260 280 300 320 340 360 380 400 4200

2x105

4x105

6x105

8x105

1x106

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)360 380 400 420 440 460 480 500 520 540

0

2x105

4x105

6x105

8x105

1x106

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)

440 460 480 500 520 5400

5x104

1x105

2x105

2x105

3x105

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)260 280 300 320 340 360 380 400 420 440

0

1x105

2x105

3x105

4x105

5x105

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)300 400 500 600 700 800 900

0.6

1.2

1.8

Abso

rban

ce(a

rb.u

nits

)

Wavelength (nm)

300 400 500 600 700 800 900

0.6

1.2

1.8

Abso

rban

ce(a

rb.u

nits

)

Wavelength (nm)

Fluorescent, water dispersible polyaniline and its composites with carbon nanotubes

Pablo Jiménez*, Wolfgang K. Maser, M. Teresa Martinez, Ana M. Benito

PANI / MWNT water dispersable

composites1

Water dispersable, nanostructured PANI

(nf-PANI)

Introduction of carbazole moietiesSynthesis

Copolymerizationwith aniline

Fluorescentproducts

Fluorescent polymers (and MWNT composites)

Mixtures of PANI and fluorescent molecules

Fluorescence due to carbazole moiety inside PANI chain

- Stable & fluorescent water dispersions -

Why they do not copolymerize?

HN

H2N NH2

N

H2N NH2

N

H2N NH2

O

N

NH2

NH2

N

NO2O2N

HN

NO2O2N

N

NO2O2N

O

HN

N

PANI-ADAC

PANI-EDAC

PANI-EAC

PANI-DAC

Introduction

Conclusions

MWNTs have a quenchingeffect on fluorescence

Polyanilines (PANI) are a singular class of conducting polymer since they are susceptible of both acid and redox doping reactions and they present an enviromentally stable conducting state (emeraldine salt)*. Nanostructured polyaniline recentlyemerged as a new kind of material, that combines the benefits of nanomaterials with an easy and low-cost production. Among them PANI nanofibers stand out becouse its simple, template-free synthesis, and its high water dispersability. In thiswork we present some attempts to introduce fluorescence in PANI, via copolymerization with carbazole derived compounds

In the same conditions that generate nanofibrillar PANI, we performed oxidative polymerizations of aniline in presence of various carbazole derivatives. Only in thecase of 3,6-diaminocarbazole a true copolymer (PANI-DAC) was obtained. Copolymers at different ‘carbazole’proportions were synthesized, and they showed a blue emission in fluorescence due to carbazole moieties. Our synthetic conditions enabled us to prepare PANI-DAC and (PANI-DAC)/MWNT composites with a goodwater dispersability.

(NH4)S2O8

NR

H2N NH

N

H2N NH

N

N NH

vs.

phenazine-type oligomer

Hypothesis: in the oxidativereaction media DAC is more proneto give oxidized products similar tothe phenazine-like molecules that

are supposed be formed in the firststages of PANI formation. In fact, DAC reduces greatly