Tailoring CO-Activated Ion Nanochannels Using Macrocyclic Pillararenes.

Gas-responsive nanochannels have great relevance for applications in many fields. Inspired by CO-sensitive ion channels, herein we present an approach for designing solid-state nanochannels that allow controlled regulation of ion transport in response to alternate CO/N stimuli. The pillar[5]arene () bearing diethylamine groups can convert into the water-soluble host , containing cationic tertiary ammonium salt groups after absorbing CO. Subsequently, the nanochannel walls are tailored using -based host-guest chemistry. The ion transport rate of K in the nanochannels under CO was 1.66 × 10 mol h m, whereas that under N was 7.98 × 10 mol h m. Notably, there was no significant change to the ion current after eight cycles, which may indicate the stability and repeatability of CO-activated ion nanochannels. It is speculated that the difference in ion conductance resulted from the change in wettability and surface charge within the nanochannels in response to the gas stimuli. Achieving CO-activated ion transport in solid-state nanochannels opens new avenues for biomimetic nanopore systems and advanced separation processes.