Synthesis and micellization of polydimethylsiloxane– carboxy-terminated poly(ethylene oxide) graft copolymer in aqueous and organic media and its application for the synthesis of core-shell magnetite particles

Abstract

An amphiphilic graft copolymer having an average of 7-8 carboxyesterterminated poly(ethylene oxide) grafted sequences on each polydimethylsiloxane main chain was obtained by a multistep procedure. Through fluorescence, surface tension and laser diffractometry methods the graft copolymer was proved to undergo micellization in aqueous media. In water, the critical micellization concentrations (CMC) are dependent on pH. Two CMC values were established for pH = 4, i.e. CMC 1 = 1.01 g/L and CMC 2 = 1.73 g/L corresponding to the transition from single chain to multiple chain micelles and to intermicellar aggregation, respectively. Between CMC 1 and CMC 2 , the dimensions of micelles increased from 18 nm to 46 nm. The graft copolymer was proved to efficiently act as surfactant in the preparation of magnetite particles with a hydrophobic siloxane shell.

Synthesis and characterization of magnetite particles covered with α-trietoxysilil-polydimethylsiloxane

“…Also, we used poly{dimethylsiloxane-g-[carboxyester-poly(ethylene oxide)]} (PDMS-PEO-COOH) copolymer as stabilizer to obtain double-shell magnetite particles [22]. This paper is centered on the synthesis of stable magnetite silicon fluids.…”

Tailored and Functionalized Magnetite Particles for Biomedical and Industrial Applications

“…Electrostatic or steric stabilization represent the main step in obtaining "core-shell" magnetic particles with magnetite core and a shell formed by different surfactants. We summarize here some examples and also some data previously reported by our group (figure 1) on the preparation of magnetite particles coated by different Si-containing compounds (monomers and polymers) (Durdureanu-Angheluta et al, 2008;Durdureanu-Angheluta et al, 2009;Durdureanu-Angheluta et al, 2010;Pricop et al, 2010).…”