SG2222-SG3135: Micro fluid flows

General information

Each group will prepare a presentation of about 20 minutes. These are presented at the end of the course according to the course schedule.

Each group should also prepare readable handouts, either as copies of transparencies, or as a summarizing text of 1-2 pages.

In addition to presenting your own project, each participant should also choose one other project and act as “opponent”.

The duties of the “opponents” are to prepare questions that can be asked during the presentation, and initiate a discussion.

A number of suggested projects will be presented here, together with suggested literature (typically a few journal articles). The suggested articles are meant as an entry point to the literature. Typically, each group is expected to find one or a few more papers that are either referenced in the suggested papers, or are referencing them (use Science Citation Index). You are welcome to suggest a project more closely related to your own research work!

The expected workload should be 4-5 workdays for the project, and about two hours for preparing the “opposition”.

Each group should contact one of the teachers to discuss the project during the work.

1. Fabrication of Three-Dimensional Microfluidic Systems by Soft Lithography.
Literature: Whitesides, Angew. Chem. Int. Ed. (Angewandte Chemie, International Edition) 1998, vol 37, 550. The presentation should describe the fabrication and how requirements set by the processes to be investigated are fulfilled.

2. Chaotic Mixing
Xia et.al, “Chaotic micromixers using two-layer crossing channels to exhibit fast mixing at low Reynolds numbers”, Lab on a Chip, vol 5, pp 748-755, (2005).
Liu et.al., “Passive mixing in a three-dimensional serpentine microchannel”, Journal of microelectromechanical systems, vol 9, pp190-, (2000).
Discuss the influence of the Reynolds number in mixing, and compare different methods.

3. The Herringbone mixer
A simple design of a mixer that has attracted a lot of attention. Explain the principle and discuss the function and experimental results.
Stroock, A. D., S. K. W. Dertinger, A. Ajdari, I. Mezic, H. A. Stone, and G. M. Whitesides, 2002, Science 295, 647.
Stroock, A. D., and G. J. McGraw, 2004, Philos. Trans. R. Soc. London, Ser. A 362, 971.

4. Visco-elastic effects at micro scale
Squires and Quake, ”Microfluidics: Fluid physics at the nanoliter scale”, Reviews of Modern Physics, 2005, 77, p 977-1026. Take one example from review paper.

5. Temperature gradients as a driving force for micro fluid flow
“Patterning liquid flow on the microscopic scale”, Kataoka and Troian, Nature, 402 (6763): 794-797, dec 16 1999. + references therein. Explain the basic phenomenon and show some example.

6. Electrowetting
Quilliet and Berge, 2001, Current Opinion in Colloid & Interface Science 6, p34-39, and references there
Explain the phenomenon and present the experimental observations.

7. Wetting
Eggers, J. “Existence of receding and advancing contact lines”, Physics of Fluids 17, 082106 (2005)
Detailed mathematical investigation of wetting, with strong claims. Try to explain the mechanism behind the difference in the behavior between advancing and receding contact lines.

8. Wetting from nano- to mesoscale
Literature: Dynamic wetting at the nanoscale, Y. Nakamura, A. Carlson, G. Amberg, and J. Shiomi, (Phys. Rev. E 88, 033010, 2013), Contact-line dynamics of a diffuse fluid interface  (D. Jacqmin, Journal of Fluid Mechanics, 2000, vol. 402), Petter Johansson and Berk Hess, Physical Review Fluids, (2018). The project presentation  should describe the contact angle modelling based on free energy and diffuse interface model (in mesoscale) and molecular interactions (in nano-scale)

9. Is the fluid velocity zero at the wall, i.e. is the no slip condition true?
Gather recent experimental evidence and try to evalutate different explanations and mechanisms. Water Slippage versus Contact Angle: A Quasi-universal Relationship Huang, et al. Phys. Rev. Lett. 101, 226101; Reconciling Slip Measurements in Symmetric and Asymmetric Systems, Zhu et al., Langmuir 2012, 28, 20, 7768-7774; Slip on Superhydrophobic Surfaces, Rothstein, Annual Review Fluid Mechanics, 2010.

10. Superhydrophobic surfaces
”Superhydrophobic States”, Lafuma and Quéré, Nature Materials, 2, (2003). “Laminar drag reduction in microchannels using ultrahydrophobic surfaces”, Ou, J. et.al., Physics of Fluids, vol 16, p4635-, (2004). ”Superhydrophobic materials for biomedical applications”, Falde et al, Biomaterials, 104, 87-103 (2016)
Describe the phenomenon, and some potential uses.

11. Surfactants as a chemical engine in micro fluid flows
Gather experimental evidence on "surfactant controlled" micro fluid flows, and explain their direct affect on the flow phenomena.
Lee S.K., Kwok D.Y., Laibinis .. Journal: Physical review E, Volume 65.

12. The hydrodynamics of swimming microorganisms
“The hydrodynamics of swimming microorganisms”, E. Lauga and T. R. Powers, Rep. Prog. Phys. 72, 096601, 2009.
Explain basic principles of locomotion at low (zero) Reynolds number.

13. Free-energy modelling of biological membranes
Literature: hase-field theories for mathematical modeling of biological membranes, Guillermo R.Lázaro, Ignacio Pagonabarraga, Aurora Hernández-Machado (Chemistry and Physics of Lipids, 2015), Rheology of red blood cells under flow in highly confined microchannels: I. Effect of elasticity( Lázaro, Hernández-Machado, Pagonabarraga, Soft Matter, 2014): The project presentation should include the concept of Helfrich free energy in modelling bending energy of a membrane and the corresponding phase field model.

14. Inertial microfluidics
Explain how inertial effects can be used for cell and particle sorting.
Di Carlo et al, PNAS (2007), 104, 18892; Masaeli et al. PRX, 2, 031017 (2012); Martel and Toner, Annu Rev Biomed Eng. 2014. doi:10.1146/annurev-bioeng-121813-120704