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ICCG short course 2018
ICCG 12 - short course - June l 11 l 2018Chemical nanotechnology and sol-gel coatingsDr. Karl-Heinz Haas
Source: Fh-ISCMitteilungen Wilhelm-Ostwald-Ges. zu Großbothen e.V. 12. Jg. (2007) Heft 2, S. 22
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Overview:
� chemical nanotechnology and sol-gel processing
� historic development
� basic reactions: Inorganic and hybrid
� coating techniques and functionalities
� application areas, products and markets
� actual trends in SG coatings
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Solutions for industrial
partnersAnalytics
� Materials characterization
� Failure analysis
� Quality control
� In situ test equipment
� Human 3D in-vitro testing models
Processing� Micro-/Nanoparticles
� Fibers
� (Wet) coatings (R2R, Dip, Spin, etc.)
� 3D/2D structurization
� 3D printing
� Tissue engineering
� Clean room, GMP like facilities
� Demonstrators, pilot plants, automation
Materials
� Glass, Ceramics, ORMOCER®s
� Bioactive materials
� Battery materials
� Magnet materials
� Smart materials
� HT materials (fibers, CMC)
Fraunhofer ISC
Core competencies: materials and processing
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ORMOCER®s, developed by Fraunhofer ISC, trademark of Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., München
ORMOCER®
creative use of adjustable material properties generates new functions
Hybrid materialsORMOCER®s
Inorganic material Organic polymer
R2
R1
R2
ISC highlight: ORMOCER® Chemistry
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„The purposeful engineering of matter at scales of less than 100 nanometers (nm)to achieve size-dependent properties and functions“
source: \Lux research\
not nano „by accident“
not nano „by accident“
What is nanotechnology ?ISO/TS 80004-1 core terms
really smallreally small
not just small: small and different
not just small: small and different
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nanostructured materials
decreasingmelting pointthermal conductivity
E-moduluslight scattering
increasing
reactivity hardness, strength
thermal expansion coeff.diffusion coeff.
spezific surface areasolubility
Nanomaterials: size induced property changes
electronic, optical and magnetic properties are size dependent
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(Nano)-coatings: Processes
� Deposition from gasphase:� physical/chemical PVD/CVD� plasma(-polymerization), sometimes at atmospheric pressure� sputtering � atomic-layer-deposition (ALD) ->
� Liquid phase� galvanics� lacquering� sol-gel
� Structuring� lithography (electronics)� embossing, nanoimprint (NIL)� self-organization (SAM), Langmuir-Blodgett� ink-jet
Al2O3 coated LDPE (source: ALD Nanosolutions Whitepaper)
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Sol-Gel (SG)
� Sol: colloidal solution, particles in liquid/gas (lyosol, hydrosol, aerosol) no sedimentation i.e. Brownian movement is responsible for stability at small particles sizes, no Rayleigh-scattering, transparent
� Gel: 2-phase system, network structure filled with liquid/gas (hydrogel, aerogel/xerogel..), often transparent, inorganic/organic/hybrid
� Solution-Gelation-Process: Gel, network formation from liquids
� Formation of inorganic/organic networks via chemical processes in solution for synthesis of glasses, ceramics and inorganic-organic hybrid polymers
� The Sol-Gel-Process is part of chemical nanotechnology
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� inorganic and
hybrid materials from chemical precursors
liquid, molecular-disperse precursors(organically modifiedmetal-alkoxides)
sol gel
powder
coatings fibers “bulk“-materials
Wet-chemistry for nanomaterials: Sol-Gel-processing
Main advantages:• low T• high purity• molecular composites
→ transparency• easy forming
source: Fraunhofer ISC; Bulk-Materialien: NASA/JPL Caltech
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Gel formation
� Network types� via secondary valences (H-bonding, partially reversible)� chain entanglement (polymers)
� main valences e.g. ≡ Si-O-Si ≡� organic networks (irreversible) – e.g. hybrid polymers
Sol
Gel
source: Fraunhofer ISC
Start
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� 1789 Bergman: acidification ofwater glass: formation of viscoelastic solid,→ Sol-Gel-transition
� 1846 Ebelman: reaction of SiCl4 with alcohol → Si(OR)4,gelation with humidity
� 1923 Patrick: catalysts on SiO2-gels → high surface area
� 1932 Kistler: supercritical drying of gels → Aerogels
� 1939 Geffcken (Schott/Jena): spray pyrolysis on hot glas surfaces
sources: Qingdao Sinoglory Chemical Co.,Ltd http://www.webexhibits.org/causesofcolor/9.html
Sol-Gel-history - 1:
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� 1941 Bell Telephone: Insulator -> alkoxysilanes and organic fillers, the first technical hybrids !
