Confined water is abundant in the narrow pores of soil, clay, rock and biological systems. The water molecules are expected to assume layered structures between the confining surfaces, but details on the ordering behavior are lacking. In this letter we report density profiles of water across a narrow gap (1.7-1.9nm) between cleaved mica surfaces studied using X-ray reflectivity. The profiles show pronounced electron density modulations within the gap. These indicate a partial hydration of cations (K+) on the mica surfaces and full hydration of desorbed cations within the gap. The average density of the confined water is close to that of bulk water.
ASJC Scopus subject areas
- Physics and Astronomy(all)