Open microfluidics, the study of microflows having a boundary with surrounding air, encompasses different aspects such as paper or thread-based microfluidics, droplet microfluidics and open-channel microfluidics.
Open-channel microflow is a flow at the micro-scale, guided by solid structures, and having at least a free boundary (with air or vapor) other than the advancing meniscus. This book is devoted to the study of open-channel microfluidics which (contrary to paper or thread or droplet microfluidics) is still very sparsely documented, but bears many new applications in biology, biotechnology, medicine, material and space sciences. Capillarity being the principal force triggering an open microflow, the principles of capillarity are first recalled. The onset of open-channel microflow is next analyzed and the fundamental notion of generalized Cassie angle (the apparent contact angle which accounts for the presence of air) is presented. The theory of the dynamics of open-channel microflows is then developed, using the notion of averaged friction length which accounts for the presence of air along the boundaries of the flow domain. Different channel morphologies are studied and geometrical features such as valves and capillary pumps are examined. An introduction to two-phase open-channel microflows is also presented showing that immiscible plugs can be transported by an open-channel flow. Finally, a selection of interesting applications in the domains of space, materials, medicine and biology is presented, showing the potentialities of open-channel microfluidics.
Author(s): Jean Berthier, Ashleigh B. Theberge, Erwin Berthier
Series: IOP Concise Physics
Publisher: IOP Publishing
Year: 2019
Language: English
Pages: 172
City: Bristol
PRELIMS.pdf
Foreword
Acknowledgments
Author biographies
Jean Berthier
Erwin Berthier
Ashleigh B Theberge
Nomenclature
Outline placeholder
0.1 Paper-based microfluidics
0.2 Thread-based microfluidics
0.3 Sessile droplets microfluidics
0.4 Open-channel microfluidics
0.5 Book contents
References
CH001.pdf
Chapter 1 Capillarity theoretical basis
1.1 Liquid surface tension
1.2 Laplace pressure
1.3 Liquid–liquid surface tension
1.4 Contact with solid surface: Young’s law
1.5 Neumann’s construction
1.6 Work of adhesion, work of cohesion and the Young–Dupré equation
1.7 Solid surface energy: Zisman’s approach
1.7.1 Using Young’s law
1.7.2 Using Zisman’s plot
1.8 Wetting and pinning
1.8.1 Wetting
1.8.2 Pinning and canthotaxis
1.9 Wenzel law
1.10 Cassie–Baxter law
1.11 Capillary rise
1.12 Marangoni convection
References
CH002.pdf
Chapter 2 Condition for capillary flow in open channels
2.1 Spontaneous capillary flow in a monolithic channel
2.2 Spontaneous capillary flow in composite open channels: the generalized Cassie condition
2.3 Enhanced open capillary flows
2.3.1 Constant additional inlet pressure
2.3.2 Overfilled reservoir: initial additional Laplace pressure
Conclusions
References
CH003.pdf
Chapter 3 Flow dynamics in open channels
3.1 Background: spontaneous capillary flow in composite, closed channels of arbitrary uniform cross section
3.2 Flow dynamics in open micro-channels of uniform cross section
3.3 Flow dynamics in open micro-channels of variable cross sections
3.3.1 Sudden constriction and enlargements
3.3.2 Sudden enlargement with pinning: open capillary valves
3.3.3 Progressive enlargements
3.3.4 Capillary pumps
3.3.5 Filters
3.3.6 One-way wicking
3.4 The capillary dynamics of non-Newtonian fluids
3.4.1 Shear-thinning fluids
3.4.2 The case of whole blood
References
CH004.pdf
Chapter 4 Open-channel geometries
4.1 Rectangular channels
4.2 Rectangular channels with imperfect corners
4.3 Rounded channels
4.4 Semi-cylindrical channel
4.5 Suspended channels
4.6 Rails
4.7 Embossed channels
4.8 Fiber bundles and flow caging
4.9 Capillary rise and uphill open capillary flows
4.10 Capillary networks
4.10.1 Example #1
4.10.2 Example #2
4.10.3 Capillary flow after a bypass or a derivation
Conclusion
References
CH005.pdf
Chapter 5 Capillary filaments
5.1 Capillary filaments: the Concus–Finn condition
5.2 The case of V-grooves
5.3 Capillary filaments in open-channel turns
5.4 Capillary filaments in non-uniform channels
5.5 Detached capillary filaments
5.6 Metastable capillary filaments
5.7 Capillary filaments driving SCF
5.8 Dynamics of capillary filaments
5.9 Drying of capillary filaments
5.10 Capillary filaments stopped by rounded wedges
Conclusion
References
CH006.pdf
Chapter 6 Two-phase open-channel capillary flows
6.1 Introduction
6.2 Plugs in uniform cross section open channels
6.2.1 Quasi steady state approach: SCF condition in the presence of plugs
6.2.2 Plugs dynamics in open-channel capillary flow
6.2.3 Conclusions
6.2.4 Capillary wagons
6.3 Bypasses and bifurcations
6.3.1 Bifurcations
6.3.2 Bypasses
6.4 Plugs and capillary filaments
6.4.1 Plugs moved by capillary filaments
6.4.2 Plugs blocked by reverse capillary filaments
Conclusions
References
CH007.pdf
Chapter 7 Applications
7.1 Materials and fabrication
7.2 Space: design of vanes
7.2.1 Space cup
7.2.2 Vanes
7.3 Microfluidics
7.3.1 Capillary channels on paper
7.3.2 Evaporation capillary pumping
7.4 Biology, biotechnology and medicine
7.4.1 Gel electrophoresis
7.4.2 Micro-dots for cell studies
7.4.3 Mimicking lungs
7.4.4 Micro-device for cell behavior studies
7.4.5 In vivo sensors
7.4.6 Open-channel microfluidics for whole blood analysis
7.5 Biochemistry: Liquid–liquid extraction
Conclusion
References
CH008.pdf
Chapter 8 Epilog
References
