In situ dispersion of non-aqueous Fe₃O₄ nanocolloids by microdroplet coalescence and their use in the preparation of magnetic composite particles

Abstract

Monodispersity and size uniformity are critical issues for nanoparticles, especially for the inorganic particles dispersed in organic carriers serving as the precursor of composites. Herein, for the first time, we have developed a method based on flow-induced droplet coalescence for in situ dispersion of surface-modified Fe3O4 nanoparticles to prepare Fe3O4/polystyrene (Fe3O4/PS) composite particles. A plate-type microchannel was constructed to initiate droplet coalescence for reducing the water-oil interfacial area and for dispersing Fe3O4 nanoparticles into the precursor suspensions. Under optimized conditions, the precursor suspensions could be composed of monodispersed Fe3O4 nanoparticles with an average size of approximately 12 nm. In this case, the saturation magnetization of the prepared superparamagnetic composites was as high as 4.012 emu g(-1) at a magnetite content of 5 wt%. The method is simple and has great potential to be tailored for the preparation of non-aqueous suspensions with uniform and monodispersed nanoparticles.

Enhancement of Ultraviolet B Irradiation with a Photoluminescent Composite Film and Its Application in Photochemical Microfluidic Synthesis

“…A solution of 5 g of PDMS, 0.5 g of TEOS, 0.2 g of DBTDL, and 15 g of n-heptane served as the continuous feed. A certain amount of LB particles was dispersed into n-heptane (10 g), which served as the dispersed fluid and mixed with the continuous feed in a self-made plate-type microchannel instead of directly mixing, 34 to avoid generating bubbles in the casting solution. Afterward, a white suspension was obtained, which was poured onto a glass plate, uniformly spread by a scraping film method, and cured in the oven at 50 °C for an hour.…”

“…In our previous studies, in situ dispersion of nanoparticles into organic solvents or monomer solutions was successfully achieved. 33,34 By virtue of the monodispersed nanoparticles, the prepared nanocomposite microspheres and films clearly exhibited the functionalities of the loaded particles without any loss in performance. In this regard, the preparation of LaB 3 O 6 :Gd, bi-based polydimethylsiloxane (LB−PDMS) composite films with photoluminescence properties was proposed, as PDMS also features high heat and chemical resistance.…”