Path-dependent and selective multi-shape recovery of a polyurethane/cellulose-whisker nanocomposite

Incorporation of cellulose nano-whiskers (CNWs) into shape memory polyurethane (SMPU) endowed the composites with thermo- and water-sensitive triple switches. The thermal transitions of the composites were measured by Differential Scanning Calorimetry (DSC). Path-dependent and selective multi-shape recovery was unprecedentedly achieved for the single CNW-SMPU nanocomposite, as determined by elaborately designed tensile tests. The composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming. Photographs recording the quadruple-shape recovery of the composite along water and heat stimulations were presented. This high level of adaptability of the composite may be beneficial for developing novel functional polymeric composites. © 2012 Elsevier B.V.