Dielectric Relaxation of PVDF/STN Nanocomposites

Dielectric relaxation behavior of poly(vinylidene fluoride), PVDF, with Lucentite$^{TM}$ STN nanoclay was investigated over the frequency range from 20 Hz to 1MHz. Lucentite$^{TM}$ STN synthetic nanoclay is based on hectrite structure with an organic modifier contained between the hectrite layers. Composition of the PVDF/STN nanocomposites ranged from 0{\%}-10{\%} STN by weight. Wide angle X-ray and Fourier transform infrared spectroscopy results are consistent with the conclusion that pure alpha phase is formed in PVDF film while STN 1{\%} sample contained majority beta phase, and a tiny amount of alpha phase. When the STN content increased to 5{\%} and 10{\%} only the beta phase was observed. The $\alpha _{a}$ (glass transition) and $\alpha _{c}$ (crystalline) relaxation rates were plotted against the reciprocal of temperature, respectively. The dielectric result shows that the relaxation rate of the $\alpha _{a}$ relaxation, related to the motions of amorphous polymer chains, is increased by the addition of STN. However, the activation energy for the $\alpha _{c}$ relaxation, related to motions of the crystalline chains, remained unchanged with STN addition. A mechanism is proposed to interpret the relative position and interaction between PVDF chains and STN