Visualization study on solid-core encapsulation behaviors of double emulsion in a flow-focusing microchannel

  • Wei Gao
  • Meimei Sun
  • Weibo Yang
  • Chengbin Zhang
Technical Paper


A flow-focusing microfluidic chip based on assembled capillary method is developed and the solid-core encapsulation behaviors of double emulsion in a flow-focusing microchannel are visually observed via high-speed microscopic imaging system. The experimental results identify the encapsulation of single, double and triple cores in a flow-focusing microchannel arising from the competition among the inertial force of inner phase, the shear force of outer phase fluid, and the interfacial tension. In addition, the solid-core encapsulation of double emulsion in flow-focusing microchannel is either in the stable state or in the transition state, depending on the flow rates of inner and outer phase fluid. The stable microencapsulation includes the stable single-core, double-cores and triple-cores encapsulation states, while the transition microencapsulation includes the single-double-cores and double-triple-cores transition encapsulation state. Irrespective of encapsulation state, the solid-core encapsulation process can be classified into four stages, including entering, neck stretch, neck shrinking and breakup.



This work was supported by National Natural Science Foundation of China (Grant Nos. U1737104, 51725602), NSAF (No. U1530260), Natural Science Foundation of Jiangsu Province (Grant No. BK20170082), “six talent peaks” project of Jiangsu Province (Grant No. 2018-XNY-042), “Zhishan Young Scholar” Program of Southeast University.


