Abstract：
Solid-state nanochannels (SSNs) have emerged as promising platforms for controlling ionic transport at the nanoscale. SSNs are highly versatile, and this feature can be enhanced through their combination with porous materials such as Metal-Organic Frameworks (MOF). By selection of specific building blocks and experimental conditions, different MOF architectures can be obtained, and this can influence the ionic transport properties through the nanochannel. Herein, we study the effects of confined synthesis of Zr-based UiO-66 MOF on the ion transport properties of single bullet-shaped poly(ethylene terephthalate) (PET) nanochannels. We have found that emerging textural properties from the MOF phase play a determinant role in controlling ionic transport through the nanochannel. We demonstrate that a transition from ion current saturation regimes to diode-like regimes can be obtained by employing different synthetic approaches, namely, counterdiffusion synthesis, where MOF precursors are kept separate and forced to diffuse through the nanochannel, and one-pot synthesis, where both precursors are placed at both ends of the channel. Also, by considering the dependence of the charge state of the UiO-66 MOF on the protonation degree, pH changes offered a mechanism to tune the iontronic output (and selectivity) among different regimes, including anion-driven rectification, cation-driven rectification, ion current saturation, and ohmic behavior. Furthermore, Poisson-Nernst-Planck (PNP) simulations were employed to rationalize the different iontronic outputs observed experimentally for membranes modified by different methods. Our results demonstrate a straightforward tool to synthesize MOF-based SSN membranes with tunable ion transport regimes.
摘要：
固态纳米通道（SSN）已成为控制纳米级离子传输的有前途的平台。SSN是高度通用的，并且该特征可以通过它们与诸如金属有机框架(MOF)的多孔材料的组合来增强。通过选择特定的构建模块和实验条件，可以获得不同的MOF架构，这可以影响通过纳米通道的离子传输特性。在这里，我们研究了有限合成Zr基UiO-66MOF对单弹形聚（对苯二甲酸乙二醇酯）（PET）纳米通道离子传输性能的影响。我们已经发现,来自MOF相的出现的纹理性质在控制通过纳米通道的离子传输中起决定性作用。我们证明，可以通过采用不同的合成方法来获得从离子电流饱和状态到类似二极管状态的转变，即,反扩散合成，MOF前体保持分离并被迫通过纳米通道扩散，和一锅法合成，其中两个前体都放置在通道的两端。此外，通过考虑UiO-66MOF的电荷状态对质子化程度的依赖性，pH值的变化提供了一种机制来调整不同方案之间的离子输出（和选择性），包括阴离子驱动整流，阳离子驱动整流，离子电流饱和，和欧姆行为。此外，采用泊松-恩斯特-普朗克（PNP）模拟来合理化实验观察到的通过不同方法修饰的膜的不同离子输出。我们的结果证明了一种简单的工具来合成具有可调离子传输机制的基于MOF的SSN膜。
