Direct Continuous Synthesis of Oleic Acid-Modified\nFe₃O₄ Nanoparticles in a Microflow System

Abstract

In\nthis work, a direct continuous synthesis route of oleic acid\n(OA)-modified Fe₃O₄ nanoparticles was proposed\nand achieved by combining flow co-precipitation of Fe₃O₄ nanoparticles in a membrane dispersion microcontactor with\nthe in-line introduction of OA. A systematic characterization confirms\nthe effective and controllable covalent binding between OA and the\nnanoparticles during an extremely short period in a microflow system.\nThrough comprehensively investigating the effects of different factors,\nthe proper time to introduce a modifier was explored, and the mechanism\nof sequential nanoparticle generation and modification was revealed.\nA quantitative regulation relationship for the modification process\nwas established as guidance to achieve an accurate and flexible modification\ndegree. Compared with the traditional multistep and hour-level duration\nin the batch process, this highly controlled continuous synthesis\nmethod within seconds opens a horizon for the broad applications of\nOA-modified Fe₃O₄ nanoparticles in the future.