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Introduction to Inorganic-Introduction to InorganicOrganic Hybrid Materials
Guido KickelbickSaarland UniversityI tit t f I i S lid St tInstitute of Inorganic Solid State [email protected]@
Saarbrücken
Saarland UniversitySaarland University
B liBerlin
Frankfurt15.500 Students
Saarbrücken
Würzburg 290 ProfessorsChemistry Department:
TschechRepublic
Luxemburg
Munich
13 Professorsaround 500 StudentsFrance
StuttgartUlm
ViennaAustria Vienna
Property Gaps where Synergistic Combinations of Materials can Fill Material Property Gaps
Material-property chart of thermal conductivity and Young’s modulus for 2300 materialsSmall circle: plot of these properties for a real materialLarge ellipses enclose, approximately, the circles for a given family of materialsLarge ellipses enclose, approximately, the circles for a given family of materialsLarge area of the chart is empty: there are no materials with high conductivity and low modulusThe challenge is to create hybrids that fill the hole.
M.F. Ashby et al. Acta Materialia 2003, 51, 5801
„Classical“ Definition of Hybrid Materials
M.F. Ashby et al. Acta Materialia 2003, 51, 5801
Outlook
• Definitions and Properties
• Precursors and ProcessesPrecursors and Processes
• Classes of sol-gel hybrid materials
• Applications
Composites – Hybrid Materials
CLASSICAL COMPOSITEScm
Property Improvement:• mechanical stability• mechanical stability• thermal stability• photochemical t bilit
µm
stability
nm Hybrid Materials From Molecules to Nanobuilding BlocksVarious properties possible depending on precursors and processingg g
Hybrid Materials - Nanocomposites
(Inorganic Organic) Hybrid Material (Definition by Function)(Inorganic-Organic) Hybrid Material (Definition by Function)inorganic + organic components (homogeneously) distributed on the molecular and/or nanometer levelL th lLength scale:
molecular compounds ↔ hybrid materials ↔ composite materials
Nanocomposites (Definition by length scale)two different (organic and/or inorganic) components from which at least one has dimensions in the nanometer (1-100 nm) size regime( ) g
fluent transition between molecular materials and nanometer sized objects but methods for preparation sometimes alter in such a way thatobjects, but methods for preparation sometimes alter in such a way that the nanometer level has its own rules (e.g. high surface energies).
Important for both materialsImportant for both materialsProperties determined by the synergetic combination of inorganic and organic componentsN l b d li i lit t b t h b id t i l dNo clear borderline in literature between hybrid materials and nanocomposites
Hybrid Materials
MacroscopicphasesComposite Material phases
Compound 1 Compound 2
Molecular ornanoscaleHybrid Materialbuilding blocks
Hybrid Material
The goal is to create materials with specific combinations of properties byThe goal is to create materials with specific combinations of properties by combining different molecular building blocks in various ratios and by controlling their mutual arrangement
Control at the nanolevel
Typical Properties of Organic and Inorganic Materials
Properties Organic materials(polymers)
Inorganic materials(glass, ceramics)
N t f b d l t [C C] d W l H i i l tNature of bonds covalent [C–C], van der Waals, H-bonding
ionic or covalent
Tg low highThermal stability low (except polyimides) highy ( y ) gDensity low highRefractive index low highMechanical properties elastic hard
flexible strongflexible strongrubbery (depending on Tg) brittle
Hydrophobicity hydrophilic or hydrophobic hydrophilic
Electronic and magnetic properties
insulating to conductive insulating to semiconductorsp p
non-magnetic magneticProcessability at low temperatures and pressures
(molding, casting, etc.)at high temperatures and/or pressures (sintering, glass forming)
C. Sanchez et al. J. Mater. Chem. 2005, 15, 3559
Inorganic-Organic Hybrid Materials in Nature
S l t i i t f b li id i id h i ( i i id)Ernst Haeckel, Kunstformen der Natur (1904)
Scleroproteins consist of carboxylic acid groups in side chain (e.g. asparaginic acid)=> Interactions with Ca2+ ions O
C CH2 C
NH3+
C
O-
O CH3 OCa
Homogeneity
vsvs.
