Introduction to Inorganic Organic Hybrid Materials - Eg-MRS

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




• 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




• 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)


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


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


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”


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


POSS for fire retardant materialsPOSS for fire retardant materials


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


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




• 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

Introduction to Inorganic Organic Hybrid Materials - Eg-MRS

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