The structure of THF-water mixtures and clathrates in nanoscale confinement - 2

Understanding the properties of fluids confined to nanometer scale pores is essential to predict and control a wide range of natural and industrial processes. In this proposal we would like to study the structure of mixtures of tetrahydrofuran (C4H8O, THF) and water in mesoporous silicas with pores of the order 3 - 10nm diameter. A the composition we would like to study (1:3.3 THF:water) the liquids are miscible at ambient temperature, but the mixture sites under a critical point for closed-loop phase separation. By measureing the structure in confinement we will be able to determine whether the interfaces destabilise the phase diagram, to cause surface adsorption of THF. Our hypothesis based on our previous experiment at a lower concentration (RB2210033) is that we will see demixing - we are excited to confirm and quantify this effect. We note also that THF-water is a clathrate forming system, and parallel studies are unearthing fascinating confinement effects at lower temperatures.

理解限域于纳米级孔隙中的流体特性，对于预测与调控各类自然及工业过程均具有重要意义。在本研究提案中，我们拟探究孔径约3~10nm的介孔二氧化硅（mesoporous silicas）内，四氢呋喃（tetrahydrofuran, C₄H₈O, THF）与水的混合体系结构。在我们选定的配比（THF:水=1:3.3）下，该混合体系在室温下可完全互溶，但该混合物处于闭环相分离的临界点附近。通过表征限域环境下的体系结构，我们将能够明确界面是否会改变相图稳定性，进而引发四氢呋喃的表面吸附行为。基于此前在低浓度条件下开展的实验（编号RB2210033），我们提出如下假设：该体系将发生相分离——我们期待能够验证并量化这一效应。此外，我们注意到THF-水体系属于笼型形成体系（clathrate forming system），相关并行研究已在低温条件下发现了极具研究价值的限域效应。