Coupled bond dynamics alters relaxation in polymers with multiple intrinsic dissociation rates
Coupled bond dynamics alters relaxation in polymers with multiple intrinsic dissociation rates
复制标题
耦合键动力学改变具有多个固有解离速率的聚合物的弛豫
DOI：
10.1039/d3sm00014a
复制
发表时间：
2023
期刊：
影响因子：
3.4
通讯作者：
Vernerey, Franck J.
中科院分区：
文献类型：
--
作者：
Wagner, Robert J.;Vernerey, Franck J.
在连续网络中包含多种键类型的动态网络为工程师提供了另一个设计参数-相对键分数-通过它来调节机械能的存储和耗散。然而，控制涌现特性的机制很难从实验上推导出来。因此，我们在这里采用一个网络模型与规定的分数的动态和稳定的债券预测松弛特性的混合网络。我们发现，在应力松弛过程中，主要是动态网络可以表现出长期的模量通过构象抑制松弛稳定的债券，由于排斥与相邻链的相互作用。同时，主要稳定的网络表现出轻微的松弛，通过非仿射重构的动态债券。鉴于此，我们引入一个单一的拟合参数，ε，瞬态网络理论通过耦合规则的混合物，其特征的程度稳定的键松弛。以α为拟合参数，混合物应力响应的耦合规律不仅与网络模型一致，而且揭示了多键解离时间尺度凝胶的微观力学特征。
Dynamic networks containing multiple bond types within a continuous network grant engineers another design parameter – relative bond fraction – by which to tune storage and dissipation of mechanical energy. However, the mechanisms governing emergent properties are difficult to deduce experimentally. Therefore, we here employ a network model with prescribed fractions of dynamic and stable bonds to predict relaxation characteristics of hybrid networks. We find that during stress relaxation, predominantly dynamic networks can exhibit long-term moduli through conformationally inhibited relaxation of stable bonds due to exclusion interactions with neighboring chains. Meanwhile, predominantly stable networks exhibit minor relaxation through non-affine reconfiguration of dynamic bonds. Given this, we introduce a single fitting parameter, ξ, to Transient Network Theory via a coupled rule of mixture, that characterizes the extent of stable bond relaxation. Treating ξ as a fitting parameter, the coupled rule of mixture's predicted stress response not only agrees with the network model's, but also unveils likely micromechanical traits of gels hosting multiple bond dissociation timescales.