Shape-shifting plastics which respond to external stimuli, similar to how Venus flytraps ensnare prey and touch-me-nots fold their leaves inwards when touched, have come a step closer thanks to a new polymer developed by US researchers. The work could lead to new classes of plastics with many applications including smart responsive coatings, sensors and controlled release vehicles. Polymers have previously been made to reversibly change shape from triggers such as light and temperature. Now, Scott Phillips” team at Pennsylvania State University, US, has broadened the scope by creating a polymer, Pcl2PA [poly(4,5-dichlorophthalaldehyde], that depolymerises from head to tail in response to multiple stimuli. ”The field of head-to-tail depolymerisable polymers is really just emerging, with only a selection of polymers showing rapid and selective depolymerisation,” says Phillips. ”This depolymerisation response, however, is critical for enabling the multi-stimuli-responsive 3D materials in this work.”