hybrid organic-inorganic, poss materials lecture 4 & quiz september 28th
TRANSCRIPT
Hybrid Organic-Inorganic, POSS Materials
Lecture 4 & Quiz
September 28th
TodayFirst hour:• Some definitions• Strategies for making HybridsSecond 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/harbin-
institute-technology---hybrid-materials-course.html
What are Hybrid Materials? Composite materials mixtures of organic and
inorganic components
Improvement on either organic or inorganic components
Metal oxide network
Introduction to polysilsesquioxanes
R SiO1.5n
Si
RSi
SiR
Si
O
O
O
Si
Si O
Si
O
R
SiO
O
O
Si
O
R
OH
OSi
O
OSiOR
OO
R
Si
O
R
Si
O
OHO
R
O
R
OH
R SiR
O
O
R
Si
Si
R
HO
Si
OHR
HO O
OH
R
R
R
n = 17
Si
O
Si SiO
RR
RSi
O
O Si
O
Si S iO
OO
O
Si
O
O
O
R
R R
R
R
n = 8
R SiO1.58
R8 Si8O12
Network of Si-O-Si Organic group (alkyl, aryl, alkenyl) attached through Si-C bondFully condensed: 1.5 oxygens per SiThree siloxane bonds per silicon
Where are the organic and inorganic phases?
Si
RSi
SiR
Si
O
O
O
Si
Si O
Si
O
R
SiO
O
O
Si
O
R
OH
OSi
O
OSiOR
OO
R
Si
O
R
Si
O
OHO
R
O
R
OH
R SiR
O
O
R
Si
Si
R
HO
Si
OHR
HO O
OH
R
R
R
RSi(OMe)3
H2O
catalyst
Si
O
Si SiO
RR
RSi
O
O Si
O
Si SiO
OO
O
Si
O
O
O
R
R R
R
Ror
Blue is inorganic 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 Oxygens
Polysilsesquioxane
Many
R SiO1.5n
Many generally means more than 10,000 Dalton Mw
Oligosilsesquioxane
Silicon 1.5 OxygensA few
R SiO1.5n
Oligo means > 1 and < 50-100 (depends on Mw or R group)
Si
O
Si SiO
RR
RSi
O
O Si
O
Si SiO
OO
O
Si
O
O
O
R
R R
R
R
n = 8
R SiO1.58
R8 Si8O12
Nomenclature of silsesquioxanes
• Polymers: poly(name of organic-silsesquioxane)
eg. R = Ph or phenyl
poly(phenylsilsesquioxane)
Ph SiO1.5n
Nomenclature of silsesquioxanes
• oligomers: oligo(name of organic-silsesquioxane)
eg. R = Ph or phenyl
poly(oligosilsesquioxane)
Ph SiO1.5n
Nomenclature of silsesquioxanes
• Polyhedral oligomers: need to describe size of rings
eg. R = Ph or phenyl
T8: n = 8
Si
O
Si SiO
PhPh
PhSi
O
O Si
O
Si SiO
OO
O
Si
O
O
O
Ph
Ph Ph
Ph
Ph
n = 8
Ph SiO1.58
Ph8 Si8O12
Ph = phenyl
Polyhedral refers to multi-sided geometric shapes like cubes.
1,3,5,7,9,11,13,15-octaphenyl pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane
IUPAC Name:
Si
O
SiSi
OSi
O
CH2
CH2
Si
Si O
Si
O
O
SiO
O
O
Si
CH2O
CH2
OSi
O
OSiCH2
OO
O
CH2
Si
CH2
Si
O
OCH2
O
OO
O
SiO
O
CH2
Si
OSi
Si
OO
OOCH2
(MeO)3Si CH2 Si(OMe)3
(MeO)3Si Si(OMe)3
(MeO)3Si Si(OMe)3
H H
+ 3n H2O
-6 n MeOHn
O1.5Si SiO1.5n
or
or
or
Si Si
n
O
O
O
or
Drawing bridged polysilsesquioxane structures:
Fully condensed: 1.5 oxygens per Si.
