Tailoring the Applicative Performance of Chitosan‐Based Composites Through the Features of <scp> BaTiO ₃ </scp> Particles Synthesized by Two Different Methods

ABSTRACT New dielectric composites were attained based on a biodegradable matrix (chitosan) and ceramic particles of barium titanate (BT), synthesized via two methods: co‐precipitation (BT‐CP) and solid‐state reaction (BT‐SS). Infrared spectroscopy and X‐ray diffraction analyses evidenced that depending on the type of BT particles, the filler‐matrix interactions are different in terms of hydrogen bonding distance and XRD pattern related to the footprint of ferroelectricity. Statistical analysis conducted on SEM images reveals an average diameter of 523 nm for BT‐SS particles and 297 nm for BT‐CP particles. AFM highlighted higher roughness for chitosan/BT‐CP composite compared to chitosan/BT‐SS smooth mound‐like topology. The force‐distance spectroscopy showed the enhancement of the adhesion force between the active dielectric substrate and the electrode to be attached, from 42 nN for the chitosan matrix to 151 nN for chitosan/BT‐SS10% and 108 nN for chitosan/BT‐CP 10%. Optical dielectric constant at 10 14 Hz, determined by refractometry, increased from 2.3 for the matrix up to 2.9 and 2.7 for the composites with 10% BT‐SS and BT‐CP, respectively. From dielectric spectroscopy, it resulted that, at 750 kHz, the effective permittivity is improved depending on the filler features, ranging from 6 for pure chitosan to 10 for the composite with 10% BT‐SS and only 9 for the one with 10% BT‐CP. When examining the piezoelectric performance, the obtained data proved that BT‐CP filler renders higher d 33 coefficient values, hence a better piezoelectric response of the corresponding composite (6.9 pC/N), compared to the pure chitosan (3.4 pC/N) and chitosan/BT‐SS (6.3 pC/N), showing promising results for sensor devices.