Surface modification techniques toward controlling the dispersion stability and particle-assembled structures of slurries

Controlling the dispersion stability of functional fine/nano-particles without forming strong uncontrollable aggregates and controlling their assembled structure during material processing is a powerful method to improve the properties of composite materials, such as ceramics and polymer nanocomposites. In this article, surface modification techniques for functional fine/nano-particles toward their homogeneous dispersion in solvents will be briefly reviewed. A suitable combination of surface-engineering protocols and the selection of surface modifiers comprising segments that effectively attach to the particle surface and possess high affinities toward solvents is one of the keys to achieve homogeneous dispersion of fine/nano-particles. Then, a concept using a series of polyethyleneimine (PEI) and fatty acid complexes as surface modifiers to control the dispersion stability of multi-component slurries will be reviewed. The dispersion stability of slurries can be tuned by simply controlling the structures of the PEI-fatty acid complex. Furthermore, processing methods to control the particle-assembly structures using the PEI-fatty acid complex will also be introduced.