MULTIFUNCTIONAL CHIRAL POLYMERIC MATERIALS CONTAINING SIDE-CHAIN

AZOCARBAZOLE CHROMOPHORES

L. Angiolini, L. Giorgini, F. Mauriello

Dipartimento di Chimica Industriale e dei Materiali, University of Bologna

R. Bozio, T. Dainese, D. Pedron

Dipartimento di Scienze Chimiche, University of Padova

Synthesis of materials and characterizationPhotomodulation optical properties

Photoconductive and photorefractive properties

A. Golemme, R. Termine

Dipartimento di Chimica, University of Calabria

N

N N

CN

O

C O

CH

O

CH3

C O

C)(CH2

CH3

*

n

Poly[(S)-MLECA]

PHOTOCHROMIC

FUNCTIONALITY

POLYMERICBACKBONE

CHIRAL FUNCTIONALIT

Y

PHOTOCONDUCTIVE &

PHOTOREFRACTIVE FUNCTIONALITY

Features of the multifunctional polymer studiedFeatures of the multifunctional polymer studiedFeatures of the multifunctional polymer studiedFeatures of the multifunctional polymer studied

Mn = 13400

Mw /Mn = 1.8

Tg = 147°C

Td = 363°C

High Tg and decomposition temperatures

High Tg and decomposition temperatures

Absorption in the visible:

azo-dyes n *, * and CT el. trans.Pump at 488 nmProbe at 633 nm

200 300 400 500 6000,0

0,5

1,0

1,5

2,0

2,5

Ab

sorb

an

ce

Wavelength (nm)

488 nm 633 nm

Carbazole Aromatic of azo-dyes

CisTrans

Chiral conformation of one prevailing helical handednessChiral conformation of one prevailing helical handedness

CHIRAL GROUP

PHOTOREFRACTIVE GROUPAZO-AROMATIC CHROMOPHORE

Potential use as chiroptical switches

Excitonic splitting-

+

Amplified Chirality

UV-vis spectra

CD spectra

Photoconductive and photorefractive materials Photoconductive and photorefractive materials Photoconductive and photorefractive materials Photoconductive and photorefractive materials

Holographic Data StorageHolographic Data StorageHolographic Data StorageHolographic Data Storage

Electroluminescents DiodesElectroluminescents DiodesElectroluminescents DiodesElectroluminescents DiodesNanolithographyNanolithographyNanolithographyNanolithography Integrals circuitsIntegrals circuitsIntegrals circuitsIntegrals circuits

Capacity in bytes

Holographic Memories

Small Mag.Disks

Large Mag.Disks

CD ROM

Magnetic Tape

Floppy disks

104

103

102

101

100

10-1

10-2

Acc

ess

time

in m

illis

econ

ds

106 107 108 109 1010 1011 1012

•Security from Forgery

•Holographic

Interferometry

• Medical Application

•Phase Conjugation

•Optical Device

•Pattern Recognition

• Optical Amplification

• Holographic Data

Storage

• 3-D Holovideo

Carbazole

Chiral group

Azobenzene

Chiral groupMultifunctional

monomer

Chiral monomer with carbazole

Chiral monomer with azobenzene

+MULTIFUNCTIONALCOPOLYMERS

MULTIFUNCTIONAL OMOPOLYMERS

MULTIFUNCTIONAL POLYMERS FOR PHOTONICS AND MULTIFUNCTIONAL POLYMERS FOR PHOTONICS AND OPTOELECTRONICS OPTOELECTRONICS

MULTIFUNCTIONAL POLYMERS FOR PHOTONICS AND MULTIFUNCTIONAL POLYMERS FOR PHOTONICS AND OPTOELECTRONICS OPTOELECTRONICS

Synthetic approach Synthetic approach Synthetic approach Synthetic approach

CarbazoleCarbazole Azobenzene Azobenzene

Multifunctional Polymers

Chiral groupChiral group

N

N

N

O

C O

C)

CH3

(CH2

*

x 1-x

Poly[(S)-(-)-MECP]Poliy(S)-(-)-MECP-co-(S)-MAP-N]

x =1x = 0.50

N

O

N

N

C O

C)

