pH-Responsive Brush-Modified Silica Hybrids Synthesized by Surface-Initiated ARGET ATRP.

ACS Macro Lett

Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia.

Published: October 2012

Brush-modified silica hybrids have been synthesized by growing poly(2-(diethylamino)ethyl methacrylate) (poly(DEA)) brushes on 120 nm diameter silica particles by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). This is the first report of using SI-ARGET ATRP to synthesize poly(DEA) brushes. The kinetics of poly(DEA) brush growth in 4:1 v/v ethanol/water was monitored. The hydrodynamic diameter of the resulting brush-modified particles was dependent on the solution pH due to the weak polybasic nature of the brushes. Below the p of poly(DEA), the hydrodynamic diameter of the brush-modified particles increased with decreasing pH as a consequence of brush protonation, rearrangement and solvent uptake. This pH-response of the brushes was reversible and the hybrid particles exhibited significant hydrodynamic volume changes of up to 200% when the solution pH was cycled from pH 7 to pH 4.

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http://dx.doi.org/10.1021/mz3003566DOI Listing

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