Dielectric properties of a superlattice containing a linear copolysiloxane substituted with aromatic acid side chains Langmuir-Blodgett films

The dielectric behaviour of the Langmuir-Blodgett (LB) superlattice containing linear copolysiloxane is investigated by examining the dielectric loss and capacitance of the superlattice at room temperature (21°C) in the frequency range of 10² to 10³ Hz. The maximum loss value occurs at a frequency of ~5000 Hz, which corresponds to a relaxation time of 3.18×10^-5 s. The static permittivity ε_s and the induced permittivity ε_∞ of the superlattice estimated by extrapolating the Cole-Cole plot of the dispersion curve of the superlattice to frequencies ω=0 and ω=∞ are 3.80 and 3.57 respectively. The Cole-Cole plot obtained experimentally is found to be broad and fall inside the semicircle of the Cole-Cole plot derived for the Debye relaxation theory, but relatively fits with the semi-empirical Cole-Cole relaxation model with α~0.68