Microfluidics and Nanofluidics

, Volume 19, Issue 6, pp 1281–1296 | Cite as

Formation and lateral migration of nanodroplets via solvent shifting in a microfluidic device

  • Ramin Hajian
  • Steffen HardtEmail author
Research Paper


Solvent shifting is a process in which a non-solvent is added to a solvent/solute mixture and extracts the solvent. The solvent and the non-solvent are miscible. Because of solution supersaturation, a portion of the solute transforms to droplets. In this paper, based on this process, we present an investigation on droplet formation and their radial motion in a microfluidic device in which a jet is injected in a co-flowing liquid stream. Thanks to the laminar flow, the microfluidic setup enables studying diffusion mass transfer in radial direction and obtaining well-defined concentration distributions. Such profiles together with the ternary phase diagram give detailed information about the conditions for droplet formation as well as their radial migration in the channel. The ternary system is composed of ethanol (solvent), de-ionized water (non-solvent), and divinylbenzene (solute). We employ analytical/numerical solutions of the diffusion equation to obtain concentration profiles of the components. We show that in the system under study droplets are formed in a region of the phase diagram between the binodal and the spinodal, i.e., via a thermally activated process. The droplets are driven to the channel centerline by the solutal Marangoni effect but are not able to significantly penetrate into the single-phase region, where they get rapidly dissolved. Therefore, the radial motion of the binodal surface carries the droplets to the centerline where they get collected.


Solvent shifting Ouzo effect Droplet Diffusion Ternary phase diagram Marangoni convection 



R. Hajian acknowledges the Ministry of Science, Research and Technology of the I. R. Iran for funding under Grant Number 89100017. He also appreciates Dorothea Paulssen for her helpful hints on the ouzo effect, and Tobias Baier for his effective discussions.


