Investigating states of gas in water
In the conventional paradigm of gases dissolved in water, only two states are assumed to exist: well-dispersed gas monomers and gas bubbles. Ing-Shouh Hwang and Wei-Hao Hsu employed transmission electron microscopy (TEM) to uncover two types of new structures in gas-supersaturated water encapsulated in graphene liquid cells: (1) individual polycrystalline nanoparticles (typically several nanometers in diameter) in liquid water, and (2) clathrate structures (often ~100 nm or larger in lateral size). In the clathrate structures, water molecules form a polycrystalline matrix hosting a high density of gas-containing cells (cell separation of 4-8 nm). These structures, particularly the clathrate structures, may resolve many long-standing puzzles about the dissolution of gases in water, such as abnormal thermodynamic properties, the iceberg model, bulk nanobubbles, and micronuclei that nucleate gas bubbles. The results were published on Chem. Sci. 12, 2635 (2021).
WebSite: https://pubs.rsc.org/en/Content/ArticleLanding/2021/SC/D0SC06262F#!divAbstract