Abstract
The dielectric constant [ε' (ω)] and dielectric loss [ε'' (ω)] have been measured in 75 MeV Oxygen- ion irradiated
(fluences; 5.6X1011 ions/cm2 and 5.6X1012 ions/cm2) 20 μm PVDF thin films in the temperature region 30°C -170 °C at
different the frequency range from 1KHz-1MHz by taking unirradiated (pristine) 20 μm thin film as reference. The ε' (ω) of
pristine film in low temperature region shows week dependence on the temperature and show strong dependence of
temperature at higher temperature region. Trapped charge carriers make a large contribution to the dielectric parameters at
lower frequencies. There is an overall decrease in ε' (ω) in ion irradiated samples. The decrease in ε' (ω) is more in
samples irradiated with higher fluences. The secondary radiation induced crystallinity (SRIC) has been observed in low
fluence ( 5.6X1011 ions/cm2) irradiated samples. The increase in crystallinity, αc-relaxation and free radical cross linking
process govern the high temperature ε'(ω) and the dominance of radiation induced free radical cross linking has been held
responsible for the sudden decline in ε' (ω) at very high temperature. Two relaxations; the αc- and the αa- relaxations,
appearing from high temperature side to low temperature side in the dielectric loss versus temperature spectrum have been
observed in present investigation.
Keywords
PVDF, SHI, Dielectric constant, Dielectric loss, Tangent loss factor.
Citation
D. SINGH RANA, D. K. CHATURVEDI, J. K QUAMARA, Dielectric constant/loss measurement in 75 MeV oxygen-ion irradiated poly (vinylidene fluoride) films, Optoelectronics and Advanced Materials - Rapid Communications, 3, 12, December 2009, pp.1354-1358 (2009).
Submitted at: Sept. 21, 2009
Accepted at: Nov. 23, 2009