Enhanced ferroelectricity and energy storage in poly(vinylidene fluoride)-clay nanocomposite films via nanofiller surface charge modulation

Ferroelectric polymer poly(vinylidene-fluoride) (PVDF) and its copolymers films have long been considered as the most promising candidates for non-volatile organic electronic devices. Fabrication of high-quality PVDF film with a high breakdown electric field and excellent ferroelectricity is required. Designing nanocomposites with a combination of the advantages of both PVDF and nanofillers provides a feasible route to obtain high-performance ferroelectric polymer films. Instead of the usually selected high-k dielectric ceramic nanoparticles, we chose nanolaminate shaped clay as the nanofiller. We used surfactant modification to tune the surface charge and the dispersion of the filler simultaneously so that enhanced ferroelectricity and energy storage in PVDF/clay nanocomposite film at rather low clay loading were realized. Compared to the pristine PVDF film, the energy density was increased from 5.34 J cm^-3 to 5.91 J cm^-3 at 1 wt% MMT content and the "maximum" energy density could reach 10.2 J cm^-3. Our results demonstrate a low-cost and facile method to tune the electrical properties of PVDF film so that it could be easily integrated into all-organic electronic devices.