Department of Chemistry, School of Science/Key Laboratory of Cosmetic, China National Light Industry , Beijing Technology and Business University , Beijing 100048 , PR China.
Langmuir. 2018 Sep 18;34(37):10889-10896. doi: 10.1021/acs.langmuir.8b02387. Epub 2018 Sep 10.
Elastic materials are candidates for process intensification of gas storage by forming gas hydrate. In this work, molecular dynamics simulations of hydrate nucleation in elastic silica double layers were performed to study the effect of elastic confined spaces on hydrate formation. It is found that in narrow confined spaces, hexagonal rings dominated the hydrogen bond network of water molecules established rapidly by a multisite nucleation mechanism. With molecules added, a bilayer water structure was formed finally because elastic space can adapt the volume expansion. In medium and wide confined spaces, hydrates were formed from a series of "pseudo cages" which are considered as precursors of complete hydrate cages. Moreover, the induction time for nucleation was a minimum when the elasticity of the silica layer changes: nucleation is fastest in the weak-elastic system. When the elasticity increases, it becomes hard to adapt the volume expansion during nucleation and also difficult to nucleate in very weak-elastic systems because of the fluctuation of the layers.
弹性材料是通过形成水合物来实现气体储存过程强化的候选材料。在这项工作中，通过分子动力学模拟研究了弹性二氧化硅双层中气体水合物成核的过程，以研究弹性受限空间对水合物形成的影响。结果发现，在狭窄的受限空间中，六元环主导了由多位置成核机制快速建立的水分子氢键网络。随着分子的加入，最终形成了双层水结构，因为弹性空间可以适应体积膨胀。在中等和宽的受限空间中，水合物是由一系列“拟笼”形成的，这些拟笼被认为是完整水合物笼的前体。此外，当二氧化硅层的弹性发生变化时，成核的诱导时间最短：在弱弹性体系中，成核速度最快。当弹性增加时，在成核过程中适应体积膨胀变得困难，而且在非常弱的弹性体系中也难以成核，因为层的波动。
