在聚合过程中单分子催化剂的超分辨率运动显示了广泛的分布
Shannon J Saluga1, David Josh Dibble1, Suzanne A Blum1
1Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
Journal of the American Chemical Society
|June 7, 2022
概括
单分子追踪揭示了环开放转化聚合过程中的多种催化剂运动. 通过传统方法无法观察到的这些明显的运动,为聚合物特性提供了新的见解.
科学领域:
- 聚合物化学 聚合物化学
- 催化剂是一种催化剂.
- 单个分子成像技术
背景情况:
- 环开放元解聚合 (ROMP) 是聚合物合成中的一个重要过程.
- 了解单个分子催化剂的行为对于控制聚合物特性至关重要.
- 传统的组合方法往往掩盖了单一催化剂的细微动态.
研究的目的:
- 在ROMP中,在单个周转事件期间和之后,对单个分子催化剂的运动进行成像.
- 为了研究具有高位置精度的催化剂的个性化扩散行为.
- 为了将单催化剂动态与宏观聚合物性质的微观起源相关联.
主要方法:
- 单分子超分辨率跟踪,位置精度为±32nm.
- 实时将光谱标记的单体单体纳入活性聚合物链末端.
- 区分活跃催化剂运动与非活跃物种.
主要成果:
- 催化剂表现出多样化,依赖时间的扩散行为,持续长达20秒.
- 确定了三种流动性群体:准静止 (23%),中间 (53%,65纳米步骤) 和大 (24%,145纳米步骤).
- 在单个聚合物之间观察到催化剂流动性群体的显著差异,表明各种微环境.
结论:
- 单催化剂显微镜揭示了独特的,不可预测的催化剂运动模式.
- 不同的催化剂运动表明有不同的局部微环境影响转化率和选择性.
- 这些微尺度动态为宏观的聚合物性质分布的起源提供了修订后的理解,例如分子重量多分散性.
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