Composite Fiber Network for Wear-Resistant Bio-Sensors
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Solution Overview
Problem
Conventional flexible electronics lack sufficient durability and surface followability, leading to issues such as electrode layer breakage and peeling off when attached to the skin, especially under wet conditions.
Innovation Solution
An electronic functional member is developed with a fiber network comprising two types of resins with different water solubility, where one resin is soluble in water and the other remains insoluble, enhancing durability by thermocompression bonding to create a stacked fiber network with a conductive member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fiber network of water-soluble PVA nanofiber with gold electrode layer is formed by electrospinning, then surface followability and stretchability are improved, but durability deteriorates due to electrode layer breakage and peeling off under wet conditions
Solution Approach 1:
The invention uses a composite fiber network structure consisting of water-soluble PVA nanofibers and water-insoluble polymer nanofibers (such as polyurethane or polyester). This composite structure combines the advantages of both materials: PVA provides excellent surface followability and biocompatibility, while the water-insoluble polymer provides mechanical strength and durability. The gold electrode layer is formed on this composite network, preventing breakage and peeling even under wet conditions, thus resolving the contradiction between surface followability and durability
Solution Approach 2:
The invention changes the solubility parameter of the fiber network by incorporating water-insoluble polymers into the electrospinning solution along with water-soluble PVA. By adjusting the ratio and types of polymers, the fiber network maintains water permeability while achieving sufficient mechanical strength. This parameter change allows the electrode layer to remain stable and attached under wet conditions while preserving the surface followability characteristics
2Reliability
If the electrode layer is formed by vapor deposition on PVA nanofiber network, then conductivity is achieved, but the electrode layer breaks easily due to lack of mechanical strength
Solution Approach 1:
The invention creates a composite fiber network where water-insoluble polymer nanofibers (such as polyurethane or polyester) provide the mechanical strength framework, while water-soluble PVA nanofibers provide flexibility and surface followability. The gold electrode layer is vapor-deposited on this reinforced composite network, which prevents breakage during handling and application. The water-insoluble component acts as a structural backbone that maintains electrode layer integrity while the PVA component ensures conformability to skin surfaces
3Reliability
If the fiber network is made entirely water-soluble for biocompatibility, then biocompatibility is improved, but water resistance deteriorates causing easy peeling off
Solution Approach 1:
The invention employs a composite fiber network combining water-soluble PVA and water-insoluble polymers (polyurethane, polyester, or acrylic). The water-insoluble component creates a water-resistant framework that prevents peeling off during wet conditions such as sweating or washing, while the water-soluble PVA maintains biocompatibility and skin conformability. This composite approach resolves the contradiction between attachment stability and water resistance while preserving biocompatibility
Solution Approach 2:
The invention applies different solubility characteristics to different regions of the fiber network: water-insoluble polymers form the structural framework that provides water resistance and attachment stability, while water-soluble PVA is distributed throughout to provide biocompatibility and surface followability. This local differentiation of material properties allows the network to simultaneously achieve water resistance and biocompatibility without compromising either characteristic
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 solution significantly improves wear resistance and water resistance, allowing the electronic functional member to maintain attachment to the skin without disconnection, even under repeated rubbing and wet conditions, exceeding the durability of conventional designs.
Implementation Method 1
The fiber network is partially solved in water and partially remains when immersed in water. The resin is, for example, a polyvinyl alcohol derivative.
Implementation Method 2
a second fiber network including a fiber containing a second resin that is water-soluble and changes to being poorly water-soluble after heating and pressure bonding; a step of changing the second resin to being poorly water-soluble by heating and pressure bonding the second fiber network
Data Source
AI summary
[Problem] Provided is an electronic functional member of superior wear resistance. [Solution] The present invention comprises a fiber network constituted by a water-soluble resin and a poorly water-soluble resin, and an electroconductive member formed on the fiber network. The water-soluble resin and poorly water-soluble resin are, for example, polyvinyl alcohol derivatives. In accordance with an embodiment of the electronic functional member according to the present invention, the fiber network is formed by layering a first fiber network constituted by fibers containing a water-soluble first resin and a second fiber network constituted by fibers containing a poorly water-soluble second resin. Alternatively, the fiber network may be constituted by fibers containing the water-soluble first resin and fibers containing the poorly water-soluble second resin. Alternatively, the fiber network may be constituted by fibers containing the water-soluble first resin and the poorly water-soluble second resin.