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Transcript of Rheology
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Complex Fluids & Molecular Rheology Lab., Department of Chemical Complex Fluids & Molecular Rheology Lab., Department of Chemical EngineeringEngineering
RheologyRheology
中央大學化材系講稿 10/28/2011
中央大學化材系講稿 10/28/2011
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Rheology is the science of fluids. More specifically, the study of Non-Newtonian Fluids
流體
什 麼 是 流 變什 麼 是 流 變 ((Rheology)Rheology)??
牛頓流體- 水、有機小分子溶劑等
非牛頓流體- 高分子溶液、膠體等
yx Y
VV
YNewton’s law of viscosity
V
黏度 η 為定值
黏度不為定值(尤其在快速流場下 )
Small moleculeMacromolecule
●Deformable
V
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非牛頓流體的三大特徵
特徵時間與無因次群分析
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非牛頓黏度 (Non-Newtonian Viscosity) - Shear Thinning
非 牛 頓 流 體 的 特 徵非 牛 頓 流 體 的 特 徵
p
牛頓流體(甘油加水 )
非牛頓流體(高分子溶液 )
Flow curve for non-Newtonian Fluids
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正向應力差值的效應 (Normal Stress Differences) - Rod-Climbing
牛頓流體 (水 ) 非牛頓流體 (稀薄高分子溶液 )
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記憶效應 (Memory effects) - Elastic Recoil
- Open Syphon Flow
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A decrease (thixotropy) and increase (anti-thixotropy) of the apparent viscosity with time at a constant rate of shear, followed by a gradual recovery when the motion is stopped
Thixotropy behavior Anti-thixotropy behavior
The distinction between a thixotropic fluid and a shear thinning fluid: A thixotropic fluid displays a decrease in viscosity over time at a constant shear rate. A shear thinning fluid displays decreasing viscosity with increasing shear rate.
Time-dependent effects (搖變性 )
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非 牛 頓 流 體 的 不 穏 定 性非 牛 頓 流 體 的 不 穏 定 性 : : 黏 彈 性 效 應黏 彈 性 效 應
收縮流道
De 0 0.2 1 3 8
牛頓流體(葡萄糖漿 )
非牛頓流體(0.057% 聚丙烯醯胺 /葡萄糖 溶液 )
flowDe or We = t Elastic forceViscous force
:
Re for all cases)31( 0
- 描述非牛頓流體行為之程度流體的特徵或 “鬆弛” 時間流動系統的特徵時間tflow : : 剪切速率
“The mountains flowed before the Lord” [From Deborah’s Song, Biblical Book of Judges, verse 5:5], quoted by Markus Reiner at the Fourth International Congress on Rheology in 1963
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典型製程之流場強度範圍
-1 ( ) s
High-speed coating
Injection molding
Lubrication
Sedimentation
Rolling
Pipe flow
Extrusion
Spraying
Chewing
710510310110110310510
Typical viscosity curve of a polyolefin- PP homopolymer, melt flow rate (230 C/2.16 Kg) of 8 g/10 min- at 230 C with indication of the shear rate regions of different conversion techniques. [Reproduced from M. Gahleitner, “Melt rheology of polyolefins”, Prog. Polym. Sci., 26, 895 (2001).]
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小振幅反覆式剪切流 : 黏性與彈性檢定Exp b: Small-Amplitude Oscillatory Shear Flow
Oscillatory shear strain, shear rate, shear stress, and first normal stress difference in small-amplitude oscillatory shear flow
0( ) sinyx t t Shear strain:
0( ) cosyx t t Shear rate:
The oscillates with frequency ,
but is not in phase with eith shear s
shear s
traier the
o
n
shea
tre
r
ss
r rate
0( ) sin( )yx A t Shear Stress:
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Storage and loss moduli, G’ and G”, as functions of frequency ω at a reference temperature of T0=423 K for the low-density polyethylene melt shown in Fig. 3.3-1. The solidcurves are calculated from the generalized Maxwell model, Eqs. 5.2-13 through 15
0 0( ) sin co( ) syx GG t t
It is customary to rewrite the above equations to display the in-phase and out-of-phase parts of the shear stress
Storage modulus
Loss modulus
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解決流變問題的途徑為何 ?
