Team #2With Passive Micro Mixer, comparison performances between three different topics ; 1. Entrance Type, 2.Ostacle, 3. Flowing way 2011. 12. 105142402 Jang, Joon-Hyuk 06142367 Lee, Byung-Joo 08112305 Kim Kyu-RiSeoul National University of Technology and Science MSDE Program

CONTENTSIntroduction Experimental method Design & Comparison Result and Discussion Entrance Type Obstacle Flowing way

Conclusion ReferencesSeoul National University of Technology and Science MSDE Program

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Introduction With the development of MEMS-base, Micro fluidic technology has developed part of chemistry, biotechnology, and other industries for successful application. Micro-mixer can be divided Active method and Passive method Incase of Active method has good efficiency but it has problem ; difficult to built up, using external power(low-economical) However, Incase of Passive has no using external power(Economic), just change internal shape More focused on this study Moreover, Micro size fluidic(laminar flow) so we should consider Reynold number different each Micro-mixer shape. Thus, in this study, we design three different topic of shape(1.Entrance Type, 2.Obstacle, 3.The flowing way) and comparison of performance, Finally finding and generate which shape has the highest efficient.

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Fabrication- Cleaning - Soft bake Photo lithography - PEB Develop photoregsist 110m - Rinse - SU-8coating - Exposure - Develop - Hard bake - Pre-coating - Molding - Baking - Mold detachment - Plasma treatment - Bonding

PDMS molding Make channel

PDMS bonding Stick on wafer

Tubing

TestSeoul National University of Technology and Science MSDE Program

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Photo lithographyCleaning Dipping in Acetone&IPA each for 2min

SU-8 Coating Low spin: 500rpm,5sec High spin: 2000rpm,45sec

Soft Bake 95 c hot plate, 25min.

Exposure Use MA-8(UV: broadband, Iline 365nm)240mJ/cm2 for 6.3 sec

PEB 95 c hot plate,25min.

Develop SU-8 Developer 10min.

Rinse IPA 3min

Inspection Inspect patterns

Hard bake 200 c hot plate, 10min

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PDMS moldingTaping Kapton tape

Pre-coating In vacuum desiccators, trichlorosilane drops 3 times

Molding Mix(Sylgard18430g/hardener3g)

Venting Remove bubble with venting for 30 min

Baking Oven80 C(20min)

Mold Detachment ParafilmFront&back

Punching Punch inlet & outlet

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PDMS bondingPlasma treatment O2:40sccm,A r:8sccm Wafer 2 times, mold 1 time

Splitting wafer Cut in 4 pieces

Cleaning Nitrogen gas

Bonding Drop Alcohol and bonding 60 C 10 min

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Tubing1) PDMS structure tubing 2) Connect tubes to mold with PDMS 3) Oven 15min

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Fabrication Result

#1 Sample

#2 Sample

#3 Sample

#4 Sample

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TestMix Ink & Water - Mixing rate 2ml(Ink) : 4ml(Water) = 1 : 2

Inject Ink Sample #1 & 2 0.05ml/min

Obseve Result

Sample #3 & 4 0.05 - 1.2ml/min

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Experiment Result#1 Sample #2 Sample

#3 Sample

#4 Sample

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Sample Design & Comparison#1 SamplePath Length 26(mm)

#2 SamplePath Length 26(mm)

19.33 (mm)

19.33 (mm)

19.55(mm)

19.55(mm)

#3 Sample

#4 Sample

Design Factors Entrance Type- T-type, Y-Type

26 (mm)

Obstacle22.7 (mm)

- Fin shape, D&S shape

Flowing way- One way, Spread and collect21.7(mm) 20(mm) Seoul National University of Technology and Science MSDE Program

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Sample Design & Comparison(Entrance Type)#1 Sample #2 Sample

Comparison Entrance Type Mixing efficiency Sample 1 & 2 : T shape Constrain Sample #3 Sample #4 Same Flow rate : 0.05ml/m Same Viscosity

Sample 3 & 4 : Y shapeSeoul National University of Technology and Science MSDE Program

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Result and Discuss(Entrance Type)

Different RGB Value

Sample #1 - T shape

40

Sample #3 - Y shape

T shape - RGBSeoul National University of Technology and Science MSDE Program

X : Distance Y : RGB

Y shape RGB14

Sample Design & Comparison(Obstacle)#1 Sample #2 Sample

Comparison Obstacle Mixing efficiency Constrain #3 Sample Flow rate : 0.05ml/m #4 Sample Same Same Viscosity Same path length : 23.6cm Sample 1 : Diamond & Square

