Research Papers

Study of Liquid-Metal Based Heating Method for Temperature Gradient Focusing Purpose

[+] Author and Article Information
L. Gui

e-mail: lingui@mail.ipc.ac.cn

J. Liu

Technical Institute of Physics and Chemistry,
Chinese Academy of Sciences,
Beijing 100190, China

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the Journal of Heat Transfer. Manuscript received June 19, 2012; final manuscript received February 15, 2013; published online July 26, 2013. Guest Editors: G. P. “Bud” Peterson and Zhuomin Zhang.

J. Heat Transfer 135(9), 091402 (Jul 26, 2013) (8 pages) Paper No: HT-12-1296; doi: 10.1115/1.4024426 History: Received June 19, 2012; Revised February 15, 2013

Temperature gradient focusing (TGF) is a highly efficient focusing technique for the concentration and separation of charged analytes in microfluidic channels. The design of an appropriate temperature gradient is very important for the focusing efficiency. In this study, we proposed a new technique to generate the temperature gradient. This technique utilizes a microchannel filled with liquid-metal as an electrical heater in a microfluidic chip. By applying an electric current, the liquid-metal heater generates Joule heat, forming the temperature gradient in the microchannel. To optimize the temperature gradient and find out the optimal design for the TGF chip, numerical simulations on four typical designs were studied. The results showed that design 1 can provide a best focusing method, which has the largest temperature gradient. For this best design, the temperature is almost linearly distributed along the focusing microchannel. The numerical simulations were then validated both theoretically and experimentally. The following experiment and theoretical analysis on the best design also provide a useful guidance for designing and fabricating the liquid-metal based TGF microchip.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.


