Acoustic investigations of pseudo-stable structures in aqueous solutions of polyethylene glycols

Abstract The velocity of ultrasound ( c ) and the density ( ρ ) have been measured in mixtures of water and polyethylene glycols in the temperature range from 288 to 328 K. Based on the data obtained, the adiabatic compressibility coefficients ( β ad ) have been calculated from Laplace's equation. The variations of c , ρ and β ad with concentration ( μ , mole fraction) and temperature have been studied. Structural interactions and the formation of a compact pseudo-stable structure in the region of very low polyethylene glycol concentrations have been reported. The structure built from these mixtures can be neither of the liquid clathrate-like hydrate type I nor type II.