引用本文:
刘金彦, 郭贵宝, 王正德, 安晓萍. Gemini表面活性剂C12-2-C12·2Br在气-液界面吸附动力学[J]. 应用化学,
2008, 25(8): 937-942.
Citation: LIU Jin-Yan, GUO Gui-Bao, WANG Zheng-De, AN Xiao-Ping. Kinetics of Adsorption of Gemini Surfactant C12-2-C12·2Br at Air-Water Interface[J]. Chinese Journal of Applied Chemistry, 2008, 25(8): 937-942.
Citation: LIU Jin-Yan, GUO Gui-Bao, WANG Zheng-De, AN Xiao-Ping. Kinetics of Adsorption of Gemini Surfactant C12-2-C12·2Br at Air-Water Interface[J]. Chinese Journal of Applied Chemistry, 2008, 25(8): 937-942.
Gemini表面活性剂C12-2-C12·2Br在气-液界面吸附动力学
摘要:
用最大泡压法考察Gemini表面活性剂C12-2-C12·2Br在气-液界面吸附动力学。研究表明,随着表面活性剂浓度的增加,表面活性剂分子的扩散速率加快,其扩散系数D随之增大。与对应的单体表面活性剂DTAB比较,由于2种表面活性剂的结构差别引起C12-2-C12·2Br的疏水性比DTAB的强,导致前者的吸附扩散系数D比后者的大将近100倍。表面活性剂在气液界面吸附后期,属于扩散-动力学控制模型,有吸附能垒Ea存在,C12-2-C12·2Br与DTAB的吸附能垒分别为17.29和9.13 kJ/mol。由于C12-2-C12·2Br在气液界面上的表面压和表面覆盖率以及分子的头基面积都大于DTAB,引起了前者在气液界面上的吸附能垒增大。
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关键词:
- 吸附动力学
- / Gemini表面活性剂
- / 扩散系数
- / 吸附能垒
English
Kinetics of Adsorption of Gemini Surfactant C12-2-C12·2Br at Air-Water Interface
Abstract:
Adsorption kinetics of Gemini surfactant C12-2-C12·2Br at the water-air interface was studied by maxium bubble pressure technique. The diffusion rate was enhanced when the bulk concentration increased, and the diffusion coefficient D increased accordingly. The diffusion coefficient D of C12-s-C12·2Br was almost 100 times larger than that for its monomer, dodecyltrimethyl-ammonium bromide(DTAB), due to its higher hydrophobicity resulting from different structures of the two surfactants. The adsorption at long period of time followed a kinetic-diffusion adsorption mechanism, and the adsorption barrier Ea was obtained. The Ea values of C12-2-C12·2Br and DTAB were 17.29 and 9.13 kJ/mol, respectively. The C12-2-C12·2Br exhibited greater surface pressure, fraction of coverage at the air-water interface, and molecular head group area than DTAB, which led to the larger Ea of C12-2-C12·2Br.
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Key words:
- adsorption kinetics
- / Gemini surfactant
- / diffusion coefficient
- / adsorption barrier
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