Resilient piezoelectric composites enabled by a microphase-separated PS-b-P(DMS-stat-VMS) matrix for stable mechano-electric response

A microphase-separated block copolymer enables resilient BTO-based composites. • PS-rich rigid nanodomains promote stress dispersion in the composite. • Reduced hysteresis and improved cyclic compression stability are achieved. • 98.4% response retention and intact interface remain after 10,000 cycles at 100 N. Stable mechano-electric response under repeated contact and compression is in high demand for resilient piezoelectric composites used in embodied intelligence and human-machine interfaces. Such composites are commonly fabricated by dispersing high-performance ceramic fillers into elastomeric matrices. However, stable mechano-electric response relies on efficient and durable stress transfer from the soft matrix to the piezoelectric phase, which is hindered by the stiffness disparity, often approaching five orders of magnitude, between rigid ceramic fillers and MPa-level soft elastomers. The soft matrix dissipates mechanical energy through viscoelastic deformation, while the abrupt ceramic-elastomer stiffness transition leads to interfacial stress concentration and unfavorable stress localization. Herein, we develop a microphase-separated block copolymer matrix, crosslinked PS- b -P(DMS- stat -VMS) (CroPSDV), loaded with barium titanate (BTO) nanoparticles. Microphase separation in CroPSDV produces PS-rich rigid nanodomains within a soft polysiloxane-rich matrix, forming a mechanically heterogeneous architecture that may facilitate local stress redistribution and mitigate stress concentration around BTO nanoparticles while buffering the ceramic-elastomer stiffness contrast. Together with in situ thiol-ene crosslinking, this architecture structurally encapsulates and confines BTO nanoparticles, reduces hysteresis loss, and stabilizes cyclic compression behavior. The BTO/CroPSDV composite retains stable mechano-electric output over 10,000 compression cycles at 100 N, with an output retention of 98.4% and without obvious matrix-filler interfacial damage after cycling. It also exhibits sensitive and rapid mechano-electric response, with a detection limit of 1 N and a response time of 43 ms. This work presents a mechanically active matrix-design strategy for resilient piezoelectric composites for stress dispersion and cyclic interfacial stability. Download: Download high-res image (264KB) Download: Download full-size image