This paper reports the manipulation of ferrofluid droplets by using a microfluidic flow-focusing device equipped with a magnetic tweezer. Besides the traditional flow rate controlling method, the magnetic field also can be applied to control the size of the droplets. Two major effects in magnetic manipulation process: magnetoviscous effect and magnetic drag effect, were studied. Under a fixed flow rate (CP = 1 mL/h, DP = 0.2 mL/h), the average sizes of ferrofluid droplets were tunable from 135 to 95 μm by varying the magnetic field from 0 to 60 mT. Moreover, square wave magnetic field can be used to periodically generate droplets with different sizes. These results are helpful to understand the generation mechanism of the ferrofluid droplet and supply a novel method for manipulating droplets with a predetermined size and distribution.
This is a preview of subscription content, log in to check access.
Buy single article
Instant unlimited access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Abdelgawad M, Wheeler AR (2009) The digital revolution: a new paradigm for microfluidics. Adv Mater 21:920–925
Anna SL, Bontoux N, Stone HA (2003) Formation of dispersions using “flow focusing” in microchannels. Appl Phys Lett 82:364
Baroud CN, Delville J-P, Gallaire F, Wunenburger R (2007) Thermocapillary valve for droplet production and sorting. Phys Rev E 75:046302
Diguet A, Guillermic RM, Magome N, Saint-Jalmes A, Chen Y, Yoshikawa K, Baigl D (2009) Photomanipulation of a droplet by the chromocapillary effect. Angew Chem Int Ed Engl 48:9281–9284
Duffy DC, McDonald JC, Schueller OJ, Whitesides GM (1998) Rapid prototyping of microfluidic systems in poly (dimethylsiloxane). Anal Chem 70:4974–4984
El-Ali J, Sorger PK, Jensen KF (2006) Cells on chips. Nature 442:403–411
Fair RB (2007) Digital microfluidics: is a true lab-on-a-chip possible? Microfluid Nanofluid 3:245–281
Garstecki P, Stone HA, Whitesides GM (2005) Mechanism for flow-rate controlled breakup in confined geometries: a route to monodisperse emulsions. Phys Rev Lett 94:164501
Huebner A, Sharma S, Srisa-Art M, Hollfelder F, Edel JB, Demello AJ (2008) Microdroplets: a sea of applications? Lab Chip 8:1244–1254
Jebrail MJ, Bartsch MS, Patel KD (2012) Digital microfluidics: a versatile tool for applications in chemistry, biology and medicine. Lab Chip 12:2452–2463
Jeong WJ, Kim JY, Choo J, Lee EK, Han CS, Beebe DJ, Seong GH, Lee SH (2005) Continuous fabrication of biocatalyst immobilized microparticles using photopolymerization and immiscible liquids in microfluidic systems. Langmuir 21:3738–3741
Link DR, Grasland-Mongrain E, Duri A, Sarrazin F, Cheng Z, Cristobal G, Marquez M, Weitz DA (2006) Electric control of droplets in microfluidic devices. Angew Chem Int Ed 45:2556–2560
Liu J, Yap YF, Nguyen N-T (2011) Numerical study of the formation process of ferrofluid droplets. Phys Fluids (1994–present) 23:072008
Nguyen N-T (2011) Micro-magnetofluidics: interactions between magnetism and fluid flow on the microscale. Microfluid Nanofluid 12:1–16
Nguyen N-T, Ting T-H, Yap Y-F, Wong T-N, Chai JC-K, Ong W-L, Zhou J, Tan S-H, Yobas L (2007) Thermally mediated droplet formation in microchannels. Appl Phys Lett 91:084102
Nie Z, Li W, Seo M, Xu S, Kumacheva E (2006) Janus and ternary particles generated by microfluidic synthesis: design, synthesis, and self-assembly. J Am Chem Soc 128:9408–9412
Nie Z, Seo M, Xu S, Lewis PC, Mok M, Kumacheva E, Whitesides GM, Garstecki P, Stone HA (2008) Emulsification in a microfluidic flow-focusing device: effect of the viscosities of the liquids. Microfluid Nanofluid 5:585–594
