A Self‐Healable, Highly Stretchable, and Solution Processable Conductive Polymer Composite for Ultrasensitive Strain and Pressure Sensing

TLDR

Electronic skins that mimic human skin have driven extensive research into soft materials, yet creating conductive materials that are both stretchable and self‑healable remains a major challenge. The authors fabricate a ternary composite of polyaniline, polyacrylic acid, and phytic acid by solution casting, leveraging dynamic hydrogen bonding and electrostatic interactions to enable large‑area, low‑cost production. The composite achieves ≈500 % stretchability, 0.12 S cm⁻¹ conductivity, ≈99 % self‑healing in 24 h, and delivers ultrahigh strain and pressure sensitivity that outperforms existing self‑healable piezoresistive sensors.

Abstract

Abstract Mimicking human skin's functions to develop electronic skins has inspired tremendous efforts in design and synthesis of novel soft materials with simplified fabrication methods. However, it still remains a great challenge to develop electronically conductive materials that are both stretchable and self‐healable. Here it is demonstrated that a ternary polymer composite comprised of polyaniline, polyacrylic acid, and phytic acid can exhibit high stretchability ( ≈ 500%) and excellent self‐healing properties. The polymer composite with optimized composition shows an electrical conductivity of 0.12 S cm −1 . On rupture, both electrical and mechanical properties can be restored with ≈ 99% efficiency in a 24 h period, which is enabled by the dynamic hydrogen bonding and electrostatic interactions. It is further shown that this composite is both strain and pressure sensitive, and therefore can be used for fabricating strain and pressure sensors to detect a variety of mechanical deformations with ultrahigh sensitivity. The sensitivity and sensing range are the highest among all of the reported self‐healable piezoresistive pressure sensors and even surpass most flexible mechanical sensors. Notably, this composite is prepared via a solution casting process, which potentially allows for large‐area, low‐cost fabrication electronic skins.