Preparation and piezoelectricity of β form poly(vinylidene fluoride) thin film by vapour deposition

Takeno, Akiyoshi; Okui, Norimasa; Kitoh, Tetsuji; Muraoka, Michiharu; Umemoto, Susumu; Sakai, Tetsuya

doi:10.1016/0040-6090(91)90090-k

Cited by 45 publications

(18 citation statements)

References 11 publications

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“…11 Higher surface temperature means higher surface mobility of the oligomer molecule, thus a better chance for each oligomer molecular chain to find the energetically most favorable site. It is difficult to fabricate the ferroelectric crystal of VDF oligomer directly onto metal surfaces because the VDF oligomer tends to crystallize in paraelectric phase crystal with normal molecular orientation to the substrate during the evaporation process.…”

Section: A Morphology and Crystal Structurementioning

confidence: 99%

The preparation and ferroelectric properties of defect-free ultrathin films of vinylidene fluoride oligomer

Zhang

et al. 2010

Journal of Applied Physics

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Articles you may be interested inThe effect of electroactive interlayer on the ferroelectric properties in poly(vinylidene fluoride-trifluoroethylene) copolymer ultrathin filmsThe ultrathin, defect-free ferroelectric films of vinylidene fluoride oligomer were fabricated by vapor deposition. A narrow substrate temperature window was found to get high quality ferroelectric films. Ferroelectric phase was obtained when the substrate temperature was −90°C. The ferroelectric phase is stable at room temperature, even after annealing at 120°C for 30 min. A full memory stack based on the ferroelectric VDF oligomer may work as nonvolatile random access memory with superhigh density due to the smaller crystal grain comparing with that of poly͑vinylidene fluoride-trifluoethylene͒ ͓P͑VDF-TrFE͔͒ copolymers. The cell shows prominent ferroelectric properties even as the thickness of VDF oligomer film is down to 60 nm with a coercive field of 95 MV/m and a remnant polarization of 125 mC/ m 2 . After 1 ϫ 10 5 cycles of switching, no ferroelectric degradation was observed, the ratio of polarization before and after fatigue is close to 1, which is in contrast to P͑VDF-TrFE͒ thin film where the ferroelectric degradation starts after 1 ϫ 10 4 times of switching. The pulse polarization test shows that switching takes place as fast as a few microseconds to reach 90% of the saturated polarization. At 60°C and 8 V operating voltage, the cell still shows excellent fatigue property.

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Section: A Morphology and Crystal Structurementioning

confidence: 99%

The preparation and ferroelectric properties of defect-free ultrathin films of vinylidene fluoride oligomer

Zhang

et al. 2010

Journal of Applied Physics

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“…For the reasons above, more attention has been paid to develop a convenient method to obtain nanoscale thin films of PVDF. Previously, evaporative deposition methods – such as thermal vapor deposition,14, 15 ionized vapor deposition,16 electric‐field‐assisted vapor deposition,17 low pressure chemical vapor deposition,12 etc. – have been studied.…”

Section: Introductionmentioning

confidence: 99%

“…Studies based on evaporative deposition have continued, using VDF oligomers instead of PVDF to overcome the problems due to pyrolytic decomposition 20, 21. Low‐temperature‐based (≈100 °C) evaporative deposition methods were made possible by the use of oligomers,15 which also favored the formation of nanoscale films showing the largest remnant polarization (130 ± 3 µC · cm −2 ) of the values reported for organic materials 22. Despite these result‐oriented advancements, the process of evaporative deposition remains still complicated and requires high vacuum and stringent conditions to control the morphology of thin films 23.…”

Section: Introductionmentioning

confidence: 99%

Direct Preparation of Nanoscale Thin Films of Poly(vinylidene fluoride) Containing β‐Crystalline Phase by Heat‐Controlled Spin Coating

Ramasundaram

Soon-Ock

Kim

et al. 2008

Macro Chemistry & Physics

106

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Nanoscale thin films of PVDF containing the β‐crystalline phase were directly prepared by heat‐controlled spin coating without the influence of external stimuli either in the form of additives or post‐treatments. Sample preparation was carried out at different temperatures, ranging from 10 to 70 °C. At elevated temperatures (40, 50, 60 and 70 °C), PVDF was crystallized into the β‐phase, while at near‐ambient conditions (20 and 30 °C) it was crystallized into the α‐phase. Some samples exhibited a phase‐segregated morphology, with varying particle sizes depending on the preparation temperature. The ferroelectric nature of a typical sample, prepared at 40 °C, was visualized by piezoresponse imaging studies.magnified image

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“…Although piezoceramic PZT transducers possess high piezoelectricity and d 33 piezoelectric constants approximately 200-400 pC N PVDF-copolymers are flexible, conformable, and can be fabricated to different sizes and thicknesses [12]. However, they possess considerably lower piezoelectric constants as compared to PZTs (*10 pC N -1 ) and require intricate mechanical stretching to enhance their bulk film piezoelectricity [5,13]. Furthermore, both PVDF films and PZTs require high-voltage poling so as to enhance their piezoelectricity.…”

Section: Introductionmentioning

confidence: 99%

Zinc oxide nanoparticle-polymeric thin films for dynamic strain sensing

Loh

Chang

2010

J Mater Sci

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Piezoelectric transducers are becoming increasingly popular for dynamic strain monitoring due to their small form factors and their ability to generate an electrical voltage drop in response to strain. Although numerous types of piezoelectric thin films have been adopted for strain sensing, it has been shown that piezo-ceramics are expensive, brittle, and can fail during operation, while piezo-polymers possess lower piezoelectricity and mechanical stiffness. Thus, the objective of this study is to develop a piezoelectric thin film characterized by high piezoelectricity (i.e., high dynamic strain sensitivities) and favorable mechanical properties (i.e., being conformable to structural surfaces yet stiff). First, zinc oxide (ZnO) nanoparticles are dispersed in polyelectrolyte solutions, and the excess solvent is evaporated for thin film fabrication. The amount of ZnO nanoparticles embedded within the films is varied to yield seven unique sample sets with ZnO weight fractions ranging from 0 to 60%. Upon film fabrication, specimens are mounted in a load frame for monotonic uniaxial testing to explore the films' stressstrain performance and to subsequently determine their mechanical properties (namely, modulus of elasticity, ultimate strength, and ultimate failure strain). Finally, film specimens are also mounted onto cantilevered beams undergoing free vibration due to an applied initial displacement. The generated voltages in response to induced strains in the beams are recorded, and the piezoelectric performance and dynamic strain sensitivities for the different weight fraction films are calculated and compared. Commercial PVDF thin films are also employed in this study for performance comparison.

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Preparation and piezoelectricity of β form poly(vinylidene fluoride) thin film by vapour deposition

Cited by 45 publications

References 11 publications

The preparation and ferroelectric properties of defect-free ultrathin films of vinylidene fluoride oligomer

The preparation and ferroelectric properties of defect-free ultrathin films of vinylidene fluoride oligomer

Direct Preparation of Nanoscale Thin Films of Poly(vinylidene fluoride) Containing β‐Crystalline Phase by Heat‐Controlled Spin Coating

Zinc oxide nanoparticle-polymeric thin films for dynamic strain sensing

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