|175. Mori, H.; Müller, A.H.E.; Klee, J.E.: Intelligent Colloidal Hybrids via Reversible pH-induced Complexation of Polyelectrolyte and Water-soluble Silica Nanoparticles, Journal of the American Chemical Society 125, 3712 (2003)|
Intelligent Colloidal Hybrids via Reversible pH-Induced Complexation of Polyelectrolyte and Silica Nanoparticles
Hideharu Mori,* Axel H. E. Müller, and Joachim E. Klee
Lehrstuhl für Makromolekulare Chemie II and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, D-95440 Bayreuth, Germany, and Dentsply DeTrey GmbH, De-Trey-Strasse 1, D-78467 Konstanz, Germany
firstname.lastname@example.org Received December 18, 2002
We present novel intelligent colloidal polymer/silica nanocomposites, in which the complexation of cationic silica nanoparticles and a weak anionic polyelectrolyte can be manipulated simply by pH change through a hydrogen-bonding interaction and ionic complexation caused by hydrogen-transfer interactions between the constituents. Special silica particles which have nanometer size (diameter 3.0 nm) and two independent proton-accepting sites were developed in this study. Both the silica and poly(acrylic acid) form transparent colloidal solutions in water, while a white turbid dispersion was obtained just after mixing the two solutions due to the complexation. The pH-induced association-dissociation behavior was confirmed by the turbidity and potentiometric titration measurements. The assembled structures of the hybrids were visualized by scanning force microscopy.