Time domain dielectric spectroscopic studies of interaction of rat tail tendon collagen with potassium oleate and cetylpyridinium chloride in aqueous acetate buffer solution

Dielectric relaxation studies of aqueous acetate buffer solutions of rat tail tendon collagen with anionic potassium oleate (PO) and cationic cetylpyridinium chloride (CPC) surfactants at four different temperatures 283, 288, 293 and 298 K as a function of surfactant concentrations have been carried out in the 10 MHz to 30 GHz frequency range using time domain dielectric spectroscopy. Apart from the dominant peak around 14.5 GHz; we have observed a peak close to 2.5 GHz for Collagen - PO complexes, whereas the same is not observed for Collagen CPC complexes. This is explained on the basis of adsorption behaviour of surfactants on to collagen macromolecules. Further, we assigned the dominant mode at high frequency around 14.5 GHz to bulk water relaxation. The other peak observed for Collagen - PO complexes around 2.5 GHz is attributed to hydration water reorientation of the collagen macromolecules in the presence of surfactant. The relaxation time of bulk water and hydration water was calculated using Single Debye and Cole-Cole method respectively. The activation enthalpy and activation entropy for the dipolar orientation for the collagen-surfactant complexes have been calculated from the Arrhenius plot.