Imaging of soft structures: Dependence of contrast in atomic force microscopy images on the force applied by the tip

Abstract

Articles you may be interested inExploring the tip-sample interaction regimes in the presence of hysteretic forces in the tapping mode atomic force microscopy

Water molecule clusters measured at water/air interfaces using atomic force microscopy

“…35 The surface of a silicon nitride tip in aqueous solution is composed of amphoteric silanol and basic silylamine [secondary (silazane, -Si 2 NH 2 ) and possibly primary (silylamine, -SiNH 3 ) amines though the latter is rapidly hydrolyzed] surface groups 43,44 at pH B6; with no added electrolyte the silicon nitride surface is either zwitterionic (zero net charge) or slightly negatively charged. 45 The commercial silicon nitride tip surface has been found to be close to electrically neutral over a wide pH range (from at least pH 6 to 8.5), thus indicating equal densities of silanol and silylamine surface groups. To verify the surface charging behavior of the tips, force vs. separation curves in solutions with pH between B5.2 and 6.8 were measured, and the isocharging point (i.c.p.)…”

“…This has been achieved in the experiment previously performed using second harmonic generation at the air/water interface by Hu et al 51 It is also known from the surface tension measurement of methanol/water solutions that 11% of methanol in bulk water leads to 25% of methanol at the air/water interface. 45 Knowing that each methanol molecule at the surface could suppress one dangling OH bond, the result indicates that one out of every four water molecules in the surface monolayer must have contributed to one dangling OH bond at the vapor/water interface. This suggests that the surface water structure is ice-like and that at the surface, each molecule in the top submonolayer must have one of its four connecting hydrogen bonds broken.…”

Two-dimensional phase transition of styrene adsolubilized in cetyltrimethylammonium bromide admicelles on mica

“…To insure the tip was clean and ready for reuse, a force curve of mica in deionized water was first captured and compared with a clean tip run. The tip and the fluid cell were considered to be clean and ready for reuse when the force curve was qualitatively similar to the "clean" tip curve [25][26][27][28].…”

Adsorption of hexyl--bis(dodecyldimethylammonium bromide) gemini surfactant on silica and its effect on wettability

“…It has crucial applications in diverse fields such as detergency, mineral flotation, lubrication, corrosion inhibition, tertiary oil recovery and so on. Over the last few decades, different methods [1][2][3][4][5][6][7][8] have been used to carry out the study of surfactant adsorption at the solid-solution interface [9][10][11][12][13][14][15][16][17] and valuable results have been obtained [18][19][20][21][22][23][24][25][26][27][28][29]. The influence of surfactants on the wettability of solid surfaces has also been studied extensively [30][31][32][33][34][35][36].…”