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9.13kJ/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。
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 C12-2-C12 · 2Br was almost 100 times larger than that for its monomer, dodecyhrimethyl-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. 1S 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.
出处
《应用化学》
CAS
CSCD
北大核心
2008年第8期937-942,共6页
Chinese Journal of Applied Chemistry
基金
内蒙古科技厅攻关计划项目(20010808)
内蒙古科技大学基金资助项目(00605303)
