Redispersible Hybrid Nanopowders: Cerium Oxide Nanoparticle Complexes with Phosphonated-PEG Oligomers

• Published in: arXiv.org
• Main Authors: L Qi, Sehgal, A, J -C Castaing, J -P Chapel, Fresnais, J, J -F Berret, Cousin, F
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 21.04.2008
• Subjects: Adsorption; Cerium oxides; Complexation; Nanoparticles; Neutron scattering; Oligomers; Physics - Soft Condensed Matter
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0804.3410

Rare earth cerium oxide (ceria) nanoparticles are stabilized using end-functional phosphonated-PEG oligomers. The complexation process and structure of the resulting hybrid core-shell singlet nanocolloids are described, characterized and modeled using light and neutron scattering data. The adsorption mechanism is non-stoichiometric, yielding the number of adsorbed chains per particle Nads = 270 at saturation. Adsorption isotherms show a high affinity of the phosphonate head for the ceria surface (adsorption energy ~ -16 kT) suggesting an electrostatic driving force for the complexation. The ease, efficiency and integrity of the complexation is highlighted by the formation of nanometric sized cerium oxide particles covered with a well anchored PEG layer, maintaining the characteristics of the original sol. This solvating brush-like layer is sufficient to solubilize the particles and greatly expand the stability range of the original sol up to pH = 9. We underscore two key attributes of the tailored sol: i) strong UV absorption capability after functionalization and ii) ability to re-disperse after freeze-drying as powder in aqueous or organic solvents in varying concentrations as singlet nanocolloids. This robust platform enables translation of intrinsic properties of mineral oxide nanoparticles to critical end use.