Functional Polymers –
Building Blocks for
Macromolecular and
Supramolecular Architectures
Bogdan C. Simionescu1,2
“Gh. Asachi” Technical University, Iasi, Romania
2 “Petru Poni”Institute of Macromolecular Chemistry, Iasi,
Romania
1
Workshop “Nanostiinta si Nanotehnologie”
Bucuresti, 17-18.09.2008
Nanostructured materials with
controlled architectures and responsive
surfaces
Building blocks
 block and graft copolymers
 micelles of micro- and macromolecular compounds
 functional polymers
 conjugated polymers
 supramolecular structures
 liquid crystalline polymers
 coordination polymers
 hybrid organic/inorganic structures
 micro- and nanoparticles
 biomacromolecules
Micro- and nanoparticles
● perfect spherical shape
● extremely uniform size distribution
● accurately controlled diameter
● well-characterized surface (functionality, morphology)
● controlled porosity
● various physical properties
 large variety
 high surface area
 controlled inner reactivity
Topics
 Poly[(N-acylimino)ethylene] (PNAI) building
blocks


Functional micro- and nanoparticles based on
PNAI building blocks
PNAI – based gels
 Functional siloxane building blocks
 Poly(ε-caprolactone) – polydimethylsiloxane diand triblock copolymers (PεCL–PDMS)
 PDMS with end or pendant pyrrolyl groups
 Polyrotaxanes
 Conclusions
Poly[(N-acylimino)ethylenes] (PNAI)
N
R
control of structural properties (living cationic polymerization)
biocompatibility or no acute toxicity
O hydrophilic or hydrophobic properties (R)
chelating ability
good adhesion to polar surfaces
facile modification to PEI
compatibility with most common organic polymers
chain flexibility
crystallization ability
H2
C
*
N
tailored polymers
multifunctional polymers
complex architectures
C n
H2
C
R
*
O
Poly[(N-acylimino)ethylene]
azo initiators
n
N
O
R
Br
Br
Br-
BrN +O
O
H3C
N
N
N
(n-1)/2
O+
O
CH3
H2O
(n-1)/2
CH3
CH3
K2CO3
O
T C
H3C
HO
O
N
n/2
O
Py
CHCl3
CH3
Cl
*
PNAI azo initiator
O
OH
N
N
CN
n/2
CH3
NC
N
O
Cl
CH3
N
N x
*
Functional polymers by end capping of
living PNAI chains
Br
Br
C6H5 Br
N O
R
N Br
+
R O
N
Br
+
O
R
C6 H5
N
C6 H5
C6 H5
end capping
BrC6 H5
C6 H5
+
R O
block
copolymer
KI
M
O
HO
Br
OH
O
O
C6 H5
O
O
C6 H5
O
O
O
C6 H5
O
*
HO
C6 H5
O
O
C6 H5
OH
O
O n
*
O
O
O
C6 H5
Functional micro- and nanoparticles
 dispersion polymerization
- monomer: styrene
- stabilizer: poly(N-acetylethylenimine) macromonomer
Dn: 10 – 1000 nm
(Dn = 0.5 - 1 m, PI = 1.02 - 1.05)
PI: 1.006 – 1.2
 soapless emulsion polymerization
core-shell structure
- monomer: styrene, methyl methacrylate
- poly(N-acetylethylenimine) macroazoinitiator
(Dn = 100 - 200 nm, PI = 1.02 - 1.04)
- monomer: styrene
- poly(N-acetylethylenimine) macromonomer
(Dn ~ 200 nm, PI = 1.006 - 1.04)
 microemulsion polymerization
- monomer: methyl methacrylate, butyl methacrylate
- co-surfactant: poly(N-acetylethylenimine) macroazoinitiator or macromer
- main surfactant: SDS
(Dn = 10 - 50 nm, PI = 1.2)
Core-shell nano/micro particles by
soapless emulsion polymerization
 size control
 high surface functionality
 high purity
(“clean” particles)
 low toxicity
 bio-compound
immobilization ability
 film forming ability
 narrow size distribution
or “monodispersity”
drug release systems
uniform thin polymer films
(electrode coating, biosensors)
high selectivity membranes
___
1μ
Stable hybrid Pt nanocatalyst/polymer
systems
Pt catalysts
PSt - hydrolysed PNAI latex
colloidal Pt nanocatalyst particles
protected by PSt-g-PNAI copolymer
retention > 90% at
136.8 μg Pt / mL
(60 min reflux)
agglomeration prevented
polymer protected
improved stability - recoverable
Pt (IV) - sorbent
