title: Intelligent colloidal hybrids via reversible pH-induced complexation of polyelectrolyte and silica nanoparticles.
abstract: 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 approximately 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.
authors.affiliation: Lehrstuhl für Makromolekulare Chemie II and Bayreuther Zentrum für Kolloide und Grenzflächen, Universität Bayreuth, Germany. hideharu.mori@uni-bayreuth.de
authors.forename: Hideharu
authors.initials: H
authors.lastname: Mori
authors.forename: Axel H E
authors.initials: AH
authors.lastname: Müller
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Klee
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000838:Anions; D003102:Colloids / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D020005:Propanols / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D000838:Anions; D003102:Colloids; D004852:Epoxy Compounds; D020005:Propanols; D012821:Silanes; C006903:carbopol 940; D012822:Silicon Dioxide; C004312:glycidol