Interaction forces between metal-chelating lipid monolayers measured by colloidal probe atomic force microscopy

Surface forces between LB films of metal-chelating lipids in water have bee n studied using colloidal probe atomic force microscopy. The LB films of an amphiphile functionalized by the iminodiacetic acid group were prepared on hydrophobic glass substrates. The electric double layer repulsion operated between these LB film surfaces changed depending on pH reflecting the diff erent protonation states of the iminodiacetic acid groups. The titration cu rve of the iminodiacetic acid monolayer was obtained from the force profile s. The Cu2+ complexation process was also monitored by measuring the force profiles at various Cu2+ ion concentrations. (C) 1999 Elsevier Science B.V. All rights reserved.