Phase Behavior And Rheological Properties Of Cationic And Anionic Surfactant Mixed System-the Influence Of Temperature,Concentration,Chain Length And Inorganic Ion Specificity

Cationic and anionic surfactant mixed system that can form an abundance of microstructures spontaneously,exhibits very complicated phase behavior and unique rheological properties,resulting in a broad application potential in many areas.In this paper,we choose cationic and anionic surfactant mixed system for investigation to explore the influence of temperature,surfactant concentration,cationic surfactant chain length,inorganic salts,counterions,ratio and other factors on the phase behavior and rheological properties and aggregate microstructures of the mixed system.1.The effect of temperature on the phase behavior and rheological properties has been investigated for 0.10 mol·kg-1 Cetyltrimethyl ammonium bromide(CTAB)/Sodium laurate(SL)/H20 mixed system.The influence of temperature on the phase behavior was discussed for the above mixed system,in according to the relationship between temperature and the Brownian motion of inorganic ions and the electrostatic shielding effect of inorganic ions on the surfactant aggregates.While for the influence of temperature on the rheological properties of the mixed system have been discussed by the relationship between temperature and the micelles average contour length.2.The phase behavior and rheological properties of CTAB/SL/H20 mixed system with different concentrations have been investigated.The effect of surfactant concentration on the phase behavior of the mixed system has been discussed by the relationship between the surfactant concentration and counterions,also the electrostatic shielding effect of the inorganic counterions on the surfactant aggregates.The influence of surfactant concentration on the rheological properties has been investigsted for the above mixed systems on the basis of the relationship between the surfactant concentration and micelles growth.3.The phase behavior and rheological properties have been explored for 0.30 mol·kg-1 Alkyltrimethyl ammonium bromide(CnTAB)/SL/H20 mixed system.With increasing of chain length,the anionic aqueous two-phase systems of the mixed system moves away from the equimolar direction then moves close to the equimolar direction;and the cationic aqueous two-phase systems of the mixed system moves away from the equimolar direction;meanwhile,the shear viscosity peak in isotropic single-phase region of the mixed systems increases.We combine the relationship between chain length and the hydrophobic of the surfactant aggregates to discuss the experimental results.4.The addition of inorganic salt NaBr makes the aqueous two-phase systems of 0.30 mol·kg-1 CTAB/SL/H20 mixed system move away from the equimolar direction and the shear viscosity peak in isotropic single-phase region of the mixed system decrease.We will discuss the experimental results by the electrostatic shielding effect of inorganic ions on the surfactant aggregates.5.The phase behavior and rheological properties results of 0.30 mol·kg-1 Cetyltrimethyl quaternary ammonium salt(CTA+X-)/SL/H2O mixed systems and CTAB/Lauric acid salt(Y+L-)/H20 mixed systems show that the effect of inorganic ions on surfactant mixed system has significant ion specificity.The inorganic anions mainly affect the area which cationic surfactant is excess,while the inorganic cations mainly affect the area which anion surfactant is excess.We combine the Hofmeister series of inorganic ions and the law of matching water affinites to discuss the experimental results.