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PVDF is a specialty plastic used in applications requiring the highest purity, as well as resistance to solvents, acids and hydrocarbons. PVDF has low density 1.78 g/cm 3 in comparison to other fluoropolymers, like polytetrafluoroethylene. It is available in the form of piping products, sheet, tubing, films, plate and an insulator for premium wire.
First reported in 1971, ferroelectric polymers are polymer chains that must exhibit ferroelectric behavior, [4] hence piezoelectric [3] and pyroelectric behavior. [3]A ferroelectric polymer must contain permanent electrical polarization that can be reversed repeatedly, by an opposing electric field. [4]
Ferroelectricity is the property of certain materials to exhibit spontaneous electric polarization that can be reversed by an external electric field.
PVDF (polyvinylidene fluoride) Kynar [7] Solef [8] Hylar [9] VF2: 175 PTFE (polytetrafluoroethylene) Sold by AGC under the tradename Fluon PTFE; Sold by Dupont and Chemours Company under the tradename Teflon; sold by Solvay Specialty Polymers under the tradenames Algoflon Hyflon and Polymist; sold by Daikin under the tradename Polyflon: TFE: 327
Piezoelectric polymers (PVDF, 240 mV-m/N) possess higher piezoelectric stress constants (g 33), an important parameter in sensors, than ceramics (PZT, 11 mV-m/N), which show that they can be better sensors than ceramics. Moreover, piezoelectric polymeric sensors and actuators, due to their processing flexibility, can be readily manufactured ...
The commercial atactic PVF film shows a melting point peak at 190 °C. [ 3 ] [ 4 ] [ 5 ] Several transition phases occur below the melting point , mainly at lower T g from -15 to ‑20 °C, and at upper T g with the temperature range of 40 to 50 °C.
The use of thin film piezoelectric materials in electronics began in the early 1960s at Bell Telephone Laboratories/Bell Labs. Earlier piezoelectric crystals were developed and used as resonators in applications like oscillators with frequencies up to 100 MHz. Thinning was applied for increasing the resonance frequency of the crystals.
The piezo-response observed from PVDF is about 20–30 pC/N. That is an order of 5–50 times less than that of piezoelectric ceramic lead zirconate titanate (PZT). [38] [39] The thermal stability of the piezoelectric effect of polymers in the PVDF family (i.e. vinylidene fluoride co-poly trifluoroethylene) goes up to 125 °C. Some applications ...