In recent years, ion transport in the nano-confinement structure has not only important theoretical research significance, but also has potential application value in the fields of molecular regulation, energy conversion, filtration and Salt removal, ion devices, and sensors. attention. The research on the unique ion transport behaviors of rectification, negative differential resistance, oscillation and hysteresis in asymmetric nanopores has become one of the hot spots in the research field of nano-ionology in recent years. Among them, the earliest found rectification phenomenon has been studied most widely. Changing the type of the transmitted ions can make the rectification decrease or reverse, but the current reversal of rectification is only observed in the multivalent ion system, the rectification and reversal phenomenon in the monovalent ion system has not been reported, and the rectification ratio size and the Hofmeister The relationship between sequences is rarely studied. Under the support of the National Natural Science Foundation of China, the Ministry of Science and Technology, and the Chinese Academy of Sciences, Yu Ping, a researcher in the laboratory of the Institute of Chemistry in the Chinese Academy of Sciences, has conducted research on polyelectrolyte brush functionalized micro-nanotube ion transport. The controllable modification of the polyimidazolium cationic brush on the inner surface of the glass micro-nanotubes was achieved by the surface-initiated atom transfer radical polymerization method. In this microtube, the rectification phenomenon was first observed, and it was proposed to be applicable to both micrometer and nanometer scales. Rectified model (J. Am. Chem. Soc., 2017, 139, 1396). Further, they used this phenomenon to successfully build an ATP sensor based on micro-rectifier to realize the ATP sensing analysis in rat brain dialysate (Anal. Chem., 2017, 89, 6794). Based on the above studies, they further studied the effect of different monovalent anions on the rectification of polyimidazolium functionalized micro-nanotubes. The results show that, unlike kosmotropes (such as Cl-), chaotropes (such as ClO4-) are driven by hydrophobic interactions and are more likely to adsorb on the surface of polyimidazole cations and adsorb at high salt concentrations, resulting in the apparent charge of polyimidazole cations. The reversal occurs so that the ion transport of the functionalized micro-nanotubes appears as a concentration-dependent rectification reversal (as shown). At the same time, they sequenced the rectification ratio of the monovalent anion in the Hofmeister sequence and found that the sequence is consistent with the Hofmeister sequence. This is the first time that the Hofmeister sequence was observed in the solid nanopore. This study provides a theoretical and experimental basis for the construction of nanopore-based ion devices and sensors through the regulation of pore wall surface chemistry. The results were published in Angew. Chem. Int. Ed., 2018, 57, 4590. Industrial Equipment & Components fastener, fittings YIBIN PERFEC INTERNATIONAL TRADE CO.,LTD , https://www.yibinbofei.com
Figure: Rectification behavior of functionalized nanotubes in different ionic solutions