傳統 vs. 現代 ( 未來 )
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基本流變性質
機械量測光學量測
本質方程式
模流分析
分子動力理論
量子、原子、多尺度計算
物質特性( 化學合
成 )
流體加工性質
closure approximationsflow pattern
flow pattern
molecular orientation / alignmentparticle size distribution/ diffusivitymicro/mesoscopic structures
macrorheology microrheology
Traditional route
the De, Wi numbers
Modern (predictive) route
monomer mobility, elastic modulus etc.
microscopy/spectroscopybirefringence/dichroismlight/ neutron scatteringsparticle tracking0NG
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Multi-angle dynamic/static light scattering
PMT
VV and VH polarizations; θ = 30° to 150°
Polarizer
Analyzer
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100 101 102 103 104
Inte
nsi
ty D
istr
ibu
tion
0.0
0.2
0.4
0.6
0.8
1.0
Rh (nm)
Internal motion
Center-of-massdiffusion &Internal motion
Rh (nm)100 101 102 103 104
Inte
nsi
ty D
istr
ibu
tion
0.0
0.2
0.4
0.6
0.8
1.0
Morphologies of MEH-PPV SolutionsMorphologies of MEH-PPV Solutions
q<Rg>0.5 1.0 1.5 2.0 2.5 3.0 3.5
q(0)
/ q3 k B
T
0.02
0.04
0.06
0.080.3 mg/mL1 mg/mL3 mg/mL
q<Rg>0.5 1.0 1.5 2.0 2.5 3.0 3.5
q(0)
/ q3 k B
T
0.02
0.04
0.06
0.08
0.1 mg/mL0.3 mg/mL1 mg/mL3 mg/mL
asymptote of the Zimm model
(0) (1)
0
Initial decay rate:
ln ( , )qt
g q tt =
¶G =
¶
h0
(1)
h0
2
2 20c
0
The can be expressed asDLS autocorrelation function at any angles
( )1 exp
( , )
where
( )e ( 2 )
( )
xp( )
( ) (2 ) ex
( )
N
i ii
N
i ii
cP x
Dq tP x
dR
g q tc dR
P xDq
x
tP
P x
xtj
j
¥
¥
-é ù
é ùê ú- - +ê úë ûê ú
ì ü
ë û
ï ïï ï+í ýï ïï ïî þ=
=
åò
åò
[ ]2 2
g h
2h
21/ 20
2h B s h2
c g 2h B s h
( ) (1.505 ) coilp( ) 1 ,
(0.775 ) sphere
( ) ( ) exp( 6) erf( 2)
(1.505 ) ( 6 ) coil
(0.775 ) ( 6 ) s
phere
qR qRx x x
qR
P x x x x
R k T RR D
R k T R
p
pht
ph
ìï =ï- - + =íïïîé ù= - ê úë û
ìïï= =íïïî
hR
1 mg/mL MEH-PPV/toluene1 mg/mL MEH-PPV/toluene
1 mg/mL MEH-PPV/chloroform1 mg/mL MEH-PPV/chloroform
-Suppressed Internal Motions of MEH PPV Aggregates
Mixed Dynamics
MEH-PPV/chloroformMEH-PPV/chloroformMEH-PPV/tolueneMEH-PPV/toluene
translationaltranslational internalinternal
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Flow Birefringence Measuring System 高分子溶液於流場下,會因流場大小的不同,造成高分子鏈被拉伸、旋轉與變形的程度不同,因此我們可以藉由流變儀搭配光學雙折射系統,量測高分子鏈於不同流場下的變化情形。
y
x
0
y
x
small
y
x
argl e
何謂雙折射: 當光經過非均向介質,會分解為兩道不同路徑的折射光,其一恆遵守折射率定律的正常光 (ordinary ray, o-ray ) ,其光的偏振方向,即電場振動方向是垂直於光軸,另一道即是違反折射率定律的光為異常光 (extraordinary ray, e-ray ) ,其光的偏振方向是平行於光軸。當光於雙折射材料中傳播時,因其具有兩個不同方向的主軸,光在兩軸中前進時的速度分別為 C1 、 C2 ,且 C1>C2 ,因此我們將軸向 1 稱為快軸 (fast axis),軸向 2 稱為慢軸 (slow axis)。所以光在兩分量間會有相位延遲現象產生,稱為光波相位差,我們即可從相位差中推得折射率差。
1 2
2 2( )
dD n n
流變雙折射: 高分子溶液的流動光學雙折射 (flow birefringnece) 有兩個來源:本質的雙折射 (intrinsic birefringence) 和形狀的雙折射 (form birefringence) 。前者與高分子片段的非均向性極化有關,當鏈的構形發生改變時,鏈局部的非均向性會變成巨觀的非均向性,因而造成本質的雙折射。後者與高分子片段密度的非均向性相關,在稀薄溶液系統中較為重要。
雙折射現象
光波之相位延遲
d為樣品厚度, 為光的波長。
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Phase modulated flow birefringence (PMFB)分析與量測: 本實驗的光學雙折射主要基於 Frattini 和 Fuller 的相位調變系統來作量測 [Frattini and Fuller J.Rheol. 28,61(1984) ; Fuller et al (1985)] 。假設 δ 和 χ 分別代表樣品的相位延遲量和方位角, I 為接收器量測到的光強, Io 為光彈調變器上的入射光強; δm 代表光彈調變器的相位延遲量, δm = A sin ωt,其中 A 為相對相位振福,ω為光彈調變器的共振頻率。 我們即可從探測器上得到光強 推算出:
進而利用應力-光學定律進行檢測 應力-光學定律目的主要為了將光學特性轉換成流變特性。高分子流體於流場下,因流場產生的應力場使其具光學的非均向性,其主應力差值的張量與折射率差值的張量成一比例關係,其比例即為應力-光學常數 C 。因此,我們可利用此比例關係來進行檢驗。
0 c1 cos 2 si n2 1 cos cos 2os si nsi n2 m m
II
1cos 2 si n
2si n4 (1 cos )
2 2
1 2 1 21/ 22 4 2
1 1 2
2cos 4 tan
2
2 2si n2 2si n4
2
nd
tan22
Cn
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實驗裝置:
示意圖
實際實驗裝置
實驗結果: 固態材料 ( 四分之一波片 ) 量測結果:
Quartar Wave Angle
5 10 15 20 25 30 35 40 45
Ret
arda
tion
Ang
le
60
80
100
120Experimental valueTheoretical value
Angle (degree)
5 10 15 20 25 30 35 40 45
Ori
enta
tion
ang
le (
5
10
15
20
25
30
35
40
45
Theoretical valueExperimental value
相位延遲量之理論與實驗值比較 方位角之理論與實驗值比較
聚苯乙烯溶液的雙折射量測結果:
2M PS/ DOP 10wt%
Shear Rate ( 1/ s )
0 5 10 15 20 25
C
1e-11
1e-10
1e-9
1e-8
1e-7
1e-6
Experimental C
5.9*10-9
4.5*10-9
以分子量 200萬之聚苯乙烯溶於 DOP 下,配置 10wt% 的溶液進行量測,利用應力-光學定律進行檢測。
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原理 : 利用同調入射光於撞擊粒子後產生之散射光,其光程差於接收器產生的干涉原理,經由適當的分析可推知溶質在溶液中的結構與動態情形。
Small-Angle Light Scattering (SALS) Small-Angle Light Scattering (SALS)
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裝置實體與示意圖 :
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實驗校正 :
Fig.1 Comparison of the predicted scattering pattern Fig. 2. Comparison of the form factor (the airy function) of a 50 μm pinhole with the predicted by the Mie theory with
experimentally measured one. the experimentally measured one.