CH3

NO2

(CH2

poly[(S)-(+)-MECSI] x=1poliy(S)-(+)-MECSI-co-(S)-(+)-MOSI](75/25) x=0.75poli[yS)-(+)-MECSI-co-(S)-(+)-MOSI](50/50) x=0.50poli[yS)-(+)-MECSI-co-(S)-(+)-MOSI](25/75) x=0.25

x

N

O

N

N

C O

C)

CH3

O O

(CH2

N

N

O

C O

C)

CH3

(CH2

OO

1-x

* *

Multifunctional copolymers synthetized Multifunctional copolymers synthetized Multifunctional copolymers synthetized Multifunctional copolymers synthetized

N

N

O

C O

CCH2

CH3

O O

*

( )n

N

N

O

C O

CCH2

CH3

O O

N

*

( )1-n

N

N

O

C O

CCH2

CH3

*

( )n

N

N

O

C O

CCH2

CH3

N

R

( )1-n

poly[(S)-MCPS] n=1poly[(S)-MCPS-co-(S)-MOSI] n=0.50

poly[(S)-MCPP] n=1poly[(S)-MCPP-co-(S)-MAP-C] n=0.50poly[(S)-MCPP-co-(S)-MAP-N] n=0.50

N

N N

CN

O

C O

CH

O

CH3

C O

C)(CH2

CH3

*

x

poly[(S)-MLECA]

Multifunctional Multifunctional homopolymers homopolymers

synthetized synthetized

Multifunctional Multifunctional homopolymers homopolymers

synthetized synthetized

Thickness 100-400 nm<900 nm

Applications as Applications as Amorphous thin films obtained by spin-coatingAmorphous thin films obtained by spin-coating

Applications as Applications as Amorphous thin films obtained by spin-coatingAmorphous thin films obtained by spin-coating

N

N

N N

N

N

N

N

Ē

rotationaldiffusionh

h

STOPtrans cis

Photoinduced trans Photoinduced trans cis cis trans isomerization cycles trans isomerization cyclesPhotoinduced trans Photoinduced trans cis cis trans isomerization cycles trans isomerization cycles

trans

C ircu la r P o l.

L in ear P o l.

LP

CP

R. Hagen, T. Bieringer Adv. Mater 13, 1805 (2001)

Reversible photoinduced orientation of azobenzene groupsReversible photoinduced orientation of azobenzene groupsReversible photoinduced orientation of azobenzene groupsReversible photoinduced orientation of azobenzene groups

30 60 90 120 150 180 210 240 270 300 330

0,00

0,02

0,04

0,06

0,08

0,10

0,12

0,14

Birefringence

Irra

diat

ion

with

CP

light

Irra

diat

ion

with

LP

light

n2

n1

n

Time (s)

Write and erase of optical information for

OPTICAL STORAGE1

0

Typical experiment of photoinduced birefringence cyclesTypical experiment of photoinduced birefringence cycles Typical experiment of photoinduced birefringence cyclesTypical experiment of photoinduced birefringence cycles

L. Angiolini, R. Bozio, L. Giorgini, D. Pedron, G. Turco, A. Daurù, Chem. Eur. J., 8, 4241 (2002)L. Angiolini, T. Benelli, R. Bozio, A. Daurù, L. Giorgini, D. Pedron, E. Salatelli, Macromolecules, 39, 489-497 (2006)L. Angiolini, T. Benelli, R. Bozio, A. Daurù, L. Giorgini, D. Pedron, E. Salatelli, Eur. Polym. J, in press (2007)

Reversible write and erase of optical information

for OPTICAL STORAGE

Temporal stability of photoinduced

signals

Photomodulation of birefringence on Poly[(S)-MLECA]Photomodulation of birefringence on Poly[(S)-MLECA]

Pump at 488 nm Ipump 100 mW/cm2

Probe at 633 nm Iprobe < 1 mW/cm2

300 350 400 450 500 550 600 650-0,20

-0,15

-0,10

-0,05

0,00

0,05

0,10

0,15 Native Irr. CP-L light Irr. CP-R light

Elli

ptic

ity [m

deg/

nm]

