Nanocontainers with controlled Nanocontainers with controlled permeability for feedback active coatingspermeability 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.

NanocontainerNanocontainer--based coatingsbased coatings

AdvantagesAdvantagesReduction of negative effect of the inhibitor on Reduction of negative effect of the inhibitor on coatingcoatingPrevention of inhibitor deactivation due to Prevention of inhibitor deactivation due to interaction with coating components interaction with coating components Controllable release of inhibitor on demandControllable release of inhibitor on demandPrevention of the inhibitor leakagePrevention of the inhibitor leakage

To use the nanocontainers loaded with corrosion To use the nanocontainers loaded with corrosion inhibitorsinhibitors

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 Corrosion inhibitor (INH) loading into mesoporous containersmesoporous containers

INHINH

INH

INH

INH

PEI

PSS

Polyelectrolyteshell

Skorb, E.V.; Fix, D.; Möhwald, H.; Shchukin, D.G. (2009): Adv. Funct. Mater., in print.

Inhibitor release from nanocontainersInhibitor release from nanocontainers

OH-OH-

OH-

controllable permeability of the polyelectrolyte shell

the release of the inhibitor startsonly after the begin of the corrosion

neutral

alkaline

pHpH--controlled release of the inhibitor from containers in controlled release of the inhibitor from containers in solutionsolution

Layer numberZe

ta Po

tentia

l (mV)

Time, min

% re

maine

d

Deposition step

INH

conte

nt mg

/1 g o

f silic

a

(A) scheme;

(B) changes of zeta potentialduring the procedure of polyelectrolyte shell formation;

(C) loading of the interior of titania containers with 2-(benzothiazol-2-ylsulfanyl)-succinic acid under vacuum;

(D) the release of inhibitor from nanocontainers at pH=10.1(a), and neutral pH (b)

The incorporation of the inhibitorThe incorporation of the inhibitor--loaded loaded containers with controlled releasecontainers with controlled release

CoatingPrecursor

subs

trat

e

sonication curing

Shchukin, D.G., Zheludkevich, M.L., Möhwald, H. (2007): J. Mater. Chem. 16, 4561-4566.

Incorporated containersIncorporated containers

θ=65

R=1,8

3µm

3µm

Release of the inhibitor from directlyRelease of the inhibitor from directly--impregnated coatings and coatings with impregnated coatings and coatings with containers. Conditions: under containers. Conditions: under deaerateddeaerated MilliMilli--Q water (no oxygen, no ions).Q water (no oxygen, no ions).

Coating directly doped with benzotriazole

0 1 2 3 4 50

20

40

60

80

100

% re

mai

ned

Days

0 1 2 3 4 50

20

40

60

80

100

% re

mai

ned

Days

Coating with the same amount of benzotriazole in nanocontainers with PE shell for controlledrelease

Incorporated containersIncorporated containers

SelfSelf--healing effect on coatings with mesoporous containershealing effect on coatings with mesoporous containerswithout containers, 0.5 M NaCl, 14 days

inhibitor-loaded containers with polyelectrolyte shell

Halloysite nanotubesHalloysite nanotubesStructure

Dimensions

15 n

m50

nm

1 µm

0 50 100 150 2000.0

0.1

0.2

0.3

0.4

0.5

DV [1

0-3 c

m3 *Å

-1*g

-1]

Pore diameter [nm]

Pore size distributiondmax = 17.8 ± 0.7 nm

Lvov, Y.M.; Shchukin, D.G.; Möhwald, H., Price, R.R. (2008): ACS Nano 2, 814-820.

Loading of halloysite nanotubesLoading of halloysite nanotubes

Molybdate-loaded nanotube

Nanotube lumen

Shchukin, D.G., Lvov, Y. (2009): ACS Appl. Mater. and Interfaces, in print.

mechanical damage+

changed pHlocally triggeredrelease of inhibitor !

aggressive medium

metal

HalloysiteHalloysite--based feedback active antibased feedback active anti--corrosive corrosive coatingscoatings

homogeneous distribution

Fix, D.; Andreeva, D.V.; Lvov, Y.M.; Shchukin, D.G.; Möhwald, H. (2009): Adv. Funct. Mater., 11, 1720-1727. .

HalloysiteHalloysite--based coatingsbased coatings

Current density observations (SVET)

0 min

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

30 min

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

120 min

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

-10

1

-3

0

3

6

9

12

-1

01

y [mm]x [mm]

pure sol-gelcoating

…with inhibitorloaded halloysite

HalloysiteHalloysite--based coatingsbased coatings

Visual observations

pure sol-gelcoating

10 h in 0.1 NaCl

…with inhibitorloaded halloysite

10 h in 0.1 NaCl

Light triggered releaseLight triggered releaseKinetics of benzotriazole release from the containersmeso-TiO2/(PEI/PSS)2 and meso-TiO2:Ag/(PEI/PSS)2under pH change and under UV and IR irradiation, respectively.

0 10 20 30 40 50

0

10

20

30

40

50

60

70

80

90

100

32

1

rem

aind

er, %

time, min0 10 20 30 40 50

0

10

20

30

40

50

60

70

80

90

100

2

3

1

rem

aind

er, %

time, min

UV IRpH=7,2 pH=7,2

pH=7,2

pH=10,1

pH=10,1

pH=7,2 + IR

+ UV

light stimulated release (UV, IR) is much faster in comparison with pHstimulate release of incorporated into the container pore chemicals.

