Released Capsule
AdvisorHsiang-Chen Hsu
AdvisorChiung-Ta Lee

I-Shou University
for the Master degree

i

w/o
w/o/w

ii
Abstract
In this study, the microfluidic emulsion chips was fabricated using
micro-electro-mechanical system(MEMS) technique. There is the research in this
thesis. It is two-step emulsification with two-dimentional hydrodynamic focusing
structure; The research is shape design in microchannel. By cascading two
hydrodynamic focusing s t ructure , double emuls ion droplets can be
generated.
The microfluidic chip proposed can also be used to generate well size-controlled
double emulsion microdroplets in liquids by integrating three mechanisms including a
traditional emulsification process by a T-junction design, hydrodynamic focusing
structure and microchannels. By the combination of these mechanisms of the
incroporated T-junction channel design and microchannels, water-in-oil (w/o) droplets
at the intersection of the water phase and the oil phase can be generated. Then, double
emulsion droplets (w/o/w) were formed by using the hydrodynamic focusing structure
at intersection of the oil phase and the external water phase. The emulsion droplets
with different diameters were produced by change water phase and oil
phase velocity.
The chip in this study is to combine SU-8 negative photoresist in the process of
photolithography to produce circular microchannel mould. This mold can then be used
to replicate circular microchannel with PDMS. Since PDMS is a soft material, there
will be a crack on structure while demolding. However, the crack can be recovered
during the process of thermal bonding of PDMS componants, for PDMS molecules
would osmose into the crack. Therefore we can reproduce circular microfluidic
channels by PDMS demolding process. We successfully fabricate emulsification chips
iii
with hydrodynamic focusing structure to produce double emulsion droplets. These
device have shown great promise in various applications including emulsification,
nano-medicine and droplet-based microfluidicds.
PDMS, MEMS


4-3 ………………………………………………………..39
4-4 ……………………………..40
3.1 ………………………………………………………29
3.1 ………………………………………………………30
3.3 ……………………………………………………30
ix

1.4 T…………………………………..........................6 1.5 W/O/W …………………………………..……6
1.6 …….…….7
1.7 ……………….……….…7
1.8 ………………..8
1.9 ………………………………………………..9
1.10 …………………9
1.11 ………......10
1.13 …………………………………..11
1.14 ………………………..11
2.1 ……………………………………....16
2.2 ……………………………………16
2.3 …………………………………………18
3.10 …………..……………………………………33
3.11 ………………...…………...35
4.1 ………………………………………………37
4.3 T -…………………………………39
4.4 -…………………………………39
DI WaterDeionized Water
HLBHydrophilic lipophilic balance
MEMSMicro-electro-mechanical-systems
PRPhotoresist
PDMSPolydimethylsiloxane
UVUltraviolet
μ-TASMicro-total-analysis-systems
o/woil-in-water
w/owater-in-oil
o/w/ooil-in-water-in-oil
w/o/wwater-in-oil-in-water






2
-





[11]
4

[12] 5%
1.2 2005
2%
5
2001 Thorsen T
[14] 1.4 Takasi Nisisako 2002
6
[16] 1.5
1.6(a)
[35]
[16]
1.7
1.7 [18]

8
1.8(b)
(a)
(b)


[23]
1.12(b)
[25]
1.14


PDMS


U 2.1
uu(y)uUy/b 2.1
(velocity gandient)
b aδδβδβ =≈tan
•
(Newtonian fluids) 2-1
FTL-2 BG 1bs/ft2 SI Ns/m2
2.1 [30]

(capillary action)()
( )
γπR2h
θσπγπ cos22 RhR =
17
pΔ πR2
22 RpR πσπ Δ=

18
Ca


(water in oil)


2.5
“” (oil in water)“” (water in oil)


(a) (b) (c) (d)
”“”

[31]
1. (anionic surfactants)


2-2HLB HLB

23
2-3
2-D Sample flow
Sheath flow

[37]
Dvd 11= …………………………………………………...…(2-4)




Start
BOE
5

1300 /(rpm) SU8(3035) 1300
/(rpm) 30 80 (μm) 3.4

28

3.5 95 30
SU8 3.1
29
( m J / c m 2 )
( 3-1 )

65 1 95 5
3.3
3.3

3.4


(1) PDMS 101 1

3.8


PDMS (Oxygen Plasma)
3.9 O2 Plasma
COOHOH PDMS
33
3.9 O2Plasma
(e)PDMS (f)

PDMS



37



(c)

()(DI Water)
115μm 2
675μm 120μm 5
600μm 135μm 10
SampleA, V2
SampleB, V1
micro droplets
165μm 50 400μm
185μm
50 115μm
1








1
(μm)
(μm)
40
4-4


w/o/w
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