A viscoelastic membrane unit fabricated from thermoplastic polyurethane, with a formed single micropore, was interfaced to a piezoelectric actuator to demonstrate rapid actuation of the pore. Changes in through-pore conductance were measured as a function of the voltage applied to the actuator. The pore was opened and closed either in a stepwise fashion, or else made to oscillate between more and less open positions at up to 200 Hz. The step-driven response exhibited both a fast (<100 ms) majority component and a slow (∼1 s) minority component. The oscillatory method indicated that the majority component reached 95% of the low frequency (5 Hz) conductance amplitude in ∼5 ms, fast enough for a pore to close upon a particle driven by a 50 Pa pressure head. This advance in the rapid control of very small pores was achieved by reducing the amount of viscoelastic material between the pore and the source of actuation. This technique has potential for measurement and manipulation of micro- and nano-particles.
Tunable pore, Micropore, Piezo-actuator, Viscoelastic, Membrane