Coalescence of Two Oppositely Charged Droplets at Constant Electric Potential

Dong Woog Lee; In Seok Kang

Korean Chemical Engineering Research, Vol.59, No.2, 247-253, May, 2021

DOI10.9713/kcer.2021.59.2.247 Export Citation

Coalescence of Two Oppositely Charged Droplets at Constant Electric Potential

Dong Woog Lee, and In Seok Kang^{1, †}

Energy and Environment Laboratory, Kepco Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon, 34056, Korea
¹Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro., Nam-gu, Pohang, Gyeongbuk, 37673, Korea

E-mail:

Electrocoalescence is an active technique in petroleum industry, formation of raindrop in cloud, and digital microfluidics. In the present work, electrocoalescence of two droplets under the constant electric potential in air was studied. Through this experiment, we found that the electrocoalescence process could be divided three phases; deformation, formation of liquid bridge, and merging. And the condition for formation of liquid bridge between two droplets was obtained. For the connection of experimental result in constant potential condition with general case in constant charge condition, relationship of charge and potential difference was deduced by numerical computation. In high electric potential case, flat interfaces after recoiling were observed. It was interpreted through a numerical simulation of electric field.

Keywords:Electrocoalescence;Droplet;Microfluidics

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[1] Eow JS, Ghadiri M, Sharif AO, Williams TJ, Chem. Eng. J., 84(3), 173 (2001)

[2] Pruppacher HR, Klett JD, “Microphysics of Clouds and Precipitation,” New York(2004).

[3] Zhang XG, Basaran OA, Wham RM, AIChE J., 41(7), 1629 (1995)

[4] Zhang X, Basaran OA, Wham RA, Sep., Sci. Technol., 30(7), 1169 (1995)

[5] Teh SY, et al., Lab Chip, 8(2), 198 (2008)

[6] Fair RB, Microfluid. Nanofluidics., 3(3), 245 (2007)

[7] Im DJ, Korean J. Chem. Eng., 32(6), 1001 (2015)

[8] Prakash R, Paul R, Kaler KVIS, Lab Chip, 10(22), 3094 (2010)

[9] Lee J, et al., Sens. Actuators A-Phys., 95(2), 259 (2002)

[10] Jung YM, Kang IS, Biomicrofluidics, 4(2), 24104 (2010)

[11] Jung YM, Kang IS, Biomicrofluidics, 3(2), 022402 (2009)

[12] Jung YM, Oh HC, Kang IS, J. Colloid Interface Sci., 322(2), 617 (2008)

[13] Im DJ, et al., Anal. Chem., 85(8), 4038 (2013)

[14] Ahn MM, Kang IS, Analyst, 138(24), 7362 (2013)

[15] Lee DW, Im DJ, Kang IS, Appl. Phys. Lett., 100(22), 221602 (2012)

[16] Choi CY, Im DJ, Korean Chem. Eng. Res., 54(4), 568 (2016)

[17] Bae SJ, Im DJ, Korean Chem. Eng. Res., 58(3), 450 (2020)

[18] Yang SH, Im DJ, Langmuir, 33(48), 13740 (2017)

[19] Im DJ, Langmuir, 36(17), 4785 (2020)

[20] Bremond N, Thiam AR, Bibette J, Phys. Rev. Lett., 100(2), 024501 (2008)

[21] Lai A, Bremond N, Stone HA, J. Fluid Mech., 632, 97 (2009)

[22] Miller AH, Shelden CE, Atkinson WR, Phys. Fluids, 8(11), 1921 (1965)

[23] Taylor GI, Proc. R. Soc. A, 306, 423 (1968)

[24] Priest C, Herminghaus S, Seemann R, Appl. Phys. Lett., 89, 134101 (2006)

[25] Eow JS, Ghadiri M, Colloids Surf. A: Physicochem. Eng. Asp., 219(1), 253 (2003)

[26] Ristenpart WD, et al., Nature, 461, 377 (2009)

[27] Bird JC, et al., Phys. Rev. Lett., 103(16), 164502 (2009)

[28] Mugele F, Nature, 461, 356 (2009)

[29] Pierre A, Aitken F, IEEE Trans. Ind. Appl., 46(4), 1578 (2010)

[30] Pierre A, Lundgaard L, Berg G, J. Electrostat., 64(7), 550 (2006)

[31] John L, Roxburgh IW, Proc. R. Soc. A, 295, 84 (1966)

[32] Atten P, J. Electrostat., 30, 259 (1993)

[33] Davis MH, Q. J. Mech. Appl. Math., 17(4), 499 (1964)