Transparent Stretchable Electronics With Liquid Metal Grid Conductors
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Solution Overview
Problem
Conventional flexible transparent conducting films (TCFs) face limitations such as low transmittance, brittleness, poor flexibility, short bending fatigue life, complex and expensive fabrication, and high raw material costs, making them unsuitable for applications requiring mechanical deformation without conductivity loss.
Innovation Solution
The development of stretchable electronics with a liquid metal coating on a stretchable substrate, specifically using a biphasic metallic grid pattern on a polydimethylsiloxane (PDMS) substrate, achieved through laser patterning to enhance stretchability, transmittance, and transparency, while maintaining conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional flexible TCFs are used, then electrical conductivity is maintained, but mechanical flexibility and stretchability are poor
Solution Approach 1:
The continuous metal film is segmented into discrete metallic islands separated by gaps. This segmentation allows the substrate to deform elastically under strain while the metal islands maintain electrical connectivity through the conductive polymer matrix, resolving the contradiction between mechanical flexibility and conductivity reliability.
Solution Approach 2:
The patent changes the physical state of the metal from continuous solid film to discrete liquid metal droplets that can deform and reconfigure. This parameter change enables the material to accommodate mechanical strain while maintaining electrical conductivity through the liquid metal's ability to flow and reform connections.
2Strength
If TCF thickness is increased to withstand mechanical deformation, then mechanical robustness is improved, but optical transmittance decreases
Solution Approach 1:
By segmenting the metal into discrete islands rather than a continuous thick film, the patent reduces the total metal coverage area while maintaining mechanical integrity. This allows light to pass through the gaps between islands, achieving both mechanical robustness and high optical transmittance.
Solution Approach 2:
The TCF structure incorporates a porous architecture with gaps between metallic islands and a conductive polymer matrix. This porous structure reduces light blocking while maintaining mechanical strength through the distributed island architecture and elastic substrate.
3Ease of manufacture
If conventional TCF fabrication methods are used, then manufacturing process is established, but fabrication complexity and cost are high
Solution Approach 1:
The patent replaces complex multi-step sputtering and patterning processes with a simplified solution involving spin-coating of conductive polymer and droplet deposition of liquid metal. This substitution of manufacturing methods dramatically reduces fabrication complexity and cost.
Solution Approach 2:
The patent uses inexpensive materials such as conductive polymer electrolytes and common liquid metal alloys (Ga-In-Sn) instead of expensive ITO or complex multilayer structures. This approach reduces raw material costs and simplifies the fabrication process.
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 provides high optical transmittance (>85%) and mechanical robustness, allowing the electronics to remain functional and imperceptible under strain, suitable for applications like wearable computing and soft robotics.
Implementation Method 1
laser patterning to enhance stretchability, transmittance, and transparency
Data Source
AI summary
A stretchable and transparent electronic structure may generally include a stretchable elastomer layer; optionally, a metal adhesion layer on top of the stretchable elastomer layer; a metal alloying layer on top of the metal adhesion layer; and a liquid metal, wherein the structure is colorless and transparent when viewed under visible light. Methods of making the stretchable and transparent electronic structure are also described.