Morphology-controlled ultrafine $$\hbox {BaTiO}₃$$ BaTiO 3 -based PVDF–HFP nanocomposite: synergistic effect on dielectric and electro-mechanical properties

Perovskite-based flexible nanocomposites were realized by dispersing $$\hbox {BaTiO}₃$$ and modified monodisperse $$\hbox {BaTiO}₃$$ in PVDF–HFP matrix. $$\hbox {BaTiO}₃$$ was modified in situ by the addition of carbon solution, which was prepared electrochemically by using graphite rod. Structural characterization revealed that the decrease in tetragonality due to reduction in particle size of modified $$\hbox {BaTiO}₃$$ than unmodified $$\hbox {BaTiO}₃$$ . The controlled morphology of treated- $$\hbox {BaTiO}₃$$ nanoparticles was well dispersed in polymer matrix and exhibited effective dielectric constant. High active surface area of modified $$\hbox {BaTiO}₃$$ suggested strong interfacial polarization, reduced dielectric loss and induced relaxation as compared to PVDF–HFP/BT nanocomposite. The experimental dielectric behaviour was fitted with theoretical Maxwell–Garnet model and composites followed up to 20 wt.% filler. The polarization effect was further proven by electric modulus studies of nanocomposites in broad frequency (0.1 Hz–1 MHz) and temperature (− 40 to $$130{^\circ }\hbox {C}$$ ). The results suggested that the shift in relaxation peaks towards higher frequencies with increase in filler content in polymer matrix. Further, a flexible-pressure sensing device was fabricated and evaluated for real applications.