Wavelength [nm]

poly[(S)-MAP-N] Tg = 208 Cthin films 100 300 nmI 160 mW/cm2 x 60 s

Reversible inversionof the CD signal by

irradiation with CP-L and/or CP-R light

L. Angiolini, R. Bozio, L. Giorgini, D. Pedron, G. Turco, A. Daurù, Chem. Eur. J., 8, 4241 (2002)L. Angiolini, R. Bozio, L. Giorgini, D. Pedron, Synth. Met., 138, 375-379 (2003)L. Angiolini, T. Benelli, R. Bozio, A. Daurù, L. Giorgini, D. Pedron, Synthetic Metals 139, 743 (2003)

0 50 100 150 200

-150

-100

-50

0

50

100

150

Native

CP-L irradiation

CP-R irradiation

Elli

ptic

ity a

t 4

70

nm

(m

de

g)

Fluence (J/cm2)

CHIROPTICAL SWITCHESCHIROPTICAL SWITCHESCHIROPTICAL SWITCHESCHIROPTICAL SWITCHES

CP-L

CP-RDipolar interactions

Side-chain

Chiral groups

Azo-aromatic groups

CP-L

CP-R

L. Angiolini, T. Benelli, L. Giorgini, A. Painelli, F. Terenziani, Chem. Eur. J. (2005) L. Angiolini, T. Benelli, L. Giorgini, E. Salatelli, Polymer, 46, 2424 (2005)L. Angiolini, T. Benelli, L. Giorgini, E. Salatelli, Polymer, 47, 1875–1885 (2006)

Reversal of the coils or of the domains Reversal of the coils or of the domains by irradiating with CP light !??by irradiating with CP light !??

Reversal of the coils or of the domains Reversal of the coils or of the domains by irradiating with CP light !??by irradiating with CP light !??

CHIROPTICAL SWITCHES

Photomodulation of the chiroptical properties of Photomodulation of the chiroptical properties of Poly[(S)-MLECA]Poly[(S)-MLECA]

Photomodulation of the chiroptical properties of Photomodulation of the chiroptical properties of Poly[(S)-MLECA]Poly[(S)-MLECA]

CHIROPTICAL SWITCHES

Irradiation of azo polymer films with an interference pattern for a period of time longer than that required for photoinduced orientation produces a modification of the

film surface.

Surface relief gratings (SRGs) photoinduced on Surface relief gratings (SRGs) photoinduced on Poly[(S)-MLECA]Poly[(S)-MLECA]

Surface relief gratings (SRGs) photoinduced on Surface relief gratings (SRGs) photoinduced on Poly[(S)-MLECA]Poly[(S)-MLECA]

Crossed Surface Relief GratingsCrossed Surface Relief GratingsCrossed Surface Relief GratingsCrossed Surface Relief Gratings

SRGs with 1m periods, in the x and y directions

SRGs, with 2 m period, in the x-direction and 1 m period, in the y-direction,

Unusual superhelix-like (LISH) patterns can be directly

photofabricated on the surface of azo polymer films by a

interference pattern obtained by EP-L (ellipticity = 0.4) and EP-R (ellipticity < 0.4) light.

Combination of the photoinduced chiral orientation and the

photoinduced SRG formation.

Helicoidal structures (LISH) superimposed to a SRG with a period of about 1m

5 m

Laser Induced Supramolecular Helix (LISH) Laser Induced Supramolecular Helix (LISH) inscribed on inscribed on Poly[(S)-MLECA]Poly[(S)-MLECA]

Laser Induced Supramolecular Helix (LISH) Laser Induced Supramolecular Helix (LISH) inscribed on inscribed on Poly[(S)-MLECA]Poly[(S)-MLECA]

PhotoconductivityPhotoconductivity properties of properties of Poly[(S)-MLECA]Poly[(S)-MLECA]PhotoconductivityPhotoconductivity properties of properties of Poly[(S)-MLECA]Poly[(S)-MLECA]

