Study of the interactions between the surface chemisorbed layer and the surrounding media in magnetite-coated nanoparticles using Raman spectroscopy

Raman spectroscopy is used to investigate surface-coated magnetite nanoparticles (9 nm diameter) dispersed in aqueous medium. In a first sample, the magnetite nanoparticle is coated with dextran. In a second sample the magnetite nanoparticle, is double-coated with a dodecanoic layer following an ethoxylated polyalcohol layer. The Raman measurements were focused on the typical intra-molecular OH-stretching mode chemiosorbed at the nanoparticle surface. The data are discussed in terms of the suppression of the symmetric and asymmetric hydrogen bonded mode in both samples. (C) 2001 Elsevier Science B.V. All rights reserved.