Nanocontainers with controlled
permeability for feedback active coatings
Contents:
1. Self-healing coatings based on nanocontainers for corrosion protection:
- with pH-triggered release,
- triggered by mechanic rupture,
- with light-triggered release.
2. Polyelectrolyte coatings for corrosion protection:
- inhibitor-free coatings,
- sandwich-like structures with controlled release of the inhibitor.
3. Ultrasonic fabrication of oil- or gas-filled containers:
- gas-filled containers,
- oil-filled carriers.
4. Bioactive coatings based on oil-filled containers.
Nanocontainer-based coatings
To use the nanocontainers loaded with corrosion
inhibitors
Advantages
9
Reduction of negative effect of the inhibitor on
coating
Prevention of inhibitor deactivation due to
interaction with coating components
Controllable release of inhibitor on demand
Prevention of the inhibitor leakage
9
9
9
Triggers: pH shift, light, pressure,
corrosion products, etc.
Shchukin, D.G., Möhwald, H. (2007): SMALL, 3, 926-943.
Shchukin, D.G., Möhwald, H. (2007): Hollow Micro- and Nanoscale Containers, "Advanced Materials Research" Ed.
by L.V. Basbanes. 2007, Nova Science Publishers, Inc.
Andreeva, A.V.; Shchukin, D.G. (2008): Materials Today, 11, 24-30.
Corrosion inhibitor (INH) loading into
mesoporous containers
INH
PEI
INH
INH
INH
INH
Polyelectrolyte
shell
Skorb, E.V.; Fix, D.; Möhwald, H.; Shchukin, D.G.
(2009): Adv. Funct. Mater., in print.
PSS
Inhibitor release from nanocontainers
OH-
neutral
alkaline
OH-
OH-
Æ controllable permeability of the
polyelectrolyte shell
Æ the release of the inhibitor starts
only after the begin of the corrosion
pH-controlled release of the inhibitor from containers in
solution
Zeta Potential (mV)
(A) scheme;
(B) changes of zeta
potential
during the procedure of
polyelectrolyte shell
formation;
% remained
INH content mg/1 g of silica
Layer number
Deposition step
Time, min
(C) loading of the interior of
titania
containers with
2-(benzothiazol-2ylsulfanyl)succinic acid under vacuum;
(D) the release of inhibitor
from
nanocontainers at
pH=10.1(a), and neutral pH
(b)
sonication
substra
te
The incorporation of the inhibitor-loaded
containers with controlled release
curing
Coating
Precursor
Shchukin, D.G., Zheludkevich, M.L., Möhwald, H. (2007): J. Mater.
Chem. 16, 4561-4566.
Incorporated containers
θ=65
R=1,8
Release of the inhibitor from directly-impregnated coatings and coatings with
containers. Conditions: under deaerated Milli-Q water (no oxygen, no ions).
Coating directly doped with benzotriazole
100
3µm
% remained
80
60
40
20
0
0
1
2
3
4
5
Days
Coating with the same amount of benzotriazole in nanocontainers with PE shell for controlled
release
100
3µm
% remained
80
60
40
20
0
0
1
2
Days
3
4
5
Incorporated containers
Self-healing effect on coatings with mesoporous containers
without containers, 0.5 M NaCl, 14 days
inhibitor-loaded containers
with polyelectrolyte shell
Halloysite nanotubes
Structure
Dimensions
3
-3
0.3
15 nm
50 nm
0.4
-1
-1
DV [10 cm *Å *g ]
0.5
0.2
Pore size distribution
0.1
1 µm
dmax = 17.8 ± 0.7 nm
0.0
0
50
100
150
200
Pore diameter [nm]
Lvov, Y.M.; Shchukin, D.G.; Möhwald, H., Price, R.R. (2008): ACS
Nano 2, 814-820.
Loading of halloysite nanotubes
Nanotube
lumen
Molybdate-loaded
nanotube
Shchukin, D.G., Lvov, Y. (2009): ACS Appl. Mater. and Interfaces, in print.
Halloysite-based feedback active anti-corrosive
coatings
aggressive medium
mechanical damage
+
changed pH
locally triggered
release of inhibitor !
homogeneous distribution
metal
Fix, D.; Andreeva, D.V.; Lvov, Y.M.; Shchukin, D.G.; Möhwald, H. (2009): Adv. Funct.
