(545h) Optimizing the Electrophoretic Assembly of Silica Nanoparticles: The Role of NaCl Electrolyte and Process Parameters

The emergence of ordering in silica nanoparticle monolayers through electrophoretic deposition (EPD) offers a promising avenue for achieving controlled assembly in the synthesis of nanomaterials. This work investigates the process of organizing nanoparticles during EPD to understand the fundamental processes that govern ordering phenomena. With a 0.01M NaCl aqueous electrolyte solution serving as the deposition medium, we analyze the effects of essential factors on the deposition rate and final structure, including particle concentration, deposition duration, pH, electrolyte conductivity, and current density. Through TEM analysis and experimental characterization, we demonstrate the importance of the 0.01M NaCl aqueous electrolyte in facilitating efficient particle migration and deposition, particularly at optimal silica nanoparticle concentrations. The precise concentration of NaCl in the electrolyte ensures a homogeneous suspension. It inhibits nanoparticle agglomeration, which is essential for uniform deposition and the development of well-ordered structures. Furthermore, we discover that the deposition rate and the ensuing ordering of nanoparticles are highly susceptible to changes in particle concentration, deposition duration, and current density. The knowledge gained from this study contributes to our understanding of the colloidal assembly of silica nanoparticles and its applications in energy, sensing, photonics, and other fields. It also has practical implications for the customized fabrication of functional nanomaterials with improved properties.