Nisisako T, Torii T, Higuchi T (2002) Droplet formation in a microchannel network. Lab Chip 2:24–26
Pipper J, Inoue M, Ng LF, Neuzil P, Zhang Y, Novak L (2007) Catching bird flu in a droplet. Nat Med 13:1259–1263
Priest C, Herminghaus S, Seemann R (2006) Generation of monodisperse gel emulsions in a microfluidic device. Appl Phys Lett 88:024106
Rich JP, Lammerding J, McKinley GH, Doyle PS (2011) Nonlinear microrheology of an aging, yield stress fluid using magnetic tweezers. Soft Matter 7:9933
Ruuge E, Rusetski A (1993) Magnetic fluids as drug carriers: targeted transport of drugs by a magnetic field. J Magn Magn Mater 122:335–339
Schmid L, Franke T (2013) SAW-controlled drop size for flow focusing. Lab Chip 13:1691–1694
Shui L, van den Berg A, Eijkel JCT (2009) Capillary instability, squeezing, and shearing in head-on microfluidic devices. J Appl Phys 106:124305
Song H, Chen DL, Ismagilov RF (2006) Reactions in droplets in microfluidic channels. Angew Chem Int Ed Engl 45:7336–7356
Srinivasan V, Pamula VK, Fair RB (2004) An integrated digital microfluidic lab-on-a-chip for clinical diagnostics on human physiological fluids. Lab Chip 4:310–315
Tan S-H, Nguyen N-T (2011) Generation and manipulation of monodispersed ferrofluid emulsions: the effect of a uniform magnetic field in flow-focusing and T-junction configurations. Phys Rev E 84:036317
Tan Y-C, Cristini V, Lee AP (2006) Monodispersed microfluidic droplet generation by shear focusing microfluidic device. Sens Actuators B 114:350–356
Tan S-H, Nguyen N-T, Yobas L, Kang TG (2010) Formation and manipulation of ferrofluid droplets at a microfluidic T-junction. J Micromech Microeng 20:045004
Teh SY, Lin R, Hung LH, Lee AP (2008) Droplet microfluidics. Lab Chip 8:198–220
Thorsen T, Roberts RW, Arnold FH, Quake SR (2001) Dynamic pattern formation in a vesicle-generating microfluidic device. Phys Rev Lett 86:4163–4166
Velev OD, Prevo BG, Bhatt KH (2003) On-chip manipulation of free droplets. Nature 426:515–516
Woodward A, Cosgrove T, Espidel J, Jenkins P, Shaw N (2007) Monodisperse emulsions from a microfluidic device, characterised by diffusion NMR. Soft Matter 3:627
Wu Y, Fu T, Ma Y, Li HZ (2013) Ferrofluid droplet formation and breakup dynamics in a microfluidic flow-focusing device. Soft Matter 9:9792
Xu J, Li S, Tan J, Wang Y, Luo G (2006) Preparation of highly monodisperse droplet in a T-junction microfluidic device. AlChE J 52:3005–3010
Yobas L, Martens S, Ong WL, Ranganathan N (2006) High-performance flow-focusing geometry for spontaneous generation of monodispersed droplets. Lab Chip 6:1073–1079
Zhang K, Liang Q, Ma S, Mu X, Hu P, Wang Y, Luo G (2009) On-chip manipulation of continuous picoliter-volume superparamagnetic droplets using a magnetic force. Lab Chip 9:2992–2999
This work was supported by Collaborative Innovation Center of Suzhou Nano Science and Technology. Financial support from the National Natural Science Foundation of China (Grant No. 11125210), the National Basic Research Program of China (973 Program, Grant No.2012CB937500) and the Anhui Provincial Natural Science Foundation of China (1408085QA17) is gratefully acknowledged.
Electronic supplementary material
Below is the link to the electronic supplementary material.
About this article
Cite this article
Yan, Q., Xuan, S., Ruan, X. et al. Magnetically controllable generation of ferrofluid droplets. Microfluid Nanofluid 19, 1377–1384 (2015) doi:10.1007/s10404-015-1652-7