Electroosmotically driven capillary transport of typical non-Newtonian biofluids in rectangular microchannels.

In this paper, a detailed theoretical model is developed for studying the capillary filling dynamics of a non-Newtonian power-law obeying fluid in a microchannel subject to electrokinetic effects. Special attention is devoted to model the effects of the electroosmotic influences in the capillary advancement process, variable resistive forces acting over different flow regimes, and the dynamically evolving contact line forces, in mathematically closed forms. As an illustrative case study, in which the flow parameters are modeled as functions of the hematocrit fraction in the sample, the capillary dynamics of a blood sample are analyzed. Flow characteristics depicting advancement of the fluid within the microfluidic channel turn out to be typically non-linear, as per the relative instantaneous strengths of the capillary forces, electroosmotic forces and viscous resistances. Non-trivial implications of the blood hematocrit level and the imposed electric field on the progression of the capillary front are highlighted, which are expected to be of significant consequence towards the dynamics of electroosmotically aided capillary filling processes of biofluidic samples.

[1]  W. Brittin.  Liquid Rise in a Capillary Tube , 1946 .

[2]  Suman Chakraborty,et al.  Analytical solutions for velocity, temperature and concentration distribution in electroosmotic microchannel flows of a non-Newtonian bio-fluid , 2006 .

[3]  K. Hosokawa,et al.  Interface motion of capillary-driven flow in rectangular microchannel. , 2004, Journal of colloid and interface science.

[4]  Suman Chakraborty,et al.  Augmentation of peristaltic microflows through electro-osmotic mechanisms , 2006 .

[5]  S. Newman.  Kinetics of wetting of surfaces by polymers; capillary flow , 1968 .

[6]  Zhmud,et al.  Dynamics of Capillary Rise. , 2000, Journal of colloid and interface science.

[7]  R. Pitchumani,et al.  A generalized analysis of capillary flows in channels. , 2006, Journal of colloid and interface science.

[8]  Suman Chakraborty,et al.  Analytical solutions for the rate of DNA hybridization in a microchannel in the presence of pressure-driven and electroosmotic flows , 2006 .

[9]  D. H. Zanette,et al.  The rise of a liquid in a capillary tube revisited: A hydrodynamical approach , 1996 .

[10]  A. Neimark,et al.  Modeling of spontaneous penetration of viscoelastic fluids and biofluids into capillaries. , 2003, Journal of colloid and interface science.

[11]  E. W. Washburn.  The Dynamics of Capillary Flow , 1921 .

[12]  P. V. Remoortere,et al.  The kinetics of wetting in a capillary , 1990 .

[13]  Tommy Nylander,et al.  Analytical approach for the Lucas-Washburn equation. , 2002, Journal of colloid and interface science.

[14]  Serafim Kalliadasis,et al.  Apparent dynamic contact angle of an advancing gas–liquid meniscus , 1994 .

[15]  Rajat Mittal,et al.  Droplet dynamics in a microchannel subjected to electrocapillary actuation , 2007 .

[16]  Alfredo M. Morales,et al.  Fabrication of Ceramic Microstructures via Microcasting of Nanoparticulate Slurry , 2005 .

[17]  Antonio Delgado,et al.  Capillary Rise of Liquid between Parallel Plates under Microgravity , 1994 .

[18]  Zhou,et al.  Immiscible-fluid displacement: Contact-line dynamics and the velocity-dependent capillary pressure. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[19]  S. Chakraborty,et al.  Microchannel flow control through a combined electromagnetohydrodynamic transport , 2006 .

[20]  Tommy Nylander,et al.  Can a Dynamic Contact Angle be Understood in Terms of a Friction Coefficient , 2000 .

[21]  E. J. Watson,et al.  A theory of capillary rise of a liquid in a vertical cylindrical tube and in a parallel-plate channel , 1980 .

[22]  Y. Fung,et al.  The surface-tension-driven flow of blood from a droplet into a capillary tube. , 2001, Journal of biomechanical engineering.

[23]  S. Sciffer.  A phenomenological model of dynamic contact angle , 2000 .

[24]  C. Tso,et al.  Capillary flow between parallel plates in the presence of an electromagnetic field , 2001 .

[25]  J. C. Slattery,et al.  Correlation for dynamic contact angle , 1979 .

[26]  Suman Chakraborty,et al.  Transverse electrodes for improved DNA hybridization in microchannels , 2007 .

[27]  D. Kwok,et al.  Dynamic interfacial effect of electroosmotic slip flow with a moving capillary front in hydrophobic circular microchannels. , 2004, The Journal of chemical physics.

[28]  E. O’Rear,et al.  Advancing Contact Angles of Newtonian Fluids During “High” Velocity, Transient, Capillary-Driven Flow in a Parallel Plate Geometry , 2002 .

[29]  S. Chakraborty.  Dynamics of capillary flow of blood into a microfluidic channel. , 2005, Lab on a chip.

[30]  J. Timonen,et al.  Lattice-Boltzmann Simulation of Capillary Rise Dynamics , 2002 .

[31]  C. Yih.  Kinetic-energy mass, momentum mass, and drift mass in steady irrotational subsonic flows , 1995, Journal of Fluid Mechanics.

[32]  H. S. Lew,et al.  Entry flow into blood vessels at arbitrary Reynolds number. , 1970, Journal of biomechanics.

[33]  S. Chakraborty,et al.  Wall effects in microchannel-based macromolecular separation under electromagnetohydrodynamic influences , 2007 .

[34]  S. Chakraborty,et al.  Modeling of coupled momentum, heat and solute transport during DNA hybridization in a microchannel in the presence of electro-osmotic effects and axial pressure gradients , 2006 .

[35]  S. Chakraborty,et al.  Analytical investigations on the effects of substrate kinetics on macromolecular transport and hybridization through microfluidic channels. , 2007, Colloids and surfaces. B, Biointerfaces.

[36]  Amit Kumar Srivastava,et al.  Generalized model for time periodic electroosmotic flows with overlapping electrical double layers. , 2007, Langmuir : the ACS journal of surfaces and colloids.