Methylene-bridged polysilsesquioxane
bridged polysilsesquioxane nomenclature:
Methylene-bridged polysilsesquioxane
Si
O
SiSi
OSi
O
CH2
CH2
Si
Si O
Si
O
O
SiO
O
O
Si
CH2O
CH2
OSi
O
OSiCH2
OO
O
CH2
Si
CH2
Si
O
OCH2
O
OO
O
SiO
O
CH2
Si
OSi
Si
OO
OOCH2
O1.5Si SiO1.5n
or
Si Si
n
O
O
O
or
Not “methane-bridged” Not “methano-bridged”Not “methano-silica”Not “methylene modified silicate”
These are not silicas These are not silicates
Different ways to put hybrids togetherClass 1: No covalent bonds between inorganic and organic phases
Class 2: Covalent bonds between inorganic and organic phases
Example: particle filled polymer
Monomers in solvent Gel or dry gel (xerogel) Close-up of hybrid particle
In practice, how do you make these hybrids?
InorganicInorganic OrganicOrganic
Physical mixing
Colloidal dispersion
Aggregation or coalescence
Class 1:Try to use high viscosity of polymer to hinder aggregationClass 2: Use covalent bonds to prevent aggregation of phases
Like oil and water
Making Hybrid Materials: Class 1A (pre-formed particles and fibers)
Pre-formed Particles
Polymers
SiO
Si SiO
RR
RSi
O
O Si
O
Si SiO
OO
O
SiO
O
O
R
R R
RR
=
or SiO2 or MOx
or O1.5Si-R-SiO1.5
or R-SiO1.5
or
Physical mixing of particles in melt or solution
Easiest hybrid to make
Inorganic PhasesMetal Oxide Networks
Organically modified Metal Oxide Networks
Inorganic Phases
Silica Particles
Preformed inorganic clusters
Ti12O16(OPri)16 Ti17O24(OPri)20Ti18O22(OBun)26(Acac)2
Ti(OR)4-x(acac)x
POSS
Making silsesquioxanes as inorganic phase
Si
RSi
SiR
Si
O
O
O
Si
Si O
Si
O
R
SiO
O
O
Si
O
R
OH
OSi
O
OSiOR
OO
R
Si
O
R
Si
O
OHO
R
O
R
OH
R SiR
O
O
R
Si
Si
R
HO
Si
OHR
HO O
OH
R
R
R
RSi(OMe)3
H2O
catalyst
Si
O
Si SiO
RR
RSi
O
O Si
O
Si SiO
OO
O
Si
O
O
O
R
R R
R
Ror
Blue is inorganic Black is organic
Surface modified inorganic
Class 1A: POSS physically dispersed in polypropylene
Si
OR'
R
OR'OR'
Si
O
Si SiO
RR
RSi
O
O Si
O
Si SiO
OO
O
Si
O
O
O
R
R R
RR
R"
n
=
POSS
Inorganic PhasesIsolated 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 PhasesCarbon Buckeyballs, nanotubes and graphene
Nature Materials 9, 868–871 (2010)
Organic need more than just carbon: CHNO
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 particles2) then, depending on polymer melting point, mix into melt or solution of polymer3) 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)
Si
OR'
R
OR'OR' Si
OR'
R
OR'OR'
Si
OR'
R'OR'O
M(OR')x Si
OR'
R'O
OR'OR'
No Solvent except for monomer(s)Generally uses low tg organic polymers or in polymer melts (< 100 °C).
Viscous environment. Confined growth.
Making Hybrid Materials: Class 1B (in situ particle growth)
CH3Si(OMe)3
Melt
LInear polymer
"Inorganic monomer"
H2O
tin catalyst
Particles form in situ 10-10000 nmPolymerize inorganic monomer
Grow inorganic particles
What must happen for this method to work?
