Revisiting The Standard Theory Of Colloidal Dispersions

The DLVO theory has long been accepted as the standard theory of colloidal dispersions. It can describe quantitatively well the stability and instability of concentrated dispersions. Recently, however, it turns out impossible to explain a variety of phenomena such as ordering formation and phase transitions in dilute dispersions of highly charged particles. Those phenomena require the colloid particles to have the interaction potential with the strong medium-range repulsion and weak long-range attraction. We review critically the existing theories of ionic solutions, argue over a new standard theory of colloid interaction which can describe the characteristics of dilute as well as concentrated dispersions, and propose experiments of laser diffraction and CCD photography in the Kibo module of ISS to verify the theory.