当前位置: X-MOL 学术J. Am. Chem. Soc. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Understanding the Impacts of Support–Polymer Interactions on the Dynamics of Poly(ethyleneimine) Confined in Mesoporous SBA-15
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2022-06-21 , DOI: 10.1021/jacs.2c03028
Hyun June Moon 1 , Jan-Michael Carrillo 2 , Johannes Leisen 3 , Bobby G Sumpter 2 , Naresh C Osti 4 , Madhusudan Tyagi 5, 6 , Christopher W Jones 1, 3
Affiliation  

Supported amines are a promising class of CO2 sorbents offering large uptake capacities and fast uptake rates. Among supported amines, poly(ethyleneimine) (PEI) physically impregnated in the mesopores of SBA-15 silica is widely used. Within these composite materials, the chain dynamics and morphologies of PEI strongly influence the CO2 capture performance, yet little is known about chain and macromolecule mobility in confined pores. Here, we probe the impact of the support–PEI interactions on the dynamics and structures of PEI at the support interface and the corresponding impact on CO2 uptake performance, which yields critical structure–property relationships. The pore walls of the support are grafted with organosilanes with different chemical end groups to differentiate interaction modes (spanning from strong attraction to repulsion) between the pore surface and PEI. Combinations of techniques, such as quasi-elastic neutron scattering (QENS), 1H T1T2 relaxation correlation solid-state NMR, and molecular dynamics (MD) simulations, are used to comprehensively assess the physical properties of confined PEI. We hypothesized that PEI would have faster dynamics when subjected to less attractive or repulsive interactions. However, we discover that complex interfacial interactions resulted in complex structure–property relationships. Indeed, both the chain conformation of the surface-grafted chains and of the PEI around the surface influenced the chain mobility and CO2 uptake performance. By coupling knowledge of the dynamics and distributions of PEI with CO2 sorption performance and other characteristics, we determine that the macroscopic structures of the hybrid materials dictate the first rapid CO2 uptake, and the rate of CO2 sorption during the subsequent gradual uptake stage is determined by PEI chain motions that promote diffusive jumps of CO2 through PEI-packed domains.

中文翻译:

了解载体-聚合物相互作用对限制在介孔 SBA-15 中的聚(乙烯亚胺)动力学的影响

负载型胺类是一类很有前途的 CO 2吸附剂,具有大的吸收能力和快速的吸收速率。在负载型胺中,广泛使用物理浸渍在 SBA-15 二氧化硅中孔中的聚(乙烯亚胺)(PEI)。在这些复合材料中,PEI 的链动力学和形态对 CO 2捕获性能有很大影响,但对受限孔隙中的链和大分子迁移率知之甚少。在这里,我们探讨了支撑-PEI 相互作用对支撑界面处 PEI 动力学和结构的影响以及对 CO 2的相应影响。吸收性能,从而产生关键的结构-性能关系。载体的孔壁接枝有具有不同化学端基的有机硅烷,以区分孔表面和 PEI 之间的相互作用模式(从强吸引到排斥)。技术组合,例如准弹性中子散射 (QENS)、1 H T 1T 2弛豫相关固态 NMR 和分子动力学 (MD) 模拟用于全面评估受限 PEI 的物理性质。我们假设当受到吸引力或排斥力较小的相互作用时,PEI 会有更快的动力学。然而,我们发现复杂的界面相互作用导致了复杂的结构-性能关系。事实上,表面接枝链的链构象和表面周围的 PEI 都影响了链的流动性和 CO 2吸收性能。通过将 PEI 的动力学和分布知识与 CO 2吸附性能和其他特性相结合,我们确定混合材料的宏观结构决定了第一个快速 CO 2在随后的逐渐吸收阶段,CO 2的吸附速率由促进 CO 2通过 PEI 填充域扩散跳跃的 PEI 链运动决定。
更新日期:2022-06-21
down
wechat
bug