Anisotropic hybrid particles based on electrohydrodynamic co-jetting of nanoparticle suspensions

Abstract

Electrohydrodynamic co-jetting of two different nanocrystal suspensions can result in anisotropic nanocomposite particles. Using this approach, we are able to prepare submicron-sized, spherical Janus particles (464 ± 242 nm), which are not only comprised of two chemically distinct compartments, but are also morphologically anisotropic. Specifically, multifunctional hybrid particles have been derived, which are composed of a crosslinked copolymer, poly(acrylamide-co-acrylic acid) (p(AAm-co-AA)), and compartmentalized with respect to two metal oxides, i.e. titanium dioxide (TiO₂) and magnetite (Fe₃O₄). Due to size as well as optical color differences between the Fe₃O₄ (∼10 nm) and TiO₂ (<100 nm) loadings, the surface morphology of the two compartments are significantly different and the particles display magnetic, optical, and interfacial anisotropy. Magnetic anisotropy of the particles has been utilized to control the particles' positioning in an external magnetic field, which—with further work—may lead to magnetically switchable surfaces for display applications.