Strange Polymer Behavior

Polymers strut their stuff under the spotlight is a Chemical Science article telling of how polymer films, having azobenzine groups, simulate an inchworm walk when exposed to alternating visible and ultraviolet light. The discovery was made by Japanese chemists who have shown that this polymer contracts in response to exposure to visible light and expands under UV light.

The reason for the strange behavior is attributed to N=N double bonds. These bonds have a cis conformation when the polymer bends but upon flattening is associated with bonds being trans.