Stretchability and compressibility of a novel layout design for flexible electronics based on bended wrinkle geometries

摘要

A novel bended wrinkle structure is proposed for layout design in flexible electronics, which is formed by compressive local buckling of the thin film bonded onto a pre-strained, finite-thickness substrate upon release of the pre-strain. The excellent performance of stretchability of this structure, which could be as high as 309%, is shown according to theoretical analyses and validated by finite element method (FEM). Furthermore, the maximum strain of the proposed design is examined to ensure reliability of application devices. Except for the approach to compressibility based on maximum strain analyses, the bended wrinkle structure is taken as a laminate with geometrical imperfections and buckling analyses are conducted to obtain the critical buckling loads, consequently another evaluation criterion for compressibility is established. It is also revealed that the stretchability can be further enhanced by bonding the two ends of the structure to another pre-strained compliant basal substrate, though the pre-strain for the basal substrate is restricted by the compressibility. In the current work, an alternative to existing planar wavelike layout designs is presented and the results obtained offer important design guidelines for future applications.