Neuron-Inspired Self-Healing Composites via Dynamic Construction of Polypyrrole-Decorated Carbon Nanotubes for Smart Physiochemical Sensing.

Mimicking human skin's functions to develop intelligent materials have inspired extensive exploration in the design and synthesis of a novel device. However, how to simulate neuron function and integrate highly sensitive, positive perceptions and self-healing into one single material remains a challenge. Here, we prepared a recycled polyurethane (PU) with high tensile strength values (11.37 ± 0.03 MPa), high maximum elongation (1130 ± 11.59%), and high self-healing property (100% for 6 h at 25 °C) and a smart PU composite of polypyrrole-decorated carbon nanotubes with higher sensitivity. The smart composite can not only actively identify physical change such as strain, moisture, and temperature but also proactively detect various chemical environment changes such as acid, alkali, oxidant, and reductant (: 25-90 °C, Δ/ values were 0.1-1.6; strain: 10-150%, Δ/ values were 2.5-27; 0.01-0.1 mol L oxidant solutions, Δ/ values were 0.66-0.75; 0.01-0.1 mol L reductant solutions, Δ/ values were 0.51-0.65; 0.1-0.5 mol L acid solutions, Δ/ values were 0.54-0.58; and 0.1-0.5 mol L alkali solutions, Δ/ values were 0.42-0.46). More importantly, the signal values of the smart composite can quickly return to the initial values after eliminating physical and chemical stimuli. The abovementioned features of the smart composite, the high physicochemical response, and significant restorability make it potentially possible to apply it in intelligent chemical manufacturing.