� 1943 Moulton (American Optical Company): Si-/Ti-alkoxide for interference filter
� 1946 Corning: Oxide powders by emulsion process
� 1958 Schott Glas: IROXTM & CalorexTM
Interference filters commercialized
� 1960 DuPont (Iler): Industrial processing of silica colloids
� 1967 DuPont: Al-Oxide fibers
� 1969 3M: Multicomponent fibers
� 1973 Yoldas: Monolithic ceramics from gels
� .......source: “Sol-Gel Chemistry“ J. Livage, Uni Rennes Nov 2005
Sol-Gel-history - 2:
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Industrial applications: fibers and abrasives
3M (1981)Al-Oxid, Ce-Oxid
source: “Sol-Gel Chemistry“ J. Livage, Uni Rennes Nov 2005
Saffil-fibers Al2O3-SiO2 (95-5%)
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Industrial applications: Aerogels – inorganic and hybrid
source: Sanchez et al 2011
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Industrial applications: oxidic coatings
source: left: “Sol-Gel Chemistry“ J. Livage, Uni Rennes Nov 2005; right: Erlus Dachziegel
� Antireflective on glass (TiO2/SiO2) Schott
� Antireflective with nanoporous SiO2
� Heat shielding
� Photocatalysis for glazing and construction materials
Erlus Lotus (TM)
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SG: Industrial implementation
Source: Wet chemical coating technologies Aegerter ISGS Summerschool 2012
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Example: reactions/structures tetraalkoxysilane
� condensation starts immediately after hydrolysis
� formation of rings, branches, chainsdepending on pH, solvent, water, catalyst,substitution (R)
� ≡ Si-OH and ≡ Si-OR containingintermediates
source: Kickelbick “Hybrid Materials“ 2007
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Basic steps of hybrid polymer formation
1st step: formation of inorganic network
hydrolysis
≡ Si-OR + H2O → ≡ Si-OH + ROH
polycondensation
≡Si-OH + HO-Si≡ → ≡Si-O-Si≡ + H2O
≡Si-OR + HO-Si≡ → ≡Si-O-Si≡ + ROH
(possible cocondensation with other metal alkoxides – Ti, Al, Zr)
2nd step: formation of organic network
≡Si-O-Si-X + X-Si-O-Si≡ → ≡Si-O-Si----Si-O-Si≡
crosslinking reactions of Si-bound monomers
addition of non-Si bound monomers also possible
X: acrylate-, vinyl-, epoxy-, isocyanat-, etc.
curing: thermal, UV, redox, plasma
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inorganic network(glass,ceramic)
modified inorganic network(silicone)
organic crosslinking, inorganic-organic network (hybrid polymer)
precursors type I
precursors type II
precursors type III
CH2 C C C
O
M
O
O
O
Si
O
OSi
O
O
O O
M OO
O
M OO
O
O Si
O
SiR
O
O
O
Si RR
O
O Si
O
O
O Si
O
O
CH2 CH2
Si
Si CH2
O
O
Si
O
O CH2 CH2 SiSi OO
O
Si CH2Si
O
INORGANIC ORGANIC
organic network (organic polymer)
precursors type IV
ORMOCER® structural units
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Multifunctional precursors: type II and IIIfunctional groups
O CH2 CH CH2
O
R = H, CH
O R
O C C CH2
CH CH2
R’Si
RO
RO
(R)RO
(CH2)n
sol-gel-process
+H2O- ROH
- H2O
O OO
O
R'R'
Si Si
R'
inorganic backbone
organic crosslinking by UV- or
thermally inducedpolymerisation (curing reaction)
3(CH2)n
(CH2)n(CH2)n
CH3
MeN 3 Cl+ -CF2)5C F3(
NH2
SH
C H6 5
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SG coating functionalities/applications:
� optical: antireflective, heat insulation, optical fiber coatings, optical filters, UV-protection, LED-displays, optical waveguides, electrochromics see short course U. Posset
� electronic properties:
� (transparent) electron conductive
� ion conductive: batteries, fuel cells
� semiconducting: solar cells, photocatalysis
� dielectric layers, ferro-/piezoelectrics
� protection: corrosion (metals, construction materials), thermal and permeation barriers, scratch/abrasion resistance, low friction
� antifouling, antimicrobial, bioactive, biodegradable
� antisoiling, anti-icing, anti-fogging, easy-to-clean, photocatalysis
� gas and liquid sensors, catalysis
� flame retardancy
� encapsulation, controlled release
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SG/coatings: Papers per year Scopus, all fields, total: 117 T
Around 40% ofall SG-papers are dealing with coatings
All SG
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SG/coatings: Patents – No. families/ytotal SG 11500, coatings 4500 (Patbase; /TA)
Around 40% ofall SG-patents are dealing with coatings
All SG
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0
500
1000
1500
2000
2500
3000
2001 2011 2013 2014 estim. 2019-estim.
