Poly(ethylenimine) (PEI) is widely recognized as an efficient carbon capture medium. When loaded onto mesoporous oxide supports, the polymer becomes particularly attractive for direct air capture (DAC) applications given the high surface area of the composites, the low volatility of the polymer, and the excellent cyclability of the system. As polymer segmental mobility is coupled with CO₂ uptake and diffusion, understanding how that mobility is influenced by nanoconfinement will ultimately be critical to the development of more efficient DAC systems. Here, we discuss our development of a fluorescent probe molecule based on tetrakis(4-hydroxyphenyl)ethylene. As the fluorescence intensity of this molecule and the shape of the emission spectra are strongly dependent on the viscosity of the supporting medium, doping PEI-composites with this fluorescent probe can provide sensitive indication of polymer glass transition and/or melting temperatures across a wide range of temperatures (−100 to +100 °C). Herein, we demonstrate how this molecule can be used as a ratiometric probe to study bulk PEI dynamics and confinement effects in mesoporous silica as influenced by pore functionality, polymer fill fraction, and polymer architecture.

中文翻译：

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散装和纳米限制直接空气 CO2 捕获载体中氨基聚合物迁移率的荧光探针

聚（乙烯亚胺）（PEI）被广泛认为是一种有效的碳捕获介质。当负载到中孔氧化物载体上时，鉴于复合材料的高表面积、聚合物的低挥发性和系统的优异循环性，聚合物对于直接空气捕获 (DAC) 应用变得特别有吸引力。由于聚合物链段流动性与 CO _2耦合吸收和扩散，了解纳米限制如何影响移动性最终对于开发更有效的 DAC 系统至关重要。在这里，我们讨论了基于四（4-羟基苯基）乙烯的荧光探针分子的开发。由于该分子的荧光强度和发射光谱的形状在很大程度上取决于支持介质的粘度，因此用这种荧光探针掺杂 PEI 复合材料可以在很宽的范围内提供聚合物玻璃化转变和/或熔化温度的灵敏指示温度（-100 至 +100 °C）。在这里，我们展示了如何将该分子用作比率探针来研究受孔功能、聚合物填充率和聚合物结构影响的介孔二氧化硅中的体积 PEI 动力学和限制效应。