Functional Polymers – Building Blocks for Macromolecular and Supramolecular Architectures

Bogdan C. Simionescu1,2

1 “Gh. Asachi” Technical University, Iasi, Romania2 “Petru Poni”Institute of Macromolecular Chemistry, Iasi,

Romania

Workshop “Nanostiinta si Nanotehnologie” Bucuresti, 17-18.09.2008

Nanostructured materials with controlled architectures and responsive surfaces

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

Building blocks

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 di-

and triblock copolymers (PεCL–PDMS) PDMS with end or pendant pyrrolyl groups

Polyrotaxanes Conclusions

Poly[(N-acylimino)ethylenes] (PNAI)

N

C

*H2C

OR

CH2

*n

control of structural properties (living cationic polymerization)biocompatibility or no acute toxicityhydrophilic or hydrophobic properties (R)chelating abilitygood adhesion to polar surfaces facile modification to PEIcompatibility with most common organic polymerschain flexibilitycrystallization ability

tailored polymersmultifunctional polymerscomplex architectures

N O

R

Poly[(N-acylimino)ethylene] azo initiators

N O

R

BrBr

H O2 K2CO3

N

CH3

NCCl

O

N

CH3

CNCl

O

NN

** x

N

OCH3

N

O CH3

N O

CH3

N

OCH3

Br-

Br-

O

NN

OCH3

OH

O CH3

OH

CHCl3

Py

n

+

+(n-1)/2

(n-1)/2

T C

n/2 n/2

PNAI azo initiator

Functional polymers by end capping of living PNAI chains

N OR

Br Br

C6H5 Br

N NO O

RR

BrBr

+ +

NOR

C6H5 Br+

C6H5

C6H5

C6H5

C6H5

BrKIM

OOH

OOH

C6H5O

OO

O

C6H5

C6H5O

O

OOH

* O

OO

O*n

C6H5OH

OC6H5

O

O

C6H5

end capping block copolymer

dispersion polymerization - monomer: styrene- stabilizer: poly(N-acetylethylenimine) macromonomer (Dn = 0.5 - 1 m, PI = 1.02 - 1.05)

soapless emulsion polymerization - 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)

Functional micro- and nanoparticles

Dn: 10 – 1000 nm PI: 1.006 – 1.2 core-shell structure

Core-shell nano/micro particles by soapless emulsion polymerization

1 μ

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

Stable hybrid Pt nanocatalyst/polymer systems

Pt catalysts

PSt - hydrolysed PNAI latex colloidal Pt nanocatalyst particles protected by PSt-g-PNAI copolymer

agglomeration preventedpolymer protectedimproved stability - recoverable

Pt (IV) - sorbent

maximum Pt (IV) recovery yield - in buffer solutions of pH = 10 sorption half time: t1/2 ≈ 90 minsorption capacity: 1111 μg / g latex

retention > 90% at 136.8 μg Pt / mL (60 min reflux)

stable until 228 μg Pt / mL

Organic – inorganic composite materials

MMA polymerization in the presence of silica andPNAI 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 homogeneouscomposite material

(t = 50 min)PI = ~ 1.0Dw = ~ 500 nm

PNAI – based gels

● PROZO modificationfollowed by a crosslinking reaction of the functional prepolymers with polyfunctional compounds

● random copolymerization of 2-substituted-2-oxazoline with bisoxazoline monomers

● 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”

M. Heskins and J. E. Guillet, 1968 M. Hahn, E. Görnitz, H. Dautzenberg, 1998

J. Rueda and B. Voit, 2003

S. Kobayashi et al., 1990T. Saegusa et al., 1990 -1993

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 microparticlesinterconnected pore structure

large channelsopen macropores

Stimuli responsive hydrogels

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

controlled structure and characteristics (hydrophilic/hydrophobic balance, crosslinking density, amount of thermosensitive chains)

(temperature responsive)

LCST – therapeutic domain ( 28 – 38 °C)

Swelling/deswelling kinetics

Self-assembling microgels

PEOZO/PNIPAAm/PHEMA hydrogel

Self-assembling network (ordered or not ordered)

“on-off” switching materialscontrolled drug delivery and storage systemsbiomacromolecules storage/releasetissue engineering, in combination with biodegradable polymers (collagen)

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)

Si O Si O

Siloxane building blocks

Functional siloxanes and siloxane copolymers blend compatibilizers

surface modifiers

biomaterials (contact lenses, implants, transdermal penetration enhancers)

Poly(ε-caprolactone) – polydimethylsiloxane di- and triblock copolymers

Si O Si (CH2)3 O CH2 CH2 OH

OR'Al

ROHTEtAl

ORe CL

COOR

R'OH

O

H

n+1Al [Al ]

n

ORCOO[Al ]

+ ORCOO[ ]n

+ ε-caprolactone

3012.5

3583.42555.8

3811.9

2099.04154.3

1756.94725.4

Maldi Tof spectra of caprolactone – siloxane copolymers

Controlled coordinating anionic polymerization

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 particlesSize: 124 – 194 nmDistribution width: 0.07 – 0.15