  1. Abrahamse A, Van Lierop R, Van der Sman R, Van der Padt A, Boom R (2002) Analysis of droplet formation and interactions during cross-flow membrane emulsification. J Membr Sci 204:125–137CrossRefGoogle Scholar
  2. Carneiro HC, Tonon RV, Grosso CR, Hubinger MD (2013) Encapsulation efficiency and oxidative stability of flaxseed oil microencapsulated by spray drying using different combinations of wall materials. J Food Eng 115:443–451CrossRefGoogle Scholar
  3. Castellanos IJ, Carrasquillo KG, López JDJ, Alvarez M, Griebenow K (2001) Encapsulation of bovine serum albumin in poly (lactide-co-glycolide) microspheres by the solid-in-oil-in-water technique. J Pharm Pharmacol 53:167–178CrossRefGoogle Scholar
  4. Chai Z, Shi B, Guo Z (2016) A multiple-relaxation-time lattice Boltzmann model for general nonlinear anisotropic convection–diffusion equations. J Sci Comput 69:355–390MathSciNetCrossRefzbMATHGoogle Scholar
  5. Chen Y, Cheng P (2005) An experimental investigation on the thermal efficiency of fractal tree-like microchannel nets. Int Commun Heat a Mass Transf 32(7):931–938CrossRefGoogle Scholar
  6. Chen YP, Deng ZL (2017) Hydrodynamics of a droplet passing through a microfluidic T-junction. J Fluid Mech 819:401–434MathSciNetCrossRefzbMATHGoogle Scholar
  7. Chen Y, Liu X, Shi M (2013) Hydrodynamics of double emulsion droplet in shear flow. Appl Phys Lett 102:051609CrossRefGoogle Scholar
  8. Chen Y, Liu X, Zhao Y (2015a) Deformation dynamics of double emulsion droplet under shear. Appl Phys Lett 106:141601CrossRefGoogle Scholar
  9. Chen YP, Wu LY, Zhang L (2015b) Dynamic behaviors of double emulsion formation in a flow-focusing device. Int J Heat Mass Transfer 82:42–50CrossRefGoogle Scholar
  10. Gao F, Su Z-G, Wang P, Ma G-H (2009) Double emulsion templated microcapsules with single hollow cavities and thickness-controllable shells. Langmuir 25:3832–3838CrossRefGoogle Scholar
  11. Hodgkin A, Huxley A (1990) A quantitative description of membrane current and its application to conduction and excitation in nerve. B Math Biol 52:25–71CrossRefGoogle Scholar
  12. Jing T, Ramji R, Warkiani ME, Han J, Lim CT, Chen C-H (2015) Jetting microfluidics with size-sorting capability for single-cell protease detection. Biosens Bioelectron 66:19–23CrossRefGoogle Scholar
  13. Kemna EW, Schoeman RM, Wolbers F, Vermes I, Weitz DA, Van Den Berg A (2012) High-yield cell ordering and deterministic cell-in-droplet encapsulation using Dean flow in a curved microchannel. Lab Chip 12:2881–2887CrossRefGoogle Scholar
  14. Kline JL, Hager JD (2017) Aluminum X-ray mass-ablation rate measurements. Matter Radiat Extremes 2:16–21CrossRefGoogle Scholar
  15. Kong L, Amstad E, Hai M, Ke X, Chen D, Zhao C-X, Weitz DA (2017) Biocompatible microcapsules with a water core templated from single emulsions. Chin Chem Lett 28:1897–1900CrossRefGoogle Scholar
  16. Koziej D, Floryan C, Sperling RA, Ehrlicher AJ, Issadore D, Westervelt R, Weitz DA (2013) Microwave dielectric heating of non-aqueous droplets in a microfluidic device for nanoparticle synthesis. Nanoscale 5:5468–5475CrossRefGoogle Scholar
  17. Lee S, Lee TY, Amstad E, Kim SH (2018) Microfluidic production of capsules-in-capsules for programed release of multiple ingredients. Adv Mater Technol 3:1800006CrossRefGoogle Scholar
  18. Liu X, Chen Y, Shi M (2013) Dynamic performance analysis on start-up of closed-loop pulsating heat pipes (CLPHPs). Int J Therm Sci 65:224–233CrossRefGoogle Scholar
  19. Liu M et al (2014) Improvement of wall thickness uniformity of thick-walled polystyrene shells by density matching. Chem Eng J 241:466–476CrossRefGoogle Scholar
  20. Liu M et al (2016) Investigation of spherical and concentric mechanism of compound droplets. Matter Radiat Extremes 1:213–223CrossRefGoogle Scholar
  21. Liu Y, Huang Q, Wang J, Fu F, Ren J, Zhao Y (2017) Microfluidic generation of egg-derived protein microcarriers for 3D cell culture and drug delivery. Sci Bull 62:1283–1290CrossRefGoogle Scholar
  22. Liu Y, Shang L, Wang H, Zhang H, Zou M, Zhao Y (2018) Multicolored photonic barcodes from dynamic micromolding. Mater Horiz 5:979–983CrossRefGoogle Scholar
  23. Man J, Li Z, Li J, Chen H (2017) Phase inversion of slug flow on step surface to form high viscosity droplets in microchannel. Appl Phys Lett 110:181601CrossRefGoogle Scholar
  24. Pan DW et al (2018) Formation mechanisms of solid in water in oil compound droplets in a horizontal T-junction device. Chem Eng Sci 176:254–263CrossRefGoogle Scholar
  25. Sauret A, Cheung Shum H (2012) Forced generation of simple and double emulsions in all-aqueous systems. Appl Phys Lett 100:154106CrossRefGoogle Scholar
  26. Seiffert S, Thiele J, Abate AR, Weitz DA (2010) Smart microgel capsules from macromolecular precursors. J Am Chem Soc 132:6606–6609CrossRefGoogle Scholar
  27. Shang LR, Cheng Y, Zhao YJ (2017) Emerging droplet microfluidics. Chem Rev 117:7964–8040CrossRefGoogle Scholar
  28. Song Y et al (2018) Budding-like division of all-aqueous emulsion droplets modulated by networks of protein nanofibrils. Nat Commun 9:2110CrossRefGoogle Scholar
  29. 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
  30. Wan J, Bick A, Sullivan M, Stone HA (2008) Controllable microfluidic production of microbubbles in water-in-oil emulsions and the formation of porous microparticles. Adv Mater 20:3314–3318CrossRefGoogle Scholar
  31. Wang W, Xie R, Ju XJ, Luo T, Liu L, Weitz DA, Chu LY (2011) Controllable microfluidic production of multicomponent multiple emulsions. Lab Chip 11:1587–1592CrossRefGoogle Scholar
  32. Wang J, Zou M, Sun L, Cheng Y, Shang L, Fu F, Zhao Y (2017) Microfluidic generation of Buddha beads-like microcarriers for cell culture. Sci China Mater 60:857–865CrossRefGoogle Scholar
  33. Wang H, Zhao Z, Liu Y, Shao C, Bian F, Zhao Y (2018a) Biomimetic enzyme cascade reaction system in microfluidic electrospray microcapsules. Sci Adv 4:eaat2816CrossRefGoogle Scholar
  34. Wang J, Gao W, Zhang H, Zou MH, Chen YP, Zhao YJ (2018b) Programmable wettability on photocontrolled graphene film. Sci Adv 4:eaat7392CrossRefGoogle Scholar
  35. Wu J, Shi M, Chen Y, Li X (2010) Visualization study of steam condensation in wide rectangular silicon microchannels. Int J Therm Sci 49:922–930CrossRefGoogle Scholar
  36. Zhang H et al (2014) Fabrication of a multifunctional nano-in-micro drug delivery platform by microfluidic templated encapsulation of porous silicon in polymer matrix. Adv Mater 26:4497–4503CrossRefGoogle Scholar
  37. Zhao X et al (2016) Injectable stem cell-laden photocrosslinkable microspheres fabricated using microfluidics for rapid generation of osteogenic tissue constructs. Adv Funct Mater 26:2809–2819CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Wei Gao
    • 1
  • Meimei Sun
    • 1
  • Weibo Yang
    • 2
  • Chengbin Zhang
    • 1
  1. 1.Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and EnvironmentSoutheast UniversityNanjingPeople’s Republic of China
  2. 2.School of Hydraulic, Energy and Power EngineeringYangzhou UniversityYangzhouPeople’s Republic of China

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