Mechanisms for crystal phase transformations by heat treatment and molecular motion in poly(vinylidene fluoride)

1982 ◽  
Vol 15 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Yasuhiro Takahashi ◽  
Yoshiaki Matsubara ◽  
Hiroyuki Tadokoro
Keyword(s):  
Heat Treatment ◽  
Phase Transformations ◽  
Molecular Motion ◽  
Vinylidene Fluoride ◽  
Crystal Phase ◽  
Poly Vinylidene Fluoride

A STUDY ON THERMO-OPTIC EFFECT OF β POLY(VINYLIDENE FLUORIDE) THIN FILMS PREPARED BY SOLUTION CASTING METHOD

2008 ◽  
Vol 15 (01n02) ◽  
pp. 175-181 ◽  
Author(s):  
YINGXUE XI ◽  
HUIQING FAN ◽  
WEIGUO LIU ◽  
CHEN YANG ◽  
XIAOLING NIU
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Infrared Imaging ◽  
Vinylidene Fluoride ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Long Wavelength ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Solution Casting Method

The Poly(vinylidene) fluoride (PVDF) thin films with a high content of β-phase were prepared by controlling heat-treatment temperature using casting from the poled solvents. The crystallite microstructure of thin films was depicted by the techniques of X-ray diffraction and FTIR. The results showed that heat treatment was favorable for inducing the β- and γ-phase formation of PVDF. The β phase films were obtained with heat treatment at temperatures ranging from 60°C to 120°C and annealing at 120°C after casting from DMF. The thermo-optical effect of β phase PVDF films was investigated using a spectroscopic ellipsometer. At temperatures ranging from 20°C to 100°C, the refractive index of PVDF was negatively correlated with the temperature between 350 and 1500 nm. The value of the t.o. coefficient of PVDF films was calculated at all temperatures. The maximum value of the t.o. coefficient was about 3.3 × 10-4/°C at the ascending stage of temperature and 3.0 × 10-4/°C at the descending stage of temperature. Therefore, it is possible to use the thermo-optic effect of the β phase PVDF for long wavelength infrared imaging.

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