Nanopipette dynamic microscopy unveils nano coffee ring

• DOI: 10.1073/pnas.2314320121
• Publication Date: 2024-07-02T16:57:47Z
• Authors: Deyi Zhang; Yi Shao; Jiayi Zhou; Qiangwei Zhan; Ziyang Wen; Sheng Mao; Jingjing Wei; Limin Qi; Yuanhua Shao; Huan Wang
• Keywords: Coffee ring effect; Particle (ecology)

Liquid-phase electron microscopy (LP-EM) imaging has revolutionized our understanding of nanosynthesis and assembly. However, the current closed geometry limits its application for open systems. The ubiquitous physical process coffee-ring phenomenon that underpins materials engineering science remains elusive at nanoscale due to lack experimental tools. We introduce a quartz nanopipette liquid cell with tunable dimension requires only standard microscopes. Depending on condition, allows evaporation-induced pattern formation, but it can also function as an ordinary closed-geometry where evaporation is negligible despite nano opening. was observed by tracking individual nanoparticles in evaporating nanodroplet created from thin film interfacial instability. Nanoflows drive assembly disruption ring absence particle–particle correlations. With surface effects, nanoflows override thermal fluctuations tens nanometers, which displayed “drunken man trajectory” performed work value much smaller than k B T .