Ross, D., and Locascio, L. E., 2002, “Microfluidic Temperature Gradient Focusing,” Anal. Chem., 74, pp. 2556–2564. [CrossRef]
Balss, K. M., Ross, D., Begley, H. C., Olsen, K. G., and Tarlov, M. J., 2004, “DNA Hybridization Assays Using Temperature Gradient Focusing and Peptide Nucleic Acids,” J. Am. Chem. Soc., 126, pp. 13474–13479. [CrossRef]
Balss, K. M., Vreeland, W. N., Phinney, K. W., and Ross, D., 2004, “Simultaneous Concentration and Separation of Enantiomers With Chiral Temperature Gradient Focusing,” Anal. Chem., 76, pp. 7243–7249. [CrossRef]
Balss, K. M., Vreeland, W. N., Howell, P. B., Henry, A. C., and Ross, D., 2004, “Micellar Affinity Gradient Focusing: A New Method for Electrokinetic Focusing,” J. Am. Chem. Soc., 126, pp. 1936–1937. [CrossRef]
Terabe, S., Otsuka, K., Ichikawa, K., Tsuchiya, A., and Ando, T., 1984, “Electrokinetic Separations With Micellar Solutions and Open-Tubular Capillaries,” Anal. Chem., 56, pp. 111–113. [CrossRef]
Terabe, S., Otsuka, K., and AndoT., 1985, “Electrokinetic Chromatography With Micellar Solution and Open-Tubular Capillary,” Anal. Chem., 57, pp. 834–841. [CrossRef]
Hoebel, S. J., Balss, K. M., Jones, B. J., Malliaris, C. D., Munson, M. S., Vreeland, W. N., and Ross, D., 2006, “Scanning Temperature Gradient Focusing,” Anal. Chem., 78, pp. 7186–7190. [CrossRef]
Shackman, J. G., Munson, M. S., Kan, C. W., and Ross, D., 2006, “Quantitative Temperature Gradient Focusing Performed Using Background Electrolytes at Various pH Values,” Electrophoresis, 27, pp. 3420–3427. [CrossRef]
Shackman, J. G., Munson, M. S., and Ross, D., 2007, “Temperature Gradient Focusing for Microchannel Separations,” Anal. Bioanal. Chem., 387, pp. 155–158. [CrossRef]
Munson, M. S., Danger, G., Shackman, J. G., and Ross, D., 2007, “Temperature Gradient Focusing With Field-Amplified Continuous Sample Injection for Dual-Stage Analyte Enrichment and Separation,” Anal. Chem., 79, pp. 6201–6207. [CrossRef]
Munson, M. S., Meacham, J. M., Locascio, L. E., and Ross, D., 2008, “Counterflow Rejection of Adsorbing Proteins for Characterization of Biomolecular Interactions by Temperature Gradient Focusing,” Anal. Chem., 80, pp. 172–178. [CrossRef]
Danger, G., and Ross, D., 2008, “Development of a Temperature Gradient Focusing Method for In Situ Extraterrestrial Biomarker Analysis,” Electrophoresis, 29, pp. 3107–3114. [CrossRef]
Kim, S. M., Sommer, G. J., Burns, M. A., and Hasselbrink, E. F., 2006, “Low-Power Concentration and Separation Using Temperature Gradient Focusing Via Joule Heating,” Anal. Chem., 78, pp. 8028–8035. [CrossRef]
Sommer, G. J., Kim, S. M., Littrell, R. J., and Hasselbrink, E. F., 2007, “Theoretical and Numerical Analysis of Temperature Gradient Focusing Via Joule Heating,” Lab Chip, 7, pp. 898–907. [CrossRef]
Zhang, H. D., Zhou, J., Xu, Z. R., Song, J., Dai, J., Fang, J., and Fang, Z. L., 2007, “DNA Mutation Detection With Chip-Based Temperature Gradient Capillary Electrophoresis Using a Slantwise Radiative Heating System,” Lab Chip, 7, pp. 1162–1170. [CrossRef]
Matsui, T., Franzke, J., Manz, A., and Janasek.D., 2007, “Temperature Gradient Focusing in a PDMS/Glass Hybrid Microfluidic Chip,” Electrophoresis, 28, pp. 4606–4611. [CrossRef]
Becker, M., Mansouri, A., Beilein, C., and Janasek, D., 2009, “Temperature Gradient Focusing in Miniaturized Free-Flow Electrophoresis Devices,” Electrophoresis, 30, pp. 4206–4212. [CrossRef]
Reineck, P., Wienken, C. J., and Braun, D., 2010, “Thermophoresis of Single Stranded DNA,” Electrophoresis, 31, pp. 279–286. [CrossRef]
Akbari, M., Bahrami, M., and Sinton, D., 2012, “Optothermal Sample Preconcentration and Manipulation With Temperature Gradient Focusing,” Microfluid. Nanofluid., 12, pp. 221–228. [CrossRef]
de Mello, A. J., Habgood, M., Lancaster, N. L., Welton, T., and Wootton, R. C. R., 2004, “Precise Temperature Control in Microfluidic Devices Using Joule Heating of Ionic Liquids,” Lab Chip, 4, pp. 417–419. [CrossRef]
Vigolo, D., Rusconi, R., Piazzaa, R., and Stone, H. A., 2010, “A Portable Device for Temperature Control Along Microchannels,” Lab Chip, 10, pp. 795–798. [CrossRef]
Cheung, Y. K., Gillette, B. M., Zhong, M., Ramcharan, S., and Sia, S. K., 2007, “Direct Patterning of Composite Biocompatible Microstructures Using Microfluidics,” Lab Chip, 7, pp. 574–579. [CrossRef]
Peterson, D. S., 2005, “Solid Supports for Micro Analytical Systems,” Lab Chip, 5, pp. 132–139. [CrossRef]
Siegel, A. C., Bruzewicz, D. A., Weibel, D. B., and Whitesides, G. M., 2007, “Microsolidics: Fabrication of Three-Dimensional Metallic Microstructures in Poly(Dimethylsiloxane),” Adv. Mater., 19, pp. 727–733. [CrossRef]
Siegel, A. C., Tang, S. K. Y., Nijhuis, C. A., Hashimoto, M., Phillips, S. T., Dickey, M. D., and Whitesides, G. M., 2010, “Cofabrication: A Strategy for Building Multicomponent Microsystems,” Acc. Chem. Res., 43, pp. 518–528. [CrossRef]
Shevkoplyas, S. S., Siegel, A. C., Westervelt, R. M., Prentissc, M. G., and Whitesides, G. M., 2007, “The Force Acting on a Superparamagnetic Bead Due to an Applied Magnetic Field,” Lab Chip, 7, pp. 1294–1302. [CrossRef]
Siegel, A. C., Shevkoplyas, S. S., Weibel, D. B., Bruzewicz, D. A., Martinez, A. W., and Whitesides, G. M., 2006, “Cofabrication of Electromagnets and Microfluidic Systems in Poly(Dimethylsiloxane),” Angew. Chem. Int. Ed., 45, pp. 6877–6882. [CrossRef]
Dickey, M. D., Chiechi, R. C., Larsen, R. J., Weiss, E. A., Weitz, D. A., and Whitesides, G. M., 2008, “Eutectic Gallium-Indium (EGaIn): A Liquid Metal Alloy for the Formation of Stable Structures in Microchannels at Room Temperature,” Adv. Funct. Mater., 18, pp. 1097–1104. [CrossRef]
So, J. H., and Dickey, M. D., 2011, “Inherently Aligned Microfluidic Electrodes Composed of Liquid Metal,” Lab Chip, 11, pp. 905–911. [CrossRef]
So, J. H., Thelen, J., Qusba, A., Hayes, G. J., Lazzi, G., and Dickey, M. D., 2009, “Reversibly Deformable and Mechanically Tunable Fluidic Antennas,” Adv. Funct. Mater., 19, pp. 3632–3637. [CrossRef]
Blaiszik, B. J., Kramer, S. L. B., Grady, M. E., McIlroy, D. A., Moore, J. S., Sottos, N. R., and White, S. R., 2012, “Autonomic Restoration of Electrical Conductivity,” Adv. Mater., 24, pp. 398–401. [CrossRef]
Viskanta, R., and Touloukian, Y. S., 1960, “Heat Transfer to Liquid Metals With Variable Properties,” ASME J. Heat Transfer, 82, pp. 333–339. [CrossRef]
Sugiyama, K., Ma, Y., and Ishiguro, R., 1991, “Laminar Natural Convection Heat Transfer From a Horizontal Circular Cylinder to Liquid Metals,” ASME J. Heat Transfer, 113, pp. 91–96. [CrossRef]
Talmage, G., 1994, “A Note on Heat Conduction in Liquid Metals: A Comparison of Laminar and Turbulent Flow Effects,” ASME J. Heat Transfer, 116, pp. 476–479. [CrossRef]
Kamotani, Y., Weng, F. B., and Ostrach, S., 1994, “Oscillatory Natural Convection of a Liquid Metal in Circular Cylinders,” ASME J. Heat Transfer, 116, pp. 627–632. [CrossRef]
Emery, A. F., and Bailey, D. A., 1967, “Heat Transfer to Fully Developed Liquid Metal Flow in Tubes,” ASME J. Heat Transfer, 89, pp. 272–273. [CrossRef]
TagawaT., and Ozoe, H., 1997, “Enhancement of Heat Transfer Rate by Application of a Static Magnetic Field during Natural Convection of Liquid Metal in a Cube,” ASME J. Heat Transfer, 119, pp. 265–271. [CrossRef]
Selver, R., Kamotani, Y., and Ostrach, S., 1998, “Natural Convection of a Liquid Metal in Vertical Circular Cylinders Heated Locally From the Side,” ASME J. Heat Transfer, 120, pp. 108–114. [CrossRef]
Deng, Y. G., and Liu, J., 2010, “Design of Practical Liquid Metal Cooling Device for Heat Dissipation of High Performance CPUs,” ASME J. Electron. Packag., 132, p. 031009. [CrossRef]
Li, P. P., and Liu, J., 2011, “Self-Driven Electronic Cooling Based on Thermosyphon Effect of Room Temperature Liquid Metal,” ASME J. Electron. Packag., 133, p. 041009. [CrossRef]
Okada, K., and Ozoe, H., 1992, “Experimental Heat Transfer Rates of Natural Convection of Molten Gallium Suppressed Under an External Magnetic Field in Either the X, Y, or Z Direction,” ASME J. Heat Transfer, 114, pp. 107–114. [CrossRef]
Braunsfurth, M. G., Skeldon, A. C., Juel, A., Mullin, T., and Riley, D. S., 1997, “Free Convection in Liquid Gallium,” J. Fluid Mech., 342, pp. 295–314. [CrossRef]
Tagawa, T., and Ozoe, H., 1998, “Enhanced Heat Transfer Rate Measured for Natural Convection in Liquid Gallium in a Cubical Enclosure Under a Static Magnetic Field,” ASME J. Heat Transfer, 120, pp. 1027–1032. [CrossRef]
Prokhorenko, V. Y., Roshchupkin, V. V., Pokrasin, M. A., Prokhorenko, S. V., and Kotov, V. V., 2000, “Liquid Gallium: Potential Uses as a Heat Transfer Agent,” High Temp., 38, pp. 954–968. [CrossRef]
Juel, A., Mullin, T., HadidH. B., and Henry, D., 2001, “Three-Dimensional Free Convection in Molten Gallium,” J. Fluid Mech., 436, pp. 267–281. [CrossRef]
Xia, Y. N., and Whitesides, G. M., 1998, “Soft Lithography,” Annu. Rev. Mater. Sci., 28, pp. 153–184. [CrossRef]
Xia, Y. N., and Whitesides, G. M., 1998, “Soft Lithography,” Angew. Chem. Int. Ed., 37, pp. 550–575. [CrossRef]
Gui, L., and Ren, L. Q., 2006, “Numerical Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous Flow PCR Chip,” Anal. Chem., 78, pp. 6215–6222. [CrossRef]
Holman, J. P., 1997, Heat Transfer, McGraw-Hill, New York.
Yang, S. M., and Tao, W. Q., 1998, Heat Transfer (in Chinese), Higher Education Press, Beijing, China.
Ozisik, M. N., 1980, Heat Conduction, John Wiley and Sons, New York.


