Probing carboxylic acid groups in replaced and mixed self-assembled monolayers by individual ionized dendrimer molecules : an atomic force microscopy study
Grim, P. C. M.
De Feyter, Steven
Wiesler, U. M.
Berresheim, A. J.
Van Haesendonck, C.
De Schryver, F. C.
Date of Issue2002
School of Materials Science and Engineering
Polyphenylene dendrimer molecules, G2Td(COOH)16, were ionized (G2 ions) and then adsorbed on a carboxylic acid (COOH) group terminated self-assembled monolayer (SAM) on a Au substrate through the linkage with Cu2+ ions. The individual G2 ions were observed by noncontact atomic force microscopy (NCAFM). The strong interaction between the G2 and Cu2+ ions, the latter of which are preadsorbed on the COOH SAM, led to a compression or deformation of the SAM and resulted in a decreased height of the G2 ions measured by NCAFM as compared to a theoretical model of the dendrimer molecules. The present method offers an approach to bind dendrimer molecules to a solid substrate and to study the nanoscale behavior of two kinds of thiol molecules in replaced and mixed SAMs.
© 2002 American Chemical Society.