Mater., 11, 1720-1727. .
Halloysite-based coatings
Current density observations (SVET)
12
12
9
9
6
6
6
3
3
3
0
0
0
-3
1
-1
x [m 0
m]
-3
0
1
-1
9
1
-1
]
mm
[
y
0 min
12
pure sol-gel
coating
x [m 0
m]
0
1
-1
x [m 0
m]
6
3
3
3
0
0
0
1
x [m 0
m]
0
1
-1
]
mm
[
y
-3
1
-1
x [m 0
m]
]
mm
[
y
9
6
-1
1
-1
12
…with inhibitor
9
loaded
halloysite
6
-3
0
120 min
12
9
1
-1
]
mm
[
y
30 min
12
-3
0
1
-1
]
mm
[
y
-3
1
-1
x [m 0
m]
0
1
-1
]
mm
[
y
Halloysite-based coatings
Visual observations
pure sol-gel
coating
10 h in 0.1 NaCl
…with inhibitor
loaded halloysite
10 h in 0.1 NaCl
Light triggered release
Kinetics of benzotriazole release from the containers
meso-TiO2/(PEI/PSS)2 and meso-TiO2:Ag/(PEI/PSS)2
under pH change and under UV and IR irradiation, respectively.
100
100
1
UV
80
pH=7,2
60
50
40
30
pH=10,1
2
20
0
10
pH=10,1
2
60
50
40
30
pH=7,2
+ IR
3
10
pH=7,2 + UV
0
70
20
3
10
IR
80
70
1
pH=7,2
90
remainder, %
remainder, %
90
0
20
30
40
50
0
10
20
30
time, min
time, min
light stimulated release (UV, IR) is much faster in comparison with pH
stimulate release of incorporated into the container pore chemicals.
Skorb, E.V.; Skirtach, A.; Möhwald, H.; Shchukin, D.G. (2009):
ACS Nano, in print.
40
50
Release of the inhibitor by light
0h
0.1 M NaCl
corrosion
12 h
1 min UV irradiation
UV-healing
Benzotriazole-loaded mesoporous TiO2 containers with
polyelectrolyte shell in SiOx/ZrOx sol-gel coating on Al
E. V. Skorb, D. G. Shchukin, H. Möhwald and D. V. Sviridov, J. Mater.
Chem., 2009, 19, 4931
Anticorrosion activity of polyelectrolyte multilayers
pH buffering activity
Stabilization of
pH change
Good adhesion to the substrate
and sealing the surface defects
Carrier for
corrosion
inhibitor
Release of
inhibitor on
demand
Barrier for
aggressive
ions
Regeneration of
coating defects
Mobility of the swollen
polyelectrolyte complex
Andreeva, D.V.; Fix, D.; Möhwald, H., Shchukin, D.G. (2008): J. Mater. Chem. 18, 1738-1740.
Anticorrosion behavior of PE coating with buffer activity
10 bilayers of weak – strong PE
PEI/PSS
0.1 M NaCl 0 hr
1.5 hr
16 hr
Loading PE multilayers with corrosion inhibitor
PSS
Inhibitor
8-hydroxyquinoline
PSS
• Prevention inhibitor leakage
• Release on demand
• Reduce negative effect of inhibitor on coatings
Surface passivation by 8-hydroxiquinoline
Scanning vibration electrode technique, 0.1M NaCl
A
0 hr
Y, µm
6 hr
X, µm
Y, µm
16 hr
X, µm
Y, µm
B
Andreeva, D.V.; Fix, D.; Möhwald, H., Shchukin, D.G. (2008): Adv. Mater., 20, 2789-2794.
X, µm
Sealing effect of polyelectrolytes
10 µm
Flow of the sealing polyelectrolyte
Visual corrosion & stability test in 0.5 M NaCl solution
12hr
4 days
7 days
21 days
Power of sonochemistry
Frequencies from 20 kHz to 1 GHz; acoustic wavelengths from 10 to 10-4 cm far above
molecular and atomic dimensions. Sonochemical effects are derived from acoustic
cavitation (negative/positive pressure cycles).