2.3x10-13 ScmW-1

at 60V/m

OPTICAL STORAGE, NLO MATERIALS AND

CHIROOPTICAL SWITCHES

Photomodulation of linear birefringence

and dichroism

MULTIFUNCTIONAL POLYMERIC MATERIAL

PHOTOCHROMIC FUNCTIONALITY

PHOTOCONDUCTIVE AND

PHOTOREFRACTIVE

FUNCTIONALITY

Photomodulation of chirooptical

properties

Photomodulation of photorefractivity PH

OTO

CO

NDU

CTIVE

, PR

MA

TER

IALS

AN

D

CH

IRO

OPTIC

AL SW

ITCHE

S

PHO

TOC

ON

DUC

TIVE

, OP

TIC

AL

STO

RAG

E, P

R A

ND

NLO

MAT

ERIA

LS

CHIRAL FUNCTIONALITY

Prof. Luigi Angiolini Dr. Tiziana BenelliDr. Francesco MaurielloDott. Elisabetta SalatelliDott. Libero DamenDott. Gianluca Perfetti

Financial support by MIUR (FIRB 2001) and Consorzio INSTM is gratefully acknowledged

University of Bologna

University of Padova

Prof. Renato BozioProf. Danilo PedronDott. Tiziano DaineseDott. Alessandro Daurù

University of CalabriaProf. Mauro Ghedini Prof. Attilio GolemmeDr. Roberto Termine

ACKNOWLEDGEMENTS:ACKNOWLEDGEMENTS:ACKNOWLEDGEMENTS:ACKNOWLEDGEMENTS:

Photomodulation of birefringence, Photomodulation of birefringence, chiroptical switches and SRGschiroptical switches and SRGs

Photomodulation of birefringence, Photomodulation of birefringence, chiroptical switches and SRGschiroptical switches and SRGs

Photoconductivity and Photorefractive Photoconductivity and Photorefractive propertiesproperties

Photoconductivity and Photorefractive Photoconductivity and Photorefractive propertiesproperties

The author dedicates this work to the memory of

Professor Carlo Carlini

Photomodulation of linear birefringence and

dichroism

PHOTORESPONSIVE PROPERTIES

CONVENTIONAL MATERIALS

CHIROPTICAL SWITCHES

OPTICAL STORAGE

AND

CHIROPTICAL SWITCHES

CHIRALPHOTOCHROMIC

POLYMERS

Photomodulation of chiroptical properties

OPTICAL STORAGE

Polimero /I (S cm W-1) Campo elettrico (V/mm)

Poli[MECSI] 100% 1.2 e-14 60

Poli[MECP] 80% DPP 20% 8.0 e-11 40

Poli[MLECA] 100% 3.0 e-14 40

Poli[MECPS] 85% DPP 15% 2.0e-12 60

ACKNOWLEDGEMENTS:

Dr. Tiziana BenelliDr. Daniele CarettiDr. Elisabetta SalatelliDr. Delio AlfinoDr. Saverio CazzoliDr. Ada delle DonneMr. Marco Toto

Dr. Alessandro DaurùDr. Giovanni TurcoMr. Andrea Barbiero

Financial support by MIUR (PRIN 2001) and Consorzio INSTM is gratefully acknowledged

University of Bologna

University of Padova

200 300 400 500 600 700

-600

-400

-200

0

200

400

600

800

Elli

ptic

ity (m

degr

ee)

wavelenght (nm)

native 5 min 10 min 15 min 20 min 25 min 30 min 40 min 50 min 60 min 75 min 100 min 115 min 130 min

poly[(S)-MAP-C] (Tg = 192 C), heated at 200 Cpoly[(S)-MAP-C] (Tg = 192 C), heated at 200 C

Heat

The application of heat seems to amplify the overall chirality of the systemThe application of heat seems to amplify the overall chirality of the system

-60

40

-40

-20

0

20

0

1

2

250 550450350

Abs

orb

ance

Elli

ptic

ity (

mde

g)

Wavelength (nm)

poly[(S)-MAP-C] Tg = 192 C

230 C

190 C

L. Angiolini et al., Synth. Met., 138, 375-379 (2003)

Heat

CP-L Heat

CP-R

250 300 350 400 450 500 550 600 650-150

-100

-50

0

50

100

150

Native

8o CP-R

6o and 10o CP-R

4o CP-R

2o CP-R

1o CP-L

3o CP-L

5o CP-L

7o and 9o CP-L

Elli

ptic

ity [

md

eg

]

