provide high surface area for humidity interaction, enhanced diffusion pathways for water molecules, and improved mechanical flexibility, thus achieving better mechanical stability and sensitivity without significantly increasing device complexity.

Inventive Principle:

Principle #31Porous materials

2Reliability

If conventional chemiresistive sensors are used, then the manufacturing process is simple, but the stability and mechanical robustness are lacking

Engineering Contradiction:

Improvesensor stabilityVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the chemical structure of the sensing materials through sulfonation of cellulose or starch derivatives, introducing conductive polyaniline nanofibers, and controlling the morphology and composition ratios. These parameter changes enhance sensor stability and mechanical robustness while maintaining compatibility with existing manufacturing techniques like electrospinning and solid-state doping, thus balancing improved reliability with ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If non-porous sensing layers are used, then the manufacturing is simpler, but the diffusion and sensitivity are reduced

Engineering Contradiction:

Improvehumidity sensing sensitivityVSAvoidsensing layer structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #31Porous materials

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 resulting sensors exhibit improved mechanical stability and sensitivity, maintaining conductivity and responsiveness across varying humidity levels, outperforming conventional thin films with enhanced diffusion and porosity.

Implementation Method 1

conductive polyaniline nanofibers doped with sulfonated cellulose or starch derivatives

Methodology Applied

Scientific EffectDoping: Dopants

Implementation Method 2

maintaining conductivity and responsiveness across varying humidity levels

Methodology Applied

Scientific EffectConduction (electrical): Conduction (electrical)

Implementation Method 3

enhanced diffusion and porosity

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS11460427B2Chemiresistor humidity sensor and fabrication method thereof

Publication Date: 2022.10.04 CYBERSWARM INC

AI summary

A sulfonated nanocellulose or sulfonated cellulose may be synthesized. A polyaniline emeraldine may be doped with the sulfonated nanocellulose or sulfonated cellulose to form a sulfonated nanocellulose-doped polyaniline or a sulfonated cellulose-doped polyaniline.