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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (18): 2081-2084. 上一篇    

研究简报

季铵盐三聚表面活性剂在空气-水界面上单分子膜的崩溃压和分子极限面积

杨红伟1, 朱谱新*,1, 冯玉军2, 陈志2, 周栋梁1, 吴大诚1   

  1. (1四川大学纺织研究所 成都 610065)
    (2中国科学院成都有机化学研究所 成都 610041)
  • 投稿日期:2006-07-07 修回日期:2006-12-10 发布日期:2007-09-28
  • 通讯作者: 朱谱新

Collapse Pressure and Limited Molecular Area of Quaternary Ammonium Salt Type Trimeric Surfactant in Monolayer at Air-Water Interface

YANG Hong-Wei1; ZHU Pu-Xin*,1; FENG Yu-Jun2; CHEN Zhi2; ZHOU Dong-Liang1; WU Da-Cheng1   

  1. (1 Textile Institute, Sichuan University, Chengdu 610065)
    (2 Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041)
  • Received:2006-07-07 Revised:2006-12-10 Published:2007-09-28
  • Contact: ZHU Pu-Xin

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利用Langmuir膜天平研究了季铵盐三聚表面活性剂12-2-12-2-12在空气-水界面单分子膜的表面压-分子面积(π-A)等温线, 得到它的崩溃压对应的表面张力gcollapse和分子极限面积Alimit. 与12-2-12-2-12溶液临界胶束浓度对应的表面张力gcmc和由Gibbs吸附方程得到的分子平均面积Acmc相比较, 发现Alimit＜Acmc, 而且gcollapse＞gcmc. 分析12-2-12-2-12单分子膜的表面压随时间的衰减, 表明这个现象是由于表面活性剂从铺展单分子膜向水中溶解造成的, 而且初始表面压越大, 表面压的衰减越快.

关键词: 季铵盐三聚表面活性剂, 单分子膜, 空气-水界面

π-A isotherm of a monolayer at air-water interface for a quaternary ammonium salt type trimeric surfactant (shortly called 12-2-12-2-12) was investigated by the Langmuir balance technology. The surface tension at collapse pressure, γcollapse, and the molecular limited area, Alimit, were determined and compared with the surface tension of the surfactant solution at CMC concentration, γcmc. In addition, the molecular average area Acmc was calculated according to the Gibbs adsorption equation. The following relationships were found: Alimit＜Acmc and γcollapse＞γcmc. These results were related to a partial dissolution of this surfactant via the spreading of the monolayer to the water subsurface, which was shown by the decrease of the surface pressure of its monolayer with time. The higher the initial surface pressure, the rapider the attenuation of the surface tension.

Key words: quaternary ammonium salt type trimeric surfactant, monolayer, air-water interface