Wetting, meniscus structure, and capillary interactions for polystyrene microspheres deposited on constant curvature cylindrical liquid interfaces, constructed from nonvolatile ionic or oligomeric liquids, were studied by optical interferometry and optical microscopy. The liquid interface curvature resulted from the preferential wetting of finite width lines patterned onto planar silicon substrates. Key variables included sphere diameter, nominal (or average) contact angle, and deviatoric interfacial curvature. Menisci adopted the quadrupolar symmetry anticipated by theory, with interfacial deformation closely following predicted dependences on sphere diameter and nominal contact angle. Unexpectedly, the contact angle was not constant locally around the contact line, the nominal contact angle varied among seemingly identical spheres, and the maximum interface deviation did not follow the predicted dependence on deviatoric interfacial curvature. Instead, this deviation was up to an order-of-magnitude larger than predicted. Trajectories of neighboring microspheres visually manifested quadrupole–quadrupole interactions, eventually producing square sphere packings that foreshadow interfacial assembly as a potential route to hierarchical 2D particle structures.

中文翻译：

---

绑定到圆柱状液体界面的微球的润湿，弯液面结构和毛细管相互作用†

通过光学干涉和光学显微镜研究了由非挥发性离子或低聚液体构成的等曲度圆柱状液体界面上沉积的聚苯乙烯微球的润湿性，弯月面结构和毛细管相互作用。液体界面曲率是由于优先湿化了图案化到平面硅基板上的有限宽度的线而引起的。关键变量包括球体直径，标称（或平均）接触角和偏斜界面曲率。梅尼西采用了理论上预期的四极对称性，界面变形紧随预测的对球体直径和标称接触角的依赖性。出乎意料的是，接触角在接触线周围局部不恒定，名义接触角在看似相同的球体之间变化，并且最大界面偏差不遵循预测的偏斜界面曲率依赖性。取而代之的是，该偏差达到了比预期大的数量级。相邻微球的轨迹从视觉上表现出四极-四极相互作用，最终产生了方形球堆积，预示了界面组装，这是通往二维二维粒子结构的潜在途径。