Unexpected entanglement dynamics in semidilute blends of supercoiled and ring DNA
Unexpected entanglement dynamics in semidilute blends of supercoiled and ring DNA
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DOI：
10.1039/c9sm01767d
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发表时间：
2020-01-07
期刊：
影响因子：
3.4
通讯作者：
Robertson-Anderson, Rae M.
中科院分区：
文献类型：
--
作者：
Peddireddy, Karthik R.;Lee, Megan;Robertson-Anderson, Rae M.
不同拓扑结构的聚合物（例如环状聚合物和超螺旋聚合物）的混合物自然存在于生物学中，并且通常表现出工业中令人垂涎的粘弹性特性。然而，由于其复杂性以及生产不同拓扑聚合物的难度，拓扑聚合物共混物的动力学仍然知之甚少。我们通过使用被动和主动微流变学来表征松弛圆形和超螺旋 DNA 混合物的线性和非线性流变特性，从而解决了这一空白。当我们将浓度从低于重叠浓度 c* 改变到高于重叠浓度 c* 时（0.5c* 到 2c*），我们描述了动态特性。令人惊讶的是，尽管研究的是稀-半稀交叉，但仍出现了纠缠动力学，例如弹性平台和多种弛豫模式。最后，即使在良好缠结的线性聚合物溶液中，共混物也表现出对非线性应变的意想不到的持续弹性响应，这是以前从未观察到的。
Blends of polymers of different topologies, such as ring and supercoiled, naturally occur in biology and often exhibit emergent viscoelastic properties coveted in industry. However, due to their complexity, along with the difficulty of producing polymers of different topologies, the dynamics of topological polymer blends remains poorly understood. We address this void by using both passive and active microrheology to characterize the linear and nonlinear rheological properties of blends of relaxed circular and supercoiled DNA. We characterize the dynamics as we vary the concentration from below the overlap concentration c* to above (0.5c* to 2c*). Surprisingly, despite working at the dilute-semidilute crossover, entanglement dynamics, such as elastic plateaus and multiple relaxation modes, emerge. Finally, blends exhibit an unexpected sustained elastic response to nonlinear strains not previously observed even in well-entangled linear polymer solutions.