Repeatably Autonomously Self-Healing Ultra-Stretchable PAAMPSA/PANI/PA Conductive Polymer Complex as Strain Sensor

Wearable strain sensors should be comfortably adhered to the skin and capable of monitoring human motions with high accuracy/sensitivity while remaining robust with excellent durability/longevity. However, it is challenging to develop electronic materials that possess the properties of skin—compliant, elastic, stretchable, and self-healable while also having a high enough conductivity for adequate sensitivty. This work demonstrates a new regenerative polymer complex composed of poly(2-acrylamido-2-methyl-1-propanesulfonic acid), polyaniline, and phytic acid as a skin-like electronic material. The type-2 (zip) templated polymerization of aniline in the presence of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) with phytic acid as a P-type dopant exhibits ultrahigh stretchability (1935%), repeatable autonomous self-healing ability (repeating healing efficiency &gt;98%), quadratic response to strain (<i>R</i>² &gt; 0.9998), and linear response to flexion bending (<i>R</i>² &gt; 0.9994), mechanically outperforming current reported wearable strain sensors. Sensitive strain-responsive geometric and piezoresistive mechanisms of the material owing to the homogeneous and viscoelastic nature provide excellent linear responses to omnidirectional tensile strain and bending deformations. Furthermore, this material is scalable and simple to process in an environmentally friendly manner, paving the way for the next-generation flexible electronics.