More on the phase diagram of laponite

The phase diagram of a charged colloidal system (Laponite) has been investigated by dynamic light scattering in a previously unexplored range of salt and clay concentrations. Specifically, the clay weight and salt molar concentrations have been varied in the ranges C-w = 0.004 divided by 0.025 and C-s = (1 X 10(-3), 5 x 10(-3)) M, respectively. As in the case of free salt water samples (C, 1 x 10(-4) M), an aging dynamics toward two different arrested phases is found in the whole examined Cw and C, range. Moreover a transition between these two different regimes is found. It is clear from these measurements that a revision of the phase diagram is necessary and a new 'transition' line between two different arrested states is drawn.