Charge origin

Calculated layer charge is 0.88 with nearly 80% of this charge originating in the octahedral sheet compared with 55% for glauconite. 

The electrostatic stabilization theory was developed for dilute colloidal systems and involves attractive van dcr Waals interactions and repulsive double layer interactions between two particles. They may lead to a potential barrier, an overall repulsion and/or to a minimum similar to that generated by steric stabilization. Johnson and Morrison [1] suggest that the stability in non-aqueous dispersions when the stabilizers are surfactant molecules, which arc relatively small, is due to scmi-stcric stabilization, hence to a smaller ran dcr Waals attraction between two particles caused by the adsorbed shell of surfactant molecules. The fact that such systems are quite stable suggests, however, that some repulsion is also prescni. In fact, it was demonstrated on the basis of electrophoretic measurements that a surface charge originates on solid particles suspended in aprotic liquids even in the absence of traces of... 

Lyso PC and Lyso PE films. The knowledge in the field of interaction forces in foam films stabilised with soluble zwitterionic phospholipids lyso PC (lysophosphatidylcholine) and lyso PE (lysophosphatidylethanolamine) has improved due to the studies of microscopic foam films [e.g. 191,192,292], The main dependences studied were of film thickness vs. electrolyte concentration and disjoining pressure vs. thickness, under specially chosen conditions in the presence of Na+ and Ca2+. The /i(pH) dependence proved to be very informative for understanding the charge origin in films from the neutral phosopholipids lyso PC and lyso PE (see Section 3.3.2). 

Particles suspended in a liquid, like solvated molecules, can carry electric charges. The sign and size of the charge depend upon the nature of the species, that of the electrolytic medium as well as on the pH (Figure 8.3). This net charge originates from the fixation to the particle surface, of ions contained in the buffer electrolyte. 

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