Free Volume and Shear Compliance of Hydrogen-Bonded Liquids

Publisher Website
Google Scholar
Abstract
A phenomenological formulation for the shear compliance of hydrogen‐bonded liquids is presented. It is based on the assumption that the compliance of these liquids is a linear function of the reciprocal density of hydrogen bonds. The bond density is expressed in terms of the free volume of the liquid and the equilibrium number of broken or bent bonds. This latter number is expressed in terms of a two‐state model. Ultrasonic shear data in glycerol, 1, 3 butanediol, and 1‐propanol are considered and good fits to the data are obtained when ΔH = 3.0 kcal/mole and ΔS = 5.0, 5.9, and 16 e.u., respectively. It is argued that these are quite reasonable values for hydrogen bonding. The above theory predicts that the difference in magnitude and temperature dependence of the shear rigidity found for different hydrogen‐bonded liquids is determined to a large extent by differences in ΔS which in turn determines the relative importance of free energy and free volume effects. In general a large value of ΔS would lead to a low and highly temperature‐dependent shear rigidity.

This publication has 11 references indexed in Scilit: