open access

https://hdl.handle.net/2115/81827

Anisotropic Double-Network Hydrogels via Controlled Orientation of a Physical Sacrificial Network

英語

anisotropic mechanical properties

2020-06-12

American Chemical Society

ACS applied polymer materials

2(6)

2350-2358

We report a method to create anisotropic double-network (DN) hydrogels, through the controlled orientation of a physical sacrificial network. A cross-linked polyacrylamide hydrogel is synthesized from a solution containing a semirigid anionic polyelectrolyte. Subsequently, the gel is stretched to orient the semirigid polyelectrolyte, which does not relax in the stretched state because of the high contour length in comparison to the mesh size of the polyacrylamide network. The polyelectrolyte is then physically cross-linked with a multivalent cation, ZrCl2O, to fix the anisotropy. Anisotropy was visualized by observing birefringence and quantified by small-angle X-ray scattering. By comparing the scattering in the oriented direction versus perpendicular to the oriented direction, a structural anisotropy factor was calculated. Uniaxial tensile testing was performed on samples of varying prestretch, both parallel and perpendicular to the stretching direction. Young's modulus, fracture stress, fracture strain, and work of extension were characterized, and the resulting mechanical anisotropy was compared to the structural anisotropy factor. We find that the anisotropy of Young's modulus and fracture stress is directly controlled by the anisotropy of the sacrificial network, while fracture strain and work of extension show little influence from structural anisotropy. The results of this work demonstrate that prestretching of a physical sacrificial network is a controllable and simple method to create anisotropic DN hydrogels.

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS applied polymer materials, copyright ©2020 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see 10.1021/acsapm.0c00290

2637-6105