Combined Photopolymerization and Localized Photochromism Generation by Aza-Diarylethene and Hemiindigo Synergy

Molecular photoswitches produce light-controlled changes at the nanometer scale and can therefore be used to alter states and behavior of materials in a truly bottom-up fashion. Here we show an escalating photonic complexity of material property control with light using a recently developed aza-diarylethene in combination with hemiindigo (HI) photoswitches. First, the aza-diarylethene can be used as a photoswitch in polystyrene (PS) and to inscribe relief-type 3D structures reversibly into PS. Second, aza- diarylethene can further be used as a photoinitiator for light-induced polymerization of acrylates, demonstrating for the first time light-controlled chemical reactivity control with its zwitterionic switching state. Third, aza-diarylethene and HIs are implemented into aza-diarylethene polymerized PMA, generating photochromic polymers. At the fourth level, the binary mixture allows to synergize aza-diarylethene induced photopolymerization with localized photochromism changes of the simultaneously entrapped functional HI. With such multi-level light response, the utility of this particular photoswitch combination for applications in advanced photonic materials is demonstrated.