Intrinsically Stretchable Piezoelectric Nanocomposites for Artificial Ultrasonic Sensory Synapse

ABSTRACT Intrinsically stretchable piezoelectric materials are very promising for next‐generation stretchable and conformal electronics. However, enhancing their performance in terms of ferroelectric phase fraction and piezoelectric properties remains a major challenge. Here, we present a cross‐linked intrinsically stretchable piezoelectric nanocomposite (IS‐PNC) of poly(vinylidene fluoride‐trifluoroethylene)‐poly(ethylene glycol) diamine (P(VDF‐TrFE)‐PEG) incorporating (3‐aminopropyl)triethoxysilane‐functionalized BaTiO 3 nanoparticles (BTO@APTES NPs). The strong hydrogen‐bonded interfaces formed between the BTO@APTES NP fillers and the stretchable P(VDF‐TrFE)‐PEG matrix promote the formation of ferroelectric phase without compromising stretchability. Furthermore, comprehensive ferroelectric hysteresis investigations reveal the polarization switching mechanisms of the cross‐linked IS‐PNCs, strongly influencing overall ferroelectric responses. Benefiting from the increased ferroelectric phase, improved ferroelectricity, and aligned dipoles, the optimized IS‐PNC at 1 wt% BTO@APTES exhibits intrinsic stretchability and stable piezoelectricity under strain up to 50%, maintaining robust electromechanical responses. Leveraging these properties, an artificial ultrasonic sensory synapse combining the IS‐PNC sensor and a flexible synaptic transistor was demonstrated, mimicking the ultrasonic detection functions found in dolphin biological echolocation. The IS‐PNCs have great potential for stretchable piezoelectronics.