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Size-dependent and spatial variations in the structural properties of spin-coated poly(Vinylidene Fluoride) films
(2025-10-01)
Sukjit, Peemases
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Munpiriyakul, Pimpaporn
;
Tuantranont, Adisorn
;
Lomas, Tanom
;
Borthai, Pawantree
The uniformity of structural properties in large spin-coated poly(vinylidene fluoride), or PVDF, films is crucial due to their widespread applications and thus requires careful investigations. In this study, variations in structural properties across PVDF films of different sizes and positions were examined. Thin PVDF films were fabricated by the spin-coating method onto rectangular substrates with lengths varying from 10 mm to 40 mm while maintaining a constant width of 10 mm. Three key characteristics – thickness, phase, and crystallinity – were characterized and analyzed. Two effects were investigated – the size-dependent effects, i.e., the property variations at a specific position due to the increasing film length, and the spatial effects, i.e., the property variations along distances from the film center within a film of a specific size. The average thickness of the fabricated film was in the range of 5.00 μm to 6.00 μm, while the crystalline size was in the range of 1.00 nm to 3.00 nm. For the size-dependent effects, at a specific position on the film, increasing the film length did not significantly affect the thickness; however, the phase of PVDF shifted toward a more chain-like β phase, while the crystalline size decreased. At the film center, the crystalline size decreased by 60.7% when the film size increased from the smallest to the largest. These changes resulted from four combined mechanisms: centripetal force, viscosity, evaporation rate, and shear force. For the spatial effects, in a film with a specific size, when the distance from the center increased, the thickness decreased, the phase remained β, and the crystalline size was smaller. For the largest 40 × 10 mm<sup>2</sup> film, the thickness and crystalline size decreased by 16.7% and 3.6%, respectively, from the center to the edge of the film. These trends were attributed to the three combined mechanisms: centripetal force, viscosity, and evaporation rate. The findings of this study provide critical insights into a deeper understanding of property variations in spin-coated PVDF films among both different film sizes and different positions on a film, which is essential for optimizing their applications.
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Impact of Dimethylformamide/Acetone Ratios and Stirring Time on Morphology and Electrical Properties of Electrospun PVDF Fibers
(2025-01-01)
Hakimi Bin Ismail, M. I.
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Syed Bakar, S. S.
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Yahud, S.
;
Chaisitsak, S.
This study examines the impact of Dimethylformamide, DMF/Acetone ratio (60/40, 70/30 and 100/0) and stirring time (16 hours and 24 hours) on Polyvinylidene Fluoride electrospun fibers. Total of six samples were prepared at 12% solution con-centration were electrospun at 20 kV, 10 cm tip-to-collector distance, and 1 mL/h flow rate. Morphological analysis showed that a 70/30 ratio produced finer fibers with fewer beads than 60/40 ratio, while prolonged stirring increased fiber diameter. Electrical analysis confirmed the lowest resistance and highest conductivity for these fibers. The 70/30 ratio and 16-hour stirring time technique optimized fiber structure and electrical performance for advanced applications.
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Production of polyvinylidene fluoride nanofibers by free surface electrospinning from wire electrode
(2017-01-01)
Chansaengsri, Kasidid
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Onlaor, Korakot
;
Tunhoo, Benchapol
;
Thiwawong, Thutiyaporn
Electrospinning is the manufacturing technology for production nanoscale fibers from the polymer solution. The technique is operated in an electric field with high voltage electrical potential between two conductive electrodes. A needle is used as the anode in laboratory generally. However, the needle process is low productivity for commercialization. Free surface electrospinning is designed for solving the problem. Component use as electrodes isn't a needle. In this work represented a needle anode by a wire electrode for increasing mass production. Polymer solution droplets were entrained on a wire and control uniformity of themselves droplet. High voltage potential could be applied between wire and ground plate on the top. Polyvinylidene fluoride (PVDF) was used as a precursor to prepared nanofiber. Morphologies of nanofibers were characterized using scanning electron microscope, which informed surface description of the nanofiber. Free surface electrospinning is alternative electrostatic fiber formation technique that can produce the nanofibers thin films continuously. This process convenient for apply in roll to roll process and useful for large scale production.
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Preparation and dielectric properties of 3-3 lead zirconate/polyvinylidene fluoride nanocomposite
(2013-01-01)
Nawanil, Chanisa
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Vittayakorn, Wanwilai
;
Prachayawarakorn, Jutarat
;
Vittayakorn, Naratip
Composites made of electroactive ceramics and a ferroelectric polymer are very attractive for applications since they exhibit good piezoelectric and pyroelectric properties, low densities and their properties can be tailored to various requirements. Here, we reported the preparation and dielectric properties of 3-3 PZ/PVDF nanocomposites by infusion of polyvinylidenedifluoride (PVDF) into the PZ nanofiber mat followed by heating of the composite at 80°C. The 3-3 PZ/PVDF composites were characterized by X-ray diffraction, FT-IR, SEM and LCR meter. The dielectric constant of the PZ/PVDF nanocomposite are relatively stable in the range of 21.98-18.21 within the measurement frequencies from 100 Hz to 2 MHz. This value is higher than the dielectric constant of the polyvinylidene fluoride. Moreover, the dielectric loss of the composite is below 0.09 at low frequencies. © 2013 Copyright Taylor and Francis Group, LLC.

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