Oriented Attachment Crystal Growth Model in Hydrothermal Synthesis of Magnetite (Fe3O4) Nanoparticles

Abstract

ABST CT: e magnetite nanoparticles (Fe 3 O 4 ) are very promising nanomaterial to be applied as drug delivery due to their excellent superparamagnetic, biocompatibility and easily modified surface properties. ose properties are influenced by the structure and size of the material which depend on the synthesis condition. Studying the evolution of crystal growth can help understand the mechanisms and factors that play a role in it more systematically. e purpose of this research is to study the evolution of crystal growth of magnetite nanoparticles in the hydrothermal system and determine the crystal growth kinetics using the Oriented A achment Growth model. Magnetite nanoparticles were synthesized using a hydrothermal method from FeCl 3 , citrate, urea and polyethylene glycol at 210˚C for 1 -12 hours at a various concentration of FeCl 3 (0.05 M, 0.10 M, and 0.15 M). e characterizations were conducted by X-ray Diffraction (XRD), Transmission Electron Microscope (TEM), Particle size analyzer (PSA), and Vibrating Sample Magnetometer (VSM). e XRD diffractogram indicated that the magnetite was begun to form at 3.5 hours synthesis. e crystallinity and the crystal size of magnetite rose with reaction time. e diameter of magnetite crystals was in the range of 9.4-30 nm. Characterization by TEM showed that the particles were formed from smaller particles which were then agglomerated. e characterization by PSA showed that an increase in FeCl 3 concentration made the particle size larger but the particle distribution narrower. PSA results also prove that the longer the reaction time, the more particle diameter increases will be. VSM result showed that the magnetite nanoparticle has superparamagnetic properties. e magnetite crystal growth can be fi ed by the Oriented A achment Growth model with an error of 29%.

Recent Advances in Magnetite Crystallization: Pathway, Modulation, and Characterization

“…The facet-dependent surface energy of these particles can further promote rotation and alignment of their grain boundaries in the same direction, which can lead to the formation of larger magnetite mesocrystals through an oriented attachment mechanism. Following this self-organization process, the building units of mesocrystals may fuse together and form single crystals. ,,− The alignment of nanocrystal subunits can be controlled by additives to create magnetite polycrystals and various collective magnetic behaviors. By tuning the oriented attachment process of nanoparticles, it is possible to create magnetite materials with new properties, such as micrometer size and ferrimagnetism.…”