Toothed Substrate Design to Improve Stretchability of Serpentine Interconnect for Stretchable Electronics

Abstract Integration of deformable serpentine interconnects and inorganic functional materials with soft elastomeric substrate enables the electronics to deform into arbitrary desired shapes. Conventionally, the serpentine interconnects are bonded to a planar substrate, which limits the out‐of‐plane buckling of the serpentine interconnects, and thus restricts their stretchability. An integrated system combining serpentine interconnects with toothed substrate is proposed here to release part of the serpentine interconnects from the substrate. The advantage of this integrated system is its superior stretchability compared with the serpentine interconnects on a conventional planar substrate. Moreover, the position deviation of the serpentine interconnects to the toothed substrate influences the stretchability only in one direction, and the influence is predictable and ranges in an acceptable region. Combined analytical models and numerical simulations establish the stretchability of the integrated system, and the considerations that dictate roof collapse between the freestanding part of the serpentine interconnects and substrates. Examples of serpentine interconnects bonded on toothed and planar substrates are prepared, and low‐cycle fatigue tests are used to confirm the superior stretchability of toothed substrate by examining fatigue cracks associated with plastic deformation.