Self-assembly of a dendron through multiple ionic interaction to give mesospacing between reactive amine groups on the surface

Abstract

A dendron having nine carboxylic acid groups at the end of the branches and a protected amine at the apex was allowed to form a molecular layer on the aminosilylated surface through multipoint ionic attraction. It was found that a compact and smooth monolayer was obtained at appropriate condition. The film quality was maintained successfully after deprotecting CBZ group with trimethylsilyl iodide. Tapping mode AFM showed individual dendron molecules self-assembled on the aminosilylated surface. The molecular layer formed through the multipoint ionic interaction was strong enough to survive heating at 100 degreesC for 1-2 h in water and dipping in aqueous solutions of pH 4-10 for 3 h. The surface density of the primary amine after the deprotection was measured with fluorometry, and 0.1-0.2 amine group per 100 Angstrom(2) was observed. This implies that the spacing between the amine functional groups is 24-34 Angstrom in hexagonal close-packing (hcp) model.