Problems: scattering of lightProblems: scattering of light,mechanical properties, change of physical properties of the building blocks etcof the building blocks etc…
Control over homogeneity:• precursor selection (functional group)precursor selection (functional group)• reaction conditions: kinetics, solvent, etc.• interactions between the components
Important Issues in the Synthesis of Hybrid Materials
H di t ib ti f b th i ti i th Homogeneous distribution of both moieties in the
material
Stable distribution: no microphase separation
Interaction between the two components
Structure-property relationships
Inclusion of functionalities
Tailoring of
molecular structure ↔ nanostructure ↔ microstructure
(= hierarchical structure design)
Outlook
• Definitions and Properties
• Precursors and ProcessesPrecursors and Processes
• Classes of sol-gel hybrid materials
• Applications
Routes to Hybrid Materials
Precursor Chemistry Building Block Approach
Chemical reactions change the properties of the precursors
Building blocks keep their molecularintegrity (at least partially)
Properties of final material aredifferent to precursors
Properties of final materials keep similarities to the precursors
Typical materials:Sol-gel, organic polymers
Typical materials:Cluster or nanoparticle cross-linked g , g p y pmaterials
OCH3 OCH3O Si
OSi
R R'
H3CO Si OCH3
OCH3
H3CO Si CH3
OCH3
+OO
SiO
Si
O
O
Si
O
SiO
O Si
Si
O
RR
RR
O SiSi OR
R
+ Polymers
Building Blocks
Inorganic Building Blocks
OO
O OO
Mechanical opticalSi
O
O
OTi
O O
O O
O
Mechanical, optical, electrical, magnetical properties
Connecting Blocks
SiO
H2C
O
Reduction of the crosslinking density, coupling sites between i i / i t
Connecting Blocks
TiO Y
O XO
Organic Building BlocksFunctional groups crosslinking
OO inorganic / organic componentsO
Fl ibilit l ti it
Functional groups, crosslinking, polymerizabilityA
H2C
C
H2C
C
Flexibility, elasticity, processability
CH2
CH2
Linking the Building Blocks
Polymerization / Polycondensation
OCH3 COOR CH3
ORCOOR CH3 COOR
O
OHO
HO
+ H2N NH2
O
O
HN
HN NH
O
Sol Gel Process
SiHO OH
OHSi
HO OHOH
- H2OSi
RO OROR
+ H2O
Sol-Gel-Process
OH
SiHO OH
OH
OH
SiHO OH
OH
O2
OR
Na4SiO4 + H+
Self-Organization
HO OH
Zn(NO3)2 +Zn4O(terephthalate)6
OHO
g
OHO
Sol-Gel Process
Functional GroupsStable to Hydrolysis
Hydrolysis:
M(OR)H2O M(OR) (OH) + HOR y y
R H C SiM = Si
M(OR)n M(OR)n-m(OH)m + HOR
Condensation:
R-H2C-Si
M = TM
M(OR)n-m(OH)m (RO)n-m(HO)mM O M(OR)n-m(OH)m
O OR3
R2R1
M O
O
O M O
O O
OO
M
MO
O
O M O
OM = Si, Ti, Zr, Sn, Al, ...
R = Me Et iPr nPr nBu sBu
Solvent-chemistry
R Me, Et, Pr, Pr, Bu, Bu,...
