Salt-driven assembly of magnetic silica microbeads with tunable porosity.
J Colloid Interface Sci
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Brossault, D., & Routh, A. (2020). Salt-driven assembly of magnetic silica microbeads with tunable porosity.. J Colloid Interface Sci, 562 381-390. https://doi.org/10.1016/j.jcis.2019.12.032
HYPOTHESIS: Porous magnetic silica beads are promising materials for biological and environmental applications due to their enhanced adsorption and ease of recovery. This work aims to develop a new, inexpensive and environmentally friendly approach based on agglomeration of nanoparticles in aqueous droplets. The use of an emulsion as a geometrical constraint is expected to result in the formation of spherical beads with tunable composition depending on the aqueous phase content. EXPERIMENTS: Magnetic silica beads are produced at room temperature by colloidal destabilization induced by addition of CaCl2 to a water-in-oil emulsion containing SiO2 and Fe3O4 nanoparticles. The impact of the salt concentration, emulsification method, concentration of hydrophobic surfactant as well as silica content is presented in this paper. FINDINGS: This method enables the production of spherical beads with diameters between 1 and 9 µm. The incorporation of magnetic nanoparticles inside the bead's structure is confirmed using Energy Dispersive X-ray spectrometry (EDX) and Scanning Transmission Electron Microscopy (STEM) and results in the production of magnetic responsive beads with a preparation yield up to 84%. By incorporating the surfactant Span 80 in the oil phase it is possible to tune the roughness and porosity of the beads.
W D Armstrong Studentship (internal Cambridge award)
Engineering and Physical Sciences Research Council (EP/P030467/1)
External DOI: https://doi.org/10.1016/j.jcis.2019.12.032
This record's URL: https://www.repository.cam.ac.uk/handle/1810/302243
Attribution-NonCommercial-NoDerivatives 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc-nd/4.0/