Microfluidic Pumps MEMS 1082 Matt Southwick, Michael Gale, Leo Li - - PowerPoint PPT Presentation

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Aug 29, 2023 26 likes •196 views

Microfluidic Pumps MEMS 1082 Matt Southwick, Michael Gale, Leo Li Pump Mechanisms Piezoelectric Capacitive Thermal Piezoelectric Microfluidics Pump Theory Piezo coupled to mechanical reservoir Resticition of chamber

SLIDE 1

Microfluidic Pumps

MEMS 1082

Matt Southwick, Michael Gale, Leo Li

SLIDE 2

Pump Mechanisms

Piezoelectric
Capacitive
Thermal

SLIDE 3

Piezoelectric Microfluidics Pump Theory

Piezo coupled to mechanical reservoir
Resticition of chamber causes volume change

E.Q. Li,Q. Xu,J. Sun,J.Y.H. Fuh,Y.S. Wong,S.T. Thoroddsen. “ Design and fabrication of a PET/PTFE-based piezoelectric squeeze mode drop-on-demand inkjet printhead with interchangeable nozzle.” Sensors and Actuators A: Physical. Elsevier. September 2010.

SLIDE 4

Mechanism of operation

Controlled electrical signals cause controlled diaphragm motion
Fluid forced from reservoir by deformation

Feng, Zhang. “Piezoelectric MicropumDrive Rrference Design. Microchip Technology Incorporated.

SLIDE 5

Device Fabrication

Reservoir Micromachining
Semiconductor fabrication techniques for diaphragm

Perçin G, Khuri-Yakub B. “Micromachined droplet ejector arrays for controlled ink-jet printing and deposition.” Review of Scientific Instruments. November 2001.

SLIDE 6

Common Uses and Performance

Bio Pumps
Precision pumping
Volume flow potential
Precision of control
Cost
Power Consumption

https://www.servoflo.com/micropumps/mp6

SLIDE 7

Thermal Microfluidic Pump

Electrical energy to thermal energy
Heat transfer into liquid and generates bubble
Only works with liquids that evaporate quickly when heat transfers in

SLIDE 8

Mechanism of Transduction

SLIDE 9

Fabrication

Microfabrication Technology

○ Photolithography ○ Deposition ○ Etching ○ Oxidization

Layer by Layer

SLIDE 10

Characterization

Location of heating element

○ Roofshoot ○ Edge shoot

Geometry

○ Nozzle Length ○ Cartridge Volume

SLIDE 11

Capacitive Microfluidic Actuator

Detection via capacitance change

○ Only channel capacitance change is significant

Actuation via electrowetting

SLIDE 12

Detection

Position

○ Saturation Capacitance indicates max radius

Velocity

○ Position vs t2 - t1 ○ Plate dimensions used

Volume

○ Magnitude of Saturation Capacitance and sensitivty

SLIDE 13

Transduction

Droplet drawn across channel via electrowetting

○ Electrodes are hydrophobic when unloaded ○ Wetting potential applied to draw droplet to next electrode

Previous plate becomes hydrophobic as next plate becomes hydrophilic

SLIDE 14

Fabrication

1. Spin Coating
2. Lift Off

(lithography)

3. Magnetron

Sputtering

SLIDE 15

Uses

Chemical/Biochemical precise volume delivery/mixing
Printing
Touch Sensor (liquid electrode)

SLIDE 16

Summary

Piezoelectric micro pump - High precision with high cost
Thermal micro pump - Easy fabrication with lower precision
High precision, does not alter fluid - low force

SLIDE 17

Citations

https://www.elveflow.com/microfluidic-tutorials/soft-lithography-reviews-and-tutorials/introduction-in-soft-lithography/pdms-

membrane-thickness-of-a-spin-coated-pdms-layer/az4562-spin-coating/

https://loolab.chem.ucla.edu/research/proteomics.html
https://www.dentonvacuum.com/products-technologies/magnetron-sputtering/
https://en.wikipedia.org/wiki/Lift-off_(microtechnology)