Mild process (RT)Organic functionalization of the inorganic components
Sol-Gel Process – Final Materials
Sol GelSolvent SupercriticalSol Fibres SolventEvaporation
SupercriticalExtraction
Sol Fibres
GelationEvaporation
Powder
Xerogel Film
Xerogel Aerogel
Drying Heating
D C i Fil
Heat TreatmentDrying, Heating
Dense Ceramic Film Dense Glas
Molecular Precursors
+ Si(OR)Sol-Gel Reaction
Network Modifier:
Si(OR)3
+ Si(OR)4
OH
OHOH
SiOHOH
Si
OH
OH
OH OO
OH
OHOH
OHSi
OSi
SiSi
SiSi
OOO
OOH
O
O
OO Si
Si
SiO
OHSiO
O
O
Si
OHO
OO
SiOSiO
SiO
O
OOH OHOH
OOHO
OSi
OH
OH
OHSiOH
Si
OHO
SiH
OHO
SiO
OOH
OHO
OHOOHOH
O
O Si
SiSi Si
SiH2Si
SiH
Si
O
O
OO
OHO SiSi
Si OO
OOSi
OSi OO
OSiO
OO
OO
Si
O Si-SiO
O
O
O
OHOHO
Si(OR)3 OH
OHSi
OH OH
Si
Si
O
OH
OH
O
OH
O
OHO
Si SiO
Si
O
Network Former:
Si(OR)3
+ Si(OR)4
Sol-Gel Reaction
OHOH
O
SiOH
O Si O
OH
OHSiO
OH
OHO
Si
OOH
OHOO
O
Si
Si
O Si
O
Si
O
O
O
O
O
Si
Si
Si
OH
OH
OHOH
OH
OSiO
OH
OH
Si
Si
O
O
OH
O
SiOSi
SiSi
Molecular Precursors
Precursors with Functional Organic GroupsNH
NH2(RO)3Si
O
(RO)3SiO(RO)3SiO
O
+ HS-Si(OR)3NO2
NN
OHN(EtO) Si
H
O(RO)3SiO O
Ti
ORORRO
NR
OO
N(EtO)3Si
(RO) TiSO (C hth l i )
polymerizable organic groups inorganic-organic hybrid polymers groups with other organic functions
(RO)3TiSO3(Co-phthalocyanine)
Nano Building Blocks: Polyhedral Oligomeric Silsesquioxanes (POSS)
Nano Building Blocks: Functionalized Metal Oxide Clusters
Ti O (OEt) (OPr)Ti16O16(OEt)24(OPr)8
(same with OCH2CH2OC(O)C(Me)=CH2)
covalent interactionZr6O4(OH)4(methacrylate)12
)
[SiW11O39(OSi2(C6H4CH=CH2)2)]4-
[(BuSn)12O14(OH)6]2+·2 methacrylate-
electrostatic interaction[ 11 39( 2( 6 4 2)2)] electrostatic interaction
Alkoxysilyl-Substituted Organic Polymers
C. Sanchez et al. J. Mater. Chem. 2005, 15, 3559
Pre-formed Nanostructures
(Nano)Particles (Nano)Fibres, NanotubesPreformed Oligomers and Polymersand Polymers
Clays / Layered MaterialsPorous Materials
Possibilities for Interactions between Inorganic and Organic Components
RRROHOH
OHHOHO
Coordinative O O
M(OR)n
OO
M(OR)n
Covalent Cl3Si R
(RO)3Si R
OHOH
OHOHOHOH
HOHO
ElectrostaticN
Strengthof theInteractions
RH-Bridges
NH NHHN
Interactions
--InteractionsHN
NHNHNH
NHNHNH
HNHN
HN
O OVan-der-Waals
(RO)3Si
NHNHNH
OH
Different Paths to Obtain Inorganic-Organic Hybrid Materials
C. Sanchez et al. C. R. Chimie 2003, 6, 1131
Outlook
• Definitions and Properties
• Precursors and ProcessesPrecursors and Processes
• Classes of sol-gel hybrid materials
• Applications
Types of Inorganic-Organic Hybrid Materials
Class I Materials: Weak InteractionsClass I Materials: Weak Interactions
Interpenetrating NetworksBlends
Class II Materials: Strong Interactions
C l t C ti C l tl C li k d P l
Progr. Polym. Sci. 2003, 28, 83
Covalent Connection Covalently Crosslinked Polymers
Entrapped Biomolecules
J.D. Brennan, Analyt. Chim. Acta 2002, 461, 1
Coatings with Optical Properties
Photochromism: fast for optical switches, for eye protection, privacy shieldsslow for optical data storage, energy conserving coatings, etc...p g , gy g g ,
Example: Spirooxazine derivative
O
N
N O
N
N
hν1
∆ hEmbedding in sol-gel coatings:For sufficient photochromism: dye concentration > 25 wt% mechanical stability of sol-gel film is deteriorated.
