The investigation of α→β phase transition in poly(vinylidene fluoride) (PVDF)

• Autor(a) principal: Constantino, C. J L [UNESP]
• Data de Publicação: 2005
• Outros Autores: Job, A. E. [UNESP], Simões, R. D. [UNESP], Giacometti, J. A. [UNESP], Zucolotto, V., Oliveira, O. N., Gozzi, G. [UNESP], Chinaglia, D. L. [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://ieeexplore.ieee.org/xpl/abstractAuthors.jsp?arnumber=1612350; http://hdl.handle.net/11449/68617
• topic: Band structure; Nondestructive examination; Polymer films; Raman spectroscopy; Vinyl resins; X ray diffraction; Band characteristics; Micro Raman spectroscopy; Non polar phases; Raman bands; Phase transitions

The phase transition from the non-polar α-phase to the polar β-phase of poly(vinylidene fluoride) (PVDF) has been investigated using micro-Raman spectroscopy, which is advantageous for being a non-destructive technique. Films of α-PVDF were subjected to stretching under controlled rates and at 80°C, the transition to β-PVDF being monitored by the decrease in the Raman band at 794 cm-1 characteristic of the α-phase, with the concomitant increase in the 839 cm-1 band characteristic of the β-phase. Poling with negative corona discharge was found to affect the a-PVDF morphology improving the Raman bands related to this crystalline phase. This effect is minimized for films stretched to higher ratios. Significantly, corona-induced effects could not be observed with the other experimental techniques, viz. X-ray diffraction and infrared spectroscopy.