maximum Pt (IV) recovery yield - in buffer
solutions of pH = 10
sorption half time: t1/2 ≈ 90 min
sorption capacity: 1111 μg / g latex
stable until 228 μg Pt / mL
Organic – inorganic composite materials
MMA polymerization in the presence of silica and
PNAI macroinitiator (soapless emulsion polymerization)
Peculiarities
 early formed amphiphilic oligomers act as dispersants
 increased polymerization rate
 increased adhesivity to inorganic particles
water–soluble PMMA-b-PNAI
dispersant
t = 0 min
t = 10 min
homogeneous
composite material
(t = 50 min)
PI = ~ 1.0
Dw = ~ 500 nm
PNAI – based gels
● PROZO modification
followed by a crosslinking reaction of
the functional prepolymers with
polyfunctional compounds
● random copolymerization of
2-substituted-2-oxazoline with
bisoxazoline monomers
M. Heskins and J. E. Guillet, 1968
M. Hahn, E. Görnitz, H. Dautzenberg, 1998
S. Kobayashi et al., 1990
T. Saegusa et al., 1990 -1993
● specific reactions of
functionalized PROZO:
photodimerization of the
photosensitive pendant groups or
coordination of the metal ions to
reactive inserted groups
● copolymerization of
ROZO and bisoxazoline with
special “macroinitiator”
J. Rueda and B. Voit, 2003
Thermosensitive gels
Precipitation polymerization
Monomers: HEMA
NIPAAm (LCST 32°C)
PNAI macromonomers (PEOZO – LCST 36°C)
Reaction conditions: HEMA/NIPAAm/PROZO w/w/w - 1:1:1
60°C, ethanol, AIBN, Ar, 20h
self assembled core-shell microparticles
interconnected pore structure
large channels
open macropores
Stimuli responsive hydrogels
(temperature responsive)
controlled structure and characteristics (hydrophilic/hydrophobic balance,
crosslinking density, amount of thermosensitive chains)
LCST – therapeutic domain ( 28 – 38 °C)
Sample
LCST
(oC)
M6
27.5
M15
32.0
M25
33.0
M45
38.0
E15
28.5
E25
30.0
E35
32.0
E45
31.5
BC1
28.5
BC2
27.6
Swelling/deswelling kinetics
Self-assembling microgels
Self-assembling network
(ordered or not ordered)
PEOZO/PNIPAAm/PHEMA hydrogel
“on-off” switching materials
controlled drug delivery and storage systems
biomacromolecules storage/release
tissue engineering, in combination with biodegradable
polymers (collagen)
Siloxane building blocks
Si O Si O
 hybrid organic - inorganic polymers
 biocompatibility (physiological inertness)
 high gas permeability
 good oxidative, thermal and UV stability
 high chain flexibility
 very low solubility parameter and low surface tension (immiscibility
with most organic polymers)
Functional siloxanes and siloxane copolymers
 blend compatibilizers
 surface modifiers
 biomaterials (contact lenses, implants, transdermal penetration enhancers)
Poly(ε-caprolactone) – polydimethylsiloxane
di- and triblock copolymers
Controlled coordinating anionic polymerization
Si O Si (CH2)3 O CH2 CH2 OH
+ ε-caprolactone
Al
ROH
TEtAl
OR
Al
e
CL
Al
[
O
[O
]
CO
OR
n
Al
R'OH
OR'
] OR
CO
n+1
+ H [O
]nOR
CO
3012.5
2555.8
3583.4
3811.9
2099.0
Maldi Tof spectra of caprolactone –
siloxane copolymers
4154.3
1756.9
4725.4
PεCL - PDMS copolymer morphology
(polarized optical microscopy)
CL2000-SiO1000-CL2000
CL6000-SiO1000-CL6000
Poly(ε-caprolactone) – polydimethylsiloxane
di- and triblock copolymers
Poly(ε-caprolactone)
 biocomatible and biodegradable
 relatively hydrophobic
 high cristallinity
 vehicles for the slow
release of drugs
 biodegradable and biocompatible
ceramers for the repair of
skeletal tissues
PεCL-PSi nanoparticles loaded
with IMC and VE
 Unloaded particles
Size: 124 – 194 nm
Distribution width: 0.07 – 0.15
 Loaded particles
 IMC
Size: 130 – 194 nm
Distribution width: 0.11 – 0.18
 VE
Size: 249 – 350 nm
Distribution width: 0.43 – 0.57
