Nanofiber Yarn Gas Sensor with Ionic Liquids

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Solution Overview

Problem

Existing colorimetric gas sensors face limitations in sensitivity, specificity, and environmental impact due to limited surface area, porosity, and high dye content, which hinders their effectiveness in detecting small gas concentrations and biomarker gases, particularly in healthcare applications.

Innovation Solution

A colorimetric gas sensor is developed using a complex polymer nanofiber yarn structure where ionic liquids and color change dyes are uniformly anchored within a 1-D nanofiber structure, forming a 3-D network, enhancing gas adsorption and minimizing dye content through an electro-spinning process, allowing for improved reactivity and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional colorimetric gas sensors use traditional film or planar structures, then the device complexity is low and ease of manufacture is high, but the surface area is limited and sensitivity to low gas concentrations is insufficient

Engineering Contradiction:
Improvesensitivity to low gas concentrationsVSAvoidsurface area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent transitions from traditional 2D planar film structures to 3D nanofiber yarn structures. The nanofibers are assembled into hierarchical yarns with core-sheath configurations, creating multiple dimensions of surface area. This dimensional transformation dramatically increases the effective surface area available for gas adsorption and colorimetric reaction, enabling detection of low gas concentrations while maintaining manufacturability through electrospinning and yarn assembly processes.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs porous nanofiber structures with controlled porosity to maximize surface area. The electrospun nanofibers inherently create porous networks that provide extensive internal surface area for gas molecule access. The core-sheath yarn architecture further enhances porosity by creating inter-yarn spaces while maintaining structural integrity, allowing gases to penetrate deep into the sensor material for improved sensitivity without increasing overall device size.

Inventive Principle:
Principle #31Porous materials

2Measurement precision

If high amounts of color change dye are used to improve detection sensitivity, then measurement precision improves, but environmental pollution increases and the sensor requires more material processing

Engineering Contradiction:
Improvedetection sensitivityVSAvoidenvironmental pollution from dye
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by concentrating color change dyes specifically within the sheath layer of the core-sheath yarn structure, rather than uniformly distributing them throughout the entire sensor. This localized placement optimizes dye utilization efficiency, allowing high detection sensitivity at the gas-exposed surface while minimizing total dye quantity. The core region can be dedicated to other functional materials, reducing overall harmful substance content while maintaining performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite material strategies by combining color change dyes with ionic liquids and various polymer matrices in the nanofiber structure. These composite formulations enhance the efficiency and stability of the dye molecules, allowing reduced dye loading while achieving comparable or superior detection sensitivity. The composite approach also improves environmental sustainability by enabling the use of less toxic dye formulations and reducing the total amount of harmful substances required.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If ionic liquids and color change dyes are uniformly distributed in the nanofiber structure, then gas adsorption capability and sensitivity improve, but the manufacturing process complexity increases

Engineering Contradiction:
Improvegas adsorption capabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-mixing ionic liquids and color change dyes into the electrospinning solution before fiber formation. This ensures uniform distribution of functional materials throughout the nanofibers during the electrospinning process itself, eliminating the need for subsequent complex post-processing steps. The hierarchical yarn assembly is also performed in advance, creating pre-structured bundles that simplify final sensor fabrication while maintaining optimal functional material distribution for enhanced gas adsorption and sensitivity.

Inventive Principle:
Principle #10Preliminary action

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 sensor achieves enhanced sensitivity and rapid color change response to low gas concentrations, including biomarker gases, with reduced dye usage and improved environmental sustainability, suitable for healthcare and industrial applications.

Implementation Method 1

ionic liquids and color change dyes are anchored within nanofibers and on a surface of the nanofiber to increase the solubility of specific gas molecules through the ionic liquids

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

color change dyes causing a color change through adsorption and a reaction with specific gas molecules

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3636817B1Method of fabricating a colorimetric gas sensor based on nanofiber yarn for gas indication including ionic liquids and chromogenic dyes
Publication Date: 2023.06.07 KOREA ADVANCED INST OF SCI & TECH
  • EP3636817B1 patent drawingFigure 1
  • EP3636817B1 patent drawingFigure 2
  • EP3636817B1 patent drawingFigure 3

AI summary

Disclosed is a colorimetric gas sensor using a complex polymer nanofiber structure for yarn-based gas indication, in which ionic liquids as effective gas adsorbents and color change dyes having varying colors have been functionalized in a nanofiber and a method of fabricating the same. In the fabrication method, after the ionic liquids and color change dyes are mixed with a polymer solution in which high-temperature stirring and quenching processes are accompanied to prepare fine crystals of color change dyes. Accordingly, the dual-electro-spinning process is conducted to produce the nanofiber yarn scaffold on which ionic liquids and color change dyes are finely functionalized.