title: Buckling in serpentine microstructures and applications in elastomer-supported ultra-stretchable electronics with high areal coverage.
abstract: Lithographically defined electrical interconnects with thin, filamentary serpentine layouts have been widely explored for use in stretchable electronics supported by elastomeric substrates. We present a systematic and thorough study of buckling physics in such stretchable serpentine microstructures, and a strategic design of serpentine layout for ultra-stretchable electrode, via analytical models, finite element method (FEM) computations, and quantitative experiments. Both the onset of buckling and the postbuckling behaviors are examined, to determine scaling laws for the critical buckling strain and the limits of elastic behavior. Two buckling modes, namely the symmetric and anti-symmetric modes, are identified and analyzed, with experimental images and numerical results that show remarkable levels of agreement for the associated postbuckling processes. Based on these studies and an optimization in design layout, we demonstrate routes for application of serpentine interconnects in an ultra-stretchable electrode that offer, simultaneously, an areal coverage as high as 81%, and a biaxial stretchability as large as ~170%.
authors.affiliation: Department of Civil and Environmental Engineering and Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA ; Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China.
authors.forename: Yihui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Civil and Environmental Engineering and Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA ; Department of Civil Engineering, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Fu
authors.affiliation: Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Juhwan
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Su
authors.affiliation: Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China ; AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Keh-Chih
authors.initials: KC
authors.lastname: Hwang
authors.affiliation: Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Rogers
authors.affiliation: Department of Civil and Environmental Engineering and Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA ; Institute of Public Health and Medicine, Northwestern University, Evanston, IL 60208, USA ; Skin Disease Research Center, Feinberg School of Medicine, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Huang
keywords: Buckling analyses; Mechanical properties; Modeling; Serpentine interconnect; Stretchable electronics