 Drug loading efficiency (%)
 IMC 10.05 – 12.80
 VE
52.80 – 54.75
Conducting polymers in rotaxane
structures
Polyrotaxanes – supramolecular inclusion complexes composed of
macrocycles (host molecules) threaded onto linear macromolecules (guests)
Rotaxane structures
Conducting polymers
 rigid structures
 low molecular weights
 insoluble, not meltable, difficult
to process
 photo- and electro-active devices
 catalysis
 membranes for mass transfer
 increased solubility
 superior balance of physical
properties and processing
capabilities
 diminished aggregation or
concentration quenching by
maintaining the co-facial πsystems at the fixed minimum
separation determined by the
thickness of macrocycle walls
Polyaniline
Polypyrrole
H
N
N
H
POLYMER
CONDUCTIVITY
(S/cm)*
SOLUBILITY
(DMF)**
4.5 x 10-2
(-)
Polyaniline / CD
8.4 x 10-4
(+)
Polyaniline / βCD
1.8 x 10-3
(+)
6.1 x 10-3
(-)
Polypyrrole / CD
4.8 x 10-4
(+)
Polypyrrole / βCD
5.2 x 10-3
(+)
Polyaniline
Polypyrrole
* after dopping with iodine
** (-), insoluble; (+), soluble
β-cyclodextrin – polydimethylsiloxane
polyrotaxanes
CH3
Si
CH3
+ H
O
CH3
Si
O
Si
CH3
4
CH3
CH3
H
H2SO4
Si
H
O
n
CH3
CH3
Si
H
CH3
H-PDMS
TMDS
D4
CH3
H2PtCl6
100oC
H2C
+ H2C
H2
C
O
H
C
CH
CH2
O
AGE
CH3
H
C
H2C
H2
C
O
CH2CH2CH2
O
Si
CH3 CH3
O
CH3
n
Si
H2
C
C
H
O
H2
C
H
C
CH2
O
CH3
E-PDMS
1. -CD
+
CH3
H
N
H2
C
H
C
H2
C
O
CHCH2CH2
OH
Si
CH3
2. H2N
CH3
O
Si
n
CH3
PRot
= -CD
NH2 = (C6H5)3CC6H4NH2
CH2CH2CH2
O
H2
C
H
C
OH
H2
C
H
N
β-cyclodextrin – polydimethylsiloxane
polyrotaxanes
Epoxy-terminated PDMS – β CD
+ free β CD
 perfect parallelepipeds
 mean edge size of
parallelepipeds – 0.81 μm
 each crystal consists of
stacked lamellae
 mean lamellae width – 0.1 μm
Epoxy-terminated PDMS – β CD
 long rod-like crystals
 mean thickness of the
crystals – the same value as
the mean lamellae size
Pyrrolyl terminated PDMS
Equilibration of D4 with AP-DS
CH
3
CH
CH CH
3
3
H N - (CH ) - Si - O - Si - (CH ) - NH
2
2 3
2 3
CH
3
CH
(AP-DS)
+
2
Si
4
3
(D )
4
3
CH
2 3
2 3
3
CH
Coupling of AP-PDMS with GPy
3
H N - (CH ) - (Si - O)n - Si - (CH ) - NH
CH
O
o
bulk,80 C
tetramethylammonium
siloxanolate
CH
2
3
2
(AP-PDMS)
N CH
+
3
2
CH
CH
O
2
(GPy)
(AP-PDMS)
isopropanol
o
80 C
CH
N - CH - CH - CH -HN - (CH ) - (Si - O)
2
2
OH
2 3
CH
CH
3
3
-
n
3
Si - (CH ) - NH- CH - CH - CH -N
2 3
CH
(PyP-PDMS)
3
2
2
OH
PDMS with pendant pyrrolyl groups
CH
CH
3
3
CH
CH
3
3
[(Si - O)n - Si - O]p- Si - CH3 +
CH
3
H
CH
CH = CH
2
3
(H-PDMS)
NH
o
Pt,100 C
CH
CH
3
3
CH
CH
3
2
3
[(Si - O)n - Si - O]p- Si - CH3
CH
3
CH
2
CH
4
3
 = 0.05 and 0.10 ppm, Si-CH
(A-PDMS)
3
NH
 = 0.5-0.8 ppm, Si-CH
-isomer
2.4 ppm, CH - 2
2
 = 1.1 ppm, CH-CH
3
-isomer
2.0 ppm, CH-
}
2
}
 = 6.6 and 6.9 ppm, 
N CH
2
CH
(GPy)
PDMS
(PyPh-PDMS)
CH
O
2
Electrocopolymerization of pyrrole with
pyrrolyl functionalized PDMS
H
N
PDMS
PDMS
N
N H
H N
N
N
N
electrolysis
N H
H N
H-type structure
H
N
PDMS
electrolysis
(PyPh-PDMS)
crosslinked
structure
Homogeneous films with good mechanical
properties and phase separated morphologies
Thermal transitions and thermal stability depend on
dopant nature
Conductivities: 2 - 5 S/cm, independent on dopant
nature
Conclusions
Functional polymers (oligomers) – versatile intermediates (building
blocks) for complex, nanostructured architectures and new polymeric
materials
- core-shell nano- and microparticles
- porous microparticles
- thermosensitive gels (hydrogels)
- organic – inorganic composite materials
- controlled drug delivery systems
- semi-conducting polymer films
- hybrid nanocatalyst/polymer systems
- supramolecular inclusion complexes (polyrotaxanes)
Thank you for your attention!