Grahic Jump Location
Fig. 1

Schematic of PDMS/PDMS microfluidic chip embedded with liquid-metal microheater for temperature gradient focusing purpose. L, W, and h are the chip length, width, and height, respectively. l and d are the liquid-metal channel length and width, respectively. s is the distance between the liquid-metal channel and the focusing channel in the x-direction.

Grahic Jump Location
Fig. 2

Schematic of four typical possible chips (plane at z = 0) for numerical simulations. (a) Design 1, (b) design 2, (c) design 3, and (d) design 4.

Grahic Jump Location
Fig. 7

Comparisons of focusing channel centerline temperature curves among numerical results (from numerical model), analytical results (from two-dimensional analytical model), and experimental results

Grahic Jump Location
Fig. 6

Schematic of two-dimensional analytical model describing temperature field of plane at z = 0. The width of the micro heater d is d = x2 − x1 and the length l is l = y2 − y1.

Grahic Jump Location
Fig. 8

Experimental setup for measuring focusing channel temperature distribution of PDMS/PDMS chip

Grahic Jump Location
Fig. 5

Three-dimensional thin layer with 2ε thickness (ranging from z = −ε to z = ε, 2ɛ≪h)

Grahic Jump Location
Fig. 4

Temperature curve of focusing channel centerline (plane at z = 0) from numerical solutions for each design of four typical possible chips

Grahic Jump Location
Fig. 3

Isothermal diagrams (plane at z = 0) of numerical solutions to four typical possible chips

Grahic Jump Location
Fig. 9

Temperature distribution of chip obtained from two-dimensional analytical solution. The black lines show the position of the two microchannels.

Grahic Jump Location
Fig. 10

Temperature distribution curves of focusing channel centerline at various current densities i for d = 50 μm, l = 15 mm, and s = 2 mm

Grahic Jump Location
Fig. 12

Temperature distribution curves of focusing channel centerline at various heater lengths l for i = 60 μA/μm2, d = 50 μm, and s = 2 mm

Grahic Jump Location
Fig. 11

Temperature distribution curves of focusing channel centerline at various heater widths d for i = 60 μA/μm2, l = 15 mm, and s = 2 mm

Grahic Jump Location
Fig. 13

Temperature distribution curves of focusing channel centerline at various distance between heater channel and focusing channel in the x-direction s for i = 60 μA/μm2, l = 15 mm, and d = 50 μm



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In