Aggregation of dendrimers with a photochromic dithienylethene core group on the mica surface-atomic force microscopic imaging

Atomic force microscopic (AFM) imaging revealed that a polyether third generation dendrimer having a photochromic dithienylethene core group forms regularly aligned (hexagonal alignment) droplets of more or less equal size (100-120 nm) and height of the long axis of the dendrimer (5.0 +/- 0.5 nm) on a mica surface when the surface is rinsed with a benzene solution of the dendrimer. The size suggests that one droplet contains around 10(4) dendrimers. The subtle balance among surface hydrophilicity, hydrophobicity of solvent and dendrimers, and structure or shape of the dendrimers is considered to control the regular alignment.