Polymer dynamics in solid-state matrices studied by field-cycling NMR

该提案的目的是通过不同的核磁共振（NMR）方法来表征局部玻璃动力学以及嵌入在固态矩阵（不同尺寸的纳米限制）中的聚合物的集体动力学。特别着重于应用电子（快速）场循环（FFC） 1H NMR，它特别适合于探测聚合物的慢动力学。选定的固态1H和2H核磁共振将补充研究。FFC核磁共振研究表明，当某些聚合物被嵌入60 nm - 1000 nm的约束中时，其整体行为的集体动力学发生了显著变化，这一长度尺度远远大于熔体中聚合物的尺寸。到目前为止，这种所谓的紧身胸衣效应还没有被很好地理解，而且是一个有争议的现象，因为其他实验也对这些结果提出了质疑。因此，该建议致力于实验验证和促进对束身衣效应的理解。我们研究了不同孔隙系统中玻璃和聚合物动力学的相互作用，孔隙大小在5nm到1000nm之间。

The aim of the proposal is to characterise the local glassy dynamics as well as the collective dynamics of polymers embedded in solid-state matrices (nanoconfinement of different sizes) by means of different nuclear magnetic resonance (NMR) methods. Special focus is given on applying electronic (fast) field-cycling (FFC) 1H NMR which is particularly suited for probing the slow polymer dynamics. Selected solid-state 1H and 2H NMR will complement the studies. FFC NMR investigations have shown for certain polymers that the collective dynamics are significantly changed with respect to their bulk behaviour when they are embedded in a confinement ranging from 60 nm – 1000 nm, a length scale much larger than the size of a polymer in the melt. So far this so called corset effect is not well understood – and a disputed phenomenon, as other experiments have challenged these results. Thus, the proposal is devoted to experimentally validating and promoting the understanding of the corset effect. We study the interplay of glassy and polymer dynamics in different porous systems with pores sizes in the range of 5 nm up to 1000 nm.