Figure: Rectifying behavior of functional nanotubes in different ionic solutions In recent years, the ion transmission in the nano-domain structure has not only important theoretical research significance, but also has the latent application value in the molecular regulation, the energy conversion, the filtration desalination, the ion device, the sensor and so on, and receives the widespread attention. In recent years, the research of the special ion transmission behavior such as rectification, negative differential resistance, oscillation and hysteresis in asymmetric nano-pores has become one of the hot spots in the field of nano-ionic research, among which the earliest discovered rectifier phenomenon has been the most widely studied.
Changes in the type of transport ions can reduce or reverse the rectifier, but the current rectification reversal is only in the system of multiple valence ions are observed, the unit price ion system in the rectification reversal phenomenon has not been reported, and the rectifier ratio of the size of the Hofmeister sequence and the relationship is rarely studied. With the support of the National Natural Science Foundation, the Science and Technology department and the Chinese Academy of Sciences, Uping, a researcher in living analytical Chemistry Laboratory of the Institute of Chemical Sciences, studied the ion transmission of polyelectrolyte brush functional micro-nanotubes. By means of surface-induced atom transfer radical polymerization, the controllable modification of the poly-imidazole cationic brush on the glass micro-nanotube surface was realized, and the rectifying phenomenon was first observed in the Micron tube, and a model for both micron and nanometer scale rectification was proposed. Chem. Soc., 2017, 139, 1396. Further, using this phenomenon, they successfully constructed the ATP sensor based on Micron Rectifier to realize ATP sensing analysis in rat brain dialysis fluid (anal.
Chem., 2017, 89, 6794). On the basis of the above research, they further studied the influence of different unit price anions on the micro-nano-tube rectification of poly-imidazole cationic function. The results show that, unlike kosmotropes (such as cl-), chaotropes (such as clo4-) is driven by hydrophobic action, it is easier to adsorb on the surface of poly-imidazole cation, and adsorption occurs at high salt concentration, so that the apparent charge of poly-imidazole cation can be reversed, The ion transmission of the functional micro-nanotubes is characterized by a concentration-dependent rectification reversal (shown in the figure). At the same time, they sorted the corresponding rectifier ratio in the hofmeister sequence, and found that the sequence was consistent with the Hofmeister sequence, which was also the first observed hofmeister sequence in the solid nano-pores. The research provides theoretical and experimental basis for the construction of ionic devices and sensors based on the pore wall surface chemistry. Related results were published in Angew.
Chem. Int. Ed., 2018, 57, 4590. Progress in the study of the functional nano-tube ion transmission of polyelectrolyte Brush
