Chapter 8 - Dielectric Relaxation and Molecular Dynamics in Associating Dipolar Liquids and Polyhydroxyl Polymers

Abstract

This chapter deals with the study on dielectric relaxation and molecular interactions in some associating dipolar liquids and the polyhydroxyl polymers binary mixtures such as propylene glycol with water (PG–water), propylene glycol with polypropylene glycol (2000) (PG–PPG), polyvinylpyrrolidone (PVP) with ethyl alcohol (PVP–EA), PVP with ethylene glycol (PVP–EG), PVP with polyethylene glycol (400) (PVP–PEG), and PVP with glycerol (PVP–Gly) under different environmental conditions. For the binary mixtures of PG–water and the PG–PPG, the measurements have been carried out using time domain reflectometry technique in the frequency range of 10MHz to 4GHz at room temperature. However, for the polymer blend of PVP–PEG, the temperature dependence of molecular behavior has been carried out, whereas for PVP–EA, PVP–EG, PVP–PEG, and PVP–Gly concentration dependence of molecular interaction has been studied by extending the frequency up to 10GHz. Molecular interactions between the solute and solvent molecules in all the associating polyhydroxyl binary systems have been explained in terms of their inter- and intramolecular hydrogen bonding through static permittivity, dielectric relaxation time, excess dielectric properties, and thermodynamical parameters under varying environmental conditions such as temperature, concentration, and frequency.