Design of element blocks for photoresponsive organosiloxane-based materials

In this chapter, preparation, structures, and photoresponsive properties of various azobenzene-siloxane hybrid nanomaterials based on the design of element blocks are described. Hydrolysis and polycondensation reactions accompanied by self-assembly of different types of azobenzene-functionalized alkoxysilane precursors yield hybrids with ordered mesostructures. Lamellar films show reversible dspacing changes and macroscopic bending-unbending motion by partial trans-cis photoisomerization of the azobenzene groups. Further, incorporation of a cage oligosiloxane into the precursor leads to the formation of cylindrical assemblies, in which efficient photoisomerization of azobenzene is achieved. These findings will contribute to the creation of novel photoresponsive materials.