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Study of Modification Mechanism of Ultrafine Silica Modified by PAMAM

Ultrafine silicon dioxide were modified by -NH2-teminated poly(amido-amine) (PAMAM) dendrimers to improve their dispersibility in the coatings. The modification mechanism was studied through density functional theory (DFT) in the gas phase. Virous initial configurations of ion bound to PAMAM were established to investigate the structures and the energetics of the complexes. Two stable conformers are found: types A ( is bound to the amine site) and C ( is bound to the amide site). Types A and C indicate the chemical bond formation of Si-N and Si-O, respectively.