Synthesis of Colloids and Polymers

1
Synthesis of Colloids and Polymers Topic
Anionic Polymerization And Macromolecular
Engineering Pierre J. LUTZ 5th Worhshop of the
IRTG (International Research Training Group Soft
Condensed Matter) Kontanz, April 3-5, 2006
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Anionic Polymerization and Macromolecular
Engineering
Some Problems that require well-defined Polymers

• ? How does the width of molar mass distribution
  influence the mechanical properties of a polymer
  ?
• ? What is the effect of branching on polymer
  properties ?
• ? What protecting effect is exerted by soluble
  grafts on an insoluble backbone in Graft
  Copolymers ?
• ? What is the size of a cyclic macromolecule as
  compared with that of the linear homologue ?
• ? How does compositional heterogeneity affect
  the properties of a Copolymer ?
• ? What are the conditions required for a block
  copolymer to exhibit phase separation ?

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Anionic Polymerization and Macromolecular
Engineering
Some structures to be discussed

• ? LINEAR HOMOPOLYMERS or COPOLYMERS
• ? FUNCTIONAL POLYMERS or COPOLYMERS INCLUDING
  MACROMONOMERS
• ? BRANCHED POLYMERS
• - GRAFT-COPOLYMERS
• - STAR-SHAPED HOMO (CO-)POLYMERS
• vaious cores DVB, C60, Polygycerol,
  Sisesquioxanes
• - COMB-LIKE POLYMERS HOMOPOLYMACROMONOMERS
• ? WELL-DEFINED  POLYMERIC NETWORKS

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Anionic Polymerization and Macromolecular
Engineering
Characterization Methods to be used to determine
the structural parameters or the behavior of
Complex Macromolecular Architectures

• ? Static and Dynamic LIGHT SCATTERING To get
  Molar Mass,
• Mw, and Radius of Gyration and Hydrodynamic
  Radius,
• ? SIZE EXCLUSION CHROMATOGRAPHY (GPC)
• Detectors required
• Differential Refractometry to get c
• UV Spectrometry
• to check for the presence of a chromophore
• Light scattering to get Mw
• Viscometry (necessary for universal
  calibration)
• ? ELEMENTAL ANALYSIS
• ? DIFFERENTIAL REFRACTOMETRY / to get overall
  composition
• ? NMR, UV SPECTROMETRY (microstructure,
  composition, functionality)
• ? VISCOMETRY
• ? Maldi-TOF MS
• ? AFM,

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Anionic Polymerization and Macromolecular
Engineering Functionalization
Functionalization
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Anionic Polymerization and Macromolecular
Engineering Macromonomers
? Macromonomers well defined polymers - Low
molar mass - Polymerizable end-groups -
Accessible via anionic, cationic, polymerization
ATRP (FRP), - PB, PE, PMMA, P2VP, PEO, PDMS -
Linear, block copolymer, star-shaped.

• ? Major interest
• Graft copolymers by (free) radical
  copolymerization, branch length
• - Access to new branched topolygies by
• homopolymerization

Macromonomers by b-elimination reactions in
coordination Polymerization
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Anionic Polymerization / Macromolecular Eng.
Macromonomer Synthesis
Deactivation
w-allyl w-undecenyl
PS (atactic) undecenyl end group
w-styrenyl

• Characterization
• Molar mass SEC Mn exp Mn,th,
• (1000 to 10 000 g.mol-1)
• Sharp molar mass distribution, no coupling
• Functionalization 1H NMR
• Chemical Tritration
• Maldi-Tof

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Anionic Polymerization / Macromolecular Eng.
Macromonomer Synthesis
Anionic Polymerization of Oxirane With K (and not
Na or Li) RT
Initiation

• Well functionalized
• Heterofunctional Polymer OH
• Deactivation also possible for PEO

