Unwinding a spiral of cellulose nanocrystals for stimuli-responsive stretchable optics

April 9, 2019

Title

Unwinding a spiral of cellulose nanocrystals for stimuli-responsive stretchable optics

Author

Osamu Kose, Andy Tran, Lev Lewis, Wadood Y. Hamad, Mark J. MacLachlan

Year

2019

Journal

Nature Communications

Abstract

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.

Instrument

J-710

Keywords

Circular dichroism, Solid state, Nanostructures, Materials, Biochemistry