Title : Design and construction of subnano channel membranes by pillararenes and their selective adsorption properties for small organic molecules
Abstract:
Pillararenes have a rigid skeleton structure, sub-nano molecular cavities and easily derivatized side chains. It is often used to construct various functional materials to recognize ions and molecules selectively. By deriving positively and negatively charged groups on the pillar[5]arene side chains and self-assembling layer-by-layer of pillar[5]arenes based on electrostatic interaction, the sub-nanomolecular channels of pillar[5]arenes were successfully constructed to achieve selective adsorption of p-dinitrobenzene. Based on this strategy, we have synthesized the positive charge of amino-derived pillar[6]arenes and the negative charge of carboxyl-derived pillar[6]arenes. The pillar[6]arene sub-nanochannels were layer-by-layer self-assembled by electrostatic interaction. Pillar[6]arenes have an open cavity of 6.7 Å, which can selectively recognize small organic molecules. Next, 10% PMMA (polymethyl methacrylate) of chlorobenzene solution was spined on the surface of the retinal modified pillar[6]arene assemble channels. Then, the dried PMMA fixed surface was immersed into the 2% HF aqueous solution to obtain the self-supporting membrane. At the same time, a layer-upon-layer covalent assembly was formed through the reaction of amino pillar[6]arene with terephthalaldehyde using an aldehyde-amine Schiff-base reaction. Then, 20%wt of polyethersulfone was prepared with N,N-dimethylacetamide (DMAc) as a solvent and dropped on the silicon wafer surface assembled with amino pillar[6]arene. Finally, the spin coating method was used to prepare the PES membrane. The PES membrane was immersed in a 2% hydrofluoric acid solution for 2 h, and the P6-LBL-membrane was removed with tweezers. The cavity of amino pillar[6]arenal is used to realize the host-guest interaction. Therefore, the pillar[6]arene subnanomolecular channel membrane can realize the selective adsorption and separation of small organic molecules ATP and metomiazol. This study presents promising prospects for using pillar arene channel membranes in agricultural technology and environmental research and holds the potential for groundbreaking advancements in this field.
