We report direct measurements of potential energy landscapes for different shaped colloidal particles interacting with nonuniform AC electric fields. Epoxy particle shapes investigated include disks, ellipses, squares, rectangles, and rhombuses, which are all part of the superelliptical prism shape class and are chosen to systematically vary particle anisotropy and corner features. The measurement configuration consists of noninteracting single particles sedimented onto microscope slides within electric fields between parallel coplanar electrodes. Thermally sampled positions and orientations of single particles in nonuniform fields are tracked in an optical microscope, and measured potential energy landscapes are obtained via Boltzmann inversions. We develop a new analytically simple model that captures all measured energy landscapes for superelliptical prism shaped colloidal particles with electrostatic double layers. The model recovers known validated potentials for spherical and ellipsoidal particles, and therefore captures energy landscapes for a variety of different colloidal particle sizes, shapes, and materials reported in prior studies.

中文翻译：

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非均匀交流电场中不同形状粒子的直接测量能量景观的简单模型


我们报告了对不同形状的胶体粒子与非均匀交流电场相互作用的势能景观的直接测量。研究的环氧树脂颗粒形状包括圆盘、椭圆、正方形、矩形和菱形，它们都是超椭圆棱柱形状类别的一部分，用于系统地改变颗粒各向异性和拐角特征。测量配置由平行共面电极之间的电场内沉积在显微镜载玻片上的不相互作用的单个颗粒组成。在光学显微镜中跟踪非均匀场中单个粒子的热采样位置和方向，并通过玻尔兹曼反演获得测量的势能景观。我们开发了一种新的分析简单模型，该模型捕获了具有静电双电层的超椭圆棱柱形胶体粒子的所有测量能量景观。该模型恢复了球形和椭球体颗粒的已知验证电位，因此捕获了先前研究中报道的各种不同胶体颗粒大小、形状和材料的能量景观。