Theoretical Study Of Compressibility Factor Of Pure Liquid Water And Mixture

The structure factor and compressibility of water are of significance to their applications.The corresponding experimental data are few or rare and that is why it has to be predicted from theoretical approach.At present,the main method for calculating the structure factor and compressibility is the empirical correlation.Because the demand of precision and good prediction of results,it is necessary to develop a new theoretical model to deal with them.In this paper,a theoretical model based on the statistical mechanics has been applied to predict the structure and properties of bulk water and water dispersed on solid surface.Under the framework of integral equation theory,the contributions from hard-sphere,dispersion,and association have been considered.With the uniform force field,the radial distribution function,direct correlation function and structure factor have been calculated to evaluate the effects of temperature and density on the structure.Accordingly,the compressibilities at different temperatures have been predicted.It has shown that the predictions are in good agreement with the available experimental data.The results indicate that the description of short-range dispersion and long-range hydrogen association are reasonable.As a result,the theory employed in this work shows a deep insight in structure description of water at molecular level.On the other hand,the density functional theory has been integrated into the integral equation theory to account for the density and energy distributions of water on the pristine and modified PVDF membrane surfaces,the density and energy are important factors in studying of water properties.It has proven that the interfacial hydrogen bonding association arising from the chemical composition of graft AAc chains have significant influence on the wettability of membrane surface.