The pH-induced swelling and collapse of a polybase brush synthesized by atom transfer radical polymerization.

Geoghegan, Mark; Ruiz-Pérez, Lorena; Dang, Cheen C; Parnell, Andrew J; Martin, Simon J; Howse, Jonathan R; Jones, Richard A L; Golestanian, Ramin et al. · Soft Matter · 2006

basic_science · Level V

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Abstract

We have used neutron reflectometry to characterize the swelling behaviour of brushes of poly[2-(diethyl amino)ethyl methacrylate], a polybase, as a function of pH. The brushes, synthesized by the "" method of atom transfer radical polymerization, were observed to approximately double their thickness in low pH solutions, although the p is shifted to a lower pH than in dilute solution. The composition-depth profile obtained from the reflectometry experiments for the swollen brushes reveals a region depleted in polymer between the substrate and the extended part of the brush.