TY - JOUR
T1 - Overlimiting current in a microchannel
AU - Dydek, E. Victoria
AU - Zaltzman, Boris
AU - Rubinstein, Isaak
AU - Deng, D. S.
AU - Mani, Ali
AU - Bazant, Martin Z.
PY - 2011/9/6
Y1 - 2011/9/6
N2 - We revisit the classical problem of diffusion-limited ion transport to a membrane (or electrode) by considering the effects of charged sidewalls. Using simple mathematical models and numerical simulations, we identify three basic mechanisms for overlimiting current in a microchannel: (i) surface conduction carried by excess counterions, which dominates for very thin channels, (ii) convection by electro-osmotic flow on the sidewalls, which dominates for thicker channels, and (iii) transitions to electro-osmotic instability on the membrane end in very thick channels. These intriguing electrokinetic phenomena may find applications in biological separations, water desalination, and electrochemical energy storage.
AB - We revisit the classical problem of diffusion-limited ion transport to a membrane (or electrode) by considering the effects of charged sidewalls. Using simple mathematical models and numerical simulations, we identify three basic mechanisms for overlimiting current in a microchannel: (i) surface conduction carried by excess counterions, which dominates for very thin channels, (ii) convection by electro-osmotic flow on the sidewalls, which dominates for thicker channels, and (iii) transitions to electro-osmotic instability on the membrane end in very thick channels. These intriguing electrokinetic phenomena may find applications in biological separations, water desalination, and electrochemical energy storage.
UR - http://www.scopus.com/inward/record.url?scp=80052464443&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.107.118301
DO - 10.1103/PhysRevLett.107.118301
M3 - Article
AN - SCOPUS:80052464443
SN - 0031-9007
VL - 107
JO - Physical Review Letters
JF - Physical Review Letters
IS - 11
M1 - 118301
ER -
