exploring the use of dlc diffusion barrier & corrosion...

Dr Eva Maria MoserPacked. The 6th Global Summit, 19-20 June Amsterdam

Packed. The 6th Global Summit, 19-20 June Amsterdam

Prof. Dr Eva Maria MOSER

Exploring the Use of DLC Diffusion Barrier & Corrosion

Protection Coating (Nano Contacts) in Packaging


Content

Exploring the Use of DLC Diffusion Barrier & Corrosion Protection Coating (Nano Contacts) in Packaging

v Production of PE-CVD thin filmsv Sustainable DLC diffusion barrier layersv Adjustable wettability of DLC diffusion barrier layers:

Developments in nano-polar coating for anti-fogging, easy to clean, and adhesion promoter onto polyolephins

v Corrosion protection by embedding “active” nano contacts in sustainable DLC diffusion barrier layer

v Impact of nano-crystalline domains of titania (TiO2*) and imbedding of nano-clusters onto antimicrobial effects


Motivation: Functionalization of sustainable packaging

TiO2*anti-germ

TiO2* barrier (UV & gas)

Replacement of varnish in metallic containers and on lids

Advanced DLC diffusion barrier

Titania*

*TiO2 with photocatalytic activity

Surfaces of everyday life products often miss

- long life durability- specifically desired functionality

Actual EU project FLEXIFUEL:900 Al-plates coated for heat exchange prototype


Production of plasma coatings: Advanced DLC and Titania*

PVD &PE-CVD processes at reduced pressure

Pilot R&D plasma coaterwith a web width of 630 mm

PE-CVD and PVD processes at ambient temperature

PVD: Physical Vapour DepositionPE-CVD: Plasma Enhanced Chemical Vapour Deposition

Production of TiO2* coatings onto flat substrates at atmospheric pressure

Upscaledplasmaprocess:30 cm


Why plasma coatings ?

Adaptation of established processes in manufacturing: Ø Nano structuring of the coatings

Ø Encapsulation of the nano particles

+/- Criteria Sol-Gel PECVD incoat/IPIMethods in general in particular

Investment coating equipment ++ - -

Chemicals (price, amount, toxicity) - + +Sustainability (process & coating) - + ++Dry process, cycle interruption - + +Ambient process temperature - - ++

Adhesion (ev. plasma pretreatment) - + +Specific coating structures + + ++Resistant, durable thin films - + +


Basic properties of DLC: Diamond Like Carbon

DLC diffusion barrier layer:

Highly cross-linked and inherently

flexible hydrocarbon thin film

I: diamond-likesp3 > sp2; C > H

II: graphite-likesp3 < sp2; C > H

III: polymer chainssp3 > sp2; C < H

HH

HH

HHH

HH

H

HH

HH H

HH

HH

HHH

H

H

H

HHH

HHHH H

H H

H

H H

HH

Amorphous DLC layer of 70 nm


Functional testing of coated PET and CPP

Coated PET/CPP

O2-Perm. 0% r.h. [ml/m2dbar]

O2-Perm. 85% r.h. [ml/m2dbar]

H2O-Permeability90% r.h. [g/m2d]

Stretch failure[%]

PET: DC/RF/GHzPET: Web coater

1.0 - 1.2 ± .20.8 - 2.1 ± .2

0.8 - 0.9 ± .20.8 - 2.1 ± .2

0.2 - 0.3 ± .20.1 - 0.8 ± .2

2.6 – 3.7 ± .23.1 – 5.1 ± .2

Hydrophobe/PETphob/phil/PET

< 1.0 ± .2 < 1.9 ± .2

< 0.8 ± .2 < 0.7 ± .2

< 0.2 ± .2< 0.2 ± .2

> 2.5 ± .2 > 4.7 ± .2

Hydrophobe/CPPphob/phil/CPP

40 ± .2 27 ± .2

--

0.4 ± .20.8 ± .2

--

Ref.: PET 12 µm < 123.9 ± .3 < 93.0 ± .3 < 20.4 ± .3 -

Ref.: CPP 75 µm 1000 - 4000 - 4 -

Barrier effect is enhanced in humid conditions due to the hydrophobic feature of DLC – contrary to SiO2 coatings

