Dielectric/ferroelectric properties of ferroelectric ceramic dispersed poly(vinylidene fluoride) with enhanced β-phase formation

Publication date: Available online 21 March 2019Source: Materials Chemistry and PhysicsAuthor(s): Hari Sankar Mohanty, Ravikant, Ashok Kumar, Pawan K. Kulriya, Reji Thomas, Dillip K. PradhanAbstractFree standing and flexible ferroelectric ceramic-polymer composites (PVDF+ ϕ wt.% of BNBT (0.94Na0.5Bi0.5TiO3-0.06BaTiO3) with 0–3 connectivity were synthesized by solution-casting technique. Composite nature and homogeneous distribution of ceramic filler particles in PVDF were confirmed with x-ray diffraction and scanning electron microscopic analysis. The intensity ratio of β-phase with respect to α–phase i.e., I20.2°/I18.4° (obtained from XRD analysis) and the fraction of electro-active beta phase i.e., F(β)% (obtained from FTIR analysis) are enhanced with increase in filler concentrations and peaked for 35 wt% of the ceramic filler. An enhancement of the % of crystallinity (calculated from XRD analysis) has been observed with increase in the filler concentrations. The increase of the fraction of β-phase has been explained on the basis of ion (negatively charged surface ion of the ferroelectric ceramic filler) -dipole (-CH2 dipole of the polymer matrix) interactions, as evidenced from FTIR and UV-VIS absorbance spectra. Relative dielectric permittivity (dielectric constant) and ferroelectric polarization were found to be highest for the composite with 35 wt% of ferroelectric ceramic filler. Percolation theory has been successfully employed to explain the observed ...
Source: Materials Chemistry and Physics - Category: Materials Science Source Type: research