ELECTROSTATIC ADHESION OF NONUNIFORMLY CHARGED DIELECTRIC SPHERES

Electric field detachment measurements in vacuum have been obtained on triboelectrically charged dielectric spheres nominally 99-mu-m in diameter. From an analysis of the particle motion, one can calculate the monopole, dipole and quadrupole moments of the non-uniform surface charge distribution. The calculated electric field for particle detachment is within 20% of the measured values. However, a description of particle bouncing by the same electrostatic analysis is inadequate for bounce heights less than approximately 10 pm. The discrepancy could be due to contact charge exchange or an enhanced electrostatic adhesion from a textured charge on a scale of micrometers.