An effective DLP 3D printing strategy of high strength and toughness cellulose hydrogel towards strain sensing

Zhengqiang Guo; Chengdong Ma; Weigui Xie; Aimin Tang; Wangyu Liu

doi:10.1016/j.carbpol.2023.121006

An effective DLP 3D printing strategy of high strength and toughness cellulose hydrogel towards strain sensing

Carbohydr Polym. 2023 Sep 1:315:121006. doi: 10.1016/j.carbpol.2023.121006. Epub 2023 May 11.

Authors

Zhengqiang Guo¹, Chengdong Ma¹, Weigui Xie¹, Aimin Tang², Wangyu Liu³

Affiliations

¹ School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road, Tianhe District, 510641 Guangzhou City, PR China.
² State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Wushan Road, Tianhe District, 510641 Guangzhou City, PR China.
³ School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road, Tianhe District, 510641 Guangzhou City, PR China. Electronic address: mewyliu@scut.edu.cn.

PMID: 37230626
DOI: 10.1016/j.carbpol.2023.121006

Abstract

Photocurable 3D printing technology has outperformed extrusion-based 3D printing technology in material adaptability, resolution, and printing rate, yet is still limited by the insecure preparation and selection of photoinitiators and thus less reported. In this work, we developed a printable hydrogel that can effectively facilitate various solid or hollow structures and even lattice structures. The chemical and physical dual-crosslinking strategy combined with cellulose nanofibers (CNF) significantly improved the strength and toughness of photocurable 3D printed hydrogels. In this study, the tensile breaking strength, Young's modulus, and toughness of poly(acrylamide-co-acrylic acid)_D/cellulose nanofiber (PAM-co-PAA)_D/CNF hydrogels were 375 %, 203 % and 544 % higher than those of the traditional single chemical crosslinked (PAM-co-PAA)_S hydrogels, respectively. Notably, its outstanding compressive elasticity enabled it to recover under 90 % strain compression (about 4.12 MPa). Resultantly, the proposed hydrogel can be utilized as a flexible strain sensor to monitor the motions of human movements, such as the bending of fingers, wrists, and arms, and even the vibration of a speaking throat. The output of electrical signals can still be collected through strain even under the condition of energy shortage. In addition, photocurable 3D printing technology can provide customized services for hydrogel-based e-skin, such as hydrogel-based bracelets, fingerstall, and finger joint sleeves.

Keywords: 3D printing; Cellulose nanofibers; Conductive hydrogels; Flexible sensors; Self-powered.