VISCOSITY OF SILICATE SOLUTIONS

High precision viscosity measurements of electrolyte solutions were us ed to obtain information about interionic interactions. In solutions o f tetramethylammonium (TMA) silicates values for the A and D coefficie nt in the Jones-Dole equation were found to be significantly higher th an for sodium and potassium silicate solutions. Ion association betwee n cations and anions in the silicate solutions investigated is exclude d by EMF measurements. The A and D coefficients of solutions which con tain both alkali metal and TMA silicate were in the range of the value s of alkali metal silicate solutions. As an explanation for this behav ior we suggest that hydrophilic and hydrophobic structured solvent reg ions are present around respectively the silicate and the TMA which ca nnot overlap. This causes a repulsion between these ions superimposed on the electrostatic attraction.