EFFECT OF SURFACE-CHARGE DENSITY ON THE ELECTROSURFACE PROPERTIES OF POSITIVELY CHARGED POLYSTYRENE BEADS

An investigation of the effect of the surface charge density on the determination of zeta potentials of positively charged polystyrene beads is described. The polystyrene beads were prepared by emulsion polymerization using a cationic initiator. The surface charge density depends on the solution pH since the superficial ionic groups (amidine) behave as weak base. The conversion of mobility values into zeta potentials at two different surface charge densities was accomplished according to Dukhin, since this theoretical treatment takes anomalous surface conductance into account. Likewise, the computer program of R.W. O'Brien and L.R. White (J. Chem. Soc., Faraday Trans. 2, 77 (1978) 1607) was also used to calculate zeta potentials from mobility data.