【摘要】 为深入了解支链化对阳离子表面活性剂在水/石英界面吸附性质的影响，用分子动力学方法模拟十六烷基醚羟丙基季铵盐(C₁₆PC)和支链十六烷基醚羟丙基季铵盐(C_<sub>16GPC)在水/石英界面的单层和双层吸附行为，分析了不同浓度（即分子排列紧密程度）下表面活性分子的倾斜角、界面层厚度、水分子和尾端碳原子密度排布。结果表明：C_<sub>16GPC在较低浓度（分子平均占有面积0.466 nm²）形成紧密的吸附单层，明显低于C₁₆PC（0.272 nm²），说明支链结构有利于阳离子表面活性剂在水/石英界面的吸附，且在高浓度下C_<sub>16GPC被压缩的优先顺序依次为：主链>长支链>短支链。直链的C₁₆PC在较紧密的吸附单层上形成类似半胶束的双层结构；而支链的C_<sub>16GPC则是通过上下层长支链尾对尾的方式形成双层结构。更多还原

【Abstract】 To better understand the effect of branching of alkyl chain on the quartz/water interface adsorption properties of cationic surfactants at water/quartz surface,the monolayer and bilayer adsorption behaviors of hexadecanol glycidyl ether ammonium chloride (C₁₆PC) and branched alcohol hexadecyl glycidyl ether ammonium chloride(C_<sub>16GPC) at the quartz/water interface were investigated by molecular dynamics method.The tilt angle of surfactant molec-ules,interfacial layer thickness,density profile of water molecules and tail-end carbon atom at different concentrations were analyzed.The results showed that C_<sub>16GPC formed a packed adsorption monolayer at the concentration of 0.466 nm² per molecule,which was significantly lower than that of C₁₆PC at 0.272 nm² per molecule,indicating that the branched chain was beneficial to the adsorption of the cationic surfactant at the quartz/water interface.Moreover,the priority order of C_<sub>16GPC being compressed at high concentrations was:main chain>long branched chain>short branched chain.C₁₆PC with linear alkyl chain formed a bilayer structure resembling a semi-micellar bundle on the tighter adsorption monolayer.While the branched C_<sub>16GPC formed a bilayer structure by tail-to-tail opposition of long branched chains in the upper and lower layers.更多还原