周末推荐Science:观察到了聚合物链增长过程

gaofenzi.org本周推荐两篇值得烧脑的文献,周末不想出去玩的童鞋可以研究下:

1、Scieng:研究人设计非常巧妙的烯烃复分解开环聚合反应”观察“到了聚合物链到底是如何增长的,与我们想象中的不一样,或者我们从来都没有认真想过这个问题,所以发science的不是我呀。

聚合物链增长机理

Abstract:In chain-growth polymerization, a chain grows continually to reach thousands of subunits. However, the real-time dynamics of chain growth remains unknown. Using magnetic tweezers, we visualized real-time polymer growth at the single-polymer level. Focusing on ring-opening metathesis polymerization, we found that the extension of a growing polymer under a pulling force does not increase continuously but exhibits wait-and-jump steps. These steps are attributable to the formation and unraveling of conformational entanglements from newly incorporated monomers, whose key features can be recapitulated with molecular dynamics simulations. The configurations of these entanglements appear to play a key role in determining the polymerization rates and the dispersion among individual polymers.

文献:Single polymer growth dynamics,Science,20 Oct 2017:Vol. 358, Issue 6361, pp. 352-355,DOI: 10.1126/science.aan6837

2、Polymer Physics :研究人员终于搞清楚了为什么有些刚开始性能超强的防弹纤维材料用着用着就不行呢。在发生一些事故后,美相关单位要求研究人员搞清楚这个问题,为此研究人员借助核反应堆的强正电子束设备找到了相关原因,发现此表征技术异常敏感,完成了x散射无法完成的任务,这项研究的结果将有利于设计、研发新型防弹衣,有利于类似高性能纤维材料的表征。

英文原文介绍:A New Way to Test Body Armor 参考文献:John A. Howarter et al. Nanostructural evidence of mechanical aging and performance loss in ballistic fibers, Journal of Polymer Science Part B: Polymer Physics (2017). DOI: 10.1002/polb.24417

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