Arcuate Stretchable Conductors for Adhesion and Conductivity
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Solution Overview
Problem
Current stretchable conductive materials, such as woven metallic fibers and printed silver inks on elastomeric substrates, are either expensive or fail to meet the stretchability and conductivity requirements for conformable electronics applications.
Innovation Solution
The development of elongate wires with arcuate regions partially embedded in an elastomeric substrate, where a portion of the wire's surface area is exposed for conductivity while the rest is embedded to maintain adhesion and prevent debonding during mechanical bending and stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If woven metallic fibers or yarns are used for stretchable conductors, then conductivity and adhesion are improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent changes the geometric parameters of the conductor from a straight configuration to an arcuate/serpentine shape with specific curvature radii. This parameter change allows the conductor to accommodate substrate stretching while maintaining adhesion, replacing the need for expensive woven metallic structures with a simpler curved wire design that achieves the same functional reliability at lower cost.
Solution Approach 2:
The conductor is segmented into multiple regions with different embedment depths: a first region with greater embedment depth for enhanced adhesion during stretching, and a second region with lesser embedment depth for flexibility. This segmentation allows different portions of the conductor to perform different functions, achieving both strong adhesion and stretchability without requiring complex woven structures.
2Ease of manufacture
If printed stretchable conductive silver inks are used on elastomeric substrates, then manufacturing cost is reduced, but stretchability and conductivity requirements are not met
Solution Approach 1:
The patent modifies the geometric parameters of the conductor by forming it into an arcuate shape with controlled curvature radii (first curvature radius in the first region, second curvature radius in the second region). This parameter change enables the simple wire structure to accommodate substrate deformation while maintaining electrical connectivity, achieving the stretchability performance that was previously only attainable with complex woven structures or expensive materials.
Solution Approach 2:
The conductor is designed with arcuate curvature rather than a straight configuration. The specific curvature radii are optimized to allow the conductor to flex and deform with the elastomeric substrate during stretching cycles. This curvature design enables the simple wire to achieve the stretchability and reliability required for conformable electronics, replacing the need for expensive printed silver inks or woven structures.
Data Source
AI summary
A stretchable conductor includes a substrate with a first major surface, wherein the substrate is an elastomeric material. An elongate wire is on the first major surface of the substrate; the wire includes a first end and a second end, and further includes at least one arcuate region between the first end and the second end. At least one portion of the arcuate region of the wire in the region has a first surface area portion embedded in the surface of the substrate and a second surface area portion unembedded on the substrate and exposed in an amount sufficient to render at least an area of the substrate in the region electrically conductive. The unembedded second surface portion of the arcuate region may lie above or below a plane of the substrate. Composite articles including a stretchable conductor in durable electrical contact with a conductive fabric are also disclosed.