Chemical reactions between carbon dioxide (CO${\hspace{0.17em}}_2$) and amine have been extensively characterized, however, their influence on the dynamics of polyamines remains largely unexplored. In this work, we compare the dynamics of polyethylenimine (PEI) before and after CO${\hspace{0.17em}}_2$ absorption through broadband dielectric spectroscopy (BDS). The molecular processes of bulk PEI are very different from those of thin film PEI, highlighting an interesting interface and nano-confinement effect. Detailed analyses show CO${\hspace{0.17em}}_2$ absorption slows down the PEI dynamics, which is consistent with an elevated glass transition temperature of PEI upon CO${\hspace{0.17em}}_2$ absorption from differential scanning calorimetry measurements. Further in situ kinetic measurements demonstrate nonmonotonic changes in relaxation times or dielectric amplitudes of some relaxation processes during CO${\hspace{0.17em}}_2$ sorption or desorption, suggesting an intriguing interplay between CO${\hspace{0.17em}}_2$ chemisorption and the dynamics of PEI. These results demonstrate that BDS is a powerful platform to resolve the temporal dynamics changes of polyamines for CO${\hspace{0.17em}}_2$ capture.

中文翻译：

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通过宽带介电谱原位监测聚乙烯亚胺动力学上的 CO 2 吸附


二氧化碳 （CO） 和胺之间的化学反应已经被广泛表征，但是，它们对多胺动力学的影响在很大程度上仍未得到探索。在这项工作中，我们通过宽带介电谱 （BDS） 比较了聚乙烯亚胺 （PEI） 吸收前后的动力学。块体 PEI 的分子过程与薄膜 PEI 的分子过程非常不同，突出了有趣的界面和纳米限制效应。详细分析表明，一氧化碳吸收会减慢 PEI 动力学，这与差示扫描量热法吸收一氧化碳后 PEI 的玻璃化转变温度升高一致。进一步的原位动力学测量表明，在 CO 吸附或解吸过程中，弛豫时间或某些弛豫过程的介电幅度的非单调变化，表明 CO 化学吸附与 PEI 动力学之间存在有趣的相互作用。这些结果表明，BDS 是解析多胺捕获 CO 的时间动力学变化的强大平台。