Hu Tingting, Tian Nan, Ali Sarmad, Wang Zhen, Chang Jiarui, Huang Ningdong, Li Liangbin
National Synchrotron Radiation Lab and College of Nuclear Science and Technology, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China , Hefei, China.
Langmuir. 2016 Mar 1;32(8):2117-26. doi: 10.1021/acs.langmuir.6b00050. Epub 2016 Feb 15.
The crystallization of poly(ethylene oxide) (PEO)-sodium iodine (NaI) composites is investigated by differential scanning calorimetry (DSC), extensional rheology, and in situ small-angle X-ray scattering (SAXS) with the aim of demonstrating versatile roles played by polymer-ion interactions. In the isothermal quiescent crystallization process, a decrease in the crystal growth rate is observed for PEO-NaI and is attributed to slow chain movement caused by the coordination between cations and polymer. In situ SAXS on extensional flow-induced crystallization (FIC) exhibits enhanced kinetics and orientation for both PEO and PEO-NaI with increasing strain rate. However, an overall weaker strain-rate dependence of FIC is observed for PEO-NaI, which can be interpreted as a synergistic consequence of promoted nucleation under flow and impeded crystal growth by polymer-ion interaction. A possible microscopic mechanism is proposed to account for the experimental observation based on the formation of transient cross-linking points in PEO-NaI and their influence on the entanglement network of polymer under various flow fields. The disclosed strain-rate dependence and various ion effects on the behavior of PEO-salt composites contribute to a comprehensive understanding of polymer-ion solid polyelectrolytes.
通过差示扫描量热法（DSC）、拉伸流变学和原位小角X射线散射（SAXS）研究了聚环氧乙烷（PEO）-碘化钠（NaI）复合材料的结晶过程，目的是证明聚合物-离子相互作用所起的多种作用。在等温静态结晶过程中，观察到PEO-NaI的晶体生长速率降低，这归因于阳离子与聚合物之间的配位导致链运动缓慢。对拉伸流动诱导结晶（FIC）进行的原位SAXS显示，随着应变速率的增加，PEO和PEO-NaI的结晶动力学和取向均增强。然而，观察到PEO-NaI的FIC对应变速率的总体依赖性较弱，这可以解释为流动下促进成核和聚合物-离子相互作用阻碍晶体生长的协同结果。基于PEO-NaI中瞬态交联点的形成及其在各种流场下对聚合物缠结网络的影响，提出了一种可能的微观机制来解释实验观察结果。所揭示的应变速率依赖性和各种离子对PEO-盐复合材料行为的影响有助于全面理解聚合物-离子固体聚电解质。
