Photoswitchable Nanomaterials Via Ordered Self-Assembly of Monodisperse Oligodimethylsiloxanes

Phase separation in segmented macromolecules such as block copolymers has emerged as a powerful tool for the fabrication of well-ordered nanomaterials. Here, we present a class of monodisperse azobenzene-functionalized oligodimethylsiloxanes (AzoODMS) which self-assemble to form multi-domain nanomaterials with sub-7nm periodicities. By balancing the effects of phase separation and directional endgroup aggregation, we can tailor the nature of self-assembly and obtain materials with drastically different morphologies. We show the importance of these morphologies in conferring bulk material properties. Using the trans-cis photoisomerization of azobenzene motifs, we further demonstrate the reversible photoactivated solid-liquid transition of AzoODMS arranged in bilayers or the rapid motion of AzoODMS arranged in hexagonally-packed cylinders.