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Title: Macroscopic strain controlled ion current in an elastomeric microchannel

We report on the fabrication of an ultra-high aspect ratio ionically conductive single microchannel with tunable diameter from ≈ 20 μm to fully closed. The 4 mm-long channel is fabricated in a Polydimethylsiloxane (PDMS) mold and its cross-sectional area is controlled by applying macroscopic compressive strain to the mold in a direction perpendicular to the channel length. We investigated the ionic conduction properties of the channel. For a wide range of compressive strain up to ≈ 0.27, the strain dependence of the resistance is monotonic and fully reversible. For strain > 0.27, ionic conduction suddenly shuts off and the system becomes hysteretic (whereby a finite strain reduction is required to reopen the channel). Upon unloading, the original behavior is retrieved. This reversible behavior is observed over 200 compression cycles. The cross-sectional area of the channel can be inferred from the ion current measurement, as confirmed by a Nano-Computed Tomography investigation. We show that the cross-sectional area decreases monotonically with the applied compressive strain in the reversible range, in qualitative agreement with linear elasticity theory. We find that the shut-off strain is affected by the spatial extent of the applied strain, which provides additional tunability. Our tunable channel is well-suited for multiple applicationsmore » in micro/nano-fluidic devices.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [2] ;  [5] ;  [1] ;  [5]
  1. Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
  2. Department of Civil and Environmental Engineering, University of California, Irvine, California 92697 (United States)
  3. Department of Chemistry, University of California, Irvine, California 92697 (United States)
  4. Department of Mechanical and Aerospace Engineering, University of California, Irvine, California 92697-3975 (United States)
  5. (United States)
Publication Date:
OSTI Identifier:
22403004
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; ASPECT RATIO; COMPRESSION; COMPUTERIZED TOMOGRAPHY; ELASTICITY; ELASTOMERS; ELECTRIC CURRENTS; FABRICATION; FLUIDIC DEVICES; IONIC CONDUCTIVITY; IONS; NANOFLUIDS; STRAINS; UNLOADING