  1. Aubry J, Ganachaud F, Addad JC, Cabane B (2009) Nanoprecipitation of polymethylmethacrylate by solvent shifting: 1. Boundaries. Langmuir 25:1970–1979CrossRefGoogle Scholar
  2. Balasubramaniam R, Subramanian RS (2000) The migration of a drop in a uniform temperature gradient at large Marangoni numbers. Phys Fluids 12:733–743CrossRefzbMATHGoogle Scholar
  3. Balasubramaniam R, Subramanian RS (2004) Thermocapillary migration of a drop; an exact solution with newtonian interfacial rheology and stretching/shrinkage of interfacial area elements for small Marangoni numbers. Ann NY Acad Sci 1027:303–310CrossRefGoogle Scholar
  4. Beck-Broichsitter M, Rytting E, Lebhardt T, Wang X, Kissel T (2010) Preparation of nanoparticles by solvent displacement for drug delivery: a shift in the “Ouzo region” upon drug loading. Eur J Pharm Sci 41:244–253CrossRefGoogle Scholar
  5. Botet R (2012) The “Ouzo effect”, recent developments and application to therapeutic drug carrying. J Phys Conf Ser 352:012047CrossRefGoogle Scholar
  6. Brodkey RS, Hershey HC (1988) Transport phenomena: a unified approach (part I). McGraw-Hill, USAGoogle Scholar
  7. Chan PCH, Leal LG (1979) The motion of a deformable drop in a second-order fluid. J Fluid Mech 92(1):131–170CrossRefzbMATHGoogle Scholar
  8. Chang YC, Keh HJ (2006) Thermocapillary motion of a fluid droplet perpendicular to two plane walls. Chem Eng Sci 61:5221–5235CrossRefGoogle Scholar
  9. Chen X, Xue C, Zhang L, Hu G, Jiang X, Sun J (2014) Inertial migration of deformable droplets in a microchannel. Phys Fluids 26:112003CrossRefGoogle Scholar
  10. Crank J (1975) The mathematics of diffusion. Oxford University Press, UKGoogle Scholar
  11. Cussler EL (1997) Diffusion mass transfer in fluid systems, 2nd edn. Cambridge University Press, UKGoogle Scholar
  12. Di Carlo D (2009) Inertial microfluidics. Lab Chip 9:3038–3046CrossRefGoogle Scholar
  13. Duraiswamy S, Khan SA (2009) Droplet-based microfluidic synthesis of anisotropic metal nanocrystals. Small 5(24):2828–2834CrossRefGoogle Scholar
  14. Ganachaud F, Katz J (2005) Nanoparticles and nanocapsules created using the ouzo effect: spontaneous emulsification as an alternative to ultrasonic and high-shear devices. ChemPhysChem 6:209–216CrossRefGoogle Scholar
  15. Griggs AJ, Zinchenko AZ, Davis RH (2007) Low-Reynolds-number motion of a deformable drop between two parallel plane walls. Int J Multiph Flow 33:182–206CrossRefGoogle Scholar
  16. Grillo I (2003) Small-angle neutron scattering study of a world-wide known emulsion: Le Pastis. Colloids Surf A Physicochem Eng Asp 225:153–160CrossRefGoogle Scholar
  17. Hasan MN, Monde M, Mitsutake Y (2011) Homogeneous nucleation boiling during jet impingement quench of hot surfaces above thermodynamic limiting temperature. Int J Heat Mass Transf 54:2837–2843CrossRefzbMATHGoogle Scholar
  18. Herrmann M, Lopez JM, Brady P, Raessi M (2008) Thermocapillary motion of deformable drops and bubbles. Center for Turbulence Research, Proceeding of the Summer Program 2008, 155-170Google Scholar
  19. Hood K, Lee S, Roper M (2014) Inertial migration of a rigid sphere in three-dimensional Poiseuille flow. arXiv:1312.4653v3Google Scholar
  20. Humphry KJ, Kulkarni PM, Weitz DA, Morris JF, Stone HA (2010) Axial and lateral particle ordering in finite Reynolds number channel flows. Phys Fluids 22:081703CrossRefGoogle Scholar
  21. Hung LH, Teh SY, Jester J, Lee AP (2010) PLGA micro/nanosphere synthesis by droplet microfluidic solvent evaporation and extraction approaches. Lab Chip 10:1820–1825CrossRefGoogle Scholar
  22. Joensson HN, Svahn HA (2012) Droplet microfluidics—a tool for single-cell analysis. Angew Chem Int Edit 51:12176–12192CrossRefGoogle Scholar
  23. Karnik R, Gu F, Basto P, Cannizzaro C, Dean L, Kyei-Manu W, Langer R, Farokhzad OC (2008) Microfluidic platform for controlled synthesis of polymeric nanoparticles. Nano Lett 8(9):2906–2912CrossRefGoogle Scholar
  24. Kitahata H, Yoshinaga N, Nagai KH, Sumino Y (2011) Spontaneous motion of a droplet coupled with a chemical wave. Phys Rev E 84:015101(R)CrossRefGoogle Scholar
  25. Kuehne AJC, Weitz DA (2011) Highly monodisperse conjugated polymer particles synthesized with drop-based microfluidics. Chem Commun 47:12379–12381CrossRefGoogle Scholar
  26. Lagus TP, Edd JF (2013) A review of the theory, methods and recent applications of high-throughput single-cell droplet microfluidics. J Phys D Appl Phys 46:114005CrossRefGoogle Scholar
  27. Lan W, Li S, Xu J, Luo G (2012) A one-step microfluidic approach for controllable preparation of nanoparticle-coated patchy microparticles. Microfluid Nanofluid 13:491–498CrossRefGoogle Scholar
  28. Langmuir I (1918) The evaporation of small spheres. Phys Rev 12:368–370CrossRefGoogle Scholar
  29. Lee I, Yoo Y, Cheng Z, Jeong HK (2008) Generation of monodisperse mesoporous silica microspheres with controllable size and surface morphology in a microfluidic device. Adv Funct Mater 18:4014–4021CrossRefGoogle Scholar
