Preparation and characterization of piezoelectric ceramic–polymer composite thick films by aerosol deposition for sensor application

Lead zirconate titanate (PZT)-based piezoelectric ceramic and polyvinylidene fluoride (PVDF) organic composite thick films (∼20 μm in thickness) were deposited on a 4-in. diameter Pt/Ti/SiO2/Si substrate and a 2-in. diameter Ag–Pd/sapphire substrate by aerosol deposition using a single 4-in. size nozzle for use as a tactile-sensor device. The PVDF content was varied from 3 to 10 vol% and the films deposited on silicon and sapphire were annealed at 700 and 900 °C, respectively. The annealed films showed a relatively high density, even at a 10 vol% of PVDF-piezoelectric ceramic composition, as well as good adhesion to the substrate after annealing. The relative dielectric constant of the composite film decreased sharply with increasing PVDF content, while the piezoelectric d33 coefficient was conserved at a relatively high value. Therefore, the g33 coefficient increased and showed the highest value at 3 vol% PVDF. The g33 values of the as-deposited, 700 °C annealed and 900 °C annealed piezoelectric ceramic-PVDF composite films were 7.77, 16.3 and 41.5 (10−3 m2/N), respectively.