Dielectric property and ac conductivity of P(VDF-CTFE)-PLZST polymer-ceramic composite films

Free-standing and flexible polymer-ceramic composite films were fabricated using P(VDF-CTFE) 91/09 mol.% (VC ₉₁ ) as polymer matrix and (Pb _0.94 La _0.04 )[(Zr _0.56 Sn _0.44 ) _0.84 Ti _0.16 ]O ₃ (PLZST) nanoparticles as ceramic filler. All the VC ₉₁ -PLZST composite films are dense and homogeneous in microstructure, and are flexible with a uniform thickness of about 5 μm. It is experimentally found that as the PLZST content increases, the dielectric constant of the composite films increases, while the dielectric loss decreases. Besides the glass-transition process, there is another relaxation process related to the motion of entire polymer chains of VC ₉₁ . These two relaxation processes determine the frequency dependences and temperature dependences of the dielectric properties observed in the composite films. The ac conductivity of the VC ₉₁ -PLZST composite films was investigated at different temperatures and the results indicate that the conductive mechanisms are related to the relaxation processes of the VC ₉₁ matrix at different temperatures and all the VC ₉₁ -PLZST composite films are good insulators.