Study on Formation Mechanism by Monitoring the Morphology and Structure Evolution of Nearly Monodispersed Fe₃O₄ Submicroparticles with Controlled Particle Sizes

Abstract

We present a facile surfactant-free solvothermal method for the fabrication of nearly monodispersed Fe3O4 submicroparticles with tunable particle sizes ranging from 130 to 420 nm by varying the concentration of single iron source FeCl3·6H2O in initial solutions. The morphology and crystal structure of the as-prepared Fe3O4 submicroparticles have been well characterized by using SEM/TEM/HRTEM, XRD, FT-IR, Raman spectroscopy, and XPS methods. It is found that the Fe3O4 particles present single-crystal nature and strong ferromagnetic property with magnetization saturation values ranged in 54.3–88.7 emu·g–1. A complexation–aggregation–phase transformation formation mechanism was first proposed for the nearly monodispersed single-crystal Fe3O4 submicroparticles based upon the quasi-in situ monitoring of the morphology and structure evolution of the samples during the synthesis process. These size-tunable nearly monodispersed Fe3O4 submicroparticles are expected to have promising applications in wide research fields such as bioseparation, targeted drug delivery, and catalysis.

Colloidal magnetic nanocrystal clusters: variable length-scale interaction mechanisms, synergetic functionalities and technological advantages

“…A metallic precursor, such as metal chlorides [14-16, 25, 26, 28, 31, 33, 35, 77-87] or acetylacetonates [36,[88][89][90] are dissolved in a solvent like ether [36,[88][89][90], or glycol [14,15,25,26,31,33,35,77,[79][80][81][82][83][84][85][86][87], or water [16], or THF-ethanol [28] in a glass flask equipped with a heating mantle or in an autoclave (Figure 2A-E). A capping agent is also added in the reaction mixture at room temperature (Table 1) to control the size and the shape of the system.…”

“…Colloidal nanoclusters have been found to be ferromagnetic/ferrimagnetic [21,32,36,80,81,83,89,98] or superparamagnetic [13-16, 22, 24, 31, 33, 35, 77, 79, 82, 84, 85] at ambient conditions. The ferrimagnatic/ferromagnetic behavior of nanoclusters may be attributed either to ferromagnetic incorporated nanoparticles of sufficient large diameter ( > 20 nm) [80,81] or to strong intra-cluster interactions [21].…”

“…The ferrimagnatic/ferromagnetic behavior of nanoclusters may be attributed either to ferromagnetic incorporated nanoparticles of sufficient large diameter ( > 20 nm) [80,81] or to strong intra-cluster interactions [21]. Lartigue et al showed that maghemite nanoclusters of 30 nm in diameter, which are illustrated in Figure 13A, were superparamagnetic (lack of hysteresis) at room temperature [31].…”

Synthesis of Tunable Fe3O4@Mesoporous-silica-pillared Clay (MSPC) and Its Performance in Lysozyme Loading and Releasing Behavior

“…The broad nature of the XRD patterns can be ascribed to the ultrasmall size of iron oxide. 8 These results show that PVA-1488 plays a key role of sample forming process.…”

“…As shown in Figure 2, all the Fe 3 O 4 @MSPCs show a parallel part of the hysteresis loop in the regions of P/P 0 > 0. 8, implying open and cylindrical pores. 9 A nearly linear uptake of nitrogen in the relative pressure ranges of 0.050.2 indicated the presence of framework pores spanning from supermicropores to small mesopores in the range 1.5 2.0 nm.…”