Impedance analysis and tunability of BaTiO3-chitosan composites: Towards active dielectrics for flexible electronics

Composite thick films BaTiO3-chitosan with different BaTiO3 additions (1% and 10%) were prepared. The electric response was investigated by Impedance Spectroscopy technique in terms of equivalent electric circuits. The dielectric non-linear properties (tunability) showed a remarkable increase with increasing the BaTiO3 addition by comparison with pure chitosan. The presence of ferroelectric particles into the chitosan matrix plays a twofold role resulting in increasing tunability: (i) increase the values of local fields in the polymer matrix by local field engineering, (ii) contribute with its own tunability to increase the field-variation of the effective permittivity. The present results show a simple approach for generating tunable flexible structures.