title: Physical gels based on charge-driven bridging of nanoparticles by triblock copolymers.
abstract: We have prepared an aqueous physical gel consisting of negatively charged silica nanoparticles bridged by ABA triblock copolymers, in which the A blocks are positively charged and the B block is neutral and water-soluble. Irreversible aggregation of the silica nanoparticles was prevented by precoating them with a neutral hydrophilic polymer. Both the elastic plateau modulus and the relaxation time increase slowly as the gel ages, indicating an increase both in the number of active bridges and in the strength with which the end blocks are adsorbed. The rate of this aging process can be increased significantly by applying a small shear stress to the sample. Our results indicate that charge-driven bridging of nanoparticles by triblock copolymers is a promising strategy for thickening of aqueous particle containing materials, such as water-based coatings.
authors: Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Wageningen, The Netherlands.
authors: Marc
authors: M
authors: Lemmers
authors: Evan
authors: E
authors: Spruijt
authors: Sabine
authors: S
authors: Akerboom
authors: Ilja K
authors: IK
authors: Voets
authors: Adriaan C
authors: AC
authors: van Aelst
authors: Martien A Cohen
authors: MA
authors: Stuart
authors: Jasper
authors: J
authors: van der Gucht
mesh_terms: D005782:Gels; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012212:Rheology; D012492:Salts / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013314:Stress, Mechanical; D014867:Water / Q000737:chemistry
chemical_list: D005782:Gels; D011108:Polymers; D012492:Salts; D014867:Water; D012822:Silicon Dioxide