4. How to formulate a dispersion?

When formulating a dispersion, the nature of the continuous phase (dispersion medium) and that of the dispersed phase are obviously dictated by the application. However, a number of choices can be made to control the dispersion's metastability and adapt its properties to the demands of the application. The main choices concern particle geometry and surface finish. Other choices concern formulation additives, which are generally molecules dissolved in the continuous phase (viscosifiers, gelling agents, surfactants, UV filters). Based on these choices, we can assess the interactions between particles, predict the dispersion's metastability and its other properties (flow, spreading, optical properties).