Polymer / MOF composite membrane much! Proton can holding the \”nose\” beam transmission
Design and preparation of proton channel transmission efficiency for efficient material separation, biosensors,, is essential to further developments in the field of nano fluidic devices and the like. In recent years, scientists bionic inspired aquaporin structure, development of a series of similar structure with an efficient water / proton channel, the maximum transmission efficiency of a single channel of up to 3.4 × 10-12cm-3 / s [Science 357, 792- 796 (2017)], aquaporin further than an order of magnitude. However, these internal channels biomimetic structure is homogeneous, and can not be transmitted in one direction as water / proton as aquaporin. To solve this problem, recently, Wang Huanting Fellow Monash University, Australia, Zhang Professor Huacheng team joint Science and Technology University of China Professor Wu Hengan team developed a nano – sub-nanometer size gradient asymmetrical hourglass structure PET / MOF composite proton channel, shows unidirectional transmission characteristics and high proton selective transmission. Wherein, the most excellent overall performance PET / MIL-121 channel maximum rectification ratio close to 500, the proton conductivity of up to 240 mScm -1 . Molecular modeling of binding found in the study, high transmission efficiency PET / MOF interior of the composite channel from the ordered \”water chain\” structure inside the intermolecular hydrogen bond and the MOF confinement effect combine to form, and will lead to different MOF different \”water chain\” configuration; such as MIL 121-type formed inside a pentagon MOF \”water chain\” structure, a three-dimensional network structure formed by the passage of the carboxylic acid groups in the MOF can be made quickly and efficiently by protons. Meanwhile, proton transport from the nanoscale channels to sub-nanometer level PET MOF energy barrier during the passage is small, thus imparting unidirectional transmission characteristics of the composite channel. Further, the special physical and chemical properties of the internal passage also makes the sub-nanometer MOF PET / MOF channel composite having a high proton selectivity – the difference between the different concentrations of HCl solution, H + / Cl [123 ] – selectivity> 20, and selectively pure PET nanochannel only about 5.6. The study, entitled \”Unidirectional and Selective Proton Transportin Artificial Heterostructured Nanochannels with Nano-to-Subnano Confined Water Clusters \”of papers published in the\” Advanced Materials \”.
adopted the use of growth despread prepared PET / MOF composite asymmetric heterostructure proton channel, the process shown in Figure 1. first, using the ion track channels etching techniques for producing hourglass configuration on a PET film of 12 um, and then a hourglass side growth technique introduced by reverse diffusion MOF, to prepare asymmetric heterostructures proton channel. physicochemical properties of MOF to investigate the effect of the internal passage of the proton transfer, the introduction of three different MOF structures in the PET compared to the hourglass channel , respectively, MIL-121, MIL-53 and MIL-53-NH2.
mScm – 1 . OF DFT calculation by unidirectional transmission characteristics found PET / MOF composite channel are transmitted in different directions due to difference of energy barrier. Since the passage of water molecules MOF ordered structure, and a large number of transmission channels exist three hydrogen bonds, proton transport speed is much faster than PET channel, so that when the proton transport channels PET MOF channel direction, from large energy barrier small, unimpeded by the proton; and the transmission in the opposite direction, the energy barrier, accumulates protons from small to large in PET passage, thus affecting subsequent transport protons.