Selective Unidirectional Transport of Protons in Sub-Nanoporous Membranes Inspired by the Influenza A M2 Channel for Nanofluidic Ionic Diodes

Abstract

Proton transport is involved in many biological processes, such as viral replication and enzymatic catalysis. However, one-way transmission is the premise of the realization of the above functions. Actually, the unidirectional transport of protons is significant not only for biology but also for practical applications. Herein, inspired by the influenza A M2 channel, a sub-nanoporous proton transport membrane was constructed by layer-by-layer assembly of two oppositely charged pillar­[n]­arenes with sub-nanometer cavities. A good selectivity of the proton transport membranes to protons was achieved by exploiting the size effect of sub-nanometer pores. And the proton transport membrane has a transport capacity of 459 μM·m–2·h–1 for protons. For nanofluidic diodes, the construction of the sub-nanopore proton transport membrane was very meaningful. For energy conversion applications such as catalytic transformations, although the flux cannot meet the application in these fields, the development of this membrane provides an idea for it. What is more, it can help deepen the understanding of the relationship between sub-nanostructure and function.

Membranes with Nanochannels Based on Pillar[6]arenes to Separate Xylenes

“…Therefore, our research group proposed a method to construct a nanochannel membrane based on pillar[n]arenes recently, which has been successfully applied to the selective proton transport. 24 In this work, positively and negatively charged pillar [6]arenes (P6 + and P6 − ), as angstrom-scale units, were directionally assembled onto negatively charged silicon wafers to construct an orderly nanochannel membrane based on pillar [6] membrane was formed by PMMA fixation and peeling from the template. o-, m-, and p-xylene are important chemical raw materials, their physical and chemical properties are very similar, which brings challenges to the separation and purification.…”

“…Although these materials have excellent selectivity, its granular solid structure is not conducive to continuous separation operations. Therefore, our research group proposed a method to construct a nanochannel membrane based on pillar­[ n ]­arenes recently, which has been successfully applied to the selective proton transport …”