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Design of Strain-Limiting Substrate Materials for Stretchable and Flexible Electronics
Yinji Ma1, Kyung-In Jang2, Liang Wang3
1Departments of Civil and Environmental Engineering, Mechanical Engineering, and Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA; Department of Engineering Mechanics, Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China.
Advanced Functional Materials
|October 17, 2017
Summary
Researchers developed strain-limiting mechanics for soft electronics using wrinkled thin films on prestrained substrates. This approach protects biomedical devices from large deformations, enhancing their durability and reliability for integration with biological tissues.
Area of Science:
- Materials Science
- Biomedical Engineering
- Mechanical Engineering
Background:
- Soft electronics for biomedical applications require mechanically compatible substrates for integration with biological tissues.
- Existing stretchable substrates lack protection against high peak strains during large deformations, risking device failure.
Purpose of the Study:
- To develop compliant substrates with strain-limiting mechanics for enhanced protection of biomedical electronics.
- To create a simple, effective method for improving the durability of soft electronic devices.
Main Methods:
- Transferring a high modulus thin film or mesh onto a prestrained compliant substrate.
- Utilizing the release of prestrain to induce a wrinkled geometry in the film/mesh.
- Developing a theoretical model to predict the mechanical behavior of the wrinkled structures.
Main Results:
- The wrinkled structures exhibit a low elastic modulus at small strains and a high tangent modulus (>1000x increase) at large strains.
- A bilinear stress-strain behavior with a sharp transition point, controlled by prestrain magnitude, was achieved.
- Theoretical model predictions showed quantitative agreement with finite element analysis and experimental results.
Conclusions:
- The wrinkled thin film/mesh on prestrained substrates provides an effective strain-limiting mechanism for soft electronics.
- This approach offers a robust solution for protecting biomedical devices from mechanical stress, improving their integration and longevity.
- The developed method complements existing strategies for creating mechanically robust and biocompatible electronic systems.