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 10⁴ dendrimers. The subtle balance among surface hydrophtlicity, hydrophobicity of solvent and dendrimers, and structure or shape of the dendrimers is considered to control the regular alignment.