Manufacturing of SiO2/DLC barrier coatings forPET bottles > 20’000 bottles/hour à tubes


Direct contact of DLC with content

CPP/PET filmplasma treated

3 wt% acetic acid (2h@90°C, 10d@40°C)

95 vol% ethanol (4h@60°C, 10d@40°C)

isooctane (2h@60°C, 2d@20°C)

Ref: CPP/PET < 1 mg/dm2 < 1 mg/dm2 < 4 mg/dm2

wincoat CPP < 1 mg/dm2 < 1 mg/dm2 < 1 mg/dm2

Phil /CPP < 1 mg/dm2 < 1 mg/dm2 < 1 mg/dm2

Phil /CPP < 1 mg/dm2 < 1 mg/dm2 < 1 mg/dm2

Phob /CPP < 1 mg/dm2 < 1 mg/dm2 < 1 mg/dm2

Global migration according to EU guidelines 2002/72/EG (detection limit: <1 mg/dm2, tolerance limit: <10 mg/dm2)

ESR and fluorescence spectroscopy; DLC coating: food for germs(1020 Spins/cm3, g-value: 2.0023 (11 Gauss):

à no free radicals in DLCà no interaction, no migration

Hydrophobic DLC

HydrophilicDLC

Welding-peeling properties:


Stable polyolefin surface due to nano structuring

AFM images of plasma treated cast polypropylene

The surface of the plasma treated cast-polypropylene is stable:à no «hydrophobic recovery phenomenon»à no additives / no VOC’s at surfacesà CPP is printable and can be coated


Additional functionality: Structuring of polymers

Hydrophilic polyolefin• sustainable (no interaction)• super-polar, anti-fogging• stretchable• chemically resistant• printable, good adhesion• weldable

Hydrophobic polyolefin• sustainable (no fluorine)• super-hydrophobic • stretchable• water repellent, easy-to-clean• chemically resistant• weldable

AFM-image of plasma nano structured CPP à stable, non-restructuring surface

SEM-image of CPP with micro structures produced by hot embossing

à Functionalization of packaging surfaces


Functionalization: Tailoring the wettability

with nano

without nano

WCA = 6°

WCA = 146°


Additional functionality: Wettability of CPP

Structured/coated CPP: 6°

Untreated CPP: 97°

Structured/coated CPP: 146°

Anti-fogging effect Water repellence

v Anti-fogging effectv Easy-to-clean surfacesv Complete emptying of content


Additional functionality of polypropylene

wettable - anti-fogging – weldable - sealable

storage @ RT storage @ 4°C storage @ 80°C

ref. ref. ref.

incoat incoat incoat printed, incoat© plasma-treated CPP film (75 µm)

removed tape

printable, ready to be coated


DLC with metallic contacts : Corrosion protection

Sustainable Nano Texturing of DLC Layers:Ø Durable encapsulation of metallic nano contactsØ Tailoring of wettabilityØ Substitution of varnish in metallic cans & containersØ Replacement of varnish on metallic lids

DLC matrix of 70 nm:Diamond Like Carbon layer

10 of 11 Alu cans: Bisphenol A


DLC thin film and active corrosion protection

Anodic corrosion protectionReaction: 2 Me + O2 à 2 MeO

Plasma layer: 50 nm

Metallic nano contacts(< 10 mg/m2)

Micro defectAdjustable wettability

Metallic substrate:Aluminium, steel,….

Metallic nano contacts: Æ 5 nm in DLC permanently immobilised

DLC: Diamond Like Carbon layer (50 nm): Highly cross-linked plasma polymer as durable matrix


Excellent corrosion protection by nano contacts

Corrosion tests performed at EMPA:- Pore test according to Verpackungsrundschau 11/1976- Determination of electrochemical parameters (impedance-spectroscopy)- Salt spray test (DIN EN ISO 9227 NSS): Storage for 3 days at 35 °C- Condensed water test climate (DIN EN ISO 6270-2 AHT: 7 days with 2 cycles at 100% rel. humidity (8 h at 40°C and 16 h at 23°C)

