Mechanical response of transient telechelic networks with many-part stickers.
Mechanical response of transient telechelic networks with many-part stickers.
复制标题
具有多部分贴纸的瞬态遥爪网络的机械响应。
DOI：
10.1063/1.4993649
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
B. Olsen
中科院分区：
文献类型：
--
作者：
M. K. Sing;Jorge Ramírez;B. Olsen
软物质的一个核心问题是理解几个单独的弱键如何共同作用以产生集体相互作用。在这里，通过布朗动力学模拟研究了在每个链端具有多个贴纸的凝胶形成的远螺旋聚合物，以了解键的集体相互作用如何影响凝胶的机械响应。这些聚合物被建模为有限可扩展的哑铃，使用显式的tau-leap算法，这些协会的结合能保持不变，而不管贴纸的数量。在远旋聚合物的缔合端添加多个键会增加或减少网络松弛时间，这取决于缔合的相对动力学，但同时会增加剪切应力和拉伸粘度。结合速率与悬垂链的劳斯时间之间的关系导致了两种不同的结合物理网络的平衡应力松弛机制。在情形1中，解离的悬垂链在重新结合到网络之前能够完全弛豫，导致两个特征弛豫时间和一个随每个聚合物端基键数增加的非单调末端弛豫时间。在情形II中，解离的悬垂链在重新附着到网络上之前只能放松一小部分，增加每个端基的键数单调地增加终端弛豫时间。在流动中，即使整体键动力学和平衡常数保持不变，增加黏贴的数量也会增加稳态剪切和拉伸粘度。模拟中耗散的增加主要是由于随着键数的增加，平均链长的增加。这些结果表明，物理关联网络中的韧性和耗散都可以通过将单个强键分解成更小的组分来增加。
A central question in soft matter is understanding how several individual, weak bonds act together to produce collective interactions. Here, gel-forming telechelic polymers with multiple stickers at each chain end are studied through Brownian dynamics simulations to understand how collective interaction of the bonds affects mechanical response of the gels. These polymers are modeled as finitely extensible dumbbells using an explicit tau-leap algorithm and the binding energy of these associations was kept constant regardless of the number of stickers. The addition of multiple bonds to the associating ends of telechelic polymers increases or decreases the network relaxation time depending on the relative kinetics of association but increases both shear stress and extensional viscosity. The relationship between the rate of association and the Rouse time of dangling chains results in two different regimes for the equilibrium stress relaxation of associating physical networks. In case I, a dissociated dangling chain is able to fully relax before re-associating to the network, resulting in two characteristic relaxation times and a non-monotonic terminal relaxation time with increasing number of bonds per polymer endgroup. In case II, the dissociated dangling chain is only able to relax a fraction of the way before it re-attaches to the network, and increasing the number of bonds per endgroup monotonically increases the terminal relaxation time. In flow, increasing the number of stickers increases the steady-state shear and extensional viscosities even though the overall bond kinetics and equilibrium constant remain unchanged. Increased dissipation in the simulations is primarily due to higher average chain extension with increasing bond number. These results indicate that toughness and dissipation in physically associating networks can both be increased by breaking single, strong bonds into smaller components.
影响因子：
5.5
作者：
Stukalin, Evgeny B.;Cai, Li-Heng;Kumar, N. Arun;Leibler, Ludwik;Rubinstein, Michael
通讯作者：
Rubinstein, Michael
影响因子：
3.4
作者：
Zhao X
通讯作者：
Zhao X
影响因子：
5.5
作者：
Olsen BD;Kornfield JA;Tirrell DA
通讯作者：
Tirrell DA