|Title||Unwinding a spiral of cellulose nanocrystals for stimuli-responsive stretchable optics|
|Publication Type||Journal Article|
|Year of Publication||2019|
|Authors||Kose, O, Tran, A, Lewis, L, Hamad, WY, MacLachlan, MJ|
|Date Published||JAN 31|
|Type of Article||Article|
Cellulose nanocrystals (CNCs) derived from biomass spontaneously organize into a helical arrangement, termed a chiral nematic structure. This structure mimics the organization of chitin found in the exoskeletons of arthropods, where it contributes to their remarkable mechanical strength. Here, we demonstrate a photonic sensory mechanism based on the reversible unwinding of chiral nematic CNCs embedded in an elastomer, leading the materials to display stimuli-responsive stretchable optics. Vivid interference colors appear as the film is stretched and disappear when the elastomer returns to its original shape. This reversible optical effect is caused by a mechanically-induced transition of the CNCs between a chiral nematic and pseudo-nematic arrangement.