Discrimination of Dendrimer Aggregates on Mica Based on Adhesion Force: A Pulsed Force Mode Atomic Force Microscopy Study

Two different types of aggregated polyphenylene dendrimer molecules, G2Td(COOH) 16 and G4-Td, obtained by spin coating a dilute solution onto freshly cleaved mica surfaces, and their adhesion properties were measured by pulsed force mode (PFM) AFM. The adhesion properties could be related to the chemical nature of the outer surface of the dendrimers and the mica surface, and the thin film of water adsorbed on mica when imaged under ambient conditions. Most importantly, from the adhesion image of mixed aggregates of G2Td(COOH) 16 and G4-Td, as measured by PFM-AFM, the two different aggregated dendrimers can be easily discriminated.