1-3 BaTiO3-PVDF hybrid nanocomposites were prepared by combining electrospinning, sol-gel and spin-coating techniques. First, one-dimensional structures of barium titanate (BaTiO3) were obtained by electrospinning. An alcoholic solution consisting of Ba2+ and Ti4+ions (1:1 molar ratio) and poly(vinylpyrrolidone) was electrospun at 15 kV, with a tip-to-collector distance of 15 cm and a feed rate of 0.5 mL/h. Ceramic fibers were obtained after sintering the as-spun fibers at 900 °C for 2 hours. In a second step, poly(vinylidene fluoride) (PVDF) was incorporated to the oxide fibers by spin-coating a dimetilformamide solution, thus conforming 1-3 ceramic-polymeric hybrid nanocomposites on stainless steel substrates.
Scanning electron microscopy images showed that the as-spun fibers were smooth, long and continuous with an average diameter of 155 ± 40 nm, ranging from 60 to 240 nm, while sintered fibers presented a reduction in size, with an average diameter of 115 ± 16 nm, ranging from 96 to 120 nm. Sintered nanofibers were also long and continuous but with a rough surface. X-ray diffraction confirmed the perovskite-type structure of the BaTiO3. A structure refinement revealed a degree of tetragonality of 1.0046.
The polymer crystalline phases were identified by infrared spectroscopy on ATR mode. This study showed the presence of both β and γ polar phases, and absence of non-polar α phase, according to the characteristic bands for such crystalline phases.
The nanocomposites exhibited a ferroelectric behavior and electrical polarization according to their ceramic and polymeric components.