Main group element and metal-containing polymers as photoresponsive soft materials

Photochemistry is used in polymer science to manipulate the physical properties of soft materials exogenously. Light is unique in its ability to act as a non-invasive trigger to induce bond cleavage, isomerisation, or rearrangement reactions within photoresponsive polymers and thus alter their physical, chemical and mechanical properties in a spatiotemporal manner. However, while many photoresponsive organic polymers are known, they frequently respond only to high-energy UV irradiation, for which undesirable side reactions are inevitable, causing damage to surrounding molecules and restricting the penetration depth in soft materials. Herein we describe the most recent efforts to expand the array of photoresponsive polymers to include inorganic and heteroatom moieties and, in doing so, to prepare polymers with potentially more sensitive and selective photochemical responses. Such novel photosensitive soft materials are expected to have significant implications, for example, in controlled release and polymer degradation, as well as in lithography and 3D printing technologies.