Synthesis and characterization of poly(vinylidene fluoride)/carbon nanotube composite piezoelectric powders

Nanocomposite piezoelectric powders comprising polyvinylidene fluoride (PVDF) and carbon nanotubes (CNTs) were synthesized using a novel process, which combines ultrasonication and solvent-nonsolvent mixture-induced crystallization at very low temperatures ≤10 °C. The morphological and thermal properties of these composite powders were extensively studied. Scanning electron microscopy characterization showed that these composite powders have polymer particles with an average diameter of 150 nm. Fourier transform infrared spectroscopy, differential scanning calorimetry and wide-angle x-ray scattering analyses confirmed that at CNT concentrations of 0.05–20 wt% this process introduces the β-phase in both PVDF/single-walled CNT (SWCNT) and PVDF/multiwalled CNT (MWCNT) composite powders. Both types of composite powders (PVDF-multiwalled and PVDF-single-walled nanotubes) have shown piezoelectric response at different voltages up to 1% loading of multiwalled nanotubes (MWCNTs) and 0.5% loading of single-walled nanotubes (SWCNTs) in composites.