Making Hybrid Materials: Class 1C(Polymerizing in pores)
•Porous metal oxide•Liquid monomer (no solvent) •UV, heat, radiation
R
R
R R
RR
R
R
R
R
R R
RR
R
R
R
R
R R
R
R R
R
R
R
RR
R
R
RR R
R
RR
R
RR
catalyst
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)
• Polymerize metal oxide around organic• pores must be small or leakage will occur•Solid state dye lasers, filters, colored glass
catalyst
O OHO
O OHO
OO
OH
O O
HO
O O
HO
H2O
© Asahi-Kirin
Describe how the starting materials must behave for this to work
Ancient Humans also made Hybrid organic-inorganic materials: Maya
Blue
L. A. Polette, N. Ugarte, M. José Yacamán and R. Chianelli, Sci. Am. Discovering Archaeology, 2000, July–August, 46
Indigo +white clay palygorskite
(Mg,Al)2Si4O10(OH)·4(H2O)(also called Fullers Earth)
Class 1B or Class 1C or Class 1D??
Making Hybrid Materials: Class 1E(Interpenetrating network)
• 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
RR
R
R
R
RR
R R
R
R
R
R
R
R
RR
R
R R
R
R
R
RR
R
R
RR R
R
R
R
R
RR
catalystR
R
What does this assume about the reaction kinetics?
Making Hybrid Materials: Class 2A(Covalent links at molecular level)
• 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
catalystR
R
RR
R
R R
R
R
R
R
R
R R
R
R
RR
R
R
R
RR
RR
R
R
R
R
R
R
R
R
R
H2O
Chromatographic Materials
Low DielectricsPhotoresists for Lithography
Making Hybrid Materials: Class 2B(Covalent links at polymer level)
• ligands attached to polymer • Reaction rates slow unless in sol. or melt
R
R
R
R
R
RR
R
R R
R
R
R
RR
R
R
RR R
R
R
R
R
RR
R
R
R
R
RR
R
R
RRR
R
R
RR
R
RR
R
R
R
R
R
R
R
R
In Melt
or in solution
excess water
H+, OH- or F-
Making Hybrid Materials: Class 2CTemplating with block copolymers and
surfactants
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
On m
A B
hydrophobicpolyisoprene
hydrophilicpolethylene oxide
Heat polymer then cool or cast from solvent
Making Hybrid Materials: Class 2C(Templating) Shown here with block copolymer
PEO, Al2O3 and RSiO1.5
polyisoprene
Block copolymer
Block copolymer Sol-gel system
Multiple phases created by varying size of blocks
1. Davis, H. T., Bodet, J. F., Scriven, L. E., Miller, W. G. Physics of Amphiphilic Layers, 1987, Springer-Verlag, New York
Templating with surfactants:(Class 2C)
• First prepare two phase surfactant system• Add monomer. Sol-gel monomers move into aqueous phase with hydrolysis• Filter precipitate • remove surfactantby calcining or extraction
Many different phases can be accessed
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 agentsAttaching organic group onto inorganic material
O
SiO
O
SiOSi
O
OH
O
O
HO
SiO
SiO
Si OSi O
Si OSi
O SiO Si
O Si
OSi
O
SiO
SiO
O
HO
HO
O
HOO
HO OHHO
O
HO
O
HO
O
OH
OOH
O
OO
OHO
HO
OH
Si Si
SiSi
Si OHOO
O
O SiO
OH
SiOOH
OO Si Si
HOO
O
SiO
OSiO
Si O
HO
OO
O
SiO
Si
OSi O
SiO Si
O SiO Si
O SiO
SiO
SiO
SiOSiO
O
HO
HO O
HOO
HO OH OH
O
OH
O
OH
OOH
O OHO
OO
OHOHO
OH
SiSi
Si
Si
Si
SiOH
O
O
O
OSi
O
OH
Si
O
OHO
Si
SiHO
O
HO
HO
OO
O
OO O Si(OEt)3
OO
OOH
OH
Classes 2E Covalent coupling agents-Attaching inorganic group onto organic
polymerγ hν
Si(OEt)3polyethylene
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