應用 : SALS 之量測角度範圍一般為 1°≦θ≦ 10° ,多半作為較大尺度結構解析之用途。其應用範圍可
為高分子材料之混合 (mixing) 、分層 (demixing) 、相變化 (phase changes) 、結構破壞 (structure break-up) 、與結構整合 (structure build-up) 等相關研究。
k a sin0 2 4 6 8 10
I( )
/ I(
0)
0.0001
0.001
0.01
0.1
1
Measured diffractionpatternAiry function
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Flow Wide-Angle Light Scattering簡介 流動光散射與一般光散射最大不同,在於流場下可同時觀測流體的機械性質及微觀結構變化,以更直接掌握高分子於加工過程中其微結構與分子型態的變化。此外本系統亦可搭配光纖,利用其體積小、可彎曲的特點而有效增加量測系統的靈活度。
原理 當所施加的剪切速率( shear rate)足夠壓制高分子鏈本身的轉動擴散
(rotational diffusion)運動,此時高分子鏈的構形將偏離其於靜止狀態下的特性,並逐漸朝流動方向伸展與排向,同時造成高分子鏈大小與形狀( orientation)不同程度的改變( deformation)。藉由測量方向角( orientation angle , χ)以及使用 Zimm-plot 分析其迴旋半徑 Rg ,可得知流場下高分子鏈的拉伸與排向的程度。
高分子在靜止狀態為捲曲體,可視為球狀體,在施加流場後高分子鏈開始變形,由球狀轉為橢圓狀,並隨流動方向排向與拉伸 ; 藉由此系統可即時量測高分子的排向情形與拉伸變形的程度。左圖中 G 為梯度方向( gradient direction), V為流體方( flow direction),χ 為方向角( orientation angle)。
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原理與實驗分析
如圖示:方向角 χ為長軸與速度梯度的夾角; θ為入射光與偵測器的夾角;ψ ’ 為速度梯度與散射向量的夾角。
[Ellen C. Lee, Macromolecules 1997, 30, 7313-7321]
[Lee et al., Macromolecules 1997, 30, 7313-7321]
max90 ' 如圖:最高點為 ,利用
可得知 χ
max'
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實驗裝置 本系統需依照流變儀之立體條件所設計,包含光學夾具、折射率匹配槽,雙圓心旋轉桌板等皆需自行設計。
實驗校正 本系統需確定散射光強與散射體積之比例關係,因此選用甲苯做靜態光散射校正。此外與一般光散射校正不同處為,需對自製桌板做校正及注意光纖光強之接收。
實驗裝置簡圖
toluene
degree
20 40 60 80 100 120 140
inte
nsity(k
coun
ts/s
ec)
10
15
20
25
30
35
40
雙圓心旋轉台之操作原理為,選定入射光及偵測器夾角 θ後,即固定散射向量 q 的大小。此時轉動桌板後散射向量 q 與梯度方向 G 的夾角 ψ’即可任意改變。
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即時光學—流變系統 示意圖與功能
I. Particle Interactions II. Microstructures III. Molecular Anisotropy
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in situ in situ rheo-optical measuring systemrheo-optical measuring system 實體圖實體圖
CCD cameraCCD camera(Flow SALS)(Flow SALS)
2-D detection (2-D detection (θ θ andand φφ dirs.)dirs.)(Flow Light Scattering)(Flow Light Scattering)
Phase-modulated lightPhase-modulated light(Flow Birefringence/Dichroism)(Flow Birefringence/Dichroism)
Quartz couette cellQuartz couette cell(Rheology)(Rheology)
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多尺度分子計算 (Multiscale Computations)
無可調參數 AND 絕對預測能力 ?
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Parameter-Free Multiscale Simulations
(1) Atomistic model & MD simulation
(2) Monomer model & CGMD/LD simulation
(3) Ellipsoid-chain model & MC simulation
(4) Bead-chain model & BD simulation
(5) Dumbbell model & BD simulation
Coarse-
graining
Coarse-
graining
Coarse-
graining
Linking
Quantum chemistry calculation
Shie, S. C.; Hua, C. C.; Chen, S. A., Macromol. Theor. Simul. 2007, 16, 111.
Shie, S. C.; Lee, C. K.; Hua, C. C.; Chen, S. A., Macromol. Theor. Simul. 2010, 19, 179.
Lee, C. K.; Hua, C. C.; Chen, S. A., J. Chem. Phys. 2010, 133, 064902.