ON ON∆ or hν2
g
Grafting of the dye to thesol-gel matrix higher chromophoreconcentrations can be achieved Si(OEt)3concentrations can be achievedwithout affecting the mechanical integrityof the sol-gel matrix
NO
O
HN
( )3
ON
Photochromic coating on paperPhotochromic coating on paper
Interpenetrating Networks
Sequential two-step process:q p pSecond network isformed in the first
IPNExamples: Generation of the organic polymer in the pores of an inorganic porous material
(in channels of zeolites or mesoporous materials, between sheets of a layered ( p ylattice, such as a clay mineral) rigid inorganic moiety with a regular pore or channel structure in the nanoscale
Inorganic structures form and interpenetrate an organic polymer (difficulties: incompatibility between the moieties phase separation)
Interpenetrating Networks
Interaction via hydrogen bonds to silanol groups of the forming silicaOrganic polymers with hydrogen bonding ability:Organic polymers with hydrogen bonding ability:
n nOH
nO
n n n
N
NMe2OOH O
O
OMeO OO
OHpoly(VP) poly(DMAA) poly(VA) poly(VAc) poly(MMA) poly(HEMA)
Si(OR)4 and/or RSi(OR)3H2O, [Kat]2 , [ ]
No macro phase separation Resulting materials: high degree of homogeneity
d ti l tand optical transparency
Important reaction parameter: pHChange of crosslinking density and interaction with polymer using RSi(OR)3/Si(OR)4g g y p y g ( )3 ( )4mixtures
Interpenetrating Networks
Organic Monomer Initiator Inorganic Monomer Catalyst Solvent
O O
g g y
AIBN TEOS HF Water
6, 8
, 727
O H
m. M
ater
.199
6
Addition of tetrakis(2-(acryloxy)ethoxy)silane improves homogenity
TEM images of the nanocomposites:
n et
al.
Che
mC
. L. J
acks
onC
Increasing Sol-Gel Catalyst Concentration => Faster Reaction
Dual Network Structures
Preparation strategies Concomitant formation of the inorganic and organic structures
Stepwise formation of the organic and inorganic networksp g g from pre-formed organic structures from pre-formed inorganic structures
Options Chemical composition of the inorganic component(s) Chemical composition of the organic component(s) Proportion of the inorganic/organic components Curing method (thermal / photochemical) Curing method (thermal / photochemical) Dimension of the inorganic / organic components (molecular, nanometer, extended)
Concomitant Formation of Inorganic and Organic Network
Precursors Metal AlkoxidesM t l S lt
Typical procedureMetal Salts
+ water (ev. catalyst or additives)- alcohol
HydrolysisCondensation
Sol
Gelation formation of inorganic network
Gel
Hardening formation of organic network
Gel
Hybrid Polymer
g(thermal or UV)
g
Hybrid Polymer
Concomitant Formation of Inorganic and Organic Network
PrecursorsO
O(RO)3Si
