FIGURE 2.

Tapping mode AFM images of (a) COOH SAMs on atomically smooth gold terraces on mica, (b) amelogenin adsorbates onto COOH SAMs showing a high coverage of oligomers and just a few remnant nanospheres (arrow), (c) higher resolution 300 nm scan of adsorbates on COOH₃ SAMs (arrow points to amelogenin dimer/trimer). The adsorption of oligomers is suggested by the ellipsometric thicknesses of 7.5–8.0 nm. Although the AFM diameters of the oligomers were large because of the tip broadening effect (16 nm), these structures had much smaller AFM heights (1.2 nm) and were clearly much smaller than the sparse remnant nanospheres (∼21 nm × 7 nm).