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Crack Blunting and Advancing Behaviors of Tough and Self-healing Polyampholyte Hydrogel
| Title: | Crack Blunting and Advancing Behaviors of Tough and Self-healing Polyampholyte Hydrogel |
| Authors: | Luo, Feng Browse this author | | Sun, Tao Lin Browse this author | | Nakajima, Tasuku Browse this author | | Kurokawa, Takayuki Browse this author | | Zhao, Yu Browse this author | | Ihsan, Abu Bin Browse this author | | Guo, Hong Lei Browse this author | | Li, Xu Feng Browse this author | | Gong, Jian Ping Browse this author →KAKEN DB |
| Keywords: | hydrogel | | soft material | | polyampholyte | | viscoelasticity | | crack blunting | | crack advancing | | modulus | | toughness |
| Issue Date: | 9-Sep-2014 |
| Publisher: | American Chemical Society |
| Journal Title: | Macromolecules |
| Volume: | 47 |
| Issue: | 17 |
| Start Page: | 6037 |
| End Page: | 6046 |
| Publisher DOI: | 10.1021/ma5009447 |
| Abstract: | Recently, we have reported that polyampholytes, synthesized from free radical copolymerization of anionic monomer and cationic monomer, form physical hydrogels of high toughness and self-healing. The random distribution of the opposite charges forms ionic bonds of a wide distribution of strength. The strong bonds serve as permanent cross-links, imparting elasticity, whereas the weak bonds serves as reversible sacrificial bonds by breaking and reforming to dissipate energy. In this work, we focus on the rupture behaviors of the polyampholyte physical hydrogel, P(NaSS-co-MPTC), copolymerized from sodium p-styrenesulfonate (NaSS) and 3-(methacryloylamino)propyltrimethylammonium chloride (MPTC). Tensile test and pure shear test were performed at various stretch rates in the viscoelastic responses region of the material. Tensile test showed yielding, strain softening, and strain hardening, revealing the dually cross-linked feature of the gel. Pure shear test showed crack blunting at the notched tip and a large yielding zone with butterfly shaped birefringence pattern ahead of the crack tip. After blunting, crack advanced at steady-state velocity with a constant angle. The conditions for the occurrence of crack blunting and variables governing the crack advancing angle are discussed. We found that even for these highly stretchable samples, significant blunting only occurs when the tensile fracture stress σf is larger than modulus E by a factor of about 2, in consistent with Hui’s theoretical prediction for elastic materials. The crack advancing angle θ was found to be proportional to σy/E over a wide stretch rate range, where σy is the yielding stress. In addition, the fracture energy was correlated to small strain modulus by a power law in the viscoelastic response region. This systematic study will merit revealing the fracture mechanism of tough viscoelastic materials including biological tissues and recently developed tough and highly stretchable hydrogels. |
| Rights: | This document is the Accepted Manuscript version of a Published Work that appeared in final form inMacromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher.To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/ma5009447. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/59740 |
| Appears in Collections: | 生命科学院・先端生命科学研究院 (Graduate School of Life Science / Faculty of Advanced Life Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 龔 剣萍 (Gong Jian Ping)
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