  30. Lewis CL, Lin Y, Yang C, Manocchi AK, Yuet KP, Doyle PS, Yi H (2010) Microfluidic fabrication of hydrogel microparticles containing functionalized viral nanotemplates. Langmuir 26(16):13436–13441CrossRefGoogle Scholar
  31. Lide DR (ed) (2008–2009) CRC handbook of chemistry and physics, 89th edn. CRC Press, Boca RatonGoogle Scholar
  32. Lignos I, Protesescu L, Stavrakis S, Piveteau L, Speirs MJ, Loi MA, Kovalenko MV, deMello AJ (2014) Facile droplet-based microfluidic synthesis of monodisperse IV–VI semiconductor nanocrystals with coupled in-line NIR fluorescence detection. Chem Mater 26:2975–2982CrossRefGoogle Scholar
  33. Lindfirs L, Forssen S, Westergren J, Olsson U (2008) Nucleation and crystal growth in supersaturated solutions of a model drug. J Colloid Interface Sci 325:404–413CrossRefGoogle Scholar
  34. Mary P, Studer V, Tabeling P (2008) Microfluidic droplet-based liquid-liquid extraction. Anal Chem 80(8):2680–2687CrossRefGoogle Scholar
  35. Matas JP, Glezer V, Guazzelli E (2004) Trains of particles in finite-Reynolds-number pipe flow. Phys Fluids 16(11):4192–4195CrossRefGoogle Scholar
  36. McCracken JR, Datyner A (1974) The preparation of uniform polystyrene latices by true emulsion polymerization. J Appl Polym Sci 18:3365–3372CrossRefGoogle Scholar
  37. Ruschak KJ, Miller CA (1972) Spontaneous emulsification in ternary system with mass transfer. Ind Eng Chem Fundam 11(4):534–539CrossRefGoogle Scholar
  38. Sang YYC, Lorenceau E, Wahl S, Stoffel M, Angelescu DE, Hoehler R (2013) A microfluidic technique for generating monodisperse submicron-sized drops. RSC Adv 3:2330–2335CrossRefGoogle Scholar
  39. Schneider T, Kreutz J, Chiu DT (2013) The potential impact of droplet microfluidics in biology. Anal Chem 85:3476–3482CrossRefGoogle Scholar
  40. Seemann R, Brinkmann M, Pfohl T, Herminghaus S (2012) Droplet based microfluidics. Rep Prog Phys 75:016601CrossRefGoogle Scholar
  41. Segré G, Silberberg A (1961) Radial particle displacement in Poiseuille flow of suspensions. Nature 189:209–210CrossRefGoogle Scholar
  42. Serra CA, Chang Z (2008) Microfluidic-assisted synthesis of polymer particles. Chem Eng Technol 31:1099–1115CrossRefGoogle Scholar
  43. Shah RK, Shum HC, Rowat AC, Lee D, Agresti JJ, Utada AS, Chu LY, Kim JW, Nieves AF, Martinez CJ, Weitz DA (2008) Designer emulsions using microfluidics. Mater Today 11(4):18–27CrossRefGoogle Scholar
  44. Sitnikova NL, Sprik R, Wegdam G (2005) Spontaneously formed trans anethol/water/alcohol emulsions: mechanism of formation and stability. Langmuir 21(16):7083–7089CrossRefGoogle Scholar
  45. Skinner LM, Sambels JR (1972) The Kelvin equation—a review. J Aerosol Sci 3:199–210CrossRefGoogle Scholar
  46. Tao L, Xiyun L (2004) Numerical simulation of drop migration in channel flow under zero-gravity. Acta Mech Sin 20(3):199–205CrossRefGoogle Scholar
  47. Teh SY, Lin R, Hungb LH, Lee AP (2008) Droplet microfluidics. Lab Chip 8:198–220CrossRefGoogle Scholar
  48. Utada AS, Lorenceau E, Link DR, Kaplan PD, Stone HA, Weitz DA (2005) Monodisperse double emulsions generated from a microcapillary device. Science 308:537–541CrossRefGoogle Scholar
  49. Vitale SA, Katz JL (2003) Liquid droplet dispersions formed by homogeneous liquid–liquid nucleation: “the ouzo effect”. Langmuir 19:4105–4110CrossRefGoogle Scholar
  50. Xu S, Nie Z, Seo M, Lewis P, Kumacheva E, Stone HA, Garstecki P, Weibel DB, Gitlin I, Whitesides GM (2005) Generation of monodisperse particles by using microfluidics: control over size, shape, and composition. Angew Chem Int Edit 44:724–728CrossRefGoogle Scholar
  51. Yabunaka S, Ohta T, Yoshinaga N (2012) Self-propelled motion of a fluid droplet under chemical reaction. J Chem Phys 136:074904CrossRefGoogle Scholar
  52. Yeh CH, Zhao Q, Lee SJ, Lin YC (2009) Using a T-junction microfluidic chip for monodisperse calcium alginate microparticles and encapsulation of nanoparticles. Sens Actuators A Phys 151:231–236CrossRefGoogle Scholar
  53. Young NO, Goldstein JS, Block MJ (1959) The motion of bubbles in a vertical temperature gradient. J Fluid Mech 6(03):350–356CrossRefzbMATHGoogle Scholar
  54. Yu JQ, Chin LK, Chen Y, Zhang GJ, Lo GQ, Ayi TC, Yap PH, Kwong DL, Liu AQ (2010) Microfluidic droplet-based liquid–liquid extraction for fluorescence-indicated mass transfer. Proc μTAS 2010:1079–1081Google Scholar
  55. Zeng L, Najjar F, Balachandar S, Fischer P (2009) Forces on a finite-sized particle located close to a wall in a linear shear flow. Phys Fluids 21:033302CrossRefGoogle Scholar
  56. Zhang L, Subramanian RS, Balasubramaniam R (2001) Motion of a drop in a vertical temperature gradient at small Marangoni number—the vertical role of inertia. J Fluid Mech 488:197–211Google Scholar
  57. Zhou J, Papautsky I (2013) Fundamentals of inertial focusing in microchannels. Lab Chip 13:1121–1132CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Center of Smart InterfacesTU DarmstadtDarmstadtGermany
  2. 2.Department of Mechanical EngineeringIranian University of Science and TechnologyNarmakIran

Personalised recommendations