Properties of Cationic Choline-Derived Surfactant with Photolabile Cinnamate Counterion

Abstract
A cationic choline-derived surfactant with photolabile cinnamate counterion (tetradecyl-(2-hydroxyethyl)-dimethylammoniumcinnamate, C14HDACin) was synthesized. The properties of C14HDACin aqueous solutions for pre- or post-UV irradiation were investigated by employing tensiometry, conductance, transmission electron microscopy (TEM) and rheometry. The effect of UV irradiation time on photoisomerization of C14HDACin solutions was evaluated, which showed that the photoisomerization efficiency decreases with an increase of C14HDACin concentration. After UV irradiation, the fraction of counterion binding (β) of the C14HDACin micelle decreases. However, the value of CMC increases. Rheometry coupled with TEM studies confirmed that the aggregation of C14HDACin could transform from wormlike to spherical micelles upon UV irradiation.