Two-dimensional layered nanomaterials
(hexagonal boron nitride
(h-BN) and expanded graphite (EG)) incorporated poly(vinylidene fluoride)
(PVDF) nanocomposites were fabricated via high-shear solution mixing
accompanied by compression molding. “Ultrasonication”
followed by “centrifugation” was employed to “de-stack”
h-BN and EG, which exhibited a decrease in “agglomerate”
size in PVDF/h-BN and PVDF/EG nanocomposites. Further, the PVDF/h-BN
nanocomposite showed a polar fraction of ∼57% at 0.50 wt %
of h-BN concentration with an increased β-phase content, whereas
the PVDF/EG nanocomposite showed a higher content of γ-phase
as compared to β-phase. Moreover, dielectric investigations
indicated that the “ultrasonicated” and “centrifuged”
h-BN- and EG-based PVDF nanocomposites exhibit the highest dielectric
properties owing to improved interfacial and dipolar polarizations.
The piezoelectric strain coefficient of PVDF/0.16BN and PVDF/0.17EG
nanocomposites exhibited d
33 values of
∼99 and ∼91 pm/V, respectively. Finally, sensor devices
were fabricated based on PVDF/EG and PVDF/h-BN nanocomposite films,
which showed a maximum peak-to-peak voltage of ∼24 V (at 0.17
wt % EG) and ∼14 V (at 0.16 wt % h-BN), respectively. A systematic
investigation was carried out to relate the influence of finely dispersed
h-BN and EG on the interfacial interactions, polar phase formation,
and the piezoelectric property of PVDF/h-BN and PVDF/EG nanocomposites.