Organic solution-phase transmission electron microscopy of copolymer nanoassembly morphology and dynamics
Organic solution-phase transmission electron microscopy of copolymer nanoassembly morphology and dynamics
复制标题
DOI：
10.1016/j.xcrp.2022.100772
复制
发表时间：
2022-03-16
影响因子：
8.9
通讯作者：
Gianneschi, Nathan C.
中科院分区：
文献类型：
--
作者：
Korpanty, Joanna;Gnanasekaran, Karthikeyan;Gianneschi, Nathan C.
直接成像有机溶剂中聚合物组装体的动力学是一个突出的挑战。在这里，我们应用液胞透射电子显微镜(LCTEM)来研究有机溶剂中的聚合物纳米材料。LCTEM不同于其他的透射电子显微镜方法，因为它可以用来表征有机溶剂中纳米材料的形貌。为了证明这一点，我们研究了两种常见有机溶剂N，N-二甲基甲酰胺和甲醇的电子-溶剂相互作用，并将这些溶剂与水进行了比较。对于每种溶剂，我们开发了蒙特卡罗模拟和动力学辐解模型，分别提供了散射和化学洞察。在理论结果的指导下，我们对聚苯乙烯-b-聚(4-乙烯基吡啶)在每种溶剂中的组装进行了LCTEM和死后质谱学成像。然后，在LCTEM过程中，通过有机溶剂混合在聚苯乙烯-b-聚(4-乙烯基吡啶)中引发了从蠕虫到胶束的转变，使得通过低温透射电子显微镜时间序列无法进行的实验成为可能。我们的工作为通过LCTEM扩大对有机溶剂中的纳米材料的研究提供了一条途径，这是一个被忽视的研究领域，尽管此类材料在化学和材料科学中显然很普遍。
Direct imaging of the dynamics of polymeric assemblies in organic solvents is an outstanding challenge. Herein, we apply liquid cell transmission electron microscopy (LCTEM) to study polymeric nano materials in organic solvents. LCTEM is distinct from other TEM methods as it can be applied to characterize the morphology of nanomaterials in organic solvents. To enable this demonstration, we examined electron-solvent interactions for two common organic solvents, N,N-dimethylformamide and methanol, and compared these solvents to water. For each solvent, we developed Monte Carlo simulations and kinetic radiolysis models, providing scattering and chemical insight, respectively. Guided by theoretical results, we applied LCTEM and postmortem mass spectral imaging of poly(styrene)-b-poly(4-vinylpyridine) assemblies in each solvent. Then, a worm-to-micelle transformation in poly(styrene)-b-poly(4-vinylpyri-dine) was triggered via organic solvent mixing during LCTEM, enabling an experiment not possible through a cryogenic TEM time series. Our work provides a pathway for an expanded examination of nanomaterials in organic solvents via LCTEM, a neglected research area despite the obvious prevalence of such materials across chemistry and materials science.