Researchers have constructed micrometre-sized, stacked layers that slide open like a folding fan when illuminated.
Yanke Che and his colleagues at the Beijing National Laboratory for Molecular Sciences created thin, ribbon-like structures up to one micrometre wide.
The ribbons are composed of multiple layers, each consisting of pairs of a long, thin molecule called perylene diimide. Under a blue-green laser, the layers slide apart because the photons excite electrons and distort molecular conformations, the researchers say. As a result, the ribbons expand, reaching around 12 micrometres in width after 3 minutes. They shrink back in seconds when exposed to an electron beam.
Materials that change shape under light could have many applications, including in artificial muscle, the team says.
Adv. Mater. http://doi.org/f2v7vc (2014)