Effect of surface modifiers on the nanoparticles electro-driven assembly
October 1-6, 2017
Understanding the colloidal behavior of particles is mandatory to prepare stable and disperse suspensions suitable for EPD. Up today, most of the proposed models for the EPD kinetics have been formulated considering the electrophoresis process, where depositing features are quantified by the sticking factor, a probabilistic and empiric parameter. Proposed models have demonstrated that interparticles forces are also the clue to understand the way in which particles compact on the electrode under the influence of an electric field in an electrostatically stabilized suspension. Empirically in those systems, the morphology, the crystallography and the reactivity of the particles, determine the charge distribution in their surfaces, while the ionic strength modulates the charge density. However, new perspectives of particles assembly verified that in suspensions stabilized by an electrosteric mechanism, under similar electric conditions, changes in nature, length and ionization strength of surface modifiers or ligands determine the interaction forces among nanoparticles, resulting in an effective tool to manage nanoparticles flocculation and hence kinetics and ordering during the film growth. This fact has been specifically proved in the electrophoretic deposition of nanoplatelets or in the spatial orientation of nanocrystals. In this paper, we will discuss the literature that evidences how the surface modifiers not only define the deposition rate, but they also determine the deposition behavior and the final microstructure of the coating. Particularly the Layer-by-Layer (LbL) technology, understood as the alternate absorption of cationic and anionic polymers onto the particle surface, will be shown as an example of the compaction tailoring in 3D ceramic electrodes for supercapacitor manufacturing.
Joaquin Luis Yus Domínguez, Begoña Ferrari, Joaquin Yus, Zoilo Gonzalez, and Claudine Filîatre, "Effect of surface modifiers on the nanoparticles electro-driven assembly" in "Electrophoretic Deposition VI: Fundamentals and Applications", Aldo R. Boccaccini, Institute of Biomaterials, University of Erlangen-Nuremberg, Germany Omer van der Biest, Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Belgium James Dickerson, Consumer Reports, USA Tetsuo Uchikoshi, National Institute for Materials Science, Japan Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/electrophoretic_vi/24