Li Xingya, Zhang Huacheng, Yu Hao, Xia Jun, Zhu Yin-Bo, Wu Heng-An, Hou Jue, Lu Jun, Ou Ranwen, Easton Christopher D, Selomulya Cordelia, Hill Matthew R, Jiang Lei, Wang Huanting
Department of Chemical Engineering, Monash University, Clayton, Victoria, 3800, Australia.
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui, 230027, China.
Adv Mater. 2020 Jun;32(24):e2001777. doi: 10.1002/adma.202001777. Epub 2020 May 10.
The construction of biological proton channel analogues has attracted substantial interest owing to their wide potential in separation of ions, sensing, and energy conversion. Here, metal-organic framework (MOF)/polymer heterogeneous nanochannels are presented, in which water molecules are confined to disordered clusters in the nanometer-sized polymer regions and to ordered chains with unique molecular configurations in the 1D sub-1-nm porous MOF regions, to realize unidirectional, fast, and selective proton transport properties, analogous to natural proton channels. Given the nano-to-subnano confined water junctions, experimental proton conductivities in the polymer-to-MOF direction of the channels are much higher than those in the opposite direction, showing a high rectification up to 500 and one to two orders of magnitude enhancement compared to the conductivity of proton transport in bulk water. The channels also show a good proton selectivity over other cations. Theoretical simulations further reveal that the preferential and fast proton conduction in the nano-to-subnano channel direction is attributed to extremely low energy barriers for proton transport from disordered to ordered water clusters. This study opens a novel approach to regulate ion permeability and selectivity of artificial ion channels.
生物质子通道类似物的构建因其在离子分离、传感和能量转换等方面的广泛潜力而备受关注。在此，我们展示了金属有机框架（MOF）/聚合物异质纳米通道，其中水分子在纳米尺寸的聚合物区域内局限于无序簇中，而在一维亚1纳米多孔MOF区域内则局限于具有独特分子构型的有序链中，以实现类似于天然质子通道的单向、快速和选择性质子传输特性。鉴于纳米到亚纳米级的受限水连接，通道在聚合物到MOF方向上的实验质子电导率远高于相反方向，显示出高达500的高整流比，与体相水中质子传输的电导率相比提高了一到两个数量级。这些通道对其他阳离子也表现出良好的质子选择性。理论模拟进一步揭示，纳米到亚纳米通道方向上优先且快速的质子传导归因于质子从无序水簇传输到有序水簇的极低能量势垒。这项研究开辟了一种调节人工离子通道离子渗透性和选择性的新方法。