Initiation not possible for PS macromonomers
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Anionic Polymerization / Macromolecular
Engineering GRAFT COPOLYMERS
Valuable polymeric materials constituted of a
polymer backbone (Poly(A) carrying a number of
grafts of different chemical nature (Poly(B)
distributed at random INTEREST Arises
from the incompatibility between backbone and
grafts ? High segment density because of the
branched structure ? High tendency to form
intramolecular phase separation ? Micelles are
formed in a preferential solvent of the grafts
(surface modification, compatibiliziers,
micelles. ) (enhancing or depressing surface
tension, making a surface hydrophobic or
hydrophilic In Graft Copolymers a variety of
Molecular Parameters can be varied - Main chain
and side chain polymer type - Degree of
polymerization and polydispersities of the main
and side chain - Graft density (average spacing
density between side chains) - Distribution of
the grafts (graft uniformity)
PS
PEO
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Anionic Polymerization / Macromolecular
Engineering GRAFT COPOLYMERS
Selected polymerization techniques can be used to
tailor graft copolymers on request Well
defined Graft copolymers

• Ionic Polymerization
• ? grafting from Grafting by anionic
  initiation from sites created on the backbone
• ? grafting onto Anionic deactivation of living
  chains by electrophilic functions located on
• a polymeric backbone
• ? grafting through Use of dangling
  unsaturations to attach grafts onto a polymeric
  backbone (Macromonomer free radical poly) .
• Classical free radical polymerization not well
  adapted absence of control of molar mass and
  polymolecularity (homopolymer, crosslinked
  material)
• NEW DEVELOPMENTS CFR POLYMERIZATION,
  COORDINATION POLYMERIZATION

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Anionic Polymerization / Macromolecular
Engineering GRAFT COPOLYMERS
Graft copolymers via Macromonomers
Macromonomer/Comonomer Copolymerization Kinetics
free radical
In such copolymerizations, owing to the large
differences in molar mass between Macromonomer M
and Comonomer A, the monomer concentration is
always very small consequently the classical
instantaneous copolymerization equation
Reduces to
As in an  ideal  copolymerization the
reciprocal of the radical reactivity of the
comonomer is a measure of the macromonomer to
take part in the process
Controlled Free Radical Copolymerization
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Anionic Polymerization / Macromolecular
Engineering BRANCHED POLYMERS
Interest of branched Polymers - Compactness -
High segment density
? Statistical branching (free radical
polymerization) Branched pEs ? Well defined
branched polymers - Homopolymerization of
macromonomers - Grafting onto or from (each
monomer unit of the main chain with a
function) ? Star-shaped polymers -
 Arm-first  by deactivation, by
copolymerization -  Core-first
plurifunctional initiator - In-out, heterostar
Miktoarm ? More complex star-shaped or
branched architectures Umbrella,
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Anionic Polymerization / Macromolecular
Engineering PolyMacromonomers

• Anionic Polymerization
• (Controlled) free radical polymerization
• ROMP
• GTP
• Coordination Polymerization ?

?
The Nature of the Unsaturation, The Chemical
Environment of the Unsaturation The Length of
the Macromonomer Chain The Thermodynamic
Interactions between the macromonomer and the
backbone to be formed The Presence, the Amount
of solvent
Bottlle brush structure DP gt 80
Star-shaped DP lt 80
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Anionic Polymerization / Macromolecular
Engineering PolyMacromonomers
Some Catalysts Tested
Mn 1000 to 10 000g.mol-1
Activated with MAO

• Homopolymerization possible ! but never
  quantitative
• Degree of Polymerization DP Ti gt DPZr
  around 7- 10
• Polym. yield decreases with increasing PS
  molar mass, DPE
• Polym time increases, DP constant, conversion
  increases
• Highest DP obtained with CGC-Ti around 300

M
PM
Elution volume SEC
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Dilute Solution characterization of PS
poly(macromonomer)s
SEC Smaller hydrodynamic volume
SEC Transition comb-shaped / Star
SEC Smaller Radius of gyration
q2. I(q)
SANS
Asymptotic Behavior of the particle Scattering
function of a PS PM (CP)
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
PE stars by Arm-first Methods
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Arm-first Typical molecules used as core
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Arm-first Methods
? Synthesis of a w-living polymer (PS, PI)

