Aqueous Solution Structure over α-Al₂O₃(0112) Probed by Frequency-Modulation Atomic Force Microscopy

Abstract

An α-Al 2 O 3 (011̅2) wafer was immersed in an aqueous KCl solution of 1 mol L −1 and observed with a frequency-modulation atomic force microscope. The tip−surface force was precisely determined as a function of the tip−surface distance. The force−distance relationship contained oscillations accompanied with an exponentially decayed, electric double layer force. The force oscillations were ascribed to liquid water layers confined over the Al 2 O 3 surface.