Dielectric properties of liquid mixtures

Abstract

Results are discussed of the microwave (1 ≤ ν/GHz ≤ 100) permittivity of liq. mixts. Relaxation modes of the system may result from the reorientation of mols., formation of H bonds, or return of the system to chem. and elec. equil. The relaxation parameters of such processes, relaxation times and dispersion amplitudes, and their dependence on mixt. compn. give valuable information on structural features controlling various properties of liq. mixts. The problem of limited frequency coverage is critically assessed. Results are presented for (i) the aprotic polar-aprotic polar component mixts. of propylene carbonate and 1,2-dimethoxyethane, (ii) the hydrogen bonding-apolar system MeOH and tetrachloromethane, (iii) the mixt. type aprotic polar-hydrogen bonding exemplified by solns. of 2:2 electrolytes in water, and (i.v.) mixts. of the two H bonding solvents, H2O and EtOH.