• ? Core formation
• either by reacting it with a plurifunctional
  electrophile in stoechiometric amount
• or by using the carbanionic sites to initiate the
  polymerization a small amount of biunsaturated
  monomer such as DVB, DEMA

PS, PI, PMMA
Advantages - Low fluctuations in molar mass -
Low composition heterogeneity (copo) -
Characterization of the individual branches -
Average number of branches accessible
Functionalization at the outer end of the
branches not possible
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Arm-first Methods
? Synthesis of a w-living diblock polymer
(PS-b-PI)
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS

• Polyfunctional Initiators CORE FIRST Method
• - Metalorganic sites tend to strongly associate,
  even in aprotic polar solvents
• - Aggregate formation is frequent some sites
  may remain hidden
• As polymerization of the monomer proceeds
  gelation of the reaction medium is to be expected
• - However Molar mass not directly accessible

From PolyDVB Cores
FIRST STEP Preparation of a dilute solution of
living cores A solution of (DVB) is added
dropwise to a dilute solution of Potassium
naphtenide in THF
Conditions to be observed to avoid microgel
formation - DVB / K ratio should be below 2
- high dilution Avoid any local excess of DVB -
efficient stirring
OE First the solution becomes turbid, After a
few hours the medium becomes biphasic Finally it
gets homogeneous and clear again when the
branches are long enough to contribute also to
the solvatation of the cations
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Polyfunctional Initiators CORE FIRST Method
CMC Determination
Molar Mass and Viscosity
QELS measurements of core-first star-shaped
PEO s
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Polyfunctional Initiators CORE FIRST Method
Other Multifunctional Iniatiators Living
poly(divinylbenzene) cores Living
poly(diisopropenylbenzene) cores

Hydrophobic Core more or less Polydisperse
A
Bifunctional coupling agent
Other Initiators Tris-alkoxides Modified
Carbosilane dendrimers
B

Polyglycerol cores
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
PEO Stars Based on Polyglycerol Cores
Controlled Polymerization of glycerol
Polyglycerol core
Star-shaped PEO
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Purification via fractional precipitation in
THF/DE fractional precipitation in
THF/Heptane dialysis in H2O dialysis in THF
possible
PEO/POLYGLYCEROL STARS
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
 In-out  Star Polymers
? Use of a w-living seed polymer (PS, PI) as
initiator (Protection and solubilization of the
poly(DVB) core
? Addition to the living core of another monomer
exhibiting higher electrophilicity (EO )

• Typical Amphiphic behavior
• High solubility in many solvents
• Protection exerted by the hydrophilic parts on
  the hydrophobic core
• High tendency to form stable emulsions in water
• Tendency to phase separation in concentrated media

Addition of styrene results in crosslinking
(remaining double bond)
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Living PS, PI, diblock
Well-defined star-shaped or related branched
structures base on anionic polymerization But
very time consuming synthesis, fractionated,
interesting morphologies
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Star-shaped Polymers Based on Diphenylethylene
Derivates
Quirk, Dumas
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
I - Addition of living polymers onto C60
C60 is constituted of 12 pentagons et 20
hexagons, 6 pyracylene units Small molecule (d ?
10 Å) et plurifunctional (30 double bonds)
Control the number of grafts
Control of the polymer chain     -The chain
end must be able to react with C60 -
Control molar mass and polymolecularity -
Grafting of block copolymers..

• Anionic Polymerization

C. Mathis
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Exemple grafting of PSLi onot C60 in toluene
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
C60 being a conjugated molecule, charge
(introduced by the carbanion present at the
living chain end) delocalizes. Therefore a second
living chain cannot be added onto pyracyclene
units and hexagones h1 to h4. (addition to the
6-6 ring double bonds)
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
? hexafunctional Star-shaped polymers
Charge delocalisation and geometrical form of C60
limit the number of grafts to 6 (molar masses up
to 2 106 g mol-1
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
II  Hexa-aducts can be used as plurifunctional
initiator for the anionic polymerization ?
Synthesis of Palmtree and Dumbbell architectures
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
(PS)6C606-(Li)6 MMA ? (PS)6C60(PMMA)2
6PS 2PMMA hetero-stars
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Synthesis of Palm tree or Dumbbell Architectures
6PSa 1PSb palm-tree
2 (PS)6C605-(Li)5PSb-Li BrCH2PhCH2Br ?
 (PS)6C60PSb- CH2PhCH2-PSbC60(PS)6
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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS

• POSS Polyoctaedralsilsesquioxanes New class of
  nanostructured materials
• Higher thermal stability
• Higher mechanical properties
• Bette resistance to fire
• Silsesquioxane hydrophobic!

