Observation of mesoscopic clathrate structures in ethanol-water mixtures

Alcohol in water is one of the fundamental liquid-liquid solutions in chemical and biological processes. Water-alcohol mixtures exhibit many abnormal physicochemical properties, the origins of which remain mysterious. In addition, the presence of a high concentration of mesoscale objects in such mixtures has caused debate; many researchers attribute these objects to bulk nanobubbles because their concentration is strongly affected by the amount of dissolved air gases. To resolve these issues, here we use transmis-sion electron microscopy (TEM), nanoparticle tracking analysis (NTA), and atomic force microscopy (AFM) to study ethanol-water mixtures. TEM reveals mesoscopic clathrate structures with water mole-cules forming a crystalline matrix hosting a high density of tiny cells. The presence of these mesoscopic clathrate structures is further supported by a refractive index of 1.27 +/- 0.02 at 405 nm measured via NTA and the hydrophilic nature of the mesoscopic structures implied by AFM observations, explaining many long-standing puzzles related to water-alcohol mixtures.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study examines ethanol-water mixtures using various techniques and discovers the presence of mesoscopic crystalline structures, which helps to explain some puzzles regarding water-alcohol mixtures.