Demonstration of artificial nocturnal flower

An imitation flower made of liquid crystals folds its petals inwards after exposure to light. Credit: O. M. Wani et al./Adv. Mater.

Materials science

A synthetic flower that unfolds in the dark

Device mimics natural nocturnal flowers that bloom in dark and humid conditions.

Researchers have moulded liquid crystals into an artificial night-blooming ‘flower’, which curls up tightly when light hits its ‘petals’.

Arri Priimagi at Tampere University of Technology in Finland, Albert Schenning at Eindhoven University of Technology in the Netherlands and their colleagues created liquid crystals — which have properties of both liquids and solids — that included molecular sections sensitive to light and humidity. The researchers chemically linked these crystals into polymer-like networks, creating a material that was stiff but capable of bending. They then cut this material into slender petals.

Next, the team coated one side of the material with an alkaline substance, which broke some of the bonds between the network’s crystals and caused the petals to curl up tightly. This treated side was then ready to absorb water, which made the petals unfurl. When the humidity level dropped, or the authors shone a light on the flower, the petals folded up again.