Effect of Solution Concentration on the Electrospray/Electrospinning Transition and on the Crystalline Phase of PVDF

Lígia Maria Manzine Costa, Rosário Elida Suman Bretas, Rinaldo Gregorio

.

DOI: 10.4236/msa.2010.14036                

Abstract

A study was conducted regarding the effect of concentration of poly (vinylidene fluoride) (PVDF)/N,N-dimethylformamide (DMF) and PVDF/DMF/acetone solutions on the transition between electrospray and electrospinning and on the formation of the ? and ? crystalline phases of PVDF. The crystalline phases present in the samples, crystallinity and morphology were determined by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. Low concentration solutions resulted in films consisting of small droplets (electrospray) containing predominantly the ? phase. High concentration solutions resulted in a non-woven mesh of nano-to-micron diameter fibers (electrospinning) containing exclusively the ? phase. These results showed that, the formation of this phase in the electrospinning is related mainly to the solvent evaporation rate, and not to drawing experienced by the polymer during the process. Solvent type affected the amount of crystalline phase present, the boundary concentration between the two processes and the average diameter of fibers. Meshes processed by electrospinning display a degree of crystallinity higher than the films obtained by electrospray.

Keywords

Poly(Vinylidene Fluoride) (PVDF), Electrospinning, Electrospray, Crystalline Phase, Fibers, Morphology

