Preparation and properties of gamma-PVDF/lead zirconium titanate composites

Variations in the Ferroelectricity and Piezoelectricity of Poly(vinylidene fluoride) Accompanying the Phase Transformation

“…From Figure (a1),(a2), it can be observed that both α- and γ′-PVDF exhibit similar frequency-dependent patterns, remaining constant in the range of 10 3 to 10 5 Hz, followed by a subsequent decrease. The occurrence of this phenomenon is mainly due to the constraints on the movement of dipoles with the increase in frequency, ultimately leading to the decrease in the permittivity. , Simultaneously, it can be observed that the permittivity of α- and γ′-PVDF are nearly identical, aligning with our previous research outcomes and suggesting that the transition from α to γ′-PVDF does not result in a change in the permittivity . Subsequently, the influence of the crystallization temperature on the permittivity of PVDF was studied.…”

“…42,43 Simultaneously, it can be observed that the permittivity of αand γ′-PVDF are nearly identical, aligning with our previous research outcomes and suggesting that the transition from α to γ′-PVDF does not result in a change in the permittivity. 15 Subsequently, the influence of the crystallization temperature on the permittivity of PVDF was studied. To facilitate comparison, the permittivity of α and γ′-PVDF at 10 3 Hz were collected and graphically represented as Figure 9(c1), (c2), respectively.…”

“…To obtain PVDF rich in the γ′-phase, a variety of effective methods have been employed, including melt-recrystallization, blending with aliphatic polyesters and cetyltrimethylammonium bromide, or coated with ionic liquids (ILs). − In our prior studies, it was found that the surface coatings of ionic liquids, such as [BMIM]­BF 4 , on α-PVDF films efficiently initiate the α-to-γ′ phase transition. This is attributed to the strong ion-dipole interactions occurring between the cations and anions in [BMIM]­BF 4 and the CF 2 and CH 2 dipoles in PVDF, respectively.…”

Local analysis of crystalline phases and properties of poly(vinylidene fluoride) electrospun composites with BaTiO3 nanorods

“…Extreme conditions such as high temperature and pressure or rapid cooling are necessary to develop the improved ⊎-phase with enhanced electroactive characteristics. [17][18][19][20][21][22] On the other hand, adding various nanofillers, such as graphene, [23][24][25][26][27] silver, [28][29][30][31] gold, [32][33][34][35] carbon nanotubes [36][37][38][39][40] and ceramics, 6,[41][42][43][44][45] permits the all-trans conformation (⊎-phase formation) in PVDF to appear, unfortunately with no explanation about the mechanism of ⊎-phase formation. 23,[46][47][48] Related to the effect of adding fillers, it has been proposed that nanofillers serve as nucleation sites for crystallization, promoting the growth of ⊎-phase crystals.…”

Process controlled microstructure of polyvinylidene fluoride/functionalized single walled carbon nanotube composites

“…As the polymer shows ferroelectric behavior when it crystallizes in the polar form, 9,10 efforts were made to control its nonpolar phase and subsequently enhance its polar phase. [11][12][13] The process such as ultrasonication produces large amount of energy, which is capable of transforming the nonpolar α phase in PVDF into polar β and γ phases. [14][15][16][17] These polar phases, with characteristic dipole moment in its unit cell become ferroelectric.…”