Investigation of hydration of macromolecules. III. Study of polyethylene glycol homologues by microwave measurements.
The microwave conductivity and permittivity of various homologues of polyethylene glycol (PEG), as well as those of dioxane, all dissolved in either water or electrolyte solutions containing 0.01 M MnSO4, were measured over the frequency range of 1.5 to 4.2 GHz, at a temperature of 30 degrees C. The conductivity was also determined at the frequency of 20 kHz, at the same temperature. We found that: The wavelength of the dielectric relaxation of water increased with the increase of the concentration of nonelectrolytes. The orientation polarization of PEG molecules with a degree of polymerization of n less than or equal to 12.5 can be detected over the microwave range studied. In solution of PEG macromolecules at a degree of polymerization n greater than 12.5 the microviscosity and the wavelength of dielectric relaxation of water significantly increase because of the cooperative action of regularly ordered hydrophilic groups. The ionic conductivity is inversely proportional to the microviscosity of the water. There is a constant conductivity over the microwave range studied, presumably due to the orientational polarization of water molecules interacting with the macromolecules (relaxation frequency f congruent to 0.25 to 0.5 GHz). The effect of PEG of a high polimerization degree on the structure of water is similar to the effect of a decreasing temperature.
D004146:Dioxanes; D004553:Electric Conductivity; D008872:Microwaves; D011092:Polyethylene Glycols; D014867:Water
D004146:Dioxanes; D014867:Water; D011092:Polyethylene Glycols; C025223:1,4-dioxane