Interfacial Engineering of Composite Piezoelectric Fibers Via an Anchor-Chain Architecture

Composite piezoelectric fibers provide a promising route toward flexible electromechanical devices, yet their engineering performance is often limited by the mechanically fragile inorganic–organic interface. In BaTiO3/poly(l-lactic acid) (PLLA) fibrous membranes, elastic mismatch, weak interfacial adhesion, and nanoparticle aggregation impede stress transfer from the polymer matrix to the piezoelectric ceramic phase, thereby restricting force-to-electricity conversion. Here, we report an anchor-chain interfacial architecture to reinforce this rigid–flexible interface. A polydopamine (PDA) layer serves as an inner anchoring unit on the BaTiO3 surface, while grafted polyethylene glycol (PEG) chains provide steric stabilization and promote topological entanglement with the PLLA matrix. This cooperative interface improves nanoparticle dispersion, and enhances interfacial bonding strength. Consequently, the BaTiO3@PDA@PEG/PLLA membrane exhibits markedly enhanced nanoscale and macroscale piezoelectric responses compared with unmodified BaTiO3/PLLA and BaTiO3@PDA/PLLA membranes. As a device-level demonstration, a 2 × 2 tactile sensor array fabricated from the reinforced fibrous membrane distinguishes tapping, touching, and stroking stimuli through characteristic voltage outputs and spatiotemporal signal patterns. This work provides an engineering-oriented interfacial reinforcement strategy for improving the structural and electromechanical performance of inorganic–organic composite piezoelectric fibers.