Asymmetric Molecular Dynamics and Anisotropic Phase Separation in the Cocrystal of the Crystalline/Crystalline Polymer Blend
Asymmetric Molecular Dynamics and Anisotropic Phase Separation in the Cocrystal of the Crystalline/Crystalline Polymer Blend
复制标题
结晶/结晶聚合物共混物共晶中的不对称分子动力学和各向异性相分离
DOI：
10.1021/acsmacrolett.1c00745
复制
发表时间：
2022
影响因子：
7.015
通讯作者：
Miyoshi, Toshikazu
中科院分区：
文献类型：
--
作者：
Zheng, Ying;Kafle, Navin;Schwarz, Derek;Eagan, James M.;Hayano, Shigetaka;Nakama, Yuki;Pan, Pengju;Miyoshi, Toshikazu
半结晶聚合物可分为移动晶体和固定晶体，这取决于晶体区域的链迁移率。在这项工作中，我们用固态核磁共振（NMR）光谱研究了由固定和移动聚合物晶体组成的共晶的分子动力学和相结构。结果表明：(1)可移动组分开始与晶-晶转变相关的大振幅运动，而固定组分在共晶中保持其刚性；(2)不对称分子动力学导致共晶在熔化温度（Tm）以下的富移动域和富固定域的纳米分离。观察到的不对称分子动力学诱导的相分离与混相非晶聚合物共混物的相分离相似；然而，由于共晶内部的茎的平行排列以及晶体-非晶边界的链连通性，它被限制在二维空间。
Semicrystalline polymers are categorized as either mobile or fixed crystals, depending on chain mobility in the crystalline region. In this work, we investigate molecular dynamics and phase structure in the cocrystal consisting of fixed and mobile polymer crystals by solid-state (ss) nuclear magnetic resonance (NMR) spectroscopy. It is demonstrated that (i) the mobile component begins large amplitude motions associated with crystal–crystal transition, while fixed ones keep their rigidity in the cocrystal, and (ii) asymmetric molecular dynamics leads to nanosegregations into mobile- and fixed-rich domains in the cocrystal below the melting temperature (Tm). The observed phase separation induced by asymmetric molecular dynamics is similar to the phase separation of the miscible amorphous polymer blend; however, it is limited to two dimensions due to the parallel packing of the stems inside the cocrystal, as well as chain connectivity at the crystalline–amorphous boundary.