Poly(amidoamine), or PAMAM, dendrimers in the G5-G10 range were imaged by t
apping mode atomic force microscopy (AFM). Individual dendrimer molecules c
ould be clearly observed in the AFM images, which showed that these dendrit
ic particles appear to be monodispersed, dome-shaped, and randomly distribu
ted on the mica surface. Molecular diameter and height can also be measured
from each particle's profile section from the AFM line scans. The diameter
and height data were used to calculate the molecular Volume of each single
molecule. Absolute molecular weight and polydispersity were then estimated
for each dendrimer generation. The calculated molecular weights for G5-G8
were in very good agreement with theoretical values. In addition, lower gen
eration dendrimers, such as G4, were also studied by AFM. Although individu
al molecules of G4 dendrimer could not be imaged,the surface morphology of
G4 dendrimer films on mica at different surface densities was observed by A
FM.