Abstract
Core-shell (C-S) particles having ultra-thin shell layers are prepared by a coacervation process using positively chargeable Polymethyl-Methacrylate (PMMA) particles with the size of approximately 9.5μm as the core particles. Negatively or positively chargeable ultra-fine particles are used to prepare single-shell and double-shell particles by a coacervation process using their aqueous suspensions. Their surface structure and the tribo-charging characteristics are studied. The tribo-charging characteristics of the single-shell C-S particles can be controlled by the small amount of shell layers less than 5000ppm. Double-shell C-S particles have also been obtainable by the coacervation on the single-shell particles. The amount of the positively chargeable outer shell required to shield the negative chargeability of the inner shell is 1000ppm. The amount of the outer shell to attain the steady positive charge is 5000ppm. This corresponds to the very thin outer layers of about 10nm. These results strongly suggest the possibility to control the tribo-charging characteristics independent of the chargeability of the inner shell and core materials.
