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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。
The maximum bubble pressure method was used to investigate the adsorption kinetics of Gemini surfactant C12-2-C12 · 2Br at gas-liquid interface. The results show that with the increase of surfactant concentration, the diffusion rate of surfactant molecules increases and the diffusion coefficient D increases. Compared with the corresponding monomeric surfactant DTAB, the hydrophobicity of C12-2-C12.2Br was stronger than that of DTAB due to the structural difference between the two surfactants, resulting in the former having an adsorption diffusion coefficient D that is nearly 100 Times The surfactant is in the diffusion-kinetic model at the late stage of adsorption at the gas-liquid interface, and has an adsorption barrier Ea. The adsorption barriers of C12-2-C12 · 2Br and DTAB are 17.29 and 9.13 kJ / mol, respectively. Due to the surface pressure and surface coverage of C12-2-C12 · 2Br at the gas-liquid interface and the head base area of the molecules are larger than that of DTAB, the adsorption barrier of the former at the gas-liquid interface is increased.