Shape Memory Cellulose-based Photonic Reflectors.

Bio-polymer based composites enable to combine different functionalities using renewable materials and cost-effective routes. Here we fabricate novel thermoresponsive photonic films combining cellulose nanocrystals (CNCs) with a polydiolcitrate elastomer exhibiting shape memory properties. In this composite, CNCs provide an intense structural coloration and improve the overall mechanical cohesion, while the elastomer drastically reduces the intrinsic brittleness of the photonic cellulose film and enables the shape memory effect. The fabricated samples are characterized by polarized optical microscopy, scanning electron microscopy and thermomechanical programming. The obtained results demonstrate that this hybrid material retains its chiral nematic structure and performs shape recovery in thermomechanical experiments thus widening the functionality of the independent components.