Hybrid Organic-Inorganic Materials

advertisement
Hybrid Organic-Inorganic, POSS
Materials
Lecture 4 & Quiz
September 28th
Today
First hour:
• Some definitions
• Strategies for making Hybrids
Second hour:
• Quiz
• Discussion of quiz answers
Course website
• For lecture slides and other info.
• Not at HIT website, at Loy research
website:http://www.loyresearchgroup.com/
• Go to loy research group home page and
select “courses” on menu at top.
• Class website “Harbin Institute of Technology,
Hybrid Materials Course” is the first entry.
Direct
url:http://www.loyresearchgroup.com/harbininstitute-technology---hybrid-materialscourse.html
What are Hybrid Materials?
Composite materials mixtures of organic and
inorganic components
Metal
oxide
network
Improvement on either organic or inorganic components
Introduction to polysilsesquioxanes
R
O
R
R
R
O Si OH
Si OH
Si
HO
O
O
O O
O
Si
Si
R Si O
R
R R Si O
R
O
O
O
O Si
OH
R Si
O
Si O Si
R
R
OH
O
Si O Si O
R
O
R O Si R
O
OH
Si
Si
O
HO
R
R
Si
R SiO1.5
n
n = 17
R
R
O Si
O Si
R
OO
O
O
R
Si
Si
R Si O Si R
O
O
O
O
Si O Si
R
R
n=8
R SiO1.5
R8 Si8O12
Network of Si-O-Si
Organic group (alkyl, aryl, alkenyl) attached through Si-C bond
Fully condensed: 1.5 oxygens per Si
Three siloxane bonds per silicon
8
Where are the organic and inorganic
phases?
R
O
R
R
R
O Si OH
Si OH
Si
HO
O
O
O O
O
Si
R
Si O Si R
R Si O
R
R
O
O
O
O Si
OH
R Si
or
O
Si O Si
R
R
OH
O
Si O Si O
R
R
Si R
O
O
OH
O
Si
Si
O
HO
R
R
Si
H2O
RSi(OMe)3
catalyst
Blue is inorganic
R
R
O Si
O Si
R
OO
O
O
R
Si
Si
R Si O Si R
O
O
O
O
Si O Si
R
R
Black is organic
•Segregation only at sub-molecular length scales.
•Hybrid, synergistic properties come from very high surface
area contact between phases
Silsesquioxane
Silicon
1.5
R SiO1.5
Oxygens
n
Polysilsesquioxane
Many
Many generally means more than 10,000 Dalto
Oligosilsesquioxane
A few
Silicon
1.5
R SiO1.5
Oxygens
n
Oligo means > 1 and < 50-100 (depends on Mw or R group)
R
R
O Si
O Si
R
OO
O
O
R
Si
Si
R Si O Si R
O
O
O
O
Si O Si
R
R
n=8
R SiO1.5
R8 Si8O12
8
Nomenclature of silsesquioxanes
• Polymers: poly(name of organic-silsesquioxane)
eg. R = Ph or phenyl
Ph SiO1.5
n
poly(phenylsilsesquioxane)
Nomenclature of silsesquioxanes
• oligomers: oligo(name of organic-silsesquioxane)
eg. R = Ph or phenyl
Ph SiO1.5
n
poly(oligosilsesquioxane)
Nomenclature of silsesquioxanes
• Polyhedral oligomers: need to describe size of
rings
eg. R = Ph or phenyl
T8: n = 8
Ph
Ph
O Si
O Si
Ph
OO
O
O
Ph
Si
Si
Ph Si O Si Ph
O
O
O
O
Si O Si
Ph
Ph
n=8
Ph SiO1.5
8
Ph8 Si8O12
Ph = phenyl
IUPAC Name:
1,3,5,7,9,11,13,15-octaphenyl
pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane
Polyhedral refers to multi-sided geometric shapes like cubes.
Drawing bridged polysilsesquioxane structures:
Si
CH2
O
or
H
n
+ 3n H2O
H
Si(OMe)3
(MeO)3Si
or
(MeO)3Si
-6 n MeOH
O
Si
CH2
O
CH2
O
O
(MeO)3Si CH2 Si(OMe)3
O
Si
O
Si
O O
O
Si
Si O
Si O Si
O O
CH2
CH2
CH2
O Si
Si
CH2
Si O Si
O
O
O
O
O
O
Si O
CH2 Si
Si O
O
CH2
O
O
O Si
O Si
C
H2
or
Si(OMe)3
SiO1.5
O1.5Si
Fully condensed: 1.5 oxygens per Si.
or
Si
O
Si O
O n
Methylene-bridged polysilsesquioxane
n
bridged polysilsesquioxane nomenclature:
Si
CH2
O
O
O
Si
O
CH2
O
O
CH2
Si
O
O O
Si
O
Si
Si O
Si O Si
O O
CH2
CH2
CH2
O Si
Si
CH2
O
Si O Si
O
O
O
O
O
Si O
CH2 Si
Si O
O
CH2
O
O
O Si
O Si
C
H2
or
O1.5Si
or
SiO1.5
n
Si
O
Si O
O n
Methylene-bridged polysilsesquioxane
Not “methane-bridged”
These are not silicas
Not “methano-bridged”
These are not silicates
Not “methano-silica”
Not “methylene modified silicate”
Different ways to put hybrids together
Class 1: No covalent bonds between inorganic and organic phases
Example: particle filled polymer
