Double layer, electrochemical electrophoresis

Moreover the exact circumstances of flocculation experiments are usually not known well enough. The surface potential is either not determined or is evaluated from electrophoresis which is usually not reliable for the reasons given in chapter V. In the few cases where the surface potential is known from electrochemical investigations (Agl see chapter IV) it is doubtful whether it is identical with the potential in the diffuse ])art of the double layer We may claim with certainty that the potential is at least 30 mV (critical potential according to the old theories), but probably much higher and of the order of 100 mV. 

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