Function, epoxy, alcohol, CC
Non reactive Group
?
?
Eight corn substituted cage
Further Chemical Reactions, (co-) polymerization
Solubilization
Stable Bond
R H , OSi(CH3)2H
?

• Functions Chemical Modification or grafting of
  existing polymers (modulation of the number of
  grafted chains ? ?)
• Polymerizable group (copolymerization with other
  monomers via ATRP, Coordination Polymerization,
  ring opening)

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Anionic Polymerization / Macromolecular
Engineering BRANCHED / STARS
Macromonomers
New hybrid Materials
Well defined Polymers - Controlled
functionality Mono, bifunctional, - Controlled
Molar Mass

• Star-shaped Polymers
• Controlled core functionality
• Controlled branch lenght

Hydrosilylation

• Networks or Hydrogels
• Controlled functionality of the cross-linking
  points
• - Controlled length of the elastic chains

Allyl / SiH H2PtCl6
- 8 SiH functions, cubic
Silsesquioxanes
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Grafting of Monofunctional PEO macromonomers onto
Silsesquioxanes
CH2CH-CH2-O-(CH2-CH2-O)n-CH2-CH2-OCH3

8-10 fois molar
POE ?-allyle
or OH
Q8M8H
or OH
Star-shaped Polymers with 8 branches (Q8M8PEO)
New Multifuntional initiator
Extended to PS arms
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Anionic Polymerization and Macromolecular
Engineering End-linking
Stoichiometric reaction betwenn a bifunctional
linear polymer and a plurifunctional antagonist
compound As result the precursor chains become
the elastically effective chains of the
network The plurifunctional compound becomes the
branch points of the network
Ideal Network macrocopically
homogenous contains a known number of elastic
chains of known length and branch points of known
functionality
However some defects are to be expected
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CYCLIC POLYMERS Introduction Synthesis of
Cyclic Structures - Ring-chain equilibria -
End-to-end Cyclization Properties of Cyclic
Structures - Dilute solution Behavior -
Influence of the nature of the preparation
solvent - Solid State Structures Derived from
cyclic Polymers Conclusion and Future
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Anionic Polymerization and Macromolecular
Engineering Cyclic Polymers
  MAY APPEAR AS A SUBJECT FOR PURE MATHEMATICS
OR THEORY NO ENDS   TO COMPARE THE MOLECULAR
DIMENSIONS OF WELL-DEFINED CYCLIC AND LINEAR
MACROMOLECULES Same molar mass, Low
polydispersity in solution as well as in the
bulk    TO STUDY THE ABILITY OF CYCLIC)
MACROMOLECULES TO DIFFUSE IN A POLYMER MATRIX
(REPTATION) OR IN NETWORK
Accessible only by Anionic Polymerization ?
Introduction
41
Anionic Polymerization and Macromolecular
Engineering Cyclic Polymers
RING-CHAIN EQUILIBRIA IN POLYCONDENSATION
Low molar mass CYCLES are formed preferentially
BACK BITTING REACTIONS IN IONIC
POLYMERIZATION Reaction of a function on the
chain with a functional link of the same chain
an alkoxide with an ester function -a
Silanolate function with a siloxane bridge - an
oxonium with an ester bridge       - increase
of the number of macromolecules - decrease of
their average molar mass  EX Upon heating of a
PDMS in the presence of some basic
catalyst  implies the presence of a functional
link in the chain
Synthesis of Cyclic Structures Ring-chain
equilibria
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Cyclic Polymers
BACK BITTING REACTIONS IN CATIONIC
POLYMERIZATION Reaction of a function on the
chain with a functional link of the same chain
an oxonium with an ester bridge
Synthesis of Cyclic Structures Ring-chain
equilibria
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Anionic Polymerization and Macromolecular
Engineering Cyclic Polymers
SEC PDMS
Logarithmic plots of the root-square radius of
gyration vs molar mass for linear and cyclic
PDMS fractions
After SEC Fractionation
Semlyen et al.
Synthesis of Cyclic Structures Ring-chain
equilibria
44
Anionic Polymerization and Macromolecular
Engineering Cyclic Polymers
End-to-end Cyclization effect of the
concentration on the cyclization yield
Intramolecular reaction
Intermolecular reaction
Synthesis of Cyclic Structures End-to-end
Cylization
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Cyclic Polymers
Synthesis via anionic polymerization

