不同电性Gemini表面活性剂界面扩张性质  

Dilational Properties of Gemini Surfactants with Different Charge at the Interface

作　　者：刘学鹏[1,2] 丰杰[1,2] 张路[1] 赵濉[1] 俞稼镛[1] 

机构地区：[1]中国科学院理化技术研究所,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《物理化学学报》2010年第5期1277-1283,共7页Acta Physico-Chimica Sinica

基　　金：国家科技重大专项(2008ZX05011)资助项目~~

摘　　要：利用Langmuir槽法研究了含聚氧乙烯醚链中间链的两性Gemini表面活性剂C8E4NC12、阳离子Gemini表面活性剂C12NE3NC12和阴离子Gemini表面活性剂C8E4C8在空气/水表面和癸烷/水界面上的扩张性质,考察浓度对3种Gemini表面活性剂溶液表、界面扩张性质的影响.结果表明,由于分子间存在库仑引力,两性Gemini分子表现出较高的扩张弹性和粘性,且界面扩张性质类似于表面.对于有相同电荷Gemini分子,C8E4C8分子中的刚性苯环导致其疏水长链在表面上的取向不同于C12NE3NC12分子,两者表现出不同的表面扩张性质;而油分子能改变同电荷Gemini分子中长链烷基的取向,造成其界面扩张弹性和粘性远低于表面.提出了不同电性Gemini分子在界面排布的示意图,并利用弛豫过程的特征参数进行了验证.The dilational properties of the zwitterionic Gemini surfactant C8E4NC12,cationic Gemini surfactant C12NE3NC12,and anionic Gemini surfactant C8E4C8 with polyoxyethylene spacers at the air/water surface and decane/water interface were investigated by the Langmuir trough method.The influence of concentration on dilational properties was explored.Experimental results showed that C8E4NC12 had higher dilational elasticity and viscosity because of the Coulombic attraction between molecules.The interfacial dilational properties are similar to those of the surface for C8E4NC12.Although C8E4C8 and C12NE3NC12 have the same sign electric charge,the rigid benzene ring of C8E4C8 leads to a different orientation of the long hydrophobic chain on the surface.Therefore,they have different surface dilational properties.Oil molecules can change the interfacial molecular orientation of long-chain alkyl groups,which results in a lower interfacial dilational elasticity and viscosity than that of the surface.Possible schematic diagrams of adsorbed Gemini molecules with different charge at the air/water surface and decane/water interface are proposed.These were verified by the characteristic parameters of the relaxation processes.

关 键 词：GEMINI表面活性剂 电性 表面 界面 扩张性质 

分 类 号：O647.2[理学—物理化学]