Pure DLC layer deposited onto Al-foil with poor protection; pores

Metal-doped DLC layer onto Al-foil with good protection; without pores


Excellent corrosion protection by nano contacts

Al-foils after 27 days condensed water test: left: Hydrophobic, metal-doped DLCright: Chemically cleaned Al-foil, without coating

Corrosion tests performed at EMPA:- Pore test according to Verpackungsrundschau 11/1976- Determination of electrochemical parameters (impedance-spectroscopy)- Salt spray test (DIN EN ISO 9227 NSS): Storage for 3 days at 35 °C- Condensed water test climate (DIN EN ISO 6270-2 AHT: 7 days with 2 cycles at 100% rel. humidity (8 h at 40°C and 16 h at 23°C)


Protection against corrosion, chemical attacks, and abrasion for metallic packaging

Ø Optimised coatings could not be attacked by aggressive acid solutions such as acetic acid Ø Excellent adhesion at dry and wet conditions : 5B (Cross hatch/scotch test,

ASTM D 3359-97 Test B and bending tests)

Poor DLC on Al, partly peeled off after 27 days in 50 % HAc

Good DLC on Al, without delamination after 27 days in 50 % acetic acid


Benefits of photo-induced titania layers (TiO2*)

disinfectionUV-protection

selective diffusion barrier

biocompatibility

bioactivity

detoxification

active self-cleaning

anti-fogging

decontamination

HRTEM image of a titania* thin film PVD ref. with a thickness of 192 nm: Crystalline domains of anatase [110] in a amorphous matrix


Photocatalytically active titania layers (TiO2*)

Activation of titania layers at 365 nm*

Bleaching of a 0.05 mmolmethylene blue solution

Activation of titania layers at 428 nm

Activation of titania under visible light at 625 nm

*CIF = 1.0 corresponds to bleaching of 1.7 mmol/m2×d of methylene blue by a PVD-TiO2 ref. layer (50 nm, on a glass slide) according to ISO 10678:2010

Titania coated surfaces:Fingerprints disappear……


Photocatalytic reactions at titania* surfaces

H2O

CO2

O2- Ti4+

CHx

O2

TiO2* (anatase) hn ³ Eg Titania TiO2*

O2-

OH*

H2O

h+

Photocatalyst reaction TiO2 à electron + hole

e- ReactionsRedox potential

3.2 eV

CB

VB

Organic compound + Mineral acid

O2


Improvement of Photocatalytic Activity by Doping

AFM-image of an atomic layer of Ag-clusters with Ø of 10-20 nm

500

nm

0

0

nm 500

Monolayers of noble metal clustersà Increase of activity > 30%

Doping of TiO2* with nitrogen, etc. à Variation of Eg and increase of activity

Doping with metal cations or non-metallic elements Large surface area, open surface morphologyParticle size: nanometer-size range (optimum size around 10 nm)


Functional properties of titania* layers

*Catalytic Improvement Factor CIF: Comparison to the internal reference layer PVD TiO2 ref.(50 nm, on a glass slide) for bleaching of 1.7 mmol/m2×d aqueous solution of methylene blue

1LED white light (LEDON 10 W, 2700 K, 600 lumen, 625 nm, distance 5 cm): CIF = 6.8

TiO2Layer/glass

Sample no.

Thick-ness[nm]

Rough-ness[nm]

n @ 633[nm]

Egap

[eV]

Wetta-bilityin dark

ActivityISO 10678[µmol/m2h]