Cycle
chain extension
Cyclization Chain extension Coupling
reaction has to be fast, quantitative and free of
side reactions Exact stoichiometry (balance
active sites / functions) High dilution to
favor intramolecular coupling with respect to
intermolecular coupling Efficient stirring to
prevent local fluctuations in concentrations
Synthesis of Cyclic Structures End-to-end
Cylization
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Cyclic Polymers
Experimental Procedure
Solvent THF Cyclohexane THF/Heptane
Initial concentration 10 wt.- after dilution 0.1
wt.-
Synthesis of Cyclic Structures End-to-end
Cyclization
47
Cyclic Polymers
SEC trace of the raw reaction product
SEC trace of cyclic and linear PS
Big difference in molar mass
Cycle
Cycle
linear
Chain extension
Elution volume
Adequate separation of linear polycondensate from
the cycles Cyclization yield from 20 to 50 wt-.
decreases with increasing molar mass Without
dilution 2.5 wt.- 20 (2500) Molar mass domain
from 5000 to 200 000g.mol-1
Elution volume
Synthesis of Cyclic Structures End-to-end
Cylization
48
Cyclic Polymers
Synthesis of Cyclic Structures End-to-end
Cylization
49
Cyclic Polymers
Different strategies for the synthesis of block
copolymer cycles
Synthesis of Cyclic Structures Block
copolymer cycles
50
Cyclic Polymers
Cyclization reactions based on unimolecular
processes
Synthesis of Cyclic Structures End-to-end
Cylization
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Cyclic Polymers
Reversible cyclization
Synthesis of Cyclic Structures Reversible
Cylization
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Cyclic Polymers
SEC
SEC h.M calibration (Roovers)
RI
Properties of Cyclic Structures Dilute
solution Behavior
53
Cyclic Polymers
Polymerization and cyclization in a good solvent
(ICS) Synthesis in cyclohexane (near q
conditions) (Roovers) Measurements on knoted
rings ?
Theta temperature 28.29C May be due to to
topological interactions enhanced segment
density, independant of M ? Stockmayer Fixmann
treatment
Logarithmic plot of the limiting viscosity
numbers versus molar mass for linear and cyclic
polystyrene, measured in cyclohexane
Properties of Cyclic Structures Dilute
solution Behavior
54
Cyclic Polymers
Cycle in a good synthesized in good solvent only
a few knotes Cycle in a bad solvent Many
knotes
Cyclization Dimensions in a good solvent
?
Good Solvent
?
Q solvent or bad solvent
Properties of Cyclic Structures Dilute
solution Behavior
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Cyclic Polymers
Properties of Cyclic Structures Dilute
solution Behavior
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Cyclic Polymers
SEC
Properties of Cyclic Structures Dilute
solution Behavior
57
Cyclic Polymers
Logarithmic plots of the root-square radius of
gyration vs molar mass for linear and cyclic
Polystyrene fractions
Cycles prepared in THF / heptane
Cycles prepared in THF OC
Polystyrene fractions measured in d12 cyclohexane
at 34 C
Properties of Cyclic Structures Dilute
solution Behavior
Properties of Cyclic Structures Dilute
solution Behavior
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Cyclic Polymers
Structures derived from cyclic polymers Eight
shaped Polymers
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Cyclic Polymers
Structures derived from cyclic polymers Rotaxane
Catenane
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Cyclic Polymers
J.P Sauvage, C. Diedrich
Structures derived from cyclic polymers catenanes

