The aggregation behavior of N-decyl-N-methylmorpholinium bromide (DMMB) in aqueous solutions was systematically investigated by experimental measurements and molecular simulation, including surface tension, electrical conductivity, fluorescence measurement, ¹H NMR and dissipative particle dynamic (DPD) simulation. The critical micelle concentration (cmc) of DMMB which was obtained by different techniques showed a pretty good agreement. From the surface tension measurements, a series of surface adsorption properties such as surface tension at the cmc (γ_cmc), effectiveness of surface tension reduction (∏_cmc), maximum surface excess concentration (Γ_max), minimum surface area per molecule (A_min), were determined. The cmc values and a variety of thermodynamic parameters (, and ) of micellization in the temperature range of 25–45°C were obtained via electrical conductivity experiments. In the investigated temperature range, the thermodynamic parameters reveal that micelle formation is entropy-driven. Furthermore, micelle aggregation number (N_agg) of DMMB was calculated through the fluorescence measurement. Analysis of the ¹H NMR spectrum indicates the micelle formation mechanism. The DPD simulation reflects the process of micro-phase separation. From the simulation results, at concentrations higher than cmc, spherical micelles can be formed. The investigation of DMMB micelles may help us gain a better understanding about surfactant micellization process and expand the range of potential application in materials science.

中文翻译：

---

含饱和氮杂环的表面活性离子液体在水溶液中聚集行为的实验研究及分子模拟

通过实验测量和分子模拟，包括表面张力、电导率、荧光测量、¹ H NMR和耗散粒子动力学（DPD）模拟，系统地研究了N-癸基-N-甲基溴化吗啉（ DMMB ）在水溶液中的聚集行为。不同技术得到的DMMB临界胶束浓度(cmc)表现出较好的一致性。从表面张力测量，一系列表面吸附特性，如 cmc 处的表面张力 ( γ _cmc )、表面张力降低的有效性 (∏ _cmc )、最大表面过量浓度 (Γ _max)，每个分子的最小表面积 ( A _min )，已确定。通过电导率实验获得了 25-45°C 温度范围内胶束化的 cmc 值和各种热力学参数（和） 。在研究的温度范围内，热力学参数表明胶束形成是熵驱动的。此外，通过荧光测量计算了DMMB的胶束聚集数( N _{agg )。}分析¹H NMR光谱表明胶束形成机制。DPD模拟反映了微相分离的过程。从模拟结果来看，在高于 cmc 的浓度下，可以形成球形胶束。DMMB胶束的研究可能有助于我们更好地了解表面活性剂胶束化过程并扩大材料科学中的潜在应用范围。