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.