Self-Assembly of surfactants in nanopores: a dissipative particle dynamics study

纳米孔中表面活性剂的自组装：耗散粒子动力学研究

• 批准号: 5410191
• 负责人: Professor Dr. Martin Schoen
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5410191?language=en
• 关键词: Self; Assembly; surfactants; nanopores; dissipative

In recent years dissipative particle dynamics (DPD) has been established as a powerful and versatile computer simulation technique by which dynamical processes in macromolecular self-assembling systems can be studied. We plan to apply DPD to investigate the dynamics of micelle formation in water-surfactant mixtures near solid surfaces or in idealized mesoporous media like MCM-41-type of materials. In order to access the relevant length and time scales of about 100 nm and 1 µs, respectively, both surfactant and water molecules are described on the basis of coarse-grained models; conservative forces between the resulting "effective particles" are then supplemented by stochastic and dissipative forces reflecting the presence of rapidly varying internal degrees of freedom. The focal point of the present project is to understand single-particle and collective dynamics in the vicinity of the critical surface aggregation concentration (CSAC) of strong amphiphiles at solid surfaces and in nanopores. Experimentally, the sharp increase of the adsorption excess for concentrations slightly above the CSAC is ascribed to surface-induced micelle formation. Shape and size of these aggregates are suspected to strongly depend not only on the architecture of the surfactant itself, but also on the degree of hydrophility and (particularly in narrow pores) on the curvature of the pore walls. By means of DPD computer simulations the dynamics of the micelle formation and its interplay with properties of the confining substrate are investigated. Thermodynamic and structural features are explored in the experimental (Findenegg) and theoretical (Gubbins) projects of this application package.

近年来，耗散粒子动力学（DPD）已成为研究大分子自组装体系动力学过程的一种强有力的、通用的计算机模拟技术。我们计划应用DPD研究胶束形成的动力学在水表面活性剂混合物附近的固体表面或在理想的介孔介质，如MCM-41型材料。为了分别获得约100 nm和1 µs的相关长度和时间尺度，表面活性剂和水分子都是基于粗粒模型描述的;所得“有效粒子”之间的保守力然后由反映快速变化的内部自由度的随机和耗散力补充。本项目的重点是了解固体表面和纳米孔中强两亲物的临界表面聚集浓度（CSAC）附近的单粒子和集体动力学。实验上，浓度略高于CSAC的吸附过量的急剧增加归因于表面诱导的胶束形成。这些聚集体的形状和大小被怀疑强烈地不仅取决于表面活性剂本身的结构，而且取决于结晶度和（特别是在窄孔中）孔壁的曲率。通过DPD计算机模拟的胶束形成的动力学和它的相互作用与限制基板的属性进行了研究。热力学和结构特征在实验（Findenegg）和理论（Gubbins）项目中进行了探索。