Transcript Effet Ouzo : Mélange, Coalescence et Répulsions

Effet Ouzo :
Mélange, Coalescence, Répulsions
Kevin Roger
[email protected]
Bernard Cabane, Robert Botet,
Bob Prud’homme, Christina Tang
Le basculement de solvant en image
30
25
20
15
10
5
0
0
200
400
Diamètre (nm)
PMMA + Acetone
Eau
Basculement de solvant, effet Ouzo et système modèle
Water
Polymer
solution
Swollen PMMA
nanoparticles
PMMA Acetone
Comprendre les mécanismes
ANR Limouzine : Limite Ouzo, Interprétation, Estimation
Hydrodynamique et Physico-chimie
Polymer
Solution
Uncoupling
Water
Coupling
Contrôler le mélange
Homogeneous mixing :
Uniform hydrodynamic
domains
Controlled mixing:
Flux control to tune the
size of the domains
B.K. Johnson and R.K. Prud’homme and B. Cabane, AIChE journal, 2003
Couplage ou découplage
250
Bad Mixing
Diameter (nm)
200
Polymer fraction
10-2
5.10-3
10-3
10-4
150
100
Good Mixing
50
0
0
10
0
2500
20 30 40 50 60
Flow rate (ml/min)
5000
7500 10000
12500
70
80
15000
Reynold number
(1) Homogeneous mixing : no more Ouzo boundary
(2) Uncoupling in good mixing conditions : opportunity to study the precipitation
K. Roger*, C. Tang, R.K. Prud’homme and B. Cabane, unpublished
Suivi cinétique SAXS
Synchrotron Xray beam
Fast-mixing
chamber (5ms)
Detector
Stop the
flow
Start
acquisition
Acetone-filled
Syringe
Water-filled (buffer)
syringe
Polymer
solution-filled
syringe
K. Roger*, R. Botet and B. Cabane, Langmuir, 2013
Instrument
ID02, ESRF,
Grenoble
Courbes de diffusion de RX résolues en temps
40
35
5ms
30
15ms
I(q)q4 / nm-5
25
25ms
45ms
20
205ms
15
1205ms
time
Oscillation
10
5
Polydispersity
0
0.04
0.06
0.08
Large
distances
0.1
q / nm
0.12
-1
0.14
0.16
0.18
0.2
Small
distances
Porod limit
Total surface
Coalescence … lente
(b)
(a)80
-3
5E-03
5.10
4E-5
Porod limit
Total Surface
70
-3
4E-03
4.10
60
3.10
3E-5 -5
40
30
2E-5 -5
2.10
nm-5
nm-4
-3
3E-03
3.10
2E-5
P/
50
Q/
Radius / nm
3E-5
-3
2E-03
2.10
1E-5 -5
1.10
20
1E-03
10-3
Invariant
Total Volume
10
0E+00
0
0
0
0.001
0.01
t/s
0.1
1
Logarithmic Growth Law
Rmean = a.ln(t)+b
10
0
0.001
0.01
0.1
5E-6
0E+0
1
10
t/s
Decreasing number of droplets
Growth through coalescence
Un chemin vers des populations étroites
0.08
5ms
0.07
0.06
f(R)
15ms
0.05
25ms 45ms 205ms
605ms
1205ms
0.04
0.03
0.02
0.01
0
10
20
30
40
50
60
70
80
90
100
R / nm
Distributions obtained through an
original inversion procedure
Method in : R.Botet & B.Cabane Journal of
Applied Crystallography 2012
The polydispersity
decreases with time !
Contrôle par les charges de surface
Adding surface charge (square dependence)
OK for concentration dependence (log scale)
Un outil sensible
--
--
…
-- ------ - - -
Surface charge determines the size of the droplets
Mean Radius decreases with the square of the surface charge
Indirect method to quantify the surface charge
…
Un vieux problème : la charge des systèmes purifiés
Air bubbles are moving to the cathode
(Quincke 1861)
Oil droplets are moving to the cathode
(Carruthers 1938)
Des observations générales
?
pH
Marinova et Al, Langmuir 1996
20 kT
|μ|
Surfactant-free conditions?
OH- adsorption?
Special water structuring?
Les impuretés sont partout…
1
99.8%-pure hexadecane
pH=11
1
oil purity
99.8%
pH=11
99%-pure hexadecane
99.8% +
2.3mM oleic acid
99.8% +
5.8mM oleic acid
99%
50
100
200
1000
d / nm
The purer the oil, the less
stabilizer is available
The stabilizer is in the oil and
is not hydroxide ions.
50
100
200
1000
d / nm
Adding fatty acids to 99.8%pure C16 reproduces the
behavior of 99%-pure C16
K. Roger* and B. Cabane, Angewandte Chemie 2012
Et quand on s’en débarrasse…
Macroscopic
aggregates
500
450
No colloidal
metastability
without
charged endgroups
400
Radius / nm
350
300
250
200
150
100
50
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
1
PMMA-C4H9 volume fraction
PMMA-COOH particles
K. Roger*, M. Eissa, A. Elaissari and B. Cabane, Langmuir 2013
PMMA-H particles
Comprendre l’importance du mélange
150
100
poor
metastability
good
metastability
1200
1000
binodal line
Diameter (nm)
200
Polymer fraction
10-2
5.10-3
10-3
10-4
diameter (t=22h) (nm)
Bad
Mixing
250
800
600
400
200
d(t=0)
50
0
Good Mixing
0
10
0
2500
20 30 40 50 60
Flow rate (ml/min)
5000
7500 10000
Reynold number
12500
70
0.2
0.3
0.4
0.5
0.6
acetone volume fraction
0
0
0.1
80
15000
Dangerous area below the
binodal : no repulsions
0.7
Mélanges de polymères : l’effet Ouzo à plusieurs soluté
1
Acetone
+Water
+PMMA
solution
Acetone mass fraction
0.9
0.8
M=25000
M=9800
0.7
M=9900
Phase separation
PMMA-poor and
PMMA-rich phases
0.6
0.5
0.4
0.0001
0.0010
0.0100
0.1000
PMMA/Acetone mass ratio
1.0000
Mélanges de polymères : l’effet Ouzo à plusieurs soluté
+
250
+ +
+
++
x=0.05
350
x=0.1
x=0.3
300
+
+
200
x=0.5
150
100
x=1
50
0
0
10
0
2500
20
30 40 50 60
Flow rate / ml.min-1
5000
7500 10000
12500
70
80
15000
Reynold number
Diameter / nm
Diameter / nm
300
250
+
+
+
x=0.1
+
+
200
150
+
+ ++
+
100
+
+
+
50
+
x=0.5
x=0.3
x=1
0
0
10
0
2500
20 30 40 50 60
Flow rate / ml.min-1
5000
7500 10000
12500
70
80
15000
Reynold number
Mixing PMMA-COOH (M=9900) and
PMMA-H (M=9800)
Mixing PMMA-COOH (M=9900) and
PMMA-H (M=25000)
Fraction en PMMA-COOH : x
Fraction en PMMA-COOH : x
Merci de votre attention
Less
favorable
states
Initial
state
with ion
withou
t
ic repuls
ionic r
ions
epulsio
ns
Equilibrium
state
More
favorable
states
Growth through coalescence (solvent-shifting method)
Suite des festivités
avec Robert Botet
sète après-midi