Figure 3
From: Interface-Induced Ordering of Gas Molecules Confined in a Small Space
Images of an HOPG-water interface acquired using the PF mode at approximately 4 hours after nitrogen-supersaturated water was deposited.
(a), (c), (d), (e) and (f) are height images. The peak force used to acquire (a) and (b) was 150 pN. Peak forces of 750 pN (c), 1500 pN (d) and 2250 pN (e) were applied and, finally, the force was reduced to 150 pN (f). The apparent heights at the center of the cap-shaped structure in (a), (c), (d), (e) and (f) were 18.5 nm, 10.2 nm, 2.7 nm, 0.2–0.4 nm and 12.6 nm, respectively. The left edge of the 3D nanostructure in (f) exhibited several changes after applying a peak force of 2250 pN. The real height of the cap-shaped nanostructure after the PF measurements was 20.3 nm, which was determined from the force curve measurements conducted at the center of the structure (see Supplementary Fig. S7). The domains of the row-like structure changed slowly with time. Furthermore, several domains exhibited damage at high peak forces (e.g., domains near the left edge of the cap-shaped structure). (b) is the corresponding adhesion map acquired along with (a). Both the cap-shaped nanostructure and the monolayer ordered structure appeared darker than the bare HOPG substrate. In (f), an increasing number of bright particles with heights ranging from 0.8 nm to 3 nm appeared after scanning with a high peak force.