Sample 2 : Fin shapeSeoul National University of Technology and Science MSDE Program

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Sample Design & Comparison(Obstacle)#1 Sample : D&S shape #2 Sample : Fin shape

#1 Line #2Line

1st Floor

1st Floor

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Result and Discuss(Obstacle)3rd Floor 2nd Floor 1st Floor #15 Line 1st Floor #13 Line 1st Floor #10 Line 1st Floor #7 Line 1st Floor #4 Line 1st Floor #1 Line

D & S

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

F I N

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

100 (

)

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Result and Discuss(Obstacle)Fin Shape is better than D&SFin shape almost completely Mixed at First Floor(#9 Line)100 ( ) 100 ( )

D&S Shape almost completely Mixed at First Floor(#13 Line)

Fin shape Sample #2

Diamond & Square Sample #1

Y : Different RGB

Why are there small differences? Lopsided flow is existed because of channel shape

Line No. 13 (sample #2)

Outlet (sample #2)

X : Line #18

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Result and Discuss(Obstacle)Real model

Ideal model

100 (

)

100

Velocity From Fluid outside into the channel of center(layer)Seoul National University of Technology and Science MSDE Program

Hard Fabrication (Developing step) Small size of obstacle and gap(10 ) Diamond ; 50X45( ) Square ;45 X50( )

100 (

)

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Sample Design & Comparison(Flowing way)#1 Sample #2 Sample

Comparison Flowing way method Mixing efficiency #3 Sample Constrain #4 Sample Same Obstacle Same Viscosity

Sample 1 & 2 : One way

Sample 2 & 4 : Spread and collect

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Result and Discuss(Flowing Way)Sample 1 : One way Sample 3 & 4 : Spread and collect

same Obstacle

Problems1. A lot of empty space having blocking channel(flow rate did not fulfill total sample volume) 2. Flowing each single color not mixed #3 sample(undiffused at center space) #4 sample(Sub path width is wider(0.1mm) than when we expected)

#3Chamber Volume Flow rate 0.00704 (mL) 0.0008 (mL/s) 1 : 0.11 Main Path Size Sub Path Size 0.2 (mm)

#40.00781 (mL) 0.0008 (mL/s) 1 : 0.1 0.3 (mm) 0.1 (mm) 3:1

Thesis0.00003 (mL) 0.000075 (mL/s) 1 : 2.5 0.05 (mm) 0.007 (mm) 7.14 : 1

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Result and Discuss(Flowing Way) #3

200um

200um

200um

200um

200um

200um

200um

200um

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Result and Discuss(Flowing Way) #4

200um

200um

200um

200um

200um

200um

200um

200um

200um

200um

200um

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PossibilityIncreasing Flow rate at #3 SampleWhen we increased Flow rate(0.05ml/m 1.2ml/m), it could increase mixing rate. Moreover, especially Round shape has generate chaos advection at high value of Flow rate(1.2ml/m)

Flow rate : 0.05ml/m

Flow rate : 1.2ml/m

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Conclusion We considered Three different factors(1. Entrance Type 2. Obstacle 3. Flowing way)- Entrance type - Did not affect mixing efficiency between T and Y shape - Obstacle Fin shape is better performance than Diamond and Square shape in terms of mixing rate and Fabrication. - Flowing way One way path have high mixing efficiency than Spread & Collect because of problems ; empty space and flowing each single color not mixed

Moreover, we would expect high mixing rate considering channel proper portion (Chamber Volume : Flow rate, Main Path Size : Sub path size) and obstacle in center space.

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References1. C. A. Cortes-Quiroz 1,*, A. Azarbadegan 1, E. Moeendarbary (2010), An efficient passive planar micromixer with finshaped baffles in the tee channel for wide Reynolds number flow range 2. Ali Asgar S Bhagat, Erik T K Peterson and Ian Papautsky (2007), A passive planar micromixer with obstructions for mixing at low Reynolds Numbers 3. Li-Yu Tseng, An-Shik Yang, Chun-Ying Lee, Chang-Yu Hsieh (2011), CFD-based Optimization of a diamond-obstacles inserted micromixer with boundary protruions 4. Jin Wook Kim, Sang Woo Kim, Do Hyung Lee, Hyung Min Kang (2010), Study of a Y-Channel Micromixer with Obstacles to Enhancing Mixing 5. Jessica Melin, Guillem Gimnez, Niclas Roxhed, Wouter van der Wijngaart and Gran Stemme (2004), A fast passive and planar liquid sample micromixer

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Thank You

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