Effect of Cationic Substitution of Metal Species in Poly(vinylidene difluoride) (C₂H₂F₂) by Ab Initio Calculations

Abstract

The stronger activity of poly(vinylidene difluoride) (PVDF; C 2 H 2 F 2 ), related with its high dielectric constant and its ferromagnetic behavior, puts it into the kinds of materials with novel mechanical features to develop new devices with numerous advantages. Even though PVDF is a common piezoelectric polymer with promising multifunctionality, there still has been little progress in theoretically understanding its band structure and the addition of itinerant electrons because of its polymorphous and multiple phases. In this work, we present the structural and electronic properties of 25% doped C 2 H 2 F(X) (X = Al, Ni, and Cu) compounds, including high-frequency dielectric constant (ϵ ∞ ) calculations. Our results show that doping induces structural changes, inducing molecular twists due to weak interactions between the different chains, besides increasing ϵ ∞ with itinerant electrons and increasing the band gap with a transition insulator−metal with 25% Ni doping.

Catalytic Thermal Decomposition of NO2 by Iron(III) Nitrate Nonahydrate-Doped Poly(Vinylidene Difluoride)

“…The α-phase is easily fabricated by deposition from low-polarity solvents or melt-casting. ,, The β-phase is the most difficult to obtain and is typically fabricated by electric field poling, that is, cooling a stretched sample under the influence of an electric field . More recently, tuning of the phase behavior and properties of PVDF has been accomplished by doping with nanoparticles or metal-ion salts. ,− All of these efforts to exploit various properties of PVDF are under continuous study to find improved sensors, ,, modified optical properties, ,, lithium-ion battery membranes, − energy-harvesting devices, ,− electromagnetic shielding materials, , catalysts, ,,,− computer memory, ,, or antifouling membranes …”