Programmable 4D Printing of Bioinspired Solvent‐Driven Morphing Composites

Abstract

In this article, we propose a bioinspired programmed 4D printing method. A combination of magnetic orientation process and grayscale 3D printing is used to achieve site‐specific orientation of the reinforcing fibers and gradient crosslinking of the matrix resin in the thickness direction within 2D composite films. After solventization and desolventization, 2D thin film structures can be transformed into complex 3D architectures, and the transformed 3D architectures can be permanently preserved without stimulation sources. Thus, the method can also be considered as an efficient 3D printing process. Then, the influences of crosslinking density, sample geometry, formulation, and fiber architecture on the deformation of the printed objects are investigated. Finally, as a proof of concept, various samples, including a hand, snowflake, and leaf, are printed to verify the feasibility of the proposed 4D printing strategy. This programmed 4D printing method provides a simple and effective reversible strategy, taking the full advantages of 4D printing and expanding the design space of 4D printing.

3D‐Printed Micro/Nano‐Scaled Mechanical Metamaterials: Fundamentals, Technologies, Progress, Applications, and Challenges

“…b) Chiral (Reproduced with permission. [ 125 ] Copyright 2022, Wiley‐VCH), and c) gradient/digital patterned. Reproduced with permission.…”

Design-encoded dual shape-morphing and shape-memory in 4D printed polymer parts toward cellularized vascular grafts

“…Shape morphing from a pre-programmed shape to a final stable shape is generally less explored in the field of additive manufacturing. The few reported examples are essentially limited to multi-component hydrogels involving gradient crosslinking 13 or anisotropic design leading to differential swelling rates. 14 However, thermoplastic polymers, including SMPs, have been minimally explored for programming multiple shape deformation.…”

Fiber-dominated Soft Actuators Inspired by Plant Cell Walls and Skeletal Muscles

“…Lacking muscles [11], plants use a variety of energy sources and release mechanisms to produce deformation and movements (pine cones [12][13][14][15], awned seeds of family Geraniaceae [7,16] and pea pods [17,18]). Most of plant pericarp cell walls are composed of reinforcing fibers (non-stretchable cellulose fibers [19][20][21]) embedded in matrix materials [5] (water-swelling matrixes containing hemicelluloses and lignin hemicelluloses and lignin) that are known as natural fiber-reinforced composites [22][23][24]. As a result, the architectures of stiff cellulose fibrils embedded in a swelling hygroscopic matrix limit the isotropic expansion/contraction of the matrix material under humidity stimulation.…”