Dispersion of dielectric permittivity in a nanocrystalline cellulose–triglycine sulfate composite at low and ultralow frequencies

The dispersion of dielectric permittivity in nanocrystalline cellulose–triglycine sulfate composites is studied in the range of frequencies from 10$^{-3}$ to 10$^6$ Hz, at temperatures varying from room temperature to the temperature of phase transition in this composite (54$^{\circ}$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 (10–10$^6$ 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.