Study On The Design And Fabrication Of Pillar[6] Arene Channel And Its Transmembrane Transport Performance

Transmembrane transport behavior in the organism is realized through protein channels embedded in the cell membrane.This kind of protein channel has a complex structure and rich functions.It can realize the highly selective recognition and transport of ions or molecules,in which the sub-nanometer level channel structure plays an important role.To respect and learn from nature has always been the best way for human beings to get along with nature.This harmonious coexistence mode also brings us inspiration.Imitating nature has become the best way for human beings to make scientific and technological progress.The construction of sub-nanoscale channels based on biomimicry strategy to achieve highly selective transmembrane transport of substances is not only beneficial to further deepen the understanding of life activities,but also can provide technical support for the realization of the practical needs of substance separation and purification.Based on this,how to construct highly selective nanoscale channels is a key problem to be solved in this paper.In this paper,we propose to construct plillararene sub-nanometer channels based on single channel sub-nanometer molecules with unique rigid sub-nanometer cavity,aiming to improve the selectivity of the channels to achieve selective transmembrane transport of isomers.The main research contents of this paper are as follows:1.The aldehyde pillar[5]arene and aldehyde pillar[6]arene were designed and synthesized,the chiral amino acids were modified to the upper and lower side chains of the pillararene to obtain the chiral amino acids,which also improves the biocompatibility of the molecule while acquiring chirality.All the target compounds were characterized by hydrogen spectrum,carbon spectrum and mass spectrum,and the conditions of the derivation reaction were optimized.which provided a molecular basis for the future work.2.A highly crosslinked pillar[6]arene channel was constructed by interfacial polymerization,and the successful construction of pillar[6]arene channel was demonstrated in terms of morphology,composition of functional groups and elements,and hydrophilic and hydrophobic properties of the surface.Pillar[6]arene channel has a certain selectivity of p-xylene in xylene isomers,and has the potential to selectively separatep-xylene from xylene isomers.According to the size matching principle,p-xylene is the only isomer that can pass through the molecular pore of pillar[6]arene,so p-xylene has more paths through the membrane.This is also the fundamental reason for the selective permeation of the pillar[6]arene channel.3.The layer-by-layer assembly strategy was adopted to construct the pillar[6]arene channel.The results of the membrane morphology,elemental composition,hydrophilic and hydrophobic properties,and ionic conductivity fully indicate that the pillar[6]arene channel has been successfully constructed.The selective response,transport and separation properties of pillar[6]arene channel to p-xylene were investigated,and it was proved that the pillar[6]arene channel has the ability of selective response,transport and separation of p-xylene from xylene isomers.The binding ability between the unit of pillar[6]arene channel and xylene isomer was calculated by Gaussian simulation,and it was proved that p-xylene was the easiest to enter the pillar[6]arene channel.The selective transport mechanism is explained reasonably from two aspects of size matching and molecular simulation.4.L-N-acetylcysteine pillar[6]arene as chiral molecular unit,the chiral pillar[6]arene channel was constructed by the method of layer-by-layer assembly.The morphology,elemental composition,chiral properties and hydrophilic and hydrophobic properties of the chiral pillar[6]arene channel were investigated comprehensively,which proved that the chiral pillar[6]arene channel was successfully constructed.D/L-alanine was used as the template molecule to demonstrate the selective response and transport properties of chiral pillar[6]arene channel.Analyzing the process of molecular transport from the changes of entropy,it is proposed that the process of entropy reduction,which determines the rate of material transport to a great extent.The selectivity mechanism of chiral pillar[6]arene channel was explained by comparing the energy barriers of chiral amino acids entering molecular pore channels.5.The chiral amplification mechanism of chiral pillar[6]arene channel was explored from three aspects.Firstly,it was proved from the assembly mode of pillar[6]arene that only the layer-by-layer assembly method of positive and negative charges could construct the molecular channels with good ion conductivity.The chiral selective response and transport experiments indicated that the layer-by-layer assembly method of pillar[6]arene was a necessary condition for the transport of amino acids.Then,the effect of different chiral layers on chiral selectivity was investigated.The results showed that the more chiral layers,the better chiral selectivity.Finally,the influence of voltage,pH and concentration of feed on amino acid transport was investigated from the perspective of driving force,and it was proved that increasing the voltage,concentration of feed and alkaline environment were beneficial to the rapid transfer of amino acids.As described in above,the chiral amplification properties of chiral pillar[6]arene channel firstly require the molecular channels of pillar[6]arene assembled layer by layer according to the positive and negative charge resistance,in which the chiral sites play a role of chiral differentiation,finally,the electric potential energy and osmotic energy drive molecules through the chiral pillar[6]arene channel.