CTAC/NaSal表面活性剂棒状胶束自组装行为的介观布朗动力学模拟

Mesoscale Brownian dynamics simulation on the self-assembly behaviors of rodlike micelles of CTAC/NaSal surfactants

表面活性剂分子在溶液中能够自组装形成多种形式的胶束结构,使溶液呈现出不同的流动特性。表面活性剂分子的自组装行为是其众多实际应用的重要基础,因此也一直是研究热点。表面活性剂分子的自组装行为受溶液条件(质量浓度、温度、流动强度等)影响显著,但目前实验条件下很难直观地、定量地对不同溶液条件下表面活性剂分子自组装行为进行系统监测和研究。本文选取CTAC/NaSal棒状胶束溶液系统为研究对象,通过介观布朗动力学模拟计算,系统研究了不同质量浓度、温度、剪切强度下CTAC棒状胶束的自组装行为。研究表明,溶液的质量浓度、温度以及对溶液施加的剪切强度对CTAC棒状胶束的自组装能力都具有促进和抑制的两面性影响,即适当的质量浓度、温度及剪切强度有利于CTAC棒状胶束之间的自组装;相反,过高或过低的质量浓度、温度及剪切强度都不利于CTAC棒状胶束之间的自组装。

Surfactant molecules can self-assemble into a variety of micellar structures in solution,and consequently,the surfactant solution presents diverse flow characteristics.The self-assembly behavior of surfactant molecules is the important basis of surfactant practical applications,which therefore has been a research hot spot in this field.But the self-assembly process is significantly affected by solution conditions(mass concentration,temperature,flow intensity,etc.),and can barely be tested visually and quantitatively under the present experimental conditions.Herein,the self-assembly behaviors of rodlike micelles in CTAC/NaSal surfactant solutions were systematically studied under different mass concentrations,temperatures and shear rates,utilizing the mesoscale Brownian dynamics simulation.It was found that the solution conditions,namely,mass concentration,temperature and shear rate,showed dual influence on the self-assembly behaviors of CTAC rodlike micelles.That was,the appropriate solution condition promoted the self-assembly between CTAC rodlike micelles,but the excessively strong/weak solution condition suppressed the self-assembly.