Overlap of colloid chemistry and photochemistry in surfactant systems

Interactions of organic photochemistry and colloid chemistry in surfactant systems can be divided in two distinct sections: (i) influences of the colloids on photochemical reactions and (ii) influences of photochemical reactions on macroscopic properties of colloidal surfactant systems. As to (i), the (generally poor) selectivity of photochemical reactions can be improved by performing the reactions in systems containing surfactant aggregates. Regioselectivity, stereoselectivity and multiplicity selectivity can be directed. As to (ii), in lyotropic liquid crystalline systems the solubilization of certain aromatic compounds specifically changes phase transition temperatures. Upon photochemically transforming such solubilizates in situ isothermal phase transitions can be brought about, provided that photoeducts and photoproducts induce distinct transition temperatures. Similarly in dilute surfactant systems solubilizates specifically affect size and shape of micellar aggregates, so that changes in flow behaviour take place, which can be switched via photochemical transformation of solubilizates. Possible exploitations of the effects are discussed and compared with the application of similar effects in related non-surfactant systems, with emphasis on photochemical information storage.