Fenton Abigail M, Xie Renxuan, Aplan Melissa P, Lee Youngmin, Gill Michael G, Fair Ryan, Kempe Fabian, Sommer Michael, Snyder Chad R, Gomez Enrique D, Colby Ralph H
Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Department of Chemical Engineering, The New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, United States.
ACS Cent Sci. 2022 Feb 23;8(2):268-274. doi: 10.1021/acscentsci.1c01396. Epub 2022 Jan 18.
The relationship between Kuhn length , Kuhn monomer volume , and plateau modulus , initially proposed by Graessley and Edwards for flexible polymers, and extended by Everaers, has a large gap in experimental data between the flexible and stiff regimes. This gap prevents the prediction of mechanical properties from the chain structure for any polymer in this region. Given the chain architecture, including a semiflexible backbone and side chains, conjugated polymers are an ideal class of material to study this crossover region. Using small angle neutron scattering, oscillatory shear rheology, and the freely rotating chain model, we have shown that 12 polymers with aromatic backbones populate a large part of this gap. We also have shown that a few of these polymers exhibit nematic ordering, which lowers . When fully isotropic, these polymers follow a relationship between , , and , with a simple crossover proposed in terms of the number of Kuhn segments in an entanglement strand .
库恩长度、库恩单体体积和平原模量之间的关系最初由格雷斯利和爱德华兹针对柔性聚合物提出，并由埃弗尔斯进行了扩展，在柔性和刚性状态之间的实验数据存在很大差距。这种差距使得无法根据该区域内任何聚合物的链结构预测其机械性能。考虑到链结构，包括半柔性主链和侧链，共轭聚合物是研究这个交叉区域的理想材料类别。通过小角中子散射、振荡剪切流变学和自由旋转链模型，我们已经表明，12种具有芳香主链的聚合物占据了这个差距的很大一部分。我们还表明，其中一些聚合物表现出向列相有序，这降低了。当完全各向同性时，这些聚合物遵循、和之间的关系，并根据缠结链中库恩链段的数量提出了一个简单的交叉点。
