Abstract: Microemulsions are usually used to prepare nanomaterials. The formation behavior of microemulsions is crucial to the preparation of nanomaterials. Water in the internal phase is usually replaced by electrolyte solutions to prepare nanomaterials. Knowing the effects of electrolyte solution on the phase behavior of microemulsion is significant to the nanomaterial preparation. Microemulsion systems were studied by a conductivity method with cyclohexane as oil, Triton X-100 as surfactant, hexanol as cosurfactant, and deionized water or the electrolyte solutions of Cu(Ac)₂ and Zn(Ac)₂ as aqueous phases. The results showed that the replacement of water with electrolyte solution had a strong effect on the phase behavior of microemulsion system. The O/W microemulsion zone in water system was not observed in the studied electrolyte system. The shape and area of the corresponding phase zone in electrolyte system were different from that in water system. The microemulsion regions of electrolyte solution systems were always larger than that of water system. Zn(Ac)₂ showed a larger microemulsion region than Cu(Ac)₂ at 0.1 mol·L^-1. The microemulsion phase region formed by 0.1 mol·L^-1 Zn(Ac)₂ + 0.1 mol·L^-1 Cu(Ac)₂ was smaller than that formed by 0.1 mol·L^-1 Zn(Ac)₂ or 0.1 mol·L^-1 Cu(Ac)₂ lonely. With the increase of electrolyte concentration in the electrolyte solution and the rise of temperature, the microemulsion region shrank gradually. The changes of interactions between different components in the system should be responsible to the variation of phase behavior. The results provide important information for the microemulsion system with electrolyte solution as aqueous phase.

Key words: TX-100, Microemulsion, Electrolyte solutions, Phase equilibrium

摘要： Microemulsions are usually used to prepare nanomaterials. The formation behavior of microemulsions is crucial to the preparation of nanomaterials. Water in the internal phase is usually replaced by electrolyte solutions to prepare nanomaterials. Knowing the effects of electrolyte solution on the phase behavior of microemulsion is significant to the nanomaterial preparation. Microemulsion systems were studied by a conductivity method with cyclohexane as oil, Triton X-100 as surfactant, hexanol as cosurfactant, and deionized water or the electrolyte solutions of Cu(Ac)₂ and Zn(Ac)₂ as aqueous phases. The results showed that the replacement of water with electrolyte solution had a strong effect on the phase behavior of microemulsion system. The O/W microemulsion zone in water system was not observed in the studied electrolyte system. The shape and area of the corresponding phase zone in electrolyte system were different from that in water system. The microemulsion regions of electrolyte solution systems were always larger than that of water system. Zn(Ac)₂ showed a larger microemulsion region than Cu(Ac)₂ at 0.1 mol·L^-1. The microemulsion phase region formed by 0.1 mol·L^-1 Zn(Ac)₂ + 0.1 mol·L^-1 Cu(Ac)₂ was smaller than that formed by 0.1 mol·L^-1 Zn(Ac)₂ or 0.1 mol·L^-1 Cu(Ac)₂ lonely. With the increase of electrolyte concentration in the electrolyte solution and the rise of temperature, the microemulsion region shrank gradually. The changes of interactions between different components in the system should be responsible to the variation of phase behavior. The results provide important information for the microemulsion system with electrolyte solution as aqueous phase.

关键词: TX-100, Microemulsion, Electrolyte solutions, Phase equilibrium