In condensed-matter physics, confined liquid designates a liquid that is subject to geometric constraints on a nanoscopic scale so that most molecules are close enough to an interface to sense some difference from standard bulk conditions. Typical examples are liquids in porous media or liquids in solvation shells.
Confinement regularly prevents crystallization, which enables liquids to be supercooled below their homegenous nucleation temperature even if this is impossible in the bulk state. This holds in particular for water, which is by far the most studied confined liquid.
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Confined liquid Wikipedia(Text) CC BY-SA