pH-Responsive Microrods Produced by Electric-Field-Induced Aggregation of Colloidal Particles


  • This study was financially supported by Kodak, the DTI, and EPSRC as part of the DTI Technology Programme. A. Olsen is acknowledged for microgel particle synthesis.


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Poly(2-vinylpyridine) microgel particles and polystyrene latex are aggregated in an alternating electric field to produce a new class of microrods. An electric field simultaneously accelerates the aggregation of oppositely charged particles, and templates the aggregates into linear structures. Rods up to 100 μm in length can be reversibly extended by 20 % by a change in solution pH because of the swelling properties of the microgel particles (see figure).