Ultrastretchable Self-Healing Paampsa/PANI/PA Polymer Complex as a Piezoresistive Sensor

Wearable sensors, stretchable electronics, and many soft robotics materials must have a sufficiently high balance of conductivity, stretchability, and robustness. Intrinsically conductive polymers offer a critical step toward improving wearable sensor materials due to their tunable conductivity, soft/compliant nature, and ability to complex with other synergistic molecules (i.e., polyacids, small molecule dopants). 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. It exhibits ultrahigh stretchability (1935%), repeatable autonomous self-healing ability (repeating healing efficiency >98%), quadratic response to strain (R2 > 0.9998), and linear response to flexion bending (R2 > 0.9994), outperforming current reported wearable strain sensors. While nanofillers typically increase conductivity at the expense of mechanical properties, here we show an increase in both conductivity and mechanical properties when silver nanowires are added, forming a polymer nanocomposite with high electronic sensitivity, unprecedented mechanical properties (a maximum strain of 4693% at ambient humidity; ~52 RH%), and repeatable, autonomous self-healing efficiencies of greater than 98%.