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Updated: May 15, 2026

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization
Published on: July 9, 2015
Co-assembly of oppositely charged particles into linear clusters and chains of controllable length
Bhuvnesh Bharti1, Gerhard H Findenegg, Orlin D Velev
1Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Abstract:
Colloidal particles with strongly attractive interactions snap on contact and form permanent, but disordered aggregates. In contrast, AC electric fields allow directional assembly of chains or crystals from repulsive particles by dielectrophoresis (DEP), but these structures fall apart once the field is switched off. We demonstrate how well-organized, permanent clusters and chains of micron-sized particles can be assembled by applying DEP to mixtures of oppositely charged microspheres. We found that the length of the formed chains depends on size ratio as well as the number ratio of the two species, and formulated a statistical model for this assembly mechanism, which is in excellent agreement with the experimental results. The assembly rules resulting from this study form a basis for tailoring new classes of permanent supracolloidal clusters and gels.
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