Siciliano Annachiara, Pastore Raffaele, Greco Francesco, Rusciano Francesco
Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Napoli 80125, Italy.
Ind Eng Chem Res. 2025 Sep 12;64(38):18938-18949. doi: 10.1021/acs.iecr.5c02702. eCollection 2025 Sep 24.
Surfactant vesicle suspensions are colloidal systems of great interest in industrial and biomedical applications. In the presence of charged vesicles and electrolytes, electrostatic interactions are crucial to determine their stability and dynamics. To elucidate how volume fraction and electrolyte concentration affect the microscopic structure and dynamics of these systems, here we employ Brownian dynamics simulations of charged spherical vesiscles in sodium-bromide solutions, using interaction parameters measured in previous experiments. Our results identify a colloidal state diagram, where both the dilute-to-dense and the fluid-to-arrested state crossovers shift toward lower volume fractions as electrolyte concentration decreases. We find how interactions augment the first-neighbor distance and shape vesicles' radial distribution. Based on the microscopic structure, we define an effective volume fraction that collapses onto salt-independent master curves for both dynamic and thermodynamic indicators, effectively making the state diagram one-dimensional. These findings improve the understanding of charged vesicles, opening new ways for predicting and designing the properties of novel formulations.
表面活性剂囊泡悬浮液是在工业和生物医学应用中极具吸引力的胶体系统。在存在带电囊泡和电解质的情况下，静电相互作用对于确定它们的稳定性和动力学至关重要。为了阐明体积分数和电解质浓度如何影响这些系统的微观结构和动力学，在此我们使用先前实验中测量的相互作用参数，对溴化钠溶液中带电球形囊泡进行布朗动力学模拟。我们的结果确定了一个胶体状态图，其中随着电解质浓度降低，稀态到密态以及流体态到停滞态的转变都朝着更低的体积分数移动。我们发现相互作用如何增加第一近邻距离并塑造囊泡的径向分布。基于微观结构，我们定义了一个有效体积分数，它对于动态和热力学指标都能坍缩到与盐无关的主曲线上，有效地使状态图成为一维。这些发现增进了对带电囊泡的理解，为预测和设计新型配方的性质开辟了新途径。
