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Autori: Hampton, M.A.; Donose, B.C.; Nguyen, A.V.
Editorial: Journal of Colloid and Interface Science, 325, p.267-274, 2008.
Atomic force microscopy (AFM) was used to examine how different alcohols affect the
hydrophobic attraction between a hydrophobic silica colloidal probe and a hydrophobic silica
wafer. The experiments were performed in water and in water after rinsing alcohol (methanol,
ethanol or 1-propanol) throughout the AFM system. In all three cases the range of the
attractive force increased after alcohol-water exchange, with 1-propanol showing the largest
increase in range followed by ethanol and methanol. Additionally, experiments were
performed before and after scanning the flat substrate with the colloidal probe. The range of
the attractive force substantially increased with increasing scanning area. The attraction was
explained by nanobubble bridging with a capillary force model with constant bridge volume
proposed. The bridge volume (constant during each of the force curve measurements), contact
angle and rupture distance were also determined for different scan sizes. The correlation
between the rupture distance and bridge volume agreed with the available prediction.
Cuvinte cheie: hydrophobic force, alcohol, nanobubble, atomic force microscopy