CONDUCTIVITY STUDIES ON MODIFIED LAPONITES

Significant increase of the a.c. conductivity of Laponite is achieved when the sodium form is totally exchanged with potassium ions; however , the rheological properties alter, e.g. the clay will no longer form a gel with water. Exchange with Li+, Rb+, Cs+ or CU2+ produces no incr ease in the a.c. conductivity over that of the sodium form. The synthe sis of fluoro-laponites, with increased sodium contents, via a sol-gel method, gives materials of enhanced a.c. conductivity, which retain s imilar theological properties to those of commercial Laponite. Some Si -29 and Li-6 MAS NMR data are reported for the new materials.