Research Article

Alumina Membrane with Hour-Glass Shaped Nanochannels: Tunable Ionic Current Rectification Device Modulated by Ions Gradient

Figure 7

Schematic representation of how the alumina nanochannel operates under both pH and concentration gradient at “on” state and “off” state. When , the direction of diffusive K+ ion flow and voltage-induced K+ ion flow is accordant to make large current at “on” state (up-left). While at “off” state, few Cl ions are replenished into the ion-depleted zone at base side and get across the membrane under the concentration gradient stimuli (bottom-left). When , the diffusive ion flow at the acid side exhibited the same ability for promoting ionic transportation properties (right) as that at the base side. Ionic selective transport also has been constructed dependent on the cooperative effect of pH and concentration gradient. The value of is 5.2 and that of is 10.0.
564694.fig.007