Abstract: The ferroelectric ultrathin multilayer of PDDA/PVDF-BT were fabricated on the pretreated quartz substrates between cationic electrolyte of poly (diallyldimethyl ammonium chloride) (PDDA) and anion reagent by electrostatic self-assembly method. Negatively charged poly (vinylidene fluoride) (PVDF) dispersed with inorganic BaTiO₃ nano-granules in organic solvent was using as anion reagent. The thickness of the 12-layer ferroelectric composite ultrathin films characterized by quartz crystal microbalance (QCM) is about 82nm, and there exists a nearly linear relationship between the thickness and layer number of ultrathin films. The results of SEM and XRD show that the composite ultrathin films are deposited on the quartz surface smoothly and densely with uniform distribution of BaTiO₃ nano-granules, and excellent crystalline performance. The hysteresis loop of ferroelectric composite ultrathin films shows that the electric polarization of the composite ultrathin films is increased to 3μC/cm².

Key words: electrostatic self-assembly, composite ultrathin films, ferroelectric polymer, nano-granules