61
Cyclic Polymers
Structures derived from cyclic polymers Catenan
es
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Cyclic Polymers
Well defined cyclic Polystyrenes are available
up to molar masses of 200 000 g/mol   Dilute
solution properties are in good agreement with
theoretical expectations hydrodynamic volume
limiting viscosity numbers Radius of gyration
Translational diffusion coefficient Solid
state properties REPTATION CONCEPT ?
Extension of the method to Poly(2vinylpyridines)
Poly(ethylene oxide) Development of other
cyclization methods and charged cycles
Conclusion
63
Cyclic Polymers
Hydrodynamic Dimensions of Ring-shaped
Macromolecules in a Good Solvent" M. Duval, P.
Lutz. C. Strazielle Makromol. Chem., Rapid
Commun. 6, 71-76 (1985) "Solution Properties of
Ring-shaped Polystyrenes P. Lutz, G.B. McKenna,
P. Rempp, C. Strazielle Makromol. Chem., Rapid
Commun. 7, 599-605 (1986) "Synthesis and Solution
Properties of Macrocyclic polymers"P. Lutz, C.
Strazielle, P. Rempp Recent Adv. in Anionic
Polymerization ed. T.E. Hogen Esch, J. Smid,
Elsevier Science Publishing, pp. 404-410 (1987)
(Revue) "Macrocyclic Polymers" P. Rempp, C.
Strazielle, P. LutzEncyclopedia of Polymer
Science and Engineering, 9, pp. 183-195 second
Ed. John Wiley Sons, Inc. (1987)
(Revue) "Thermodynamic and Hydrodynamic
Properties of Dilute Solutions of Cyclic and
Linear Polystyrenes" G. Hadziioannou, P.M. Cotts,
G. ten Brinke, C.C. Han, P. Lutz, C. Strazielle,
P. Rempp, A.J. KovacsMacromolecules 20, 493-497
(1987)  "Dilute Solution Characterization of
Cyclic Polystyrene Molecules and Their Zero-shear
Viscosity in the Melt" G.B. McKenna, G.
Hadziioannou, P. Lutz, G. Hild, C. Strazielle, C.
Straupe, P. Rempp, A.J. KovacsMacromolecules 20,
498-512 (1987) "Diffusion of Polymer Rings in
Linear Polymer Matrices" P.J. Mills, J.W. Mayer,
E.J. Kramer, G. Hadziioannou, P. Lutz, C.
Strazielle, P. Rempp, A.J. Kovacs ,
Macromolecules 20, 513-518 (1987) "Polymer
Topology and Diffusion a Comparison of Diffusion
in Linerar and Cyclic Macromolecules" S.F. Tead,
E.J. Kramer, G. Hadziioannou, M. Antonietti, H.
Sillescu, P. Lutz, C. Strazielle, Macromolecules
25, 3942 (1992) "Recent Developments in the
Field of Star-shaped Polymers" D. Rein, P. Rempp,
P.J. Lutz Makromol. Chem., Macromol. Symp. 67,
237-249 (1993) "Osmotic Pressure of Linear, Star,
and Ring Polymers in Semi-dilute Solution". A
comparison Between Experiment and Theory" G.
Merkle, W. Burchard, P.J. Lutz, K.F. Freed, J.
Gao, Macromolecules 26, 2736-2742
(1993) "Synthesis of Cyclic Macromolecules" Y.
Ederlé, K. Naraghi, P.J. Lutz Materials Science
and Technology, A Comprehensive Treatment, Volume
Synthesis of Polymers, Ed. A.D. Schlüter,
chapitre de livre, pp. 622-647, Wiley-VCH
Weinheim-New-York (1999) (Revue) J. Wittmer, et
al. F. Isel, Equipe LLB (A. Lapp, F. Boué, J.
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Acknowledgements