ON THE UNIVERSAL GROWTH OF 2-DIMENSIONAL AGGREGATES OF HYDROPHOBED GLASS-BEADS FORMED AT THE (AQUEOUS-SOLUTION OF ELECTROLYTE)-AIR INTERFACES

Two-dimensional aggregation of surface-modified glass beads was carried out at water (aqueous solution of electrolyte)-air interfaces. The effects of particle hydrophobicity and electrolyte concentration on the structure of the forming aggregates and on the growth process were investigated. The growth was characterized by density functions which demonstrate the change in mean particle number density as a function of aggregate size. The aggregation yielded fractal or non-fractal structures, depending on aggregate size. The fractal character for small aggregates was found to be dependent on particle hydrophobicity as well as on electrolyte concentration. However, above a certain electrolyte concentration, where restructuring of the growing aggregates was hindered slightly, practically the same values of fractal dimensions were obtained for investigated systems having different hydrophobicities. This result was attributed to the universal aspect of two-dimensional growth.