Spirally\nStructured Conductive Composites for Highly\nStretchable, Robust Conductors and Sensors

Abstract

Flexible and stretchable electronics\nare highly desirable for next\ngeneration devices. However, stretchability and conductivity are fundamentally\ndifficult to combine for conventional conductive composites, which\nrestricts their widespread applications especially as stretchable\nelectronics. Here, we innovatively develop a new class of highly stretchable\nand robust conductive composites via a simple and scalable structural\napproach. Briefly, carbon nanotubes are spray-coated onto a self-adhesive\nrubber film, followed by rolling up the film completely to create\na spirally layered structure within the composites. This unique spirally\nlayered structure breaks the typical trade-off between stretchability\nand conductivity of traditional conductive composites and, more importantly,\nrestrains the generation and propagation of mechanical microcracks\nin the conductive layer under strain. Benefiting from such structure-induced\nadvantages, the spirally layered composites exhibit high stretchability\nand flexibility, good conductive stability, and excellent robustness,\nenabling the composites to serve as highly stretchable conductors\n(up to 300% strain), versatile sensors for monitoring both subtle\nand large human activities, and functional threads for wearable electronics.\nThis novel and efficient methodology provides a new design philosophy\nfor manufacturing not only stretchable conductors and sensors but\nalso other stretchable electronics, such as transistors, generators,\nartificial muscles, etc.