1.D.196. The Metal-Organic Framwork NanoPore (MOF-NP) Family
The use of track-etched membranes allows fine-tuning of transport regimes and thus enables their use in (bio)sensing and energy harvesting applications, among others (Laucirica et al. 2022). MOFs have been combined with membranes to increase their potential. The creation of a single track-etched nanochannel modified with the UiO-66 MOF was achieved. By the interfacial growth method, UiO-66 confined synthesis filled the nanochannel, yet its constructional porosity rendered a heterostructure along the axial coordinate of the channel. The MOF heterostructure confers notorious changes in the transport regime of the nanofluidic device. In particular, the tortuosity provided by the micro- and mesostructure of UiO-66 added to its charged state led to iontronic outputs characterized by an asymmetric ion current saturation for transmembrane voltages exceeding 0.3 V. This behavior could be easily and reversibly modulated by changing the pH of the media, and it could also be maintained for a wide range of KCl concentrations. The modified-nanochannel functionality cannot be explained by considering just the intrinsic microporosity of UiO-66; rather, the constructional porosity that arises during the MOF growth process plays a central and dominant role (Laucirica et al. 2022).