CIF*@ 365

nm

CIF*@ 428

nm

Stearic acide

[mmol/h]@365 nm

Stearic acide

[mmol/h]@428 nm

PVD TiO2 ref. 09.11.18 130 3.4 2.18 3.29 27 2.4 2.3 1.3 4.8 0.08

TiO2 a 11.04.20-IC 223 12.9 2.15 3.04 38 4.4 4.1 1.5 4.2 -

TiO2 b 11.04.19-IB 186 11.2 2.17 3.15 28 5.6 5.3 1.7 2.6 0.03

TiO2 c 11.04.21-IB 225 14.7 2.11 2.85 55 5.1 4.8 1.7 4.8 -

TiO2 black1 12.10.08-IB 1000 14.9 2.17 3.15 24 10.1 10.1 1.3 19.6 -

PE-MOCVD TiO2 09.08.21 MA 230 1.1 1.79 3.48 75 4.8 4.5 1.3 0.1 0.02

TiO2 a 11.04.27 MA 339 0.5 1.71 3.27 67 3.6 3.4 1.7 0.1 -

TiO2 b 11.05.23 MA 276 0.9 1.76 3.33 68 7.5 7 2.2 0.1 -

TiO2 c 11.05.19 MA 237 1.0 1.79 3.39 86 7.8 7.3 3.1 0.4 0.02

TiO2 ATMO 200 5.6 1.99 3.44 3.1 2.6 1.7 - -

Pilkington ~ 30 - - - - 1.3 1.5 0.3 - -

Improvement of photocatalytic activity by doping and co-doping the titania layers*

PVD TiO2 layers are more efficient in destroying stearic acid than PE-MOCVD TiO2 layers

*Eva Maria Moser et al., Surface & Coatings Technology 227 (2013) 2-9


Destruction of stearic acid: Fingerprints & germs

Roughness [nm]: 14.9 7.2 4.7 5.4 3.5

AFM-Images: ~ 200 nm thick PVD-TiO2

0

5

10

15

20

25

0 1 2 3 4 5 6 7 24 32 48

Concen

trationofstearic

acid[m

ol×10-

3 ]

Timeofirradiation[h,@365nm]

PVD-b 1000 nm PVD-b 200 nm PVD 1000 nm PVD 200 nm PECVD-c 130 nm

1 h 1 h 1 h


Germ-inhibiting features of titania*

*Tests were performed according to ISO 22196: Sterilisation if <1 of 1 mio germs after 24 hours

Antibacterial activity under visible light

Tests according to ISO 22196:Growth reduction efficacy [log cfu]

PVD TiO2-b 13.8.3.0047-1 (300 nm, CIF = 7.0/1.7RMS = 5.2 nm, hydrophilic)

E. coli: 0.75 (slight)S. aureus: 0.62 (slight)

PE-MOCVD TiO2-c 13.8.3.0047-2(200 nm, CIF = 7.3/3.1RMS = 1.0 nm, hydrophobic)

E.coli: 2.35 (significant)S. aureus: 2.46 (significant)E. coli do not stick well to the titania surface and can be removed easily

PVD TiO2 black 13.8.3.0047-3(1.4 µm, CIF = 10.1/1.3RMS = 5.0 nm, hydrophilic)

E. coli: > 5.52 (strong) à 20 of 1 mio germsS. aureus: > 3.68 (strong)

no illumination illumination for 1 day illumination for 6 days

AFM images of E. coli on the TiO2 surface: Kayano Sunada et al., Journal of Photochemistry and Photobiology A: Chemistry 156 (2003) 227–233


Combination of structuring and plasma layers

The surfaces “easy-to-clean” are distinguished by their surface energies and the micro-nano structures of the surfaces. (Θ = water contact angle)

DLC phob flat orwith micro structure

super-hydrophobicΘ >120°

surface with very weak polarity

hydrophobic120 °

80°< Θ <120°surface with weak polarity

hydrophilic20°

10°< Θ <80° surface with high polarity

super-hydrophilic Θ < 10° surface with very high polarity

DLC and polymers (-C-H, Si-C-, F-Si-,)

TiO2* and

micro structure

Passive, not interacting surfaces

Active*, interacting surfaces

TiO2* flat or with

micro structure

TiO2* smooth

or nano structure

TiO2* smooth

or nano structure

DLC phil, SiOx, TiOx(-C-OH, -CO, -NOx)

DLC phil, SiOx, TiOx(-C-OH, -CO, -NOx)


Summary

multi functio-nality

advancedbarriers

structuring

wettabilityDLC phob and TiO2

*

clusters


Thank you !

The human tendencyto regard little things as importanthas produced very many great things.

Georg Christoph Lichtenberg (1742-1799)

R&D projects No. 7960.2, 10778.1, 10747.2 PFNM-NM have been funded by CTI

Several patents are hold for all presented thin films and deposition processes.

Prof. Dr Eva Maria [email protected] GmbHCH-8212 Neuhausen am Rheinfall+41 76 321 21 59

exploring the use of dlc diffusion barrier & corrosion...

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