自愈水凝胶
聚电解质
流变学
化学工程
扩散
放松(心理学)
应力松弛
化学
活化能
高分子化学
材料科学
离子键合
聚合物
离子
复合材料
热力学
有机化学
蠕动
工程类
物理
社会心理学
心理学
作者
Yong Liu,Jian Hu,Zhenhua Xiao,Xiaolin Jin,Chuanxia Jiang,Panchao Yin,Liqun Tang,Taolin Sun
标识
DOI:10.1016/j.carbpol.2022.119403
摘要
In this work, we investigated the dynamics of hydrogels from the polyelectrolyte complexation of sodium hyaluronate (HA) and chitosan under various temperature and salt concentration. Raising temperature and adding salt remarkably reduce the mechanical behavior of hydrogels. The stress relaxation of semi-flexible chain segments is accelerated at high temperature and salt concentration, which is controlled by thermally activated bond disassociation process. The flow activation energy determined from temperature-dependent dynamic light scattering decorrelation and rheological relaxation are in very good agreement. Our results suggest that the chain aggregations are physical crosslinked by surrounded semi-flexible chains, and their diffusion is highly hindered by the topological entanglements and ionic associations. The synergistic effect of aggregations diffusion and chain dynamics causes the slow macroscopic stress relaxation behavior of hydrogels before yield, independent of applied strain. Above yield, the amplitude of strain accelerates the stress relaxation, resulting in chain disentanglements and slipping.
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