Optically Decoupling Electrochromic Dynamics and <i>In Situ</i> Morphological Evolution of a Single Soft Polyaniline Nanoentity

Electroresponsive multicolored materials have tremendous potential in flexible electronics and smart wearable devices. Herein, the electrochromic dynamics and <i>in situ</i> morphological evolution of a single soft polyaniline nanoentity can be visualized and decoupled by an opto-electrochemical imaging strategy. The durability, tinting speed, and reversibility down to the single-nanoparticle level are quantified, and the switching of transient intermediate electrochromic states is trapped. The mechanistic studies suggest that the heterogeneity of electrochromic activity is attributed to the nonuniformity of the polymer network interspersed at the nanometric level. Furthermore, the representative Pauli repulsion effect is uncovered from the self-stretching behavior of the conductive state of polyaniline at the oxidized potential. It provides novel insights for advancing high-performance electrochromic devices and flexible strain sensors, which can be dynamically manipulated by external stimuli.