Azobenzene Polymers as Photo-Mechanical and Multifunctional Smart Materials
Yager, K.G.; Barrett, C.J. "Azobenzene Polymers as Photo-Mechanical and Multifunctional Smart Materials" Intelligent Materials, Shahinpoor, M. and
Schneider, H.-J., eds. Royal Society of Chemistry Publishing 2008
, Chapter 17
ISBN: 978–085404–335–4.doi: 10.1039/9781847558008-00424
We review the photo-mechanical effects observed in azo-polymer materials.
Among the many classes of novel advanced materials now being researched worldwide are photofunctional and photoresponsive materials. The advantages of materials that respond to light are numerous: natural light is a plentiful and effectively unlimited energy source, light is correlated to many everyday (and even industrial) activities, light stimulation can be performed remotely and without disturbing intervening materials, and light activation can be highly localised and specific. The intent with photofunctional materials is to generate substances that respond automatically to light in a desired way. As with all ‘smart’ materials, the desired response is programmed into the material architecture, rather than being actively induced after material is prepared. Photofunctional smart materials promise to make a significant impact in modern industry, which relies heavily upon optical processes (e.g. telecommunications and lithography), and in daily life, where photoresponsive materials could be designed to respond appropriately to changing illumination. A variety of photoresponsive molecules have been characterised, including those that photodimerise, such as coumarins and anthracenes; those that allow intra-molecular photoinduced bond formation, such as fulgides, spiro-pyrans, and diarylethenes; and those that exhibit photoisomerisation, such as stilbenes, crowded alkenes and azobenzene. Photoinduced molecular motion can be used as a molecular rotor or as a molecular device.