Integration of Interfacial Chemistry-Guided BaTiO_<b>3</b> Nanoparticle Arrangements in Polymer Film Stacks for Pressure-Sensing Devices

Precise spatial arrangement of nanoparticles (NPs) within soft polymer matrices is essential for enabling hierarchical architectures with tailored dielectric and piezoelectric properties. However, constructing well-ordered, multilayered NP structures remains challenging due to interfacial aggregation, solvent-driven instabilities, and poor layer-to-layer registration. Here, we report a solvent-mediated confinement assembly approach that utilizes patterned polymer templates to direct the assembly of barium titanate (BaTiO₃) nanoparticles in a poly(vinylidene fluoride-<i>co</i>-hexafluoropropylene) [P(VDF-HFP)] matrix. By controlling interfacial wettability, solvent evaporation, and polymer-nanoparticle interactions, we achieve highly ordered nanoparticle arrays with a feature size of 1 μm and an integration density of 2000 lines/cm. Multilayered architectures are further constructed via layer-by-layer (LbL) assembly, demonstrating enhanced dielectric energy storage (4.8 J/cm³) and piezoelectric sensing (2 mg detection limit). This work provides a generalizable approach for manipulating nanoparticle assemblies in soft matter, with potential applications in flexible electronics and energy devices.