Photoswitchable Magnetic Films: Prussian Blue Intercalated in LangmuirBlodgett Films Consisting of an Amphiphilic Azobenzene and a Clay Mineral

A novel photocontrollable magnetic thin film consisting of amphiphilic azobenzene cations, a smectite clay, and Prussian Blue has been designed and prepared by using the Langmuir-Blodgett method and an ion-exchange reaction. This magnetic thin film possesses a well-organized nanoscale layered structure. Reversible photoisomerization of the azobenzene chromophore realized photoswitching of the magnetization. The changes in the magnetization values were estimated to be ca. 11%. This figure was much larger than our previous system, which contained azobenzene multi-bilayered vesicles in a poly(vinyl alcohol) matrix (J. Am. Chem. Soc. 1999, 121, 3745). These larger changes in the magnetization values are due to the highly ordered structure of the hybrid multilayered films.