Lee, C. K.; Hua, C. C., J. Chem. Phys. 2010, 132, 224904.
Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2009, 113, 15937. Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2008, 112, 11479.
Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641.
Lee, C. K.; Hua, C. C.; Chen, S. A., Macromolecules, 2011, 44, 320–324
Lee, C. K.; Hua, C. C, Optoelectronics / Book 1,( InTech, ISBN 978-953-307-276-0)Lee, C. K.; Hua, C. C.; Chen, S. A., (to be submitted).
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A Software Package under Development for Multiscale simulationsMain programMain programAnalysis toolsAnalysis tools
RDFRDF
Structure factorStructure factor
IntensityIntensity
Atomistic model & Atomistic model & MD simulationMD simulation
Monomer model & Monomer model & CGMD/LD simulationCGMD/LD simulation
Ellipsoid-chain model & Ellipsoid-chain model & MC simulationMC simulation
Bead-chain model & Bead-chain model & BD simulationBD simulation
Dumbbell model & Dumbbell model & BD simulationBD simulation
Back-Mapping techniquesBack-Mapping techniques
The mutiscale simulation package developed at Complex Fluids & Molecular Rheology Laboratory by C. K. Lee, S. C. Shie, and C. C. Hua, in the Department of Chemical Engineering, National Chung Cheng University, Taiwan, R.O.C
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Number Ratio
CF 100% CF 75 % CF 66 % CF 50 % CF 33 % CF 25 % CF 0 %
Rg (
An
gs
tro
m)
30
35
40
45
50
55
60
CF / TCF / CB
vdw + HB + π-π vdw only
Single-Chain Conformations of Conducting Conjugated Polymers from Solution to the Quenching State: A Multiscale Simulation
PANI-EB MEH-PPV
Vacuum (V) Chloroform (CF)
Chlorobenzene (CB)
Toluene (T)
Mixed CF and T
Angstrom
5 10 15 20 25 30
Lo
ca
l Ra
tio
(C
F :
T)
/ Bu
lk R
ati
o
0.5
1.0
1.5
2.0
3:12:11:11:21:3
Angstrom
5 10 15 20 25 30
Lo
ca
l Ra
tio
(C
F :
CB
) / B
ulk
Ra
tio
0.5
1.0
1.5
2.0
3:12:11:11:21:3
distance (Angstrom)
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
RD
Fs
0
1
2
3
4
5
6
7
8
9
10
11
VCFTCBCF+TCF+CB
3.0 3.5 4.0 4.5 5.00
1
2
3
4
5
6
Mixed CF and T
Mixed CF and CB
Mixed CF and CB
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Morphologies and Pair Interactions in Fullerene-Conjugated Oligomer Hybrids Investigated by Atomistic Molecular Dynamics
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Links between Molecular dynamics and Quantum chemical calculations
Chlorobenzene (CB)
Excitation energies of a single chain MEH-PPV, calculated by ZINDO/S method
Mixed Nonane and CB (1:1)
Quantum calculations were carried out using Gaussian 09 software package as provided by the NCHC
Angle, deg
-25 -20 -15 -10 -5 0
En
erg
y,
kJ/m
ol
0
10
20
30
40
50
60
MP2_6-31GMD(original)MD (fit)
Angle, deg
0 20 40 60 80 100 120 140 160 180
En
erg
y,
kJ/m
ol
-2
0
2
4
6
8
10
12
14
16
MP2_6-31GMD(original)MD (fit)
Angle, deg
0 5 10 15 20 25 30
En
erg
y,
kJ/m
ol
0
5
10
15
20
25
30
MP2_6-31GMD(original)MD (fit)
Compound (eV) SE(PM3) DFT(B3LYP/3-21G*)
MEH-PPV LUMO -0.754 -1.211
HOMO -8.549 -5.204
C60 LUMO -2.886 -3.769
HOMO -9.480 -6.364
PCBM LUMO -2.807 -3.386
HOMO -9.165 -6.115
Force-field validation:PPV backbone, dihedral angle
Energy level diagram for a donor–acceptor heterojunction: Structuresrefined by semi-empirical (SE) and density functional theory (DFT)
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誰把流變做大了 ?