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Brittle-ductile transition of double network hydrogels : Mechanical balance of two networks as the key factor
| Title: | Brittle-ductile transition of double network hydrogels : Mechanical balance of two networks as the key factor |
| Authors: | Ahmed, Saika Browse this author | | Nakajima, Tasuku Browse this author | | Kurokawa, Takayuki Browse this author →KAKEN DB | | Haque, Md Anamul Browse this author | | Gong, Jian Ping Browse this author →KAKEN DB |
| Keywords: | Double network hydrogels | | Brittle-ductile transition | | Fracture |
| Issue Date: | 12-Feb-2014 |
| Publisher: | Elsevier sci ltd |
| Journal Title: | Polymer |
| Volume: | 55 |
| Issue: | 3 |
| Start Page: | 914 |
| End Page: | 923 |
| Publisher DOI: | 10.1016/j.polymer.2013.12.066 |
| Abstract: | Tough double network (DN) hydrogels are a kind of interpenetrating network (IPN) gels with a contrasting structure; they consist of a rigid and brittle 1st network with dilute, densely cross-linked short chains and a soft and ductile 2nd network with concentrated, loosely cross-linked long chains. In this work, we focus on how the brittle gel changes into a tough one by increasing the amount of ductile component. By comparing the molecular structures of the individual first network and second network gels, we found that the true key mechanical factor that governs the brittle ductile transition is the fracture stress ratio of the two networks, sigma(f,2)/sigma(f,1). This ratio is related to the density ratio of elastically effective polymer strands of the two networks, nu(e,2)/nu(e,1), where the inter-network topological entanglement makes dominant contribution to nu(e,2). When nu(e,2)/nu(e,1) < k = 3.8-9.5, the second network fractures right after the fracture of the first network, and the gels are brittle. When nu(e,2)/nu(e,1) > k, only the first network fractures. As a result, the brittle first network serves as sacrificial bonds, imparting toughness of DN gels. The study also confirms that the load transfer between the two networks is via inter-network topological entanglement. This result provides essential information to design tough materials based on the double network concept. (C) 2014 Elsevier Ltd. All rights reserved. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/55147 |
| 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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