Effect of Salt on Dynamic Mechanical Behaviors of Polyampholyte Hydrogels
Effect of Salt on Dynamic Mechanical Behaviors of Polyampholyte Hydrogels
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DOI：
10.1021/acs.macromol.2c02003
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发表时间：
2022-12-16
期刊：
影响因子：
5.5
通讯作者：
Gong, Jian Ping
中科院分区：
文献类型：
--
作者：
Li, Xueyu;Luo, Feng;Gong, Jian Ping
了解具有离子动态键的韧性水凝胶在盐水溶液中的动态力学行为对其应用，特别是在生物医学领域具有重要意义。在这项工作中，使用由共价交联剂和/或捕获缠结形成的初级网络和由离子键形成的动态网络双重交联的两性凝胶水凝胶作为模型体系，我们研究了盐对流变响应和力学行为的影响。通过对一种不含化学交联剂的凝胶和一种含有化学交联剂的凝胶的系统研究，我们证明了盐对力学性能的影响，包括小应变模数、大变形能量耗散和断裂伸长率，可以有效地转化为频率或应变率的依赖关系，遵循时间-盐叠加原理。因此，我们在室温下获得了从10-11到102rad/S的广泛的观测时间尺度，包括三个区域：(I)来自动力和初级网络的高频高原区域，(Ii)来自离子缔合的粘性罗兹运动的粘弹性区域，以及(Iii)来自初级网络的低频平台区域。此外，我们还揭示了在长时间尺度下的纠缠行为的深入理解。这项工作不仅为水凝胶在盐度环境中的生物应用提供了指导，也为在其他具有双交联结构的体系中通过动态键增韧机制提供了重要的见解。
Understanding the dynamic mechanical behaviors of tough hydrogels with ionic dynamic bonds in saline solution is crucial for applications, particularly in the biomedical field. In this work, using polyampholyte hydrogels, dually crosslinked with a primary network from covalent crosslinkers and/or trapped entanglements, and a dynamic network from ionic bonds, as a model system, we investigate the salt effect on rheological response and mechanical behaviors. Through a systematic study on one gel without a chemical crosslinker and one gel with a chemical crosslinker, we demonstrate that the salt effect on mechanical properties, including small-strain moduli, large deformation energy dissipation, and fracture stretch ratio, can be effectively converted into frequency or strain rate dependences following the time-salt superposition principle. Accordingly, we access a wide range of observation time scales from 10-11 to 102 rad/s at room temperature, covering three regimes: (I) the high-frequency plateau regime from the dynamic and primary networks, (II) the viscoelastic regime from sticky Rouse motion of ionic associations, and (III) the low-frequency plateau regime from the primary network. Moreover, we disclose an in-depth understanding of the entanglement's behavior in the long-timescale regime III. This work not only provides a guide to biological applications of hydrogels in saline environments but also gives important insights into the toughening mechanism via dynamic bonds in other systems with dually crosslinked structures.