Silica, SiO2, structure

Except for the Interesting fact that the polymeric SIO2 structures do not destabilize the mlcroemulslon there Is also an Intriguing feature of the competition for water between the surfactants and the silicone tetraethoxlde. Figure 1 clearly shows a minimum amount of water to be necessary In order to dissolve the surfactant and Equation 6 shows a need for water for the hydrolysis reaction. The minimum amount of water needed Is 2 when x In Equation 6 Is close to 4, which actually Is the case In the experiment. For that case two water molecules are needed for each molecule of silicone tetraethoxlde. A calculation of the lower limit of water In Figure 8 shows the Increase of water concentration to be approximately four times this value. Water Is obviously needed to retain the silica In the mlcroemulslon state. 

The molten sodium sulphate/sodium silicate system of composition Na2SO4 Na2O-SiO2 has one liquid phase at 1475 K, but as the proportion of silica increases, the melt separates into two layers (, 2). The change from the miscible to immiscible phase of the system has been explained by alterations in the silicate structure as the ratio of Na20 to Si02 decreases. In more basic, less viscous melts, the silicate ions exist in the form of SiO "... 

---