Interfacial agents for polymer/liquid crystal dispersions

Liquid crystals (LC) were covalently and ionically bonded to one (or both) end(s) of polystyrene chains. These compounds were tested as interfacial agents in polystyrene/liquid crystal dispersions. In case of covalent bonding, the additive is too much "soluble" in polystyrene and no interfacial activity is observed. Ionic bonding of the LC to polystyrene chains deeply changes the situation, all the other conditions being the same. The dipolar interactions of the ion pairs are clearly favorable to the localization of the additive at the polymer/LC interface. The higher polarity of the ammonium sulfonate pairs compared to the parent ammonium carboxylate ion pairs accordingly accounts for a higher interfacial activity.