The compression of bubbles during cavitation leads to the enormous concentration of energy:
~5200 K, ~1000 atm, heating and cooling rates ~ 1010 K/s
Potential of ultrasound:
•
•
•
To perform chemistry and physics at high temperature but with a reactor near room
temperature.
Highly nonequilibrium structures can be made which meets the demands of technology as
well as physical sciences.
Surface energy is converted into chemical energy and its control can make rapid progress in
interfacial science.
Shchukin, D.G., Möhwald, H. (2006): Phys. Chem. Chem. Phys. 8, 3496-3506.
Surface of the cavitation microbubble
~5200 K
~1900 K
Room temperature
The work of evolution R(r) of a bubble with a radius r in metastable liquids is
(thermodynamic nucleation theory):
4
R (r ) = 4π r 2σ + π r 3 ( P1 − Pv ) + ( μ v − μ1 )mv
3
[
]
The probability of the formation of microbubbles
ω n ∝ exp − R (r * ) / k B T , R (r*) ~ σ3
is:
For a typical surfactant concentration of cs= 1 mM and d= 10 µm the surfactant density is:
cs ⋅ v
Θ s = 2 ≈ 1014 mole/cm2
πd
A monolayer coverage and hence a reduction of σ may be expected!
Surface active materials in the sonicated liquid will result in drastic reduction of the surface
tension increasing the efficiency of the ultrasonic treatment. They decrease “surface”
component of the evolution work and change the difference of the chemical potentials
between liquid and gas phases, which is of special interest for sonochemical reactions.
Cavitation microbubbles as templates
heating, 45 ºC
Intensity, a.u.
Polymer/polyelectrolyte air-containing microbubbles
Span/Tween
Span/Tween
H2O
PSS
500
1000
PSS
1500
2000
2500
Raman shift, cm
Shchukin, D.G., Köhler, K., Möhwald, H., Sukhorukov, G.B.:
(2005) Angew. Chem. Int. Ed., 44, 3310-3314.
3000
3500
4000
-1
Raman confocal microscopy spectra from an aircontaining microbubbles (blue) and surrounding water
solution (black).
Ultrasound in nanocontainer fabrication
SiO2 containers
Grigoriev, D.; Miller, R.;
Shchukin, D.; Möhwald, H.
(2007): SMALL, 3, 665-671.
Containers with oil core and polymer shell
Statistics Graph (1 measurements)
60
US
generator
ive
Act rial
te
ma
I n t e n s ity ( % )
50
40
30
20
10
0
1
10
100
Size (d.nm)
er
ym
pol
Son.
LbL
Coating
General scheme:
A. emulsification of active material presenting in oil phase in aqueous polymer
solution by ultrasonication;
B. shell functionalization (if necessary);
C. embedding of nanocontainers into coating film.
1000
10000
Ultrasound in nanocontainer fabrication
Oil-filled polymer containers
Teng, X.; Shchukin, D.G.; Möhwald, H. (2007): Adv. Funct. Mater.,
17, 1273-1278.
Containers with oil core and polymer shell
Polystyrene shell
Polyurithane shell
Teng, X.; Shchukin, D.G.;
Möhwald, H. (2008):
Langmuir,24, 383-389.
Protein shell
Containers with oil core and polymer shell
5.00
2.50
0
0
2.50
5.00
AFM image of nanocontainers entrapped into polymer film
Borodina T., unpublished results.
Containers with oil core and polymer shell
20 µm
20 µm
20 µm
CLSM of the nanocontainers embedded into polymer coating
1µm
1µm
SEM photographs
Release profile of VE from bioactive film in
H2O/EtOH solution
Acknowledgements
Max Planck Institute of Colloids
and Interfaces:
Prof. Dr. Helmuth Möhwald
Dr. D. Grigoriev, Dr. X. Teng, Dr. E. Skorb, Dr. D. Andreeva, D. Fix, A. Praast, Dr. I.
Dönch, Dr. T. Borodina, Dr. Y.-S. Han, M. Haase, Dr. J. Hartmann
Institute for Micromanufacturing, Louisiana Tech:
Prof. Dr. Y. Lvov