Spin-coated synthesis of polyvinylidene fluoride-barium titanate nanocomposite piezoelectric flexible thin films

Abstract

Energy derived from mechanical deformation is one of the cleaner energy options known as piezoelectric. Polyvinylidene fluoride (PVDF) has been identified to hold the characteristics of piezoelectric and dielectric properties due to good energy storage capacity and electrical breakdown strength. However, lower piezoelectricity limits its applicability, and therefore, advancement is needed, potentially through doping or filler like barium titanate (BaTiO3 or BTO). Several fabrication approaches have been proposed, yet spin coating is desirable vis. for its reliability, ease of replicable, cost-effectiveness, and uniform coating. In this study, thin films were fabricated using spin coating with 5 wt.% and 12 wt.% BTO/PVDF compositions at 1000 rpm and 4000 rpm. The morphological characteristics of the materials were studied using Fourier transform infrared (FTIR) and scanning electron microscope (SEM) analysis techniques. The results showed that the 5wt.% BTO/PVDF film at 4000 rpm and annealed at 120 °C for 6 hours exhibited a maximum relative beta (β) fraction of around 94%. SEM images revealed the uniform distribution of BTO particles with less agglomeration in the PVDF matrix, indicating that adding BTO promotes nucleation sites for forming a more ordered crystalline structure. Despite that, further validation of crystallinity percentage is required to assess the enhancement made by the BTO fillers in a polymer matrix entirely. Overall, the experiment demonstrated that spin coating can effectively enhance the β-phase of PVDF (β-phase is desirable due to relatively high dielectric constant and piezoelectricity) with the addition of ceramic fillers such as BTO.