Wavelegth [nm]

0 50 100 150 200 250 300

-150

-100

-50

0

50

100

150

Native

CP-L irradiation

CP-R irradiation

Elli

ptic

ity a

t 4

70

nm

(m

de

g)

Fluence (J/cm2)

poly[(S)-MAP-C] 184 nm

I 200 mW/cm2 x 180 s 1th - 6th

I 100 mW/cm2 x 180 s 7th - 8th

I 50 mW/cm2 x 180 s 9th - 10th

Chirality increaseswith the increaseof the tot. fluence

L. Angiolini et al., Synth. Met., (2003) in press

250 300 350 400 450 500 550 600 650-150

-100

-50

0

50

100

150

Native

8o CP-R

6o and 10o CP-R

4o CP-R

2o CP-R

1o CP-L

3o CP-L

5o CP-L

7o and 9o CP-L

Elli

ptic

ity [

md

eg

]

Wavelegth [nm]

300 400 500 600

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

Native

2o CP-L

4o CP-L

6o CP-L

8o CP-L

10o CP-L

9o CP-R

7o CP-R

5o CP-R

3o CP-R

1o CP-R

Elli

ptic

ity [

md

eg

/nm

]

Wavelegth [nm]

poly[(S)-MAP-C] 184 nm

I 200 mW/cm2 x 180 s 1th - 6th

I 100 mW/cm2 x 180 s 7th - 8th

I 50 mW/cm2 x 180 s 9th - 10th

poly[(R)-MAP-C] 210 nm

I 100 mW/cm2 x 400 s 1th - 10th

Synthesis of multifunctional monomers Synthesis of multifunctional monomers Synthesis of multifunctional monomers Synthesis of multifunctional monomers

SONa

OO

CH3(CH2)10CH2O

Biphasic medium H2O/CH2Cl2

N

OH

+N

OH

N N

CNHECA

CNN2+

N

N N

CN

O

O

CH

C O

C

CCH2

CH3

O

CH3*

(S)-MLECA

C

O

CH

C

CCH2

CH3

O

O

OH

CH3*

DPTS

DIPC

250 300 350 400 450 500 550 600 650-150

-100

-50

0

50

100

150

Native9o CP-L

8o CP-RE

llip

ticity

[m

de

g]

Wavelength [nm]

200 300 400 500 600 700

0,0

0,4

0,8

1,2

1,6 Native After 10 irr. CP-L/CP-R

Ab

sorb

an

ce

Wavelegth [nm]

Modification in shapeand intensity of theCD and abs. spectra

Photoinduced aggregation?

CP-L

CP-R

300 400 500

-50

0

50

Elli

ptic

ity (

md

eg

)

Wavelength (nm)

Native Irr. CP-L After heating After 1 year

poly[(S)-MAP-C] 170 nmI 400 mW/cm2 x 180 s

Temporal and thermal stability

Temporal and thermal stability

L. Angiolini et al., Synth. Met., in press (2003)

Temporal and thermal stability of photoinduced CD signalsTemporal and thermal stability of photoinduced CD signals

CP-L

CP-R

250 300 350 400 450 500 550 600 650-150

-100

-50

0

50

100

150

Native

8o CP-R

6o and 10o CP-R

4o CP-R

2o CP-R

1o CP-L

3o CP-L

5o CP-L

7o and 9o CP-L

Elli

ptic

ity [

md

eg

]

Wavelegth [nm]

0 50 100 150 200

-150

-100

-50

0

50

100

150

Native

CP-L irradiation

CP-R irradiation

Elli

ptic

ity a

t 4

70

nm

(m

de

g)

