Water solubilization of hydrophobic nanocrystals by means of poly(maleic anhydride-alt-1-octadecene)

Journal of Materials Chemistry (Impact Factor: 7.44). 01/2008; 18(17):1991-1996. DOI: 10.1039/B717801H

ABSTRACT Poly(maleic anhydride-alt-1-octadecene), a cheap and commercially available polymer, was used to water-solubilize colloidal nanocrystals with various compositions, morphologies, and sizes. Highly pure nanoparticles with homogeneous distributions of sizes and surface charges were obtained after a single purification step of the polymer-coated particles by ultracentrifugation, saving precious time as compared to a previously published and similar polymer coating procedure. This simple strategy proved also to be generally applicable and represents a valid methodology to water-solubilize nanoparticles.

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    • "The phase transfer of hydrophobic nanoparticles of a variety of different core materials has been demonstrated by Pellegrino et al. (2004), using commercial poly(maleic anhydride alt-1-tetradecene), which is no longer available. The still available analogue poly(maleic anhydride alt-1-octadecene) can be used with an adopted procedure (Di Corato et al. 2008). A similar commercial derivative with tertiary amino groups has also been used for nanoparticle coating and phase transfer (Qi & Gao 2008), saving the step of postmodification with dimethylethylenediamine and EDC (Yezhelyev et al. 2008). "
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    ABSTRACT: Iron oxide nanoparticles (NPs) with diameters of 16.1, 20.5, and 20.8 nm prepared from iron oleate precursors were coated with poly(maleic acid-alt-1-octadecene) (PMAcOD). The coating procedure exploited hydrophobic interactions of octadecene and oleic acid tails while hydrolysis of maleic anhydride moieties allowed the NP hydrophilicity. The PMAcOD nanostructure in water and the PMAcOD-coated NPs were studied using transmission electron microscopy, zeta-potential measurements, small-angle X-ray scattering, and fluorescence measurements. The combination of several techniques suggests that independently of the iron oxide core and oleic acid shell structures, PMAcOD encapsulates NPs, forming stable hydrophilic shells which withstand absorption of hydrophobic molecules, such as pyrene, without shell disintegration. Moreover, the PMAcOD molecules are predominantly attached to a single NP instead of self-assembling into the PMAcOD disklike nanostructures or attachment to several NPs. This leads to highly monodisperse aqueous samples with only a small fraction of NPs forming large aggregates due to cross-linking by the copolymer macromolecules.
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