壬基酚聚氧乙烯醚在油相中的CMCo及相关问题研究

对壬基酚聚氧乙烯醚在油相中的临界胶束浓度(CMC_o)及与之相关的问题进行了研究,并获得了部分CMC_o值.对CMC_o与表面活性剂自身结构的关系进行分析和数学处理后,发现CMC_o与活性物质自身结构间仍为对数关系.同时在对某些具体体系的界面张力随表面活性剂不同而发生的变化进行了详细分析,发现CMC_w和CMC_o是评价表面活性剂性能的有效工具.

CMCo of Nonylphenol Polyoxyethylene Ethers in Oil Phases and the Problems Concerned

Critical micelle concentration (CMC) is a very useful parameter in the study of emulsions. And there are some interesting relations between CMC and the molecular structure of surfactant. Although surfactant molecular is composed of hydrophilic part and lipophilic part, the common point of view about CMC is still focused on CMC of surfactant in aqueous solution(CMC w). Because of the lack of CMC o (CMC of surfactant in oil phase) in the study on emulsion, it is impossible to explain the function of surfactant in the emulsification completely by CMC w. And because of the importance of CMC o is often ignored, the information of CMC o is not easily available at present. In this paper, simple method was designed to determine the ranges of CMC in oil phases of some common surfactants. The relationship between CMC in oil phases and the molecular structure of surfactants was also investigated. The solubility of surfactant in oil phase is the key factor influencing CMC o. Through the analysis about the change interface tension between water and oil phases. It was found that the best result of the decrease in the interface tension was caused by the suitable CMC w and CMC o simultaneously. CMC w and CMC o could be used to determine the situations of surfactant molecules in the systems correctly. The useful conclusion means that the relationship between CMC w and CMC o could be used to evaluate the effectiveness of surfactants in different systems. And the importance of CMC o in the study of emulsion could be clearly seen.