O(RO)3Si (RO)3Si
O(RO)3SiO
OO
O
+ Z (OR)O OH O O
Oor + Zr(OR)4
+ Si(OR) Zr(OR) + acrylate epoxide+ Si(OR)4, Zr(OR)4, Al(OR)3, etc.increase of “inorganic
+ acrylate, epoxide monomers, etc.decrease of
/ organic ratio” “inorganic / organic ratio”
Concomitant Formation of Inorganic and Organic Network
O
H O / NaFO
CH2OSi
H2O / NaF
aq. ROMPSiO2 +
n4 CH2OH
O(CH2)2O
O
Si
H2O / NaF
Free RadicalP l i ti
SiO2 +
4Polymerization O O(CH2)2OH 4
B.M. Novak et al. 1991-1993
Hybrid Polymers from Pre-Formed Inorganic Structures
Improved Properties through ControlledReinforcement of Polymer Chains at the Molecular Level
Property enhancements via POSSobserved in POSS-copolymers and blends
Reinforcement of Polymer Chains at the Molecular Level
• Increased Tdec• Increased Tg• Reduced Flammability OO Si
OSi
R
R R'
y• Reduced Heat Evolution • Lower Density • Disposal as Silica • Extended Temperature RangeOO
SiO
SiO
OO
R
R
R
• Extended Temperature Range • Increased Oxygen Permeability • Lower Thermal Conductivity • Thermoplastic or Curable
OSi
O
Si
O
OSi
OO Si
RR
p• Enhanced Blend Miscibility • Oxidation Resistance • Altered Mechanicals • Reduced Viscosity
ORR
www hybridplastics com • Reduced Viscositywww.hybridplastics.com
Hybrid Polymers from Pre-Formed Inorganic Structures
Hybrid Polymers from Pre-Formed Inorganic Structures
POSS for fire retardant materialsPOSS for fire retardant materials
Hybrid Polymers from Pre-Formed Inorganic Structures
Polymerizable Metal Oxo Clusters
XX
XX
X
XX
X
X
Polymerizable groups X
Zr6O4(OH)4(methacrylate)12for free radical polymerization
Zr O (OH) (5-norbornene-2-carboxylate) forZr6O4(OH)4(5-norbornene-2-carboxylate)12 for ROMP
Hybrid Polymers from Pre-Formed Inorganic Structures - Metal Oxo Clusters as Initiators for ATRP
+multifunctional initiator monomer + catalyst + solvent
PMMA PS PtB A
XX
XX
multifunctional initiator monomer catalyst solvent
catalyst = pmdeta / CuBr or CuCl
= PMMA, PS, PtBuAX
XX
XX
0.7
0.8
0.9 ln (M0/M) linear Fit for ln (M0/M) 80
90100
e.g. Ti6O4(OOCCBrMe2)(OiPr)8
0 3
0.4
0.5
0.6Y=0,0058*XR=0,997
n (M
0/M)
40506070 C
onversion
0 20 40 60 80 100 120 140 1600.0
0.1
0.2
0.3l0102030 [%
]
Polydispersities <1.5.90% of the chain ends
0 20 40 60 80 100 120 140 160
Time [min]G.Kickelbick et al. still active after isolation
Hybrid Polymers from Pre-Formed Inorganic Structures
OH OH OHOHPreparation of nanoparticles
Si(OEt)4 + NH4OH„Stöber-Process“
OHOH
OHOHOH
OHOH
OH
OHOH
OHOH
OHOHOH
OHOH
OH O
SiO2
OHOH OH OH
Surface modification O
FG
SiO O
FG
SiO OO FG
SiOO
Si OO
O
FG
(RO)3Si FGSiO2
O
SiO
OO FG
O
SiOOO
FG
Si
OO
OFG
O O O
FG
3
(EtO)3Si(H2C)3O Br
O
CH3
CH3
(EtO)3Si(H2C)3ON
N CN
O
CH3NC
CH3CH3
Initiators at the surface, e.g.