Fluence (J/cm2)

poly[(S)-MAP-N-co-DR1M] 50/50

Film thin 290 nm

I 50 mW/cm2 x 180 s 1th - 3th

I 100 mW/cm2 x 180 s 4h - 7th

I 200 mW/cm2 x 180 s 8th - 10th

CHIROPTICAL SWITCHES

G. Iftime, et al., J. Am. Chem. Soc. 2000, 122, 12646.

M. Ivanov, et al., J. Mod. Opt. 2000, 47, 861.

After ordering withLP light

After ordering withLP light

LC smectic-A phaseLC smectic-A phase

0 50 100 150 200 250 300 350 400

0,00

0,05

0,10

0,15

0,20

0,25

poly[(S)-MAP-N-co-DR1M] 25/75

DDD

CCC BBB

AAA

Bir

efr

ing

en

ce,

n

Time (sec)

30 60 90 120 150 180 210 240 270 300

0,00

0,05

0,10

0,15

0,20

0,25

D

C

poly[DR1M]

B

A

Bir

efr

ing

en

ce,

n

Time (sec)

0 50 100 150 200 250 300 350 400

0,00

0,05

0,10

0,15

0,20

0,25

poly[(S)-MAP-N-co-DR1M] 50/50

DDDD

CCCC BBBB

AAAA

Bir

efr

ing

en

ce,

n

Time (sec)

0 20 40 60 80 100 120 140 160 180

0,00

0,05

0,10

0,15

0,20

0,25

poly[(S)-MAP-N-co-DR1M] 10/90

D

CB

A

Bir

efr

ing

en

ce,

n

Time (sec)

0 200 400 600 800 1000 1200 1400 1600

0,00

0,05

0,10

0,15

0,20

0,25

poly[(S)-MAP-N-co-DR1M] 75/25

D

C

B

A

D

C

B

A

D

C

B

A

Bir

efr

ing

en

ce,

nTime (sec)

30 60 90 120 150 180 210 240 270 300

0,00

0,05

0,10

0,15

0,20

0,25 CB

poly[(S)-MAP-N]

DA

Bir

efr

ing

en

ce,

n

Time (sec)

0,0 0,2 0,4 0,6 0,8 1,00,05

0,10

0,15

0,20

0,25

poly[DR1M]

poly[(S)-MAP-N]

Bir

efr

ing

en

ce, n

Mole fraction of (S)-MAP-N units

The properties of the materials change by using different co-monomersThe properties of the materials change by using different co-monomers

poly[(S)-MAP-N] x=1poly[(S)-MAP-N-co-DR1M]75/25 x=0.75poly[(S)-MAP-N-co-DR1M]50/50 x=0.50poly[(S)-MAP-N-co-DR1M]25/75 x=0.25poy[(S)-MAP-N-co-DR1M]10/90 x=0.10poly[DR1M] x=0

(S)-MAP-N DR1M

N

NO2

N

NO2

CH3

C

C O

O

N

H

N

CH2

CH3

C

C O

O

N

N

CH2( ) ( )x 1-x

*

Materiali fotorifrattiviMateriali fotorifrattiviMateriali fotorifrattiviMateriali fotorifrattivi

Effetto fotorifrattivoEffetto fotorifrattivoEffetto fotorifrattivoEffetto fotorifrattivo

DEFINIZIONE: L’effetto fotorifrattivo (PRe) si riferisce alla modulazione spaziale dell’indice di rifrazione generato da un meccanismo specifico: la ridistribuzione fotoindotta di carica in un materiale nel quale l’indice di rifrazione dipende dal campo elettrico applicato.

I processi fisici legati al meccanismo fotorifrattivo sono:

1.Assorbimento della radiazione luminosa con generazione di cariche2.Trasporto delle cariche 3.Intrappolamento delle cariche4.Generazione di un campo elettrico interno5.Riorientazione molecolare interna con variazione dell’indice di rifrazione

Materiali fotorifrattiviMateriali fotorifrattiviMateriali fotorifrattiviMateriali fotorifrattivi

