ABSTRACT

This chapter discusses that in a model clay system, the “naked” clay particle with a thickness of about 10 A is covered by two ordered layers of water molecules on each side. It is followed by a layer of counterions and another layer of partially ordered water molecules, to produce a “dressed” clay particle of a thickness of about 35 A. It gives rise to an effective clay plate thickness of about 35 Å in a swollen clay. The author stresses that the clay particles sit at about 7 Debye lengths from each other when the clay is in its swollen gel state. The interplate separation in the gel state is therefore inversely proportional to the square root of the electrolyte concentration. The chapter concludes that there is no evidence for the formation of any micellelike structure or of strong bonding of the ammonium groups to the negatively charged clay plates.