4D printing of multiscale filler–reinforced thermoplastic polyurethane nanocomposites with electro-activated shape memory properties

Four-dimensional printing of shape memory materials has been developed to dynamically control the shapes of printed structures for applications such as self-deployable structures, actuators, and sensors. Herein, a novel electro-activated shape memory nanocomposite material for the selective laser sintering (SLS) process is developed. The nanocomposite powder incorporates a new type of multiscale hybrid filler, consisting of carbon fibres and carbon nanotubes (CNTs), with CNT-coated thermoplastic polyurethane nanocomposite powders. The shape recovery process of the nanocomposite with a 20 wt% hybrid-filler addition is almost four times faster when triggered by electric currents than that triggered by the direct heating method and exhibits a higher shape recovery ratio. A remotely and selectively controlled smart component is fabricated to demonstrate the potential applications of the novel nanocomposites. This work provides a promising solution to achieve function–structure integration through SLS for future high-tech applications.