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K. Tashiro, “Crystal Structure and Phase Transition of PVDF and Related Copolymers,” In: H. S. Nalwa, Ed., Ferroelectric Polymers: Chemistry, Physics and Applica- ons, Marcel Dekker, New York, 1995, pp. 63-180.
[2]	R. Gregorio Jr., and E. M. Ueno, “Effect of Crystalline Phase, Orientation and Temperature on the Dielectric Properties of Poly(Vinylidene Fluoride) (PVDF),” Journal of Materials Science, Vol. 34, 1999, pp. 4489-4500.
[3]	V. Sencadas, V. M. Moreira, S. Lance-ros-Mendez, A. S. Pouzada and R. Gregorio Jr., “Alpha-to-Beta Transformation on PVDF Films Obtained by Uniaxial Stretch,” Advanced Materials Forum III, Vol. 514-516, 2006, 872- 876.
[4]	P. Sajkiewicz, A. Wasiak and Z. Goclowski, “Phase Transitions during Stretching of Poly(Vinylidene Fluoride),” European Polymer Journal, Vol. 35, No. 3, pp. 423-429.
[5]	D. T. Grubb and F. R. Kearney, “Phase Transi-tions during Stretching of Poly(Vinylidene Fluoride),” Journal of Polymer Science Part B: Polymer Physics, Vol. 28, No. 11, 1990, pp. 2071-2078.
[6]	M. C. Branciforti, V. Sencadas, S. Lanceros-Mendez and R. Gregorio Jr., “New Technique of Processing Highly Oriented Poly(Vinylidene Fluoride) Films Exclusively in the ? Phase,” Journal of Polymer Science Part B: Polymer Physics, Vol. 45, 2007, pp. 2793-2801.
[7]	R. Gre-gorio Jr., and M. Cestari, “Effect of Crystallization Temperature on the Crystalline Phase Content and Morphology of Poly(Vinylidene Fluoride),” Journal of Polymer Science Part B: Polymer Physics, Vol. 32, No. 5, pp. 859-870.
[8]	R. Gregorio Jr. and D. S. Borges, “Effect of Crystallization Rate on the Formation of the Polymorphs of Solution Cast Poly(Vinylidene Fluoride),” Polymer, Vol. 49, No. 18, 2008, pp. 4009-4016.
[9]	D. L. Chinaglia, R. Gregorio Jr., J. C. Stefa-nello, R. A. P. Altafin, W. Wirges, F. Wang and R. Gerhard, “Influence of the Solvent Evaporation Rate on the Crystalline Phases of Solution-Cast Poly(Vinylidene Fluoride) films,” Journal of Applied Polymer Science, Vol. 116, No. 2, 2010, pp. 785-791.
[10]	A. Formhals, “Process and Apparatus for Preparing Artificial Threads,” U.S. Patent 1,975,504, 1934.
[11]	J. Doshi and D. H. Reneker, “Electrospinning Process and Application of Electrospun Fibers,” Journal of Electro- statics, Vol. 35, No. 2-3, 1995, pp. 151-160.
[12]	M. Nasir, H. Matsumoto, T. Danno, M. Minagawa, T. Irisawa, M. Shioya and A. Tanioka, “Control of Diameter, Morphology, and Structure of PVDF Nanofiber Fabri- cated by Electrospray Deposition,” Journal of Polymer Science Part B: Polymer Physics, Vol. 44, No. 5, pp. 779-786.
[13]	W.A. Yee, M. Ko-taki, Y. Liu and X. Lu, “Morphology, Polymorphism Behavior and Molecular Orientation of Electrospun Poly(Vinylidene Fluoride) Fibers,” Polymer, Vol. 48, No. 2, 2007, pp. 512-521.
[14]	E. Ogut, O. S. Yordem, Y. Z. Menceloglu and M. Papila, “Poly(Vinylidene Fluoride)/Zinc Oxid Smart Composite Material,” Proceeding of SPIE, Vol. 6526, 2007, p. 65260Q-1-10
[15]	J. Zheng, A. He, J. Li and C. C. Han, “Po-lymorphism Control of Poly(Vinylidene Fluoride) through Electrospinning,” Macromolecular Rapid Communications, Vol. 28, No. 22, 2007, pp. 2159-2162.
[16]	W. A. Yee, A. C. Nguyen, P. S. Lee, M. Kotaki, Y. Liu, B. T. Tan, S. Mhaisalkar and X. Lu, “Stress-Induced Structural Changes in Electrospun Polyvinylidene Difluoride Nanofibers Colleted Using a Modified Rotating Disk,” Polymer, Vol. 49, No. 19, 2008, pp. 4196-4203.
[17]	J. S. Andrew and D. R. Clarke, “Effect of Electrospin- ning on the Ferroelectric Phase Content of Poly-vinylidene Difluoride Fibers,” Langmuir, Vol. 24, No. 3, 2008, pp. 670-672.
[18]	H. Na, Y. Zhao, C. Zhao, C. Zhao and X. Yuan, (2008) Effect of Hot-Press on Electrospun Poly(Vinylidene Fluo- ride) Membranes,” Polymer Engineering and Science, Vol. 48, No. 5, pp. 934-940.
[19]	G. Taylor, “Electrospray,” Proceedings of Royal Society of London, Vol. A280, 1964, pp. 383-387.
[20]	K. Nakagawa and Y. Ishida, “Dielectric Relaxations and Molecular Motions in Poly(Vinylidene Fluoride) with Crystal Form II,” Journal of Polymer Science Part B: Polymer Physics, Vol. 11, No. 8, pp. 1503-1533.
[21]	I. B. Rietveld, K. Kobayashi, H. Yamada and K. Matsu- shige, “Model Supported Morphology Control of Electrospray Deposited Poly(Vinylidene Fluoride) Film,” Ma-cromolecular Symposium, 2007, pp. 249-250, 322- 329.
[22]	M. Kobayashi, K. Tashiro and H. Tadokoro, “Mole-cular Vibrations of Three Crystal Forms of Poly(Vilidene Fluo-ride),” Macromolecules, Vol. 8, No. 2, 1975, pp. 158-170.
[23]	R. Gregorio Jr., “Determination of the ?, ? and ? Crystalline Phases of Poly(Vinylidene Fluoride) Films Prepared at Different Conditions,” Journal of Applied Polymer Science, Vol. 100, No. 4, 2006, pp. 3272-3279.