季铵盐二聚表面活性剂C_(12)-S_2-C_(12)·2Br复配体系在氯仿中形成反胶团的增溶水状态

Water States in Reverse Micelle Formed from C_(12)-S_2-C_(12)·2Br Quaternary Ammonium Dimetric Surfactant Mixed System in Chloroform

采用近红外光谱技术,研究了季铵盐Gemini表面活性剂C12-S2-C12.2Br/氯仿体系中反胶团的增溶水状态,使用Peakfit解峰技术,将水的近红外光谱分为3个亚带,分别对应分散于溶剂中的水、反胶团中的类似本体水和结合水。将以上3种状态的水换算成每个表面活性剂分子对应的各种状态水分子数,即分散在溶剂中的水ns、类似本体水nf和结合水nb。向C12-S2-C12.2Br/氯仿体系中加入不同头基的离子型表面活性剂十二烷基三甲(乙)基溴化铵(DTAB、DTEB),发现随着添加剂摩尔分数αA的增大,ns和nb增大,nf减小。加入非离子表面活性剂聚乙二醇辛基苯基醚(OP-10),随着αA的增大ns减小,nb增大,nf略有增大趋势。可见加入表面活性剂头基的大小、所带电荷以及亲水性等均会对反胶团的增溶水能力和状态产生影响。

Near-infrared （NIR） spectroscopy technique was used to study the states of water in reversed micelle formed from gemini quaternary ammonium surfactants C12-S2-C12·2Br in chloroform. The NIRspectroscopy of water could be categorized into three subbands corresponding to different water states. These water states were calculated into three kinds with molecular number of each surfactant molecular correspondingto dispersed solvent water ns, bulk like water nf and bound water %. By mixing ionic surfactants dodecyltrimethylammonium bromide （ DTAB ） or dodecyltriethlyammonium bromide （ DTEB ） to theC12-S2-C12 ·2Br/chloroform system, it showed that with the increase of the molar fraction of added agent aA, n, and nb were increased, while/If was reduced ; when nonionic surfactant octyl polyethylene glycol phenyl ethers （OP-10） was added, it showed that n, was reduced, while nb and rtf were increased as aA was increased. It was found that the water solubilizing ability and states were influenced by the size of head group, electric charge and hydrophilicity of the surfactants.