Skorb, E.V.; Skirtach, A.; Möhwald, H.; Shchukin, D.G. (2009): ACS Nano, in print.

Release of the inhibitor by lightRelease of the inhibitor by light

Benzotriazole-loaded mesoporous TiO2 containers with polyelectrolyte shell in SiOx/ZrOx sol-gel coating on Al

corrosion UV-healing

0 h 12 h 1 min UV irradiation0.1 M NaCl

E. V. Skorb, D. G. Shchukin, H. Möhwald and D. V. Sviridov, J. Mater. Chem., 2009, 19, 4931

Stabilization of pH change

Regeneration of coating defects

Release of inhibitor on demand

Barrier for aggressive

ions

Anticorrosion activity of polyelectrolyte multilayersAnticorrosion activity of polyelectrolyte multilayers

Carrier for corrosion inhibitor

Mobility of the swollen polyelectrolyte complex

Good adhesion to the substrate and sealing the surface defects

pH buffering activity

Andreeva, D.V.; Fix, D.; Möhwald, H., Shchukin, D.G. (2008): J. Mater. Chem. 18, 1738-1740.

Anticorrosion behavior of PE coating with buffer activityAnticorrosion behavior of PE coating with buffer activity

0.1 M NaCl 0 hr 1.5 hr 16 hr

10 bilayers of weak – strong PEPEI/PSS

Loading PE multilayers with corrosion inhibitorLoading PE multilayers with corrosion inhibitor

PSSInhibitorPSS

8-hydroxyquinoline

• Prevention inhibitor leakage• Release on demand • Reduce negative effect of inhibitor on coatings

Surface Surface passivationpassivation by 8by 8--hydroxiquinolinehydroxiquinoline

Y, µm Y, µm Y, µmX, µm X, µm X, µm

A

B

0 hr 6 hr 16 hrScanning vibration electrode technique, 0.1M NaCl

Andreeva, D.V.; Fix, D.; Möhwald, H., Shchukin, D.G. (2008): Adv. Mater., 20, 2789-2794.

SealingSealing effecteffect of polyelectrolytesof polyelectrolytes

10 µmFlow of the sealing polyelectrolyte

12hr 4 days 7 days 21 days

Visual corrosion & stability test in 0.5 M Visual corrosion & stability test in 0.5 M NaClNaCl solution solution

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

Power of Power of sonochemistrysonochemistry

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 Surface of the cavitation microbubblemicrobubble

~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):

vvv mPPrrrR )()(344)( 11

32 μμπσπ −+−+=

The probability of the formation of microbubblesis:

[ ]TkrR Bn /)(exp *−∝ω , R (r*) ~ σ3

For a typical surfactant concentration of cs= 1 mM and d= 10 µm the surfactant density is:

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 potentialsbetween liquid and gas phases, which is of special interest for sonochemical reactions.

sΘ 142 10≈⋅

dvcs

π= mole/cm2

A monolayer coverage and hence a reduction of σ may be expected!

Cavitation microbubbles as templates Cavitation microbubbles as templates Polymer/polyelectrolyte air-containing microbubbles

500 1000 1500 2000 2500 3000 3500 4000

PSS

Span/Tween

PSS

Span/Tween

H2OInte

nsity

, a.u

.Raman shift, cm-1

heating, 45 ºC

Raman confocal microscopy spectra from an air-containing microbubbles (blue) and surrounding water solution (black).

Shchukin, D.G., Köhler, K., Möhwald, H., Sukhorukov, G.B.: (2005) Angew. Chem. Int. Ed., 44, 3310-3314.

Ultrasound in nanocontainer fabricationUltrasound in nanocontainer fabricationSiO2 containers

Grigoriev, D.; Miller, R.; Shchukin, D.; Möhwald, H. (2007): SMALL, 3, 665-671.

Son. LbL Coating

Active

material

polymer

US generator

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.

Containers with oil core and polymer shellContainers with oil core and polymer shell

0

10

20

30

40

50

60

1 10 100 1000 10000

Inte

nsity

(%)

Size (d.nm)

Statistics Graph (1 measurements)

Ultrasound in nanocontainer fabricationUltrasound in nanocontainer fabricationOil-filled polymer containers

Teng, X.; Shchukin, D.G.; Möhwald, H. (2007): Adv. Funct. Mater.,17, 1273-1278.

Containers with oil core and polymer shellContainers with oil core and polymer shell

Polystyrene shell Polyurithane shell

Protein shell

Teng, X.; Shchukin, D.G.; Möhwald, H. (2008): Langmuir,24, 383-389.

Containers with oil core and polymer shellContainers with oil core and polymer shell

0 2.50 5.00

0

2.50

5.00

AFM image of nanocontainers entrapped into polymer film

Borodina T., unpublished results.

Containers with oil core and polymer shellContainers 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 Release profile of VE from bioactive film in HH22O/EtOH solutionO/EtOH solution

AcknowledgementsAcknowledgements

Max Planck Institute of Colloidsand 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