Unraveling bio-inspired pre-swollen effects of tetra-polyethylene glycol double network hydrogels with ultra-stretchable yielding strain

Wang, Xiaodong, Lu, Haibao, Wu, Nan, Hui, David and Fu, Yong Qing (2019) Unraveling bio-inspired pre-swollen effects of tetra-polyethylene glycol double network hydrogels with ultra-stretchable yielding strain. Smart Materials and Structures, 28 (3). 035005. ISSN 0964-1726

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Official URL: https://doi.org/10.1088/1361-665X/aaf5b6

Abstract

Incorporating flexible cross-links into a brittle network for hydrogel not only significantly improves its toughness, but also effectively provides opportunities to design novel double network (DN) hydrogels with targeted properties and multi-functionalities. However, the principles and toughening mechanisms behind many of experimental studies have not been investigated. In this paper we proposed, for the first time, a phenomenological model for the DN hydrogels, which were derived from homogenous tetra-polyethylene glycol (tetra-PEG) first network, molecular stent and flexible polyacrylamide (PAAm) second network, and theoretically and then experimentally studied the pre-swollen effects on their ultra-stretchable yielding strains. Based on the Flory-Huggins solution theory, the pre-swollen effect of polar molecular stents on the mechanical properties of tetra-PEG/PAAm DN hydrogels was investigated. Finally, the constitutive stress-strain relationships of two-stage loading process were established for the overall response of mechanical behavior, and a good agreement between the numerically simulated results with the experimental ones has been achieved. This study provides a fundamental understanding of the working mechanism of pre-swollen effects and the design guidance for the ultra-stretchable and toughened DN hydrogels.

Item Type: Article
Uncontrolled Keywords: double-network hydrogel, modeling, pre-swollen effect, yielding
Subjects: F200 Materials Science
J400 Polymers and Textiles
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Becky Skoyles
Date Deposited: 03 Dec 2018 09:40
Last Modified: 27 Feb 2019 16:30
URI: http://nrl.northumbria.ac.uk/id/eprint/37013

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