A morphing-wing demonstrator that changes shape using a thin liquid-crystal polymer skin actuated by light-emitting diodes (LED) will be built and tested at the University of Delft in the Netherlands over the next eight to 12 months, writes Rob Coppinger.
The liquid-crystal polymer film is an orange-coloured rubber-like material that has light-sensitive azobenzene molecules held within its liquid-crystal matrix, which gives all the molecules a single directional order.
The Delft researchers consider the polymer/LED system lighter in mass and more energy efficient than the competing piezoceramic and electro-active gel technologies being developed elsewhere.
When light is shone upon the polymer the directional change in the azobenzene molecules is strong enough to provide a dimensional change.
The polymer starts life in its most extended form, which means that the first time it is irradiated with one wavelength it contracts.
Irradiation with a second wavelength will make it extend again. Because extension is slower then contraction, researchers will design a system as a “muscle” pair, where one muscle aids the other.
“You get a huge dimensional change with this polymer. We could change the camber of the wing and we want to do windtunnel testing with it and see how fast it changes,” says University of Delft aerospace engineering department associate professor in fundamentals of advanced materials, Theo Dingemans.
The next step is to find the best molecule design for the polymer. Dingemans will give the overall project to a final- year masters degree research student.
Source: Flight International
