Grafting of dendritic polyethers onto nanometre silica surface

Frechet-type polyether dendrons bearing COOH groups at the focal points have been grafted onto nanometre silica premodified with 3-aminopropyltriethoxysilane by N,N'-dicyclohexylcarbodiimide mediated amidation. The dendron grafted silicas have been characterized by FTIR spectroscopy, elemental analysis and thermogravimetric analysis (TGA). The percentages of net grafting were 4-16% (thus the percentages of total grafting were 11-23%), as determined by TGA and elemental analysis, suggesting that 4-19% of the total amino groups were involved in amidation. The effects of solvent, catalyst and generation number have also been studied.