4D printing of highly printable and shape morphing hydrogels composed of alginate and methylcellulose

• Published in: Materials & design Vol. 205; p. 109699
• Main Authors: Lai, Jiahui, Ye, Xinliang, Liu, Jia, Wang, Chong, Li, Junzhi, Wang, Xiang, Ma, Mingze, Wang, Min
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2021; Elsevier
• Subjects: 4D printing; Alginate and methylcellulose; Excellent printability; Shape morphing hydrogel; Excellent printability; 4D printing; Alginate and methylcellulose; Shape morphing hydrogel
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2021.109699

[Display omitted] •A versatile strategy to develop shape morphing hydrogel with swelling anisotropy.•The use of single ink to create heterogeneous structures without using chemical reactions.•Excellent printability of the shape morphing hydrogel.•Ability to print out a series of simple and complex dynamic structures with high accuracy.•Relatively fast shape morphing process within just a few minutes. 4D printing of swellable/shrinkable hydrogels has been viewed as an appealing approach for fabricating dynamic structures for various biomedical applications. However, 4D printing of precise hydrogel structures is still highly challenging due to the relatively poor printability of hydrogels and high surface roughness of printed patterns, when micro extrusion-based 3D printers are used. In this study, a highly printable and shape morphing hydrogel was investigated for 4D printing by blending alginate (Alg) and methylcellulose (MC). The optimized Alg/MC hydrogel exhibited excellent rheological properties, extrudability and shape fidelity of printed structures. The printable Alg/MC hydrogel was 4D printed into a series of patterned 2D architectures which were encoded with anisotropic stiffness and swelling behaviors by strategically controlling the network density gradients vertical to the orientation of the patterned strips. By controlling the strip interspacing and angle, these 2D architectures could transform into various prescribed simple 3D morphologies (e.g., tube-curling and helix) and complex 3D morphologies (e.g., double helix and flowers) after immersion in a calcium chloride solution. This shape morphing Alg/MC hydrogel with excellent printability has high potential for 4D printing of delicate hydrogel patterns, which are increasingly needed in the tissue engineering, biomedical device and soft robotics fields.