Effects of particle size and molecular weight of polyethylenimine on properties of nanoparticulate silicon dispersions

The effect of particle size on the zeta potential and theology of nanoparti culate SiO2 dispersions stabilized with the polymer polyethylenimine (PEI) was investigated experimentally, The particle size and molecular weight of the polymer had only a small influence on the amount of PEI needed and the achieved zeta potential of the suspensions. The polymer concentration range within which a stable dispersion could be produced was very narrow for the smallest particle size. Higher-molecular-weight PEI was more suitable to s tabilize small particle dispersions. Under optimum conditions, Newtonian fl ow behavior was achieved for dispersions of 20 nm particles with a solids c ontent as high as 25 vol%.