| Abstract
| - Interaction forces have been measured between (i) apposing layers of 2.0 ± 0.05 nm thick polydiallyldimethylammonium chloride, PDDA, self-assembled onto a silicon wafer, silicon-substrate/PDDA, and ontoa silicon microparticle, attached to a tipless AMF catilever, SMP-AFM-tip/PDDA; (ii) apposing layers of 2.0± 0.05 nm thick montmorillonite, M, platelets, self-assembled onto the silicon-substrate/PDDA (silicon-substrate/PDDA/M) and onto the SMP-AFM-tip/PDDA (SMP-AFM-tip/PDDA/M); (iii) apposing layers ofsilicon-substrate/PDDA and SMP-AFM-tip/PDDA/M; and (iv) apposing layers of silicon-substrate/PDDA/Mand SMP-AFM-tip/PDDA by scanning force microscopy. Interactions between the bare silicon substrate andthe bare SMP-AFM-tip and those between the silicon-substrate/PDDA and the bare SMP-AFM-tip have alsobeen measured. The experimentally obtained force/radius vs probe−sample separation distance plots havebeen fitted to a simple exponential, taking advantage of the Derjaguin approximation for assessing the double-layer force between a charged sphere and a flat surface, and to the DLVO theory using the constant potentialnumerical approximation (with the exception of ii, where constant charge numerical approximation wasused). Values for the adhesion (the pull back) force, Debye-length, and surface potential have also beenevaluated.
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