Self-limiting deposition ofN-(3-trimethoxysilylpropyl) ethylenediaminetriacetic acid for the production of aqueous-stable iron oxide nanoparticles

This paper presents a novel self-limiting deposition of a carboxysilane functional group to the surface of maghemite iron oxide nanoparticles (IOP). Self-limited deposition of N-(3-trimethoxysilylpropyl) ethylenediaminetriaceticacidoniron oxide is achieved by rapid injection of the basicsilane into acid-stabilized iron oxide. The instant pH shift from 2.3 to 11 through neutral promotes silane deposition on the iron oxide surface but is rapid enough to prevent aggregation and free condensation. Carboxysilane iron oxide particles (CSIOP) are rendered aqueous stable inall pH >5.95. Silane coating is characterized by FTIR, TEM, and DLS.