Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.
Department of Chemistry, University of Arkansas, Fayetteville, Arkansas 71656, United States.
J Phys Chem B. 2022 Feb 3;126(4):953-963. doi: 10.1021/acs.jpcb.1c09439. Epub 2022 Jan 26.
Aerosol-OT reverse micelles represent a chemical construct where surfactant molecules self-assemble to stabilize water nanodroplets 1-10 nm in diameter. Although commonly assumed to adopt a spherical shape, all-atom molecular dynamics simulations and some experimental studies predict a nonspherical shape. If these aggregates are not spherical, then what shape do they take? Because the tools needed to evaluate the shape of something that lacks regular structure, order, or symmetry are not well developed, we present a set of three intuitive metrics─coordinate-pair eccentricity, convexity, and the curvature distribution─that estimate the shape of an amorphous object, and we demonstrate their use on a simulated aerosol-OT reverse micelle. These metrics are all well-established methods and principles in mathematics, and each provides unique information about the shape. Together, these metrics provide intuitive descriptions of amorphous shapes, facilitate ways to quantify those shapes, and follow their changes over time.
气溶胶-O/T 反胶束代表了一种化学结构，其中表面活性剂分子自组装以稳定直径为 1-10nm 的水纳米液滴。尽管通常假定其采用球形，但全原子分子动力学模拟和一些实验研究预测了非球形形状。如果这些聚集体不是球形的，那么它们是什么形状？由于评估缺乏规则结构、有序或对称的物体形状所需的工具尚不完善，我们提出了一组三个直观的指标——坐标对偏心率、凸度和曲率分布——来估计无定形物体的形状，并在模拟气溶胶-O/T 反胶束上展示了它们的用途。这些指标都是数学中成熟的方法和原理，每个指标都提供了关于形状的独特信息。这些指标共同提供了对无定形形状的直观描述，有助于量化这些形状，并跟踪它们随时间的变化。