FG3
Polymerization from the functionalised surface
AFM
Matyjaszewski, Kickelbick et al., JACS 2001, 123, 9445
Particle in Particle Technique
1. H2N(CH2)3Si(OEt)3, H2O2. 27% Na2SiO3
3. Si(OEt)4, EtOH
15 nm Au 45 nm Au@SiO2
O
O(CH2)3Si(OR)3
BrCH3
CH3
HF
ATRP (Cu/pmdeta)Isopren
50 nm Au@SiO2@PI Au Nanoparticle inPI-Hull
J. Nanosci. Nanotechn. 2006
Au@SiO2@Silane Elastomer Nanocomposites
0.3
0.4
rban
ce
0 0
0.1
0.2
Abs
o
400 500 600 700 8000.0
Wavelength (nm)
PDMS
polymerization
Au@SiO @Silane2 Au-doped PDMS network
J. Nanosci. Nanotechn. 2006
Layer-by-Layer Deposition
G. Decher, Science 1997, 277, 1232 - 1237
Layer-by-Layer Deposition
Typical Polyelectrolytes
Formation of Discrete Hybrid Nanoparticlesy p
Xiangyang Shia, M. Shenb, H. Möhwald, Prog. Polym. Sci. 2004, 29, 987–1019
Outlook
• Definitions and Properties
• Precursors and ProcessesPrecursors and Processes
• Classes of sol-gel hybrid materials
• Applications
Applications of Inorganic-OrganicHybrid Materials and Nanocomposites
Optical Materials with aPackaging materialswith tailored nanosized structure
(Polymer + TiO2)with tailoredgas permeability(Polymer + SiO2)
Electrical conductingOptical polymers with extraordinary Polymers for decorative applications Electrical conducting polymers
(Polymer + PZT)
Optical polymers with extraordinary mechanical properties
(Polymer + SiO2, TiO2, Al2O3 or ZrO2)
Polymers for decorative applications(Polymer + SiO2/Al2O3 and organic dyes)
Scratch-Resistant CoatingsExample: ophthalmic lenses (fromExample: ophthalmic lenses (from organic materials) Hybrid sol-gel based materials as coatings:coat gs• fast curing • patternable coatings• compatibility with organic dyesp y g y
G. Schottner et al. ; Chem. Mater. 2001, 13, 3422; ibid. J. Sol-Gel Sci. Techn. 2003, 27, 71
Anti-Reflective Surface Patterning
G. Schottner et al. Chem. Mater. 2001, 13, 3422; ibid. J. Sol-Gel Sci. Techn. 2003, 27, 71
Nanocomposites as Dental Materials
Required materials properties:Hardness- Hardness
- Breaking strength- Low weight
O ti l t t- Optical transparent
Problems:Sh i k- Shrinkage
- Inhomogenities
New Approach:Toolbox of organic and inorganic building blocksinorganic building blocks(LEGO chemistry)
Molecular Fuel Tanks
The external shape of microscopic MOF-5 crystals (left) reflects their well-definedThe external shape of microscopic MOF 5 crystals (left) reflects their well defined cubic lattice (middle). The structure consists of [OZn4]6+ clusters and organic connectors, with persistent pores that are continuous in three dimensions (right)
O.M. Yaghi, Science 2003, 300, 1127; A.U. Czaja, N. Trukhanb, U. Müller Chem. Soc. Rev. 2009, 38, 1284
Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire worldwhile imagination embraces the entire world,and all there ever will be to know and understand.
Albert Einstein
Further Reading
Chapters• Introduction to Hybrid Materials• Nanocomposites of Polymers and Inorganic
Particles• Hybrid Organic/Inorganic ParticlesHybrid Organic/Inorganic Particles
Intercalation Compounds and Clay NanocompositesP H b id M t i l• Porous Hybrid Materials
• Sol-Gel Processing of Hybrid Organic-Inorganic Materials Based on Polysilsesquioxanes
• Natural and Artificial Hybrid Biomaterials• Medical Applications of Hybrid Materials• Hybrid Materials for Optical Applications• Hybrid Materials for Optical Applications• Electronic and Electrochemical Applications of
Hybrid Materials• Inorganic/Organic Hybrid Coatings