Photorefractive material = Photoconducting material +NLO chromophore

Effetto fotorifrattivoEffetto fotorifrattivoEffetto fotorifrattivoEffetto fotorifrattivo Molecole organiche Molecole organiche coinvolte nel processocoinvolte nel processoMolecole organiche Molecole organiche

coinvolte nel processocoinvolte nel processo

Indice Modulazione Elettro-ottica

Intrappolamento carica

Trasporto carica

Generazione carica

De

ns

ità

di

cari

ca

in

tra

pp

ola

taD

en

sit

àd

i ca

ric

a

ilib

era

Inte

ns

ità

luc

eC

am

po

sp

azi

ale

di

ca

ric

a:

ind

ice

di

rifr

azi

on

e d

i c

ari

ca

n

Ioni Immobili

HoleIntrappolati

Holemobili

Indice Modulazione Elettro-ottica

Intrappolamento carica

Trasporto carica

Generazione carica

De

ns

ità

di

cari

ca

in

tra

pp

ola

taD

en

sit

àd

i ca

ric

a

ilib

era

Inte

ns

ità

luc

eC

am

po

sp

azi

ale

di

ca

ric

a:

ind

ice

di

rifr

azi

on

e d

i c

ari

ca

n

Ioni Immobili

HoleIntrappolati

Holemobili

Il gruppo carbazolico forma relativamente cationi radicalici stabili (holes)

Differenti sostituenti possono essere facilmente introdotti nell’anello carbazoico.

Il gruppo carbazolico permette una maggiore coniugazione lungo la catena laterale

Materiali contenenti i gruppi carbazolici sono caratterizzati da una elevata stabilità termica e fotochimica

Il carbazolo è un intermedio relativamente economico.

Scelta gruppo fotoconduttoreScelta gruppo fotoconduttoreScelta gruppo fotoconduttoreScelta gruppo fotoconduttore

CarbazoloCarbazoloCarbazoloCarbazolo

45,2

g h

8,1,6

*

ac

e,f

b

d

45,2

g h

8,1,6

*

ac

e,f

b

d

45,2

h g

8,1,6

*

ac

e,f

b

d

a

b

Scomparsa delsegnale dei protoni del CH2 metacrilico

(S)-MLECA

poli[(S)-MLECA]

Spettroscopia Spettroscopia 11H-NMRH-NMRSpettroscopia Spettroscopia 11H-NMRH-NMR

Omopolimero poli[(S)-MLECAOmopolimero poli[(S)-MLECA]] Omopolimero poli[(S)-MLECAOmopolimero poli[(S)-MLECA]]

*

(S)-MLECA

N

N N

CN

O

C O

C

O

CH3H

C O

C

CH3

CH2

a

b

c d

e

f

gh

12

345

6

78

200 300 400 500 6000,0

0,5

1,0

1,5

2,0

2,5

Abs

orba

nce

Wavelength (nm)

0

2

4

6

Elli

ptic

ity (

mde

gree

)

Misure di dicroismo circolare stato solidoMisure di dicroismo circolare stato solidoMisure di dicroismo circolare stato solidoMisure di dicroismo circolare stato solido

Potenziali swithes chiroottici

couplet eccitonico-

+

STATO SOLIDOSOLUZIONE

Conservazione ordinamento cromofori

0 5 10 15 20 25 30 35 40 45 50 55 60 65 700,0

5,0x10-13

1,0x10-12

1,5x10-12

2,0x10-12

2,5x10-12 BO 08 zona 4 15 settembre 2006

polimero 4 85%DPP 15%

= 533 nm

= 118 cm-1

ph/

I (S

cmW

-1)

Electric Field (V/m)

N

N

O

C O

CCH2

CH3

O O

*

( )n

Misure di fotoconduzioneMisure di fotoconduzioneMisure di fotoconduzioneMisure di fotoconduzione

Risultati PreliminariRisultati PreliminariRisultati PreliminariRisultati Preliminari

Poly [(S)-MECPS]

0 5 10 15 20 25 30 35 40 450,0

1,0x10-11

2,0x10-11

3,0x10-11

4,0x10-11

5,0x10-11

6,0x10-11

7,0x10-11

8,0x10-11 MECP 80%DDP 20%

= 533 nm

= 386 cm-1

ph/

I (S

cmW

-1)

Electric Field (V/m)

Poly [(S)-(+)-MECP]

*

N

N

O

C O

C

CH3

CH2

OO

( )n

PROPRIETA’FOTOCONDUTTIVE

2 ordini di grandezza maggiore