Four-dimensional (4D) active shape-changing structures based on shape memory polymers (SMPs) and shape memory nanocomposites (SMNCs) are able to be controlled in both space and time and have attracted increasing attention worldwide. However, conventional processing approaches have restricted the design space of such smart structures. Herein, 4D active shape-changing architectures in custom-defined geometries exhibiting thermally and remotely actuated behaviors are achieved by direct-write printing of ultraviolet (UV) cross-linking poly(lactic acid)-based inks. The results reveal that, by the introduction of a UV cross-linking agent, the printed objects present excellent shape memory behavior, which enables three-dimensional (3D)-one-dimensional (1D)-3D, 3D-two-dimensional (2D)-3D, and 3D-3D-3D configuration transformations. More importantly, the addition of iron oxide successfully integrates 4D shape-changing objects with fast remotely actuated and magnetically guidable properties. This research realizes the printing of both SMPs and SMNCs, which present an effective strategy to design 4D active shape-changing architectures with multifunctional properties. This paves the way for the further development of 4D printing, soft robotics, flexible electronics, minimally invasive medicine, etc.
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http://dx.doi.org/10.1021/acsami.6b12824 | DOI Listing |
J Mater Chem B
January 2025
Smart Photonic Materials, Faculty of Engineering and Natural Sciences, Tampere University, Tampere, P.O. Box 541, FI-33101, Finland.
As biomimicry advances, liquid crystal elastomers (LCEs) are gaining attention for their (multi-)stimuli-responsiveness and reversible shape morphing. Introduction of dynamic bonds into the LCEs provides versatile means towards programmable shape morphing and adaptation to environmental cues, and new designs for dynamic LCEs are actively sought for. Here, we present a supramolecular LCE that integrates shape memory programming, humidity sensitivity, and photochemical actuation.
View Article and Find Full Text PDFSci Rep
November 2024
Dyson School of Design Engineering, Imperial College London, London, SW7 2DB, UK.
ACS Appl Mater Interfaces
October 2024
Henan International Joint Laboratory of Carbon Fiber Composites, School of Mechanical and Electrical Engineering, Henan University of Technology, Zhengzhou 450001, P.R. China.
Adv Mater
September 2024
Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, Kemistintie 1, Espoo, 02150, Finland.
Phys Rev Lett
June 2024
Instituto de Física, Pontificia Universidad Católica de Chile, 8331150 Santiago, Chile.
Active solids such as cell collectives, colloidal clusters, and active metamaterials exhibit diverse collective phenomena, ranging from rigid body motion to shape-changing mechanisms. The nonlinear dynamics of such active materials remains, however, poorly understood when they host zero-energy deformation modes and when noise is present. Here, we show that stress propagation in a model of active solids induces the spontaneous actuation of multiple soft floppy modes, even without exciting vibrational modes.
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