Light-induced motions in azobenzene-containing polymers

The following article is a tribute to the late Almeria Natansohn and is based on a brief summary of her research in azopolymers. She showed that reversible trans-cis-trans photoisomerization of aromatic azo groups covalently bonded within polymers could trigger a variety of motions in the polymer materials at molecular, nanometer, and micrometer levels. The photoinduced motions could be limited only to the azo rigid chromophore or could involve many polymer chains and ordered domains. Some of the effects of these motions such as reversible photo-orientation of chromophores, amplification effects, photorefractive effects, formation of surface relief gratings (SRGs), and photoinduced chirality and switching in amorphous and liquid-crystalline (LC) polymer films are discussed in relation to the polymer structure and physical parameters. Possible photonic applications originating from these phenomena are also mentioned.