The infinite diluted activity coefficients of solvents in polyisopropyl methylacrylate was measured using inverse gas chromatography. The solvents used were benzene, toluene, ethyl benzene, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methanol, ethanol isopropyl alcohol, butyl alcohol, 1,2-dichloroethane, and chloroform. It was observed that the infinite diluted activity coefficient of alcohols are well above those of the other solvents investigated.
An interfacial equation of state based on perturbation theory for surfactant-oil-water system has been developed. By combining the interfacial equation of state with Boudh-Hir and Mansoori's model, a molecular ther-modynamic model has been proposed. The interfacial tension of surfactant-oil-water systems can be calculated from the surface tensions of pure oil and water by this model. The interfacial tension data for sodium dodecyl sulphate-heptane-water system, polyoxyethylene n-octylphenol-heptane-water system and hexadecyl trimethyl ammonium bromide-heptane-water system have been correlated. By using the adjustable parameters obtained, the interfacial tensions of these systems at other temperatures have been predicted. Both the correlated and the predicted values are satisfactory.
A novel simple two-dimensional square-lattice model of amphiphile at oil-water interface is developed,in which oil and water act as solvent and occupy empty sites and amphiphile occupies chains of sites. In this model, the oil-water interface is fixed, And amphiphile molecules will be enriched at the oil-water interface. The interfacial concentration of amphiphile calculated by Monte Carlo method shows that it is easier for the hydrophilic-hydrophobic balanced amphiphile to stay at the interface. And the adsorption of amphiphile increases with the increase of amphiphile concentration and the decrease with temperature.
The configuration-bias-vaporization Monte Carlo simulation method developed by Yan et al . has been used to simulate the phase equilibria of AB random copolymers based on the close-packed Flory-Huggins lattice model. Random copolymers are represented as linear chains consisted of r A segment A and r B segment B with segment-segment attractive interaction energy parameters ε AA / kT=-1.0/T *, ε AB / kT=-0.8/T * and ε BB / kT=-0.6/T *. The phase diagrams of random copolymers with a chain length up to 200 segments are obtained. The corresponding critical points for different chain lengths with fixed chain composition are also calculated.
A molecular thermodynamic model of polyelectrolyte developed previously was extended to polyelectrolyte solutions with added salts.Thermodynamic properties,such as activity coefficients of polyelectrolytes or added salts and osmotic coefficients of solvent, of a number of aqueous mixtures of polyelectrolytes and salts are analyzed with the proposed model.Successful correlation is obtained in the range of moderate or higher polyion concentration.For the same sample,thermodynamic properties of polyelectrolytes with and without simple electrolytes can be predicted mutually using parameters from regression data.
An ionic conductivity prediction equation at low concentration for two acid salts is proposed taking into account the dissociation and association equilibria among ions. The salts considered are sodium and potassium hydrogen tartrates. There is no additional parameter of high order terms except for the Onsager's coefficient of limited term in the new equation. Results show a complex conductance of acidic tartrates in aqueous solution. The molar conductivities of metal ions are nearly constant such that the contributions from hydrogen and tartrate ions decrease with concentration, while the molar conductivity of bitartrate ion increases with concentration.
