Dispersion of Dielectric Permittivity in a Nanocrystalline Cellulose–Triglycine Sulfate Composite at Low and Ultralow Frequencies

Resumo

The dispersion of dielectric permittivity in nanocrystalline cellulose–triglycine sulfate composites is studied in the range of frequencies from 10^–3 to 10⁶ Hz, at temperatures varying from room temperature to the temperature of phase transition in this composite (54°C), in weak electric fields (1 V cm^–1). Two behaviors for the dielectric dispersion are identified in the studied frequency range: at ultralow frequencies (10^–3–10 Hz), the dispersion is due to Maxwell–Wagner polarization, while at higher frequencies (10–10⁶ Hz), the dispersion is due to the movement of domain walls in the embedded triglycine sulfate crystallites. An additional peak in the temperature-dependent profiles of dielectric permittivity is detected at lower temperatures in freshly prepared samples of the considered composite; we associate it with the presence of residual water in these samples.