Force trace hysteresis and temperature dependence of bridging nanobubble induced forces between hydrophobic surfaces

TY - JOUR

T1 - Force trace hysteresis and temperature dependence of bridging nanobubble induced forces between hydrophobic surfaces

AU - Thormann, Esben

AU - Simonsen, Adam C.

AU - Hansen, Per L.

AU - Mouritsen, Ole G.

PY - 2008/9/1

Y1 - 2008/9/1

N2 - An atomic force microscope and the colloidal probe technique are used to probe the interaction between a hydrophobic particle and a hydrophobic surface in water. The characteristics of the observed force curves strongly suggest that a gas bubble is formed when the particle is moved toward the surface and that the bubble ruptures when the particle subsequently is retracted from the surface. We demonstrate that this type of interaction is not unique for hydrophobic surfaces in water since the interaction between hydrophilic surfaces in air provides very similar force curves. However, the interaction between hydrophobic surfaces vanish if water is replaced by an organic solvent with low polarity. The bridging bubble model is employed to explain the hysteresis observed between approach and retraction force traces and experimental conditions where the hysteresis can be almost eliminated are identified. Finally, it is demonstrated that the hydrophobic interaction is strongly temperature dependent and this dependence can be attributed mainly to the decreasing solubility of air in water with increasing temperature.

AB - An atomic force microscope and the colloidal probe technique are used to probe the interaction between a hydrophobic particle and a hydrophobic surface in water. The characteristics of the observed force curves strongly suggest that a gas bubble is formed when the particle is moved toward the surface and that the bubble ruptures when the particle subsequently is retracted from the surface. We demonstrate that this type of interaction is not unique for hydrophobic surfaces in water since the interaction between hydrophilic surfaces in air provides very similar force curves. However, the interaction between hydrophobic surfaces vanish if water is replaced by an organic solvent with low polarity. The bridging bubble model is employed to explain the hysteresis observed between approach and retraction force traces and experimental conditions where the hysteresis can be almost eliminated are identified. Finally, it is demonstrated that the hydrophobic interaction is strongly temperature dependent and this dependence can be attributed mainly to the decreasing solubility of air in water with increasing temperature.

KW - AFM

KW - Bubbles

KW - Colloidal probe

KW - Fluorocarbon

KW - Hydrophobic interaction

KW - Hysteresis

KW - Temperature dependence

UR - http://www.scopus.com/inward/record.url?scp=54249130734&partnerID=8YFLogxK

U2 - 10.1021/nn800218s

DO - 10.1021/nn800218s

M3 - Journal article

C2 - 19206420

AN - SCOPUS:54249130734

SN - 1936-0851

VL - 2

SP - 1817

EP - 1824

JO - A C S Nano

JF - A C S Nano

IS - 9

ER -