|174. Mori, H.; Müller, A.H.E.; Klee, J.E.: Reversible pH-induced complexation of polyelectrolyte and water-soluble silica nanoparticles as intelligent colloidal hybrids, Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 44(1), 646 (2003)|
REVERSIBLE pH-INDUCED COMPLEXATION OFPOLYELECTROLYTE AND WATER-SOLUBLE SILICA NANOPARTICLES AS INTELLIGENT COLLOIDAL HYBRIDS
Hideharu Mori, Axel H. E. Müller, and Joachim E. Klee
Lehrstuhl für Makromolekulare Chemie II, Bayreuther Zentrum für Kolloide und Grenzflächen Universität Bayreuth, D-95440 Bayreuth, Germany Dentsply DeTrey GmbH, De-Trey-Straße 1, D-78467 Konstanz, Germany
Specific intermolecular interactions, such as hydrogen-bonding, acidbase interactions, and oppositely charged ionic interactions to prepare selforganized materials have attracted much interest in academic researches as well as in numerous important technologies, such as biotechnology and advanced microelectronics. A variety of self-assembled systems have been reported, including polymer-polymer,1 colloid-colloid,2,3 and polymercolloid. 4,5 Recently, Boal et al. have demonstrated the self-assembly of colloidal gold nanoparticles (~ 2 nm) by bricks and mortar approach, inwhich complementarity between colloid and polymer was achieved using the diaminotriazine-thymine three-point hydrogen bonding interaction.4 Socalled "intelligent" or "smart" materials that can sense signals and produce a definite dynamic response in the form of a change in shape, size, or structure, is another central to developments in various scientific fields, such as shapememory systems, drug-delivery system, and actuators. We present novel intelligent colloidal polymer/silica nanocomposites, in which the complexation of water-soluble cationic silica nanoparticles (diameter = 2.8 nm) and a weak anionic polyelectrolyte can be manipulated simply by pH change through hydrogen-bonded interaction and ionic complexation caused by hydrogen-transfer interactions between the constituents.