Mio. US $(BCC-reports)
� around 1/3 in US, Germany is leading in Europe
� high number of coating applications
� high growth rates: electronics, biomaterials and hybrids
Sol-Gel world market (conservative estimate):
Source: BCC-Report “Sol-Gel Processing of Ceramics and Glass” 2014
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Nanocoatings and SG-coatings are sometimes not well separatedMain application areas: Construction, medical, household, electronics
Recent drivers: automotive and aerospace
Source: SG nanocoatings 2016, Future markets
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SG typical coating techniques
dip-coating
spin-coating
spray-coating
Sources: Wikipedia-Sol-Gel
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SG coatings:
� typical thickness (one coat):inorganic: few hundert nm; hybrid: 4-10 µm
� curing: thermal, UV, plasma
� substrates:
� metals and ceramics: inorganic/hybrid
� polymers, paper, wood, textiles: hybrid
� including of (nano)-fillers, pigments, dyestuffs possible
� dense and porous films
� organic functionalities with covalent bonding to hybrid network -> stability
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original PV-glass
ISC anti-dust
up to – 30%
typical– 5%
transmission losses :
vs.
� nanotechnology: antireflective and anti-dust functions
� self-cleaning through wind/humidity due to 3D-surface structure
� low transmission losses in dry or urban areas
Example: Antireflective/antidust coatings - nanoporous SiO2
sources: Fraunhofer-ISC
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catalytic particles
Photoactivity
Self cleaning roof tiles
TiO2
nanoparticles
Application: Photocatalytic active surfaces
Erlus Lotus (TM)
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Example of commercialization: temperature resistant inorganic glass-like coatingson metal
Under-surfaces of steam irons Exhaust pipes
http://www.e-p-g.de/en/surface-finishing/#Temperatureresistance-2
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Hybrid polymer coatings: Comparison with organic lacquers and glass-like oxidic surfaces
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0
5
10
15
20
25
30
35
40
45
0 100 200 300 500
abrasion cycles
% haze
ORMOCER®-coating plane
glass
polycarbonate
in use for eyeglass lenses, mobile phone displays, optical polymer parts
O
O
O
O
O
O
O
O
O
OO
OO
O
O
O
Hybrid polymers as transparent hardcoats: Wet coatings
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Hard and abrasion resistantcoatings on PC/PMMA
Ima
ge
:sR
H &
Esc
he
nb
ach
Examples of commercialization: Transparent hybrid polymer hardcoat
fast UV-curing
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Examples of commercialization: automotive clearcoat i-Gloss TM BASF in-situ fillersiGloss combines two kinds of materials in a nanostructured hybrid.