Loaded particles

IMCSize: 130 – 194 nmDistribution width: 0.11 – 0.18 VESize: 249 – 350 nmDistribution width: 0.43 – 0.57

Drug loading efficiency (%) IMC 10.05 – 12.80 VE 52.80 – 54.75

Conducting polymers in rotaxane structures

Conducting polymers rigid structures

low molecular weights

insoluble, not meltable, difficult to process

Rotaxane structures increased solubility

superior balance of physical properties and processing capabilities

diminished aggregation or concentration quenching by maintaining the co-facial π-systems at the fixed minimum separation determined by the thickness of macrocycle walls

photo- and electro-active devices

catalysis

membranes for mass transfer

Polyrotaxanes – supramolecular inclusion complexes composed of macrocycles (host molecules) threaded onto linear macromolecules (guests)

Polyaniline Polypyrrole

POLYMER CONDUCTIVITY (S/cm)*

SOLUBILITY (DMF)**

Polyaniline 4.5 x 10-2 (-)

Polyaniline / CD 8.4 x 10-4 (+)

Polyaniline / βCD 1.8 x 10-3 (+)

Polypyrrole 6.1 x 10-3 (-)

Polypyrrole / CD 4.8 x 10-4 (+)

Polypyrrole / βCD 5.2 x 10-3 (+)

* after dopping with iodine** (-), insoluble; (+), soluble

NH

NH

β-cyclodextrin – polydimethylsiloxane polyrotaxanes

Si

CH3

CH3

O

4

+ Si

CH3

CH3

OH Si

CH3

CH3

HH2SO4 Si

CH3

CH3

OH Si

CH3

CH3

H

D4

H-PDMSTMDS

n

H2PtCl6100oC

H2C CH

H2C OH2C

HC CH2

O+AGE

Si

CH3

CH3

O Si

CH3

CH3

CH

E-PDMS

n

H2C O

H2C

HC CH2

O

CH2CH2CH2OH2C

HCH2C

O

1. -CD

H2N+

2.

Si

CH3

CH3

O Si

CH3

CH3

CH2CH2CH2

PRot

nO

H2C

HC

H2CCHCH2CH2O

H2C

HC

H2C

OH OH

HN

HN

= -CD

NH2 = (C6H5)3CC6H4NH2

CH3

β-cyclodextrin – polydimethylsiloxane polyrotaxanes

Epoxy-terminated PDMS – β CD + free β CD

Epoxy-terminated PDMS – β CD

perfect parallelepipeds

mean edge size of parallelepipeds – 0.81 μm

each crystal consists of stacked lamellae

mean lamellae width – 0.1 μm

long rod-like crystals

mean thickness of the crystals – the same value as the mean lamellae size

Pyrrolyl terminated PDMS

bulk,80oCtetramethylammonium siloxanolate

(AP-PDMS)

(D4)(AP-DS)

H2N - (CH

2)3

- (Si - O)n - Si - (CH2)3

- NH2

CH3

CH3

CH3

CH3

CH3

CH3

CH3

CH3

CH3

CH3

4H

2N - (CH

2)3

- Si - O - Si - (CH2)3

- NH2 + Si O

Equilibration of D4 with AP-DS

(AP-PDMS)

CH3

CH3

CH3

CH3

HN - (CH2)3- (Si - O)

n- Si - (CH

2)3- NH

(PyP-PDMS)

N

OH

- CH2- CH - CH

2- - CH

2- CH - CH

2-

OH

N

isopropanol

80oC

(GPy)

CH2 CH CH

2O

N+

Coupling of AP-PDMS with GPy

PDMS with pendant pyrrolyl groups

PDMS

NO

CH2 CH CH

2

(GPy)

Pt,100oC

(A-PDMS)

CH3

- [(Si - O)n

- Si - O]p

- Si - CH3

CH3

CH3

CH3

CH3

C2H

4

CH3

H

+ CH2= CH

NH2

CH3

CH3

CH3

CH3

CH3

CH3

- [(Si - O)n

- Si - O]p

- Si - CH3

NH2

(H-PDMS)

(PyPh-PDMS)

= 0.05 and 0.10 ppm, Si-CH3

= 0.5-0.8 ppm, Si-CH2

= 1.1 ppm, CH-CH

3

-isomer}2.4 ppm, CH2-

2.0 ppm, CH- } -isomer

= 6.6 and 6.9 ppm,

Electrocopolymerization of pyrrole with pyrrolyl functionalized PDMS

(PyPh-PDMS)

NPDMS

NN

HH N

electrolysis

N

N NPDMS

NH N

PDMS

H-type structure

electrolysis

H

N

crosslinkedstructure

H

H

Homogeneous films with good mechanical properties and phase separated morphologiesThermal transitions and thermal stability depend on dopant natureConductivities: 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!