Evaluating the effect of 2D printing and solvent casting on the crystallographic and morphological properties of PVDF/barium titanate nanocomposites for ultra-thin piezoelectric films

The study of fabrication methods and their impact on PVDF/BaTiO 3 nanocomposites' structural and functional attributes is crucial to creating high-performance ultra-thin piezoelectric films for next-generation sensing and energy-harvesting technologies. In this study an effort has been made on fabricating piezoelectric thin films by two different approaches: (a) 2D printing and (b) solvent casting. Polymeric inks were prepared by dispersing barium titanate (BaTiO 3 ; BT) nanoparticles into a 5 wt% polyvinylidene fluoride (PVDF)/dimethylformamide (DMF) solution with BT loading from 0 to 28 wt%. The rheological analysis indicated that the inks exhibited shear-thinning behavior, which is characteristic of polymeric solutions , having the best viscosity at 10.5 wt% BT at low angular frequencies. From the results of rheological investigations, all manufactured PVDF/BT composites proved to be adequately suited for use in 2D printing. FTIR and XRD crystallographic investigations revealed that BT nanoparticles assist in nucleation of the β-phase in PVDF, where 62.8 % peak β-phase level was noted at 14 wt% BT using 2D printing as compared to 58.5 of β-phase for solvent casting. Further increase beyond 14 wt% BT caused agglomeration and failure to align polymer chain, leading to a decrease in β-phase content. XRD also confirmed BT to remain in its tetragonal phase along with increased crystallinity up to 15 wt% reinforcement. The morphological studies using SEM established significant nanoparticle agglomeration at heightened BT concentrations as in line with diminished chain alignment and the film's inferior quality. The comparative analysis indicated that 2D printing gave rise to films with finer structures and more β-phase than solvent casting. The results highlight the promise of 2D printing as a newer and potentially more effective technique for production of BT-reinforced PVDF thin films , which may advance the application of piezoelectric materials .