Permanent Shape Reconfiguration and Locally Reversible Actuation of a Carbon Nanotube/Ethylene Vinyl Acetate Copolymer Composite by Constructing a Dynamic Cross-Linked Network

Given the rapid developments in modern devices, thereis an urgentneed for shape-memory polymer composites (SMPCs) in soft robots andother fields. However, it remains a challenge to endow SMPCs withboth a reconfigurable permanent shape and a locally reversible shapetransformation. Herein, a dynamic cross-linked network was facilelyconstructed in carbon nanotube/ethylene vinyl acetate copolymer (CNT/EVA)composites by designing the molecular structure of EVA. The CNT/EVAcomposite with 0.05 wt % CNT realized a steady-state temperature of & SIM;75 & DEG;C under 0.11 W/cm(2) light intensity, whichgave rise to remote actuation behavior. The dynamic cross-linked networkalong with a wide melting temperature offered opportunities for chemicaland physical programming, thus realizing the achievement of the programmablethree-dimensional (3D) structure and locally reversible actuation.Specifically, the CNT/EVA composite exhibited a superior permanentshape reconfiguration by activating the dynamic cross-linked networkat 140 & DEG;C. The composite also showed a high reversible deformationrate of 11.1%. These features endowed the composites with the capabilityof transformation to 3D structure as well as locally reversible actuationperformance. This work provides an attractive guideline for the futuredesign of SMPCs with sophisticated structures and actuation capability.

Automated summary

Given the rapid developments in modern devices, there is an urgent need for shape-memory polymer composites (SMPCs) in soft robots and other fields. However, it remains a challenge to endow SMPCs with both a reconfigurable permanent shape and a locally reversible shape transformation. In this study, a dynamic cross-linked network was created in carbon nanotube/ethylene vinyl acetate copolymer (CNT/EVA) composites by designing the molecular structure of EVA. The resulting CNT/EVA composite demonstrated the capability of remote actuation and programmable three-dimensional (3D) structure and locally reversible actuation.