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Design of Strain‐Limiting Substrate Materials for Stretchable and Flexible Electronics
Author(s) -
Ma Yinji,
Jang KyungIn,
Wang Liang,
Jung Han Na,
Kwak Jean Won,
Xue Yeguang,
Chen Hang,
Yang Yiyuan,
Shi Dawei,
Feng Xue,
Rogers John A.,
Huang Yonggang
Publication year - 2016
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201600713
Subject(s) - materials science , stretchable electronics , stiffness , tangent modulus , elastic modulus , composite material , substrate (aquarium) , modulus , stress (linguistics) , electronics , deformation (meteorology) , electrical engineering , linguistics , oceanography , philosophy , geology , engineering
Recently developed classes of electronics for biomedical applications exploit substrates that offer low elastic modulus and high stretchability, to allow intimate, mechanically biocompatible integration with soft biological tissues. A challenge is that such substrates do not generally offer protection of the electronics from high peak strains that can occur upon large‐scale deformation, thereby creating a potential for device failure. The results presented here establish a simple route to compliant substrates with strain‐limiting mechanics based on approaches that complement those of recently described alternatives. Here, a thin film or mesh of a high modulus material transferred onto a prestrained compliant substrate transforms into wrinkled geometry upon release of the prestrain. The structure formed by this process offers a low elastic modulus at small strain due to the small effective stiffness of the wrinkled film or mesh; it has a high tangent modulus (e.g., >1000 times the elastic modulus) at large strain, as the wrinkles disappear and the film/mesh returns to a flat geometry. This bilinear stress–strain behavior has an extremely sharp transition point, defined by the magnitude of the prestrain. A theoretical model yields analytical expressions for the elastic and tangent moduli and the transition strain of the bilinear stress–strain relation, with quantitative correspondence to finite element analysis and experiments.