Stabilization of Silicon Carbide (SiC) micro- and nanoparticle dispersions in the presence of concentrated electrolyte.
Achieving a stable and robust dispersion of ultrafine particles in concentrated electrolytes is challenging due to the shielding of electrostatic repulsion. Stable dispersion of ultrafine particles in concentrated electrolytes is critical for several applications, including electro-codeposition of ceramic particles in protective metal coatings. We achieved the steric stabilization of SiC micro- and nano-particles in highly concentrated electroplating Watts solutions using their controlled coating with linear and branched polyethyleneimines (PEI) as dispersants. Branched polyethyleneimine of 60,000 MW effectively disperses both microparticles and nanoparticles at a concentration of 1000 ppm. However, lower polymer dosages and smaller polymers fail to disperse, presumably due to insufficient coverage and bridging flocculation. Dispersion stability correlates well with the adsorption density of PEI on microparticles. We discuss the results in the framework of DLVO theory and suggest possible dispersion mechanisms. However, though the dispersion is enhanced with extended adsorption time, the residual PEI in solution adversely affects electroplating. We overcome this drawback by precoating the particles with the polymer and resuspending them in Watts solution. With this novel approach, we obtained robust dispersions. These results offer new possibilities to control dispersion at high electrolyte concentration, as well as bring new insights into the dispersion phenomenon.
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA. Electronic address: av2473@columbia.edu.
Annamaria
A
Vilinska
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA. Electronic address: sp2522@columbia.edu.
Sathish
S
Ponnurangam
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA. Electronic address: ic2228@columbia.edu.
Irina
I
Chernyshova
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA. Electronic address: ps24@columbia.edu.
Ponisseril
P
Somasundaran
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
Damla
D
Eroglu
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
Jose
J
Martinez
Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA.
Alan C
AC
West
D017554:Carbon Compounds, Inorganic / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009994:Osmolar Concentration; D011094:Polyethyleneimine / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D012995:Solubility
D017554:Carbon Compounds, Inorganic; D004573:Electrolytes; D017655:Silicon Compounds; D011094:Polyethyleneimine; C022088:silicon carbide
Dispersion stability; High ionic strength; Polyethyleneimine; SiC