抄録
The deformation of a viscous liquid polybutadiene (LPB) drop in an electrostatic field was studied. Three types of electrodes, i.e., a thin plate, a single-needle, and a twin-needle electrodes, were employed in connection with a stabilized high voltage DC source. A PTFE-coated aluminum plate (a counter-electrode) was horizontally settled and connected to the above-mentioned electrode via the high voltage source. A drop of LPB was allowed to stand on the PTFE surface of the counter-electrode and one of the three electrodes was placed above the drop. The LPB drop was deformed responding to the magnitude of the electrostatic field and the deformation manner directly reflected the electrode employed. When the drop was placed between a couple of plate electrodes, it merely behaved as an insulator in a capacitor. The use of the single-needle electrode caused a deformation to doughnut-shaped drop. The most complicated deformation behavior was observed for the twin-needle electrode system: If a gap between the needles, d, was longer than the initial diameter of the drop, W0, the drop expanded in the direction perpendicular to the needleto-needle direction. If d was shorter than W0, however, the expansion was more significant in the needle-to-needle direction than in its perpendicular direction. It is concluded that the coulombic forces, which act between charges stored or induced on the drop surface and the PTFE substrate, resulted in the deformation of the LPB drop.
