The influence of temperature on surface concentration and interaction energy between components in binary liquid systems

Abstract

Surface tension of two binary mixtures of DMSO (dimethyl sulfoxide) − water and DMSO − acetonitrile were measured over the whole range of composition at ambient pressure in the temperatures range between 298.15 K and 328.15 K. Surface tension deviations (Δσ) were calculated by using the experimental data. The values of Δσ for two binary systems (at all temperatures) are negative that reflect the strong hydrogen bonding between unlike components of mixtures (except for some mole fractions in the DMSO/acetonitrile system). Surface tension data of the binary systems were correlated using Fu et al., Li et al., Myers–Scott, Wang–Chen and Redlich–Kister models. The mean value of standard deviation (S) for binary systems with four models at different temperatures is less than 0.42. Additionally, the obtained results of the Li et al. model were used to estimate the interaction energy between DMSO − water and DMSO − acetonitrile in binary mixtures, and then, the influence of temperature on interaction energy was investigated, which is an important parameter in thermodynamics. Finally, the results have been discussed in terms of surface mole fraction (xi,s) and lyophobicity (β) by the extended Langmuir (EL) isotherm.