RESUMO

Monodisperse magnetite nanoparticles modified with poly(ethylene glycol) (PEG) were synthesized using a silane functionalized PEG obtained by reacting 3-aminopropyl triethoxysilane with carboxylic acid-methoxy PEG (mPEG-COOH) using amide reactions. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential measurements show the particles are monodisperse (sigma(gv) approximately 0.2) and stable in water for pH of 3-9 and ionic strengths, up to 0.3 M NaCl. Thermogravimetric analysis coupled with TEM and DLS indicates formation of a dense graft layer on the particle surface. An analysis of the interparticle interaction energy indicates that the particles are stabilized by strong steric repulsions between PEG chains on their surface.

Assuntos

Óxido Ferroso-Férrico/síntese química , Nanopartículas/química , Nanopartículas/ultraestrutura , Polietilenoglicóis/síntese química , Silanos/síntese química , Coloides/química , Óxido Ferroso-Férrico/química , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Transmissão , Modelos Químicos , Tamanho da Partícula , Polietilenoglicóis/química , Silanos/química , Espectroscopia de Infravermelho com Transformada de Fourier