Class 2: Covalent bonds between inorganic and organic phases
Monomers in solvent
Gel or dry gel (xerogel)
Close-up of hybrid
particle
In practice, how do you make these
hybrids?
Inorganic
Organic
Physical mixing
Colloidal dispersion
Aggregation or coalescence
Like oil and water
Class 1:Try to use high viscosity of polymer to hinder aggregation
Class 2: Use covalent bonds to prevent aggregation of phases
Making Hybrid Materials: Class 1A
(pre-formed particles and fibers)
R
=
Pre-formed Particles
R
Si O Si
O
R
OO
O
Si O Si R
R Si O Si R
O
OO
O
Si O Si
R
R
or SiO2
or MOx
or O1.5Si-R-SiO1.5
or R-SiO1.5
or
Polymers
Physical mixing of particles in melt
or solution
Easiest hybrid to make
Inorganic Phases
Metal Oxide Networks
Organically modified Metal Oxide Networks
Inorganic Phases
Preformed inorganic clusters
Ti(OR)4-x(acac)x
Ti12O16(OPri)16
Silica Particles
Ti18O22(OBun)26(Acac)2
POSS
Ti17O24(OPri)20
Making silsesquioxanes as
inorganic phase
R
O
R
R
R
O Si OH
Si OH
Si
HO
O
O
O O
O
Si
R
Si O Si R
R Si O
R
R
O
O
O
O Si
OH
R Si
or
O
Si O Si
R
R
OH
O
Si O Si O
R
R
Si R
O
O
OH
O
Si
Si
O
HO
R
R
Si
H2O
RSi(OMe)3
catalyst
Blue is inorganic
Surface modified inorganic
R
R
O Si
O Si
R
OO
O
R
Si O Si
R Si O Si R
O
O
O
O
Si O Si
R
R
Black is organic
Class 1A: POSS physically dispersed in
polypropylene
R
OR'
R Si
OR'
OR'
R
Si O Si
R O
OO
O
O
Si R
Si
R Si O Si R =
O
O
O
O
Si O Si
R
R
POSS
n
R"
Inorganic Phases
Isolated metal atoms in polymeric
architectures (organometallic polymers)
While formally “inorganic” these behave more like organic
Organic phases: Polymers
Commercially available from Dow, BASF \
or from research chemical vendors: Aldrich or Polyscience
Inorganic Phases
Carbon Buckeyballs, nanotubes
and graphene
Organic need more
than just carbon:
CHNO
Nature Materials 9, 868–871 (2010)
Class 1: No covalent bonds between inorganic
and organic phase (easiest hybrid to prepare)
Example: particle filled polymer
1) First need to prepare or buy inorganic particles
2) then, depending on polymer melting point, mix into
melt or solution of polymer
3) Cool (if melt) or evaporate solvent (if solution)
If you were making this hybrid, what would you be worrying
about? And how would you check experimentally?
Making Hybrid Materials: Class 1B
(in situ particle growth)
OR'
M(OR')x R'O Si
OR'
OR'
No Solvent except for monomer(s)
Generally uses low tg organic polymers
or in polymer melts (< 100 °C).
Viscous environment. Confined growth.
OR'
OR'
R Si
OR' R'O Si
OR'
R'O
OR'
R Si
OR'
OR'
Making Hybrid Materials: Class 1B
(in situ particle growth)
"Inorganic
monomer"
CH3Si(OMe)3
Particles form in situ
Polymerize
inorganic
monomer
H2O
LInear polymer
10-10000 nm
Grow
inorganic
particles
tin catalyst
What must happen for this method to work?
Melt
Making Hybrid Materials: Class 1C
(Polymerizing in pores)
R
R
R
R
R
R
R
R
R
R
R
R
R
R
catalyst
R
R
R
R
R
R
R
R
R
R
R
R
R
•Porous metal oxide
•Liquid monomer (no solvent)
•UV, heat, radiation
R
R
R
R
R R
R
R
R
R
R
R
Non-porous composite material
Same issues as in 1B, but organic polymerization must not be
chemically hindered by metal oxide
What polymerization chemistry is incompatible with silica or
silsesquioxanes? Why?
Making Hybrid Materials: Class 1D
(encapsulation of small organics)
HO
HO
OH
O O
catalyst
HO
O O
H2O
O
O
O
HO
O
• Polymerize metal oxide around organic
• pores must be small or leakage will
occur
•Solid state dye lasers, filters, colored
glass
Describe how the starting materials
must behave for this to work
O
© AsahiKirin
O
Ancient Humans also made Hybrid
organic-inorganic materials: Maya Blue
Indigo
+
white clay palygorskite
