Self-assembled monolayer of carboxyl-terminated poly(amido amine) dendrimer.
Adlayer formation and adsorption structure of 2.5th-generation poly(amido amine) dendrimer with carboxyl-terminated groups on solid substrates were investigated by atomic force microscopy, surface plasmon resonance spectroscopy, and surface enhanced infrared absorption spectroscopy. Dendrimer molecules are not uniformly adsorbed on solid surface but form aggregates with a width of approximately 100 nm and a height less than 1 nm. Adsorption reaches in equilibrium at 100-1000 sec, depending on the dendrimer concentration. The adsorption-desorption process is considerably reproducible and repeatable. Although the adsorption at equilibrium increases with dendrimer concentration and reaches maximum at neutral pH, monolayer is always maintained after the desorption with solvent. This indicates the formation of self-assembled monolayer. Such monolayer is preserved even at the variation of pH. Although most carboxylates are protonated at acidic pH, small amount of carboxylate remains even at acidic pH. The adsorption structure of dendrimer was illustrated.
Ito
Masahiro
M
Graduate School of Science and 2Research Center for Materials Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
Imae
Toyoko
T
D000327:Adsorption; D050091:Dendrimers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D036103:Nanotechnology / Q000379:methods*; D011073:Polyamines / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D020349:Surface Plasmon Resonance; D013499:Surface Properties
D050091:Dendrimers; C104700:PAMAM Starburst; D011073:Polyamines