DEPOSITION OF POLYSTYRENE PARTICLES IN A PARALLEL PLATE FLOW CELL .1. THE INFLUENCE OF COLLECTOR SURFACE-PROPERTIES ON THE EXPERIMENTAL DEPOSITION RATE

Deposition of polystyrene particles on different materials with various surface free energies has been studied as a function of the concentration of a potassium phosphate buffer. The results are correlated with theoretical calculations based on the DLVO theory and taking into account prevailing hydrodynamic conditions. Generally it was found that deposition rates increase gradually as a function of the buffer concentration, contrary to the theory, predicting a steep increase at a critical ionic strength. This discrepancy is ascribed to surface heterogeneity and polymer hairs protruding from the particle surface. Furthermore, the collector surface free energy greatly influenced the difference between the theoretically calculated and experimentally measured buffer concentration beyond which deposition starts to increase steeply. For a low surface free energy of the collector a large difference is observed, whereas for a high surface free energy of the collector small differences were observed between theory and experimental observations within the range of buffer concentrations applied. © 1990.