(Mg,Al)2Si4O10(OH)·4(H2O)
(also called Fullers Earth)
Class 1B or Class 1C or Class 1D??
L. A. Polette, N. Ugarte, M. José Yacamán and R. Chianelli, Sci. Am. Discovering
Archaeology, 2000, July–August, 46
Making Hybrid Materials: Class 1E
(Interpenetrating network)
R
R
R
R
R
R R
R
catalyst
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
• Both organic and inorganic phases
grow simultaneously
•Timing is more difficult
• Reproducibility is a challenge
• May need to use crosslinking organic
monomers to ensure solid product
R
R
R
R
R
R
What does this assume
about the reaction
kinetics?
Making Hybrid Materials: Class 2A
(Covalent links at molecular level)
R
R
R
R
R
R
R
R
R
R
R
R
H2O
R
R
R
R
R
R
R
catalyst
R
R
R
R
R
R
R
R
R
• Organic group is attached to network
at molecular level
•Hypercrosslinking is possible
•Pendant or bridging monomers
•Bridging groups can be small or
macromolecule
•This class also includes the
organometallic polymers
R
R
R
R
R
R
Chromatographic
Materials
Photoresists for
Lithography
Low K Dielectrics
Making Hybrid Materials: Class 2B
(Covalent links at polymer level)
R
R
R
R
R
R
R
R
R
In Melt
R
R
R
R
R
R
or in solution
R
R
R
R
R
• ligands attached to polymer
• Reaction rates slow unless in sol. or
melt
R
R
R
R
R
R
R
R
R
RR
R
R
R
R
R
R
R
R
R R
R
R
R
R
R
R
R
R
R
R
R
Making Hybrid Materials: Class 2C
Templating with block copolymers and
surfactants
excess water
H+, OH- or F-
Self-assembly surfactant into 3-D biphase system then
polymerize in one of the phases (usually in the water
phase)
Making Hybrid Materials: Class 2C
(Templating) Shown here with block
copolymer
A
B
O
n
hydrophobic
polyisoprene
m
hydrophilic
polethylene oxide
Heat polymer then cool
or cast from solvent
Making Hybrid Materials: Class 2C
(Templating) Shown here with block copolymer
polyisoprene
Block copolymer
Sol-gel system
PEO, Al2O3 and
RSiO1.5
Block copolymer
Multiple phases
created by
varying size of
Templating with surfactants:(Class 2C)
• First prepare two
phase surfactant
system
• Add monomer. Solgel monomers move
into aqueous phase
with hydrolysis
• Filter precipitate
• remove surfactant
by calcining or
extraction
Many different
phases can be
accessed
1. Davis, H. T., Bodet, J. F., Scriven, L. E., Miller, W. G. Physics of
Amphiphilic Layers, 1987, Springer-Verlag, New York
Surfactant templating to make
hierarchical materials (Class 2C)
Surfactant templating (Class 2C)
Benzene-silica hybrid material
with 3.8 nm pore diameter
(Inagaki, Nature, 2002).
Classes 2D Covalent coupling agents
Attaching organic group onto inorganic material
O
O
O
Si(OEt)3
HO HO
OH
HO
Si
Si
OH
Si
HO
Si O O
O
OH
Si O
O
OO
O O
O Si
HO
OH
Si O Si O
O Si O O Si
O
Si
O
HO
Si O Si O
O
OO
O
O OH
OO
HO Si O Si
Si O Si O Si OH
Si
OH
O
O Si O
O O
HO O
O
Si
Si
HO
Si
O Si O
O
HO
OH
OH
HO OH OH
OH
Si
O OHO Si O Si OH
Si O O O O Si
OH
Si
O O
Si
Si
Si
O
OHO O Si O O
O O Si OH
HO
O Si O
Si
Si O
O Si O O
O
HO
Si O O Si O O Si OH
Si O Si
O
O Si
HO
OH HO
HO O Si O
OH
O Si
HO
O
Si
OO
HO
Si
O O
Si
HO
OHO
O
O
O
OH
O
O
O
Classes 2E Covalent coupling agentsAttaching inorganic group onto organic
polymer
 h
polyethylene
Si(OEt)3
Si(OEt)3
For tough electrical wire coating
& shrink fit wrap
Summary
• Silsesquioxane nomenclature is hard to
pronounce
• Organosilica is improper nomenclature
• Mixing polymer with anything is hard & may
not work
• Good mixing is necessary for hybrids
• Surfactants can template hierarchical
structures
Download
Related flashcards

Gases

44 cards

Physical chemistry

44 cards

Icebreakers of Russia

25 cards

Speed skating venues

16 cards

Icebreakers

16 cards

Create Flashcards