https://www.basf.com/no/en/company/news-and-media/science-around-us/car-finish-higher-gloss-and-fewer-scratches.html
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PET 1 µm
SEM of hybrid flexible barrier film
POLO concept: Inorganic vacuum-coated layers combined with barrier coatings based on hybrid poly-mers to close the pinholes from sputtering
inorganic layer (SiOx)
hybrid polymer: ORMOCER®
Roll to roll magneton sputteringFh-FEP
ORMOCER® coating by Reverse Gravure Application Fh-IVV
1
250nm
Hybrid materials as barrier systems
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Ultrabarrier foils: Encapsulation of organic solar cells/OLED-displays on flexible substrates using hybrid polymer coatings
© Fraunhofer ISC/IAP
inorganic coating, 20-60 nm
ORMOCER© (< 0,5 µm)
inorganic layer, 20-60 nm
carrier film (PET)
Ultra barrier films2. generation
Barrier values: H2O: ca. 10-5 g/m2 dO2: ca. 10-5 cm3/m2 d bar
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Hybrid multifunctional coatings for packaging materialssee also presentation S. Amberg-Schwab
AimBio-degradable packaging materials basedon renewable raw materials
Properties� Antimicrobial� Barrier (humidity, oxygen, oil/fat)� Indicator functionality (condition of
packaged goods)
Possible with multifunctionalbiodegradable coatings for biopolymers
Benefits� Lower environmental burden� Better CO2 footprint� Extension of functionality
© DIBBIOPACK
EU-Project DIBBIOPACK: 19 partners from 11 countries
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Source © K. Dobberke für Fraunhofer ISC
� avoiding corrosion using hybrid polymer coatings
� excellent adhesion on various substrates
� also useful as primer layer for subsequent coatings
Corrosion protection
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© BASF
Hybrid polymers as passivation for electronics
� electronic control units have to work in ever more severe conditions e.g. near the motor
� ORMOCER®s can be used as thin filmpassivation coating:
� chemical bonding to metallic surfaces ->suppressing ion migration
� low gas permeation (even for sulfur containing gases)
� low space requirement (thin film instead of bulk encapsulation)
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Hybrid polymer: Low-energy surfaces e.g. on metals
source: Fraunhofer-ISC
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Transparent hybrid polymer coating with TiO2 nanoparticles showing photocatalytic activity
Source: Fraunhofer-ISC
Hybrid polymers with TiO2-nanoparticles: Photocatalysis
© Fh-ISC Würzburg
© Fh-ISC Würzburg
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� Bragg-grating in glass fiber is sensitive towards mechanical stresses � change of optical properties
� Coating is responsible for mechanical stress transfer towards fiber and also protects sensitive fiber
� Fast UV-curable coating
Protective hybrid polymer coatings for Bragg-grating fiber sensors
source: FBGS Technologies, Jena source: Fraunhofer-ISC
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Microstructured ORMOCER®s: Optical components
Source: Fraunhofer-IOF-ISC
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structure
Two-photon-absorption: TPA technology
[1]c
a
[1] S. Fessel et al J Sol-Gel Sci Technol (2012)
no solvent
voxel
lens
ORMOCER®
resin
substrate
development
with solvent
� organic crosslinking of ORMOCER® resins induced by 2-photon-absorption TPA
� high photon density necessary-> focused fs-pulses
� inherent 3D structuring possible
� scalable process (sub-100 nm…µm)
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10 µm 10 µm
10 µm 2 µm
3D ORMOCER® structures using TPA
pictures: Fraunhofer ISC
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Elektroden-
partikel
electrode
particle
ORMOCER®
coating
electrode
particle
Electrochemistry: ORMOCER® coatings of/on active materials
Core-Shell� stability of electrode materials� high voltage possible
–> 5 V batteries� good current stability� better cycling stability
→ longlife→ energy density→ power density
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ORMOCER®
50 nm
50 nm
ORMOCER®
50 nm
LMNO
ORMOCER®
LTO NCM
TEM: Ultrathin coatings on LTO: Li4Ti5O12, NCM: Li(Ni,Mn,Co)O2 and LMNO: LiNi1,6Mn0,4O4 particles
50 nm
Coating on electrode materials with Li-Ion conducting hybrid polymers
Source: Fraunhofer-ISC
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ORMOCER® coating of active materials:voltage stability in a NCM-graphite cell
4,3 V
4,2 V; 4,3 V; 4,5 V
4,2 V
NCM with ORMOCER®
NCM uncoated/1
NCM uncoated/2
�Increased cycle stability and charging-end voltage
Number of cycles
Dis
charg
e c
ap
aci
ty/%
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Bild © F. Frech
Si(100)
Li1+xAlxTi2-x(PO4)3
500 nm
>200 nm
� Ultrathin electrolyte layer as
key component in solid state batteries
� Dip coating or other printing processes
All solid-state-electrolytes: based on ceramics
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Conclusion
� Chemical nanotechnology and especially sol-gel processing are leading to more and more industrial applications especially due to the versatility of functionalities based on hybrid inorganic-organic systems and the relative ease of processing various forms (powders, coatings, fibers etc.)
� Scientific interest and also patenting activities are still increasing
� Areas like biomedical applications, additive manufacturing (2D -> 3D), battery materials and the possible use of biogenic precursors will widen the use of sol-gel materials even further
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Dr. Karl-Heinz Haas
Fraunhofer Institute for Silicate Research ISC
Neunerplatz 2 | 97082 Würzburg | Germany
www.isc.fraunhofer.de
Thank you for your attention!
Prisms, 3D-micro-patterned by fs-laser-induced polymerization (2PP) © Fraunhofer ISC