Pneumatic Control microfluidic systems and...
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/57 Pneumatic Control microfluidic systems and applications Songjing Li Department of Fluid Control and Automation Harbin Institute of Technology, Harbin, China
Transcript of Pneumatic Control microfluidic systems and...
/57
Pneumatic Control microfluidic systems
and applications
Songjing Li
Department of Fluid Control and Automation
Harbin Institute of Technology, Harbin, China
/57
Contents
Background
Pneumatic off-chip valves
Applications
Conclusions and outlooks
Pneumatic microvalves and systems
/57
1 Background
Chip size: several cm2
All kinds of functionsChemical reaction, biomedical analysis
Drug delivery
Micro-channel networkControllable fluidic system
Lab on a chip
/57
Pneumatic microfluidic chips
large scale integrated pneumatic microfluidic chips
1 Background
Quake's Group, Stanford University, 2000
Large scale integrations with hundreds pneumatic micro valves and
actuators
/57
1 Background
/57/57
To make the off-chip supporting
devices smaller, portable and easily
to be integrated with the chips
1 Background
Prof. Whitesides, Harvard University
Schematic of a pneumatic actuated multi-
layer microfluidic chip with its pneumatic
supporting systems
/57
Schematic design of the microvalve in open state (left) and closed state (right)
Advantages： PDMS valve body, smaller friction
force on the spool Better sealing Better to be linked with the chip Rapid prototyping
Schematic design of the electromagnetic actuator (a), 1.plastic housing;
2. ferromagnetic shell; 3.coil; 4=static iron; 5.moving iron; 6.return
spring; 7.positioning pins; 8.fixing device; 9.glass slide; 10.valve core.
PDMS valve body + low cost actuation
2 Pneumatic off-chip valves
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2 Pneumatic off-chip valves
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Driving methods of the PDMS pneumatic off-chip valve
2 Pneumatic off-chip valves
Micro stepper motor
/57
Fabrication of the off-chip valve-
soft lithography
Valve-seat Spool
Stainless
steel tube
Electromagnetic
actuator
Valve-
membrane
PDMS block with
air channel
The packaged Electromagnetic actuator
The packaged the off-chip valve
2 Pneumatic off-chip valves
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Simulation results of the off-chip microvalve
0 10 20 30 40-30
-20
-10
0
10
响应时间 [ms]
反向电动势
[V
]
0 10 20 30 40 50-0.5
0
0.5
1
响应时间 [ms]
阀芯出力
[N
]
0 10 20 30 40
0
50
100
150
电磁驱动器吸合时间 [ms]
阀芯位移
[μ
m]
0 10 20 30 40
0
50
100
150
电磁驱动器释放时间 [ms]
阀芯位移
[μ
m]
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
30kPa
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
50kPa
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
100kPa
0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
占空比0.2
0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
占空比0.5
0 0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [t]
片下微阀出口流量
[m
l/m
in]
占空比0.8
Back electromotive voltage Spool actuated force Spool pull dynamic response
Outlet flow rate of the
off-chip micrvalve
under different
