4D Printing of MXene Composites for Deployable Actuating Structures

Abstract

The development of innovative materials for three-dimensional (3D) printing is creating potential opportunities for advancements in additive manufacturing (AM) technologies, including in four-dimensional (4D) printing. Through the creation of next-generation shape memory polymer composites (SMPCs), printed parts can now be bestowed with increased functionalities including the ability to transform their shape, acting as smart actuators that respond to the stimuli around them. These materials are of great interest for development of soft robotic systems, which can be quickly and affordably manufactured. In this work, a SMPC consisting of a TPU:PLA polymer blend system with embedded MXene (Ti3C2) flakes is fabricated and evaluated. The mechanical, thermal, and morphological properties prove to be greatly improved with the addition of MXene at 0.5 wt %. At higher loadings of 2 wt % MXene, the composite shows superb shape memory effect results in fast recovery to ∼98% its original position in under 14 s. Rheological behavior and thermal properties were evaluated, followed by 3D printing using material extrusion. Results show great potential of MXene-loaded composites for fast shape memory actuation in 3D/4D printed structures. The potential of such composites is demonstrated through several printed designs, which show large deformation suitable for deployable structures.

Mechanical Properties, Energy Absorption, and Shape Memory Behavior of 3D Printed PLA‐MXene Nanocomposites and Gyroid Lattices

“…McLellan et al [ 39 ] added MXene to TPU/PLA blend to enhance mechanical performance and it also induced a fast shape memory response in a reinforced, 3D‐printed shape memory polymer composite. Their hexagonal and auxetic honeycomb structure illustrated the potential applications in deployable structures.…”

“…Although MXenes have been extensively explored as fillers in polymers, there seems to have been only one report on 3D printed PLA‐TPU‐MXene composites. [ 39 ] In ref. [39], the authors focused on the SME of PLA‐TPU‐MXene polymer composites.…”

“…[ 39 ] In ref. [39], the authors focused on the SME of PLA‐TPU‐MXene polymer composites. Synergies between the MXene infill and the polymer blend allowed substantial enhancements of the SME.…”

“…The study revealed that higher PLA concentration and lower programming temperatures resulted in greater programming stresses and restricted polymer mobility, with TPU significantly enhancing shape recovery across all conditions. [38] McLellan et al [39] added MXene to TPU/PLA blend to enhance mechanical performance and it also induced a fast shape memory response in a reinforced, 3D-printed shape memory polymer composite. Their hexagonal and auxetic honeycomb structure illustrated the potential applications in deployable structures.…”

4D printing of shape memory polylactic acid/ethylene-glycidyl methacrylate (PLA/E-GMA) blends

“…In recent years, 4D printing has emerged as an extension of 3D printing, introducing an additional dimension of time [20][21][22][23][24][25]. 4D printing involves the fabrication of objects that can change their shape, properties, or functionality over time in response to external stimuli [3,9,17].…”