Capillary and van der Waals interactions on CaF₂ crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

• Annalisa Calò,
• Oriol Vidal Robles,
• Sergio Santos and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

• employ the surfaces of CaF2, on which nanoscale water films form, to report on the range and force profiles that might originate by dynamic capillary interactions occurring between an AFM tip and nanoscale water patches. Three types of force profiles were observed under ambient conditions. One in which

• , and a third one in which the attractive force is almost constant, i.e., forms a plateau, up to 3–4 nm above the surface when the formation of a capillary neck dominates the tip–sample interaction. Keywords: amplitude modulation (AM) AFM; dynamic capillary interactions; dissipative nanoscale

• in dynamic AFM and interpreted as the result of dynamic capillary interactions. In the experiments reported on graphite additional spectroscopic IR measurements were performed [9][10] to exclude that the observed change in force profiles could depend on chemical contamination or aging of the sample