pressures
Outlet flow rate of the
off-chip micrvalve
under different duty
cycles
Spool release dynamic response
30kPa 50kPa 100kPa
0.2 0.5 0.8
2 Pneumatic off-chip valves
Time（s）
Flo
w r
ate（
ml/m
in）
Time（s）F
low
rate（
ml/m
in）
Time（s）
Flo
w r
ate（
ml/m
in）
Time（s）
Flo
w r
ate（
ml/m
in）
Time（s）
Flo
w r
ate（
ml/m
in）
Time（s）
Flo
w r
ate（
ml/m
in）
Time（ms）
Flo
w r
ate（
ml/m
in）
Time（ms）
Flo
w r
ate（
ml/m
in）
Time（ms）
Flo
w r
ate（
ml/m
in）
Time（ms）
Flo
w r
ate（
ml/m
in）
/57
0 10 20 30 40
0
50
100
150
微阀打开时间 [ms]
阀芯位移
[μ
m]
仿真结果
试验结果
0 10 20 30 40
0
50
100
150
微阀关闭时间 [ms]
阀芯位移
[μ
m]
仿真结果
试验结果
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
600
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
30kPa 仿真结果
30kPa 试验数据压差30kPa
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
600
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
50kPa 仿真结果
50kPa 试验结果压差50kPa
0.2 0.4 0.6 0.8 1
0
100
200
300
400
500
600
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
100kPa 仿真结果
100kPa 试验数据压差100kPa
0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
仿真结果
试验数据占空比0.2
0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [s]
片下微阀出口流量
[m
l/m
in]
仿真结果
试验数据占空比0.5
0 0.2 0.4 0.6 0.8 1-50
0
50
100
150
200
250
300
350
响应时间 [t]
片下微阀出口流量
[m
l/m
in]
仿真结果
试验数据占空比0.8
Comparison between
experimental data about outlet
flow of the off-chip micrvalve
under different pressures and
simulation results
Comparison between
experimental data about outlet
flow of the off-chip micrvalve
under different duty cycles and
simulation results
Testing schematic diagram and response time
experimental results of the electromagnetic
microvalve
2 Pneumatic off-chip valves
Time（s）Time（s）Time（s）
Time（s）Time（s）Time（s）
Flo
w r
ate（
ml/m
in）
Flo
w r
ate（
ml/m
in）
Flo
w r
ate（
ml/m
in）
Flo
w r
ate（
ml/m
in）
Flo
w r
ate（
ml/m
in）
Flo
w r
ate（
ml/m
in）
Time（ms）Time（ms）
Dis
pla
cem
ent(μ
m)
Dis
pla
cem
ent(μ
m)
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Structure and working principle of the on-chip microvalve
Schematic of one membrane microvalve
with a pneumatic actuator
Schematic diagrams in Fully open/ partially open/ fully
closed state of the membrane microvalve
Three-dimensional structure view
3 Pneumatic microvalve and system
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Structure of the PDMS pneumatic pressure driven microvalve
3 Pneumatic microvalve and system
PDMS pneumatic pressure driven microvalve and the
system
三通微阀
PDMS气压控制微阀
气源
电磁驱动器1 电磁驱动器2
膜阀
电磁微阀1
三通微阀
膜阀
气源
排气口
电磁微阀1
液体微通道
PDMS驱动薄膜
电磁微阀2
驱动腔
电磁微阀2
液体微流道
气动微流控芯片
气动微驱动器
排气口芯片外部
Compressed
air
atmosphere
Off-chip
valve
pipe
pneumatic
channel
PDMS
membrane
Liquid
channel
Liquid
channel
Pneumatic
microfluidic
chip
Pneumatic
actuation
Liquid
channel
/57
(a) Undeformed configuration of 1/4 structure; (b) Deformed configuration
of 1/4 structure; (c) Cross-sectional view (pmd <pclose); (d) Cross-sectional
view (pmd ≥pclose); (e) Longitudinal sectional view (pmd＝pclose); (f)
Longitudinal sectional view (pmd>pclose).
conclusion：1.Large deformation theory;
2.Nonlinear characteristics;
3.Uniform deformation in length.
a b
c
d
e
f
3.2 Multi-physical fields coupling mechanism and mathematic models research
PDMS actuated membrane deflection mathematic
model and characteristics analysis
213
4
13 mm md mmax
m
( )w vp w
Eh
2
3m m max
ml w
V
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Flow rate mathematical model of the on-chip microvalve under different valve-openings
and calculation analysis
b0
a0/2
b
y
x
0
2( )
3
aA b b
Size of the valve port of the on-chip microvalve
Cross-section area
2 d
Pq C A
Driven liquid pressure kPa
Pneumatic pressure kPa10 20 30
0 2.05×103 1.85×103 1.72×103
10 1.87×103 2.89×103 2.26×103
20 2.13×103 3.74×103 3.54×103
30 1.62×103 3.01×103 5.61×103
40 1.14×103 2.26×103 3.69×103
50 0.69×103 1.61×103 2.80×103
60 0.30×103 0.98×103 1.97×103
70 0 0.42×103 1.20×103
80 0 0 0.52×103
90 0 0 0
Theoretical calculated liquid flow rate with different valve-openings of
the on-chip microvalve (μL/min)
3 Pneumatic microvalve and system
/57
Model of the actuated chamber with
variable volume
可变容积控制体外界
可变容积控制体可移动边界
出口约束节流口
进气约束节流口
S管A管
Q
dt
1dm
dt
2dm
dt
1p 2p
2T1T
. .pV T
m
3 Pneumatic microvalve and system
Variable volume
chamber outside
surface
Variable volume
chamber control
interfaceOutlet
orifice
inlet
orifice
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Numerical calculation results of response time for TBC under different
pressures, the initial differential pressure is 10kPa, 52kPa, 90kPa, 120kPa,
150kPa, separately
0 12864
单位:μm
The actuated PDMS membrane
deformation under 100kPa
3 Pneumatic microvalve and system
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
/57
min
max
0 ( )( )
1 ( )
e k Ek
e k Eu
Bang-Bang controller: Set two control limit values
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6100
120
140
160
180
200
220
时间ｔ[ｓ ]
绝对压力
p [
kP
a]
130kPa
150kPa
200kPa
0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1128.5
129
129.5
130
130.5
时间t [s]
绝对压力
p [
kP
a]
0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
199
200
201
202
时间t [s]
绝对压力
p [
kP
a]
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8100
110
120
130
140
150
160
时间t [s]
绝对压力
p [
kP
a]
下阈值0kPa
下阈值-0.5kPa
下阈值-1kPa
下阈值-2kPa
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8100
110
120
130
140
150
160
时间t [s]
绝对压力
p [
kP
a]
上阈值0kPa
上阈值0.5kPa
上阈值1kPa
上阈值2kPa
Step response process of the actuator
under different inlet pressures
Step response process under different
Bang-Bang lower thresholds
0.2 0.25 0.3 0.35 0.4 0.45 0.5148.5
149
149.5
150
150.5
151
151.5
152
152.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5148.5
149
149.5
150
150.5
151
151.5
152
152.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5148.5
149
149.5
150
150.5
151
151.5
152
152.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5148.5
149
149.5
150
150.5
151
151.5
152
152.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5147.5
148
148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5147.5
148
148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5147.5
148
148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.2 0.25 0.3 0.35 0.4 0.45 0.5147.5
148
148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
-2kPa -1kPa
-0.5kPa 0kPa
2kPa 1kPa
0.5kPa 0kPa
130kPa
150kPa
200kPa
Step response process under different
Bang-Bang super thresholds
3 Pneumatic microvalve and system
Time（ms）C
ham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
/57
1 ( 1) ( 1 )( ) 1,2,...,
0 ( 1 )
j T t j D Tu t j n
j D T t jT
PWM controller: modulations duty cycles
0 0.2 0.4 0.6 0.8 1 1.2 1.4100
110
120
130
140
150
160
时间 t [ms]
绝对压力
p [
kP
a]
P控制
无P控制
0.4 0.45 0.5 0.55 0.6 0.65148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [k
Pa]
0.4 0.45 0.5 0.55 0.6 0.65148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0 0.2 0.4 0.6 0.8 1 1.2 1.4100
110
120
130
140
150
160
时间 t [s]
绝对压力
p [
kP
a]
10Hz
20Hz
50Hz
100Hz
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
时间t [s]
绝对压力
p [
kP
a]
0 0.2 0.4 0.6 0.8 1 1.2 1.4100
110
120
130
140
150
160
时间t [s]
绝对压力
p [
kP
a]
设定误差0.1kPa
设定误差0.5kPa
设定误差1kPa
设定误差2kPa
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
0.5 0.6 0.7 0.8 0.9 1148.5
149
149.5
150
150.5
151
151.5
时间t [s]
绝对压力
p [
kP
a]
Pressure control
performance impact of the
pneumatic micro actuator
with P controller or without
P controller
Without P controller
Pressure control
performance impact of the
pneumatic micro actuator
with different PWM carrier
frequencies
10Hz 20Hz
50Hz 100Hz
2kPa 1kPa
0.5kPa 0.1kPa
With P controller
Pressure control
performance impact
of the micro actuator
with different PWM
carrier amplitudes
3 Pneumatic microvalve and system
Time（s）Cham
ber pre
ssure
(kP
a)
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（ms）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（s）
Cham
ber pre
ssure
(kP
a)
Time（ms）
Cham
ber pre
ssure
(kP
a)
Time（ms）
Cham
ber pre
ssure
(kP
a)
Time（ms）
Cham
ber pre
ssure
(kP
a)
Time（ms）
/57
Composite controller：Bang-Bang+P+PWM composite controller
0 0.2 0.4 0.6 0.8 1 1.2 1.4100
110
120
130
140
150
160
时间t [s]
绝对压力
p [
kP
a]
1 1.1 1.2 1.3 1.4149
150
151
0 0.5 1 1.5 2 2.5 3100
150
200
时间t [s]
绝对压力
p [
kP
a]
实际压力
设定压力
0 0.5 1 1.5 2 2.5 3-100
-50
0
50
100
时间t [s]
压力误差
pee
r[kP
a]
Actuated chamber pressure change
process of the actuator chamber
tracking step signal
Tracking error change process
Composite controller
model of the actuated
chamber pressure
3 Pneumatic microvalve and systemC
ham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Cham
ber
pre
ssure
(kP
a)
Time（ms）
Step response curve of the actuated chamber
pressure using composite control method
(150kPa)
/57
Microscope
pictures of arc
molds
Pictures of damaged
mold and patterned
PDMS block
Pictures of arc
molds
surface profiles
Microscope
pictures of PDMS
cast surfaces
128μm
40μm
202μm
58μm276μm
62.6μm
3 Pneumatic microvalve and system
/57
Experimental research
Schematic diagram of performance measurement
for the off-chip microvalve
Comparison between the spool actuated force results
NO Parameters Valves
1 Experiment /N 0.844
2Simulation / N
0．88
1
2 Theory /N 0.983
3 Design demand /N 0.220
流量
[m
l/m
in]
25 50 75 100
流量
[m
l/m
in]
压差50kPa流量
[m
l/m
in]
100
150
200
250
50
0
0 0.2 0.4 0.6 0.8 1
阀口开度
试验值
仿真值
Measurement results when
differential pressure is
50kPa
Leak rate Flow rate under fully open
3 Pneumatic microvalve and system
Flo
w r
ate
(ml/m
in)
Time（ms）
Flo
w r
ate
(ml/m
in)
Time（ms）
Flo
w r
ate
(ml/m
in)
Time（ms）
/57
0 50 100 1500
50
100
150
200
压差P [kPa]
m
ax [
μm
]
理论值
仿真值
试验值
0 5 10 15 20 25 30
100
101
102
反应时间 [ms]
m
ax [
μm
]
data1
16kPa
52kPa
90kPa
120kPa
150kPa
8
响应时间 [ms]
充气压力（kPa） 16 52 90 120 150
Theoretical inflation time tⅠ(ms) 0 0 0 1.26 2.23
Theoretical inflation time tⅡ(ms) 9.69 16.01 20.65 21.86 23.05
Theoretical total inflation time t(ms) 9.69 16.01 20.65 23.12 25.28
Experimental total inflation time ts(ms) 10.05 15.2 19.72 24.93 27.19
Error δ% -3.72% 5.06% 4.52% -7.85% -7.55%
Comparison between experimental results and theoretical calculation results about response time
of the pneumatic micro actuator (valve-opening of the electromagnetic microvalve 1 is 20%)
0 0.2 0.4 0.6 0.8 10
10
20
30
40
50
阀口开度
TB
C反应时间
[m
s]
20kPa
50kPa
80kPa
100kPa
150kPa
Response time simulation results of the
pneumatic micro actuator with different valve-
openings of the electromagnetic microvalve 1
Experimental results compared with the
theoretical calculation and FEM results of the
PDMS actuated membrane maximum deflection
versus different pressures with dimension
500μm×200μm×40μm
Dynamic response testing curves of the pneumatic
micro actuator maximum deflection with the
actuated part dimension 200μm×500μm
Microscope images of the PDMS actuated
membrane deformations versus different
pressures with the actuated part dimension
200μm×500μm
3 Pneumatic microvalve and system
Response
tim
e(m
s)
Time（ms）Valve openingPressure difference（kPa）
/57
Test bench for liquid flow rate of the membrane
microvalve
Driven liquid kPa
Pneumatic pressure kPa10 20 30
0 85 189 240
10 93 200 274
20 75 226 310
30 45 112 374
40 28 66 148
50 12 42 93
60 4 19 56
70 1 7 30
80 0 4 12
90 0 1 5
100 0 0 4
110 0 0 1
120 0 0 0
Liquid flow rates measuring results with different valve-openings of the
membrane microvalve (μL/min)
Comparison between modified theoretical results
and experimental datas about liquid flow rate of
the membrane microvalve
3 Pneumatic microvalve and system
Flo
w r
ate
(ml/m
in)
pressure（kPa）
/57
Compressed-air driven liquid system， a compressed-air driven liquidsystem is used for controlling the accurate differential pressure for theliquid microchannels, The compressed air system linked to the airchannels is used for control the air pressure in the pneumatic actuators.
Diagram of fluid driving setup
3 Pneumatic microvalve and system
/57
Experimental setup of PDMS pneumatic micro actuator of the on-
chip microvalve
Main performances
1.Less than accuracy 1kPa；2.Working pressure 100kPa；3.Responding speed（1ms<rt<1s）；
Computer Power amplifier N2 tankPrecision regulator
Pneumatic micro actuator with the 3-way microvalve
Data acquisition card
Linear power supply
Signal amplification
Miniature pressure sensor
Miniature pressure sensor XCQ-062
PCI-1710-CE data acquisition card
Signal amplification
3 Pneumatic microvalve and system
/57
pneumatic micro mixing chip
Structure of the pneumatic micro mixing chip
PDMS actuated membrane
motion in a cycle
Reagents motion of the micro
mixing chamber in a cycle
4 Applications
/57
Pictures of reagents
and their containers
Test bench for measuring the
micro mixing chip performances
4 Applications
/57
0 5 10 15 20 250
0.2
0.4
0.6
0.8
1
时间t [min]
混合效率
inde
x
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
inde
x
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [t]
混合效率
index
振动频率 0.5Hz
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
index
振动频率 1Hz
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
index
振动频率 2Hz
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
index
驱动气压 10kPa
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
index
驱动气压 20kPa
0 2 4 6 8 100.2
0.4
0.6
0.8
1
时间t [s]
混合效率
index
驱动气压 30kPa
Influence of vibrating frequency on mixing efficiency
Influence of
actuated pressure
on mixing
efficiency
4 Applications
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5 Conclusions and outlooks
Conclusions
• pneumatic microvalves can be easily integrated with microchips and
fabricated if the valve body was made of PDMS.
• pneumatic microfluidic systems can be controlled by the PDMS
microvalves to realize the pressure control below 200kPa.
• PDMS pneumatic microvalves can be applied in micro-mixer chips to
improve the mixing effieciency.
Future work
• Improve the accuracy of the pressure control and responding speed.
• Make further integration of the valve group for large scale integration.
• To develop wireless and remote control model for microfluidic systems.
