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.

Graphical AbstractPath-dependent and selective multi-shape recovery was unprecedentedly achieved for a single CNW-SMPU nanocomposite. Due to the triple-switch-netpoint structure, the composite offered five paths of shape recovery with choices of dual, triple and quadruple shapes using only one-step programming.Figure optionsDownload as PowerPoint slideHighlights
► CNW–SMPU nano-composites had thermo- and water-sensitive triple switches.
► Path-dependent and selective multi-shape recovery were achieved for the composites.
► Dual, triple and quadruple shapes were obtained after one-step programming.