3. Light-responsive Wormlike Micelles

UV/Vis light as a trigger displays a set of advantages over other types of stimuli in terms of its “clean” character, low cost, and precise spatial localization, and for these reasons it has been widely exploited in the development of smart materials. Light-responsive wormlike micelles take advantage of light-induced cis–trans isomerization or dimerization of light-sensitive surfactants or additives containing a suitable chromophore. These changes alter the packing of surfactant molecules in the aggregates and drive micellar transitions between wormlike micelles and other structures, thus tuning the viscoelasticity. This chapter summarizes two types of strategies in manipulating light-sensitive wormlike micelles—either to incorporate light-sensitive additives into classical existing wormlike micellar solutions or to directly introduce light-sensitive functional moieties on the surfactant molecules. In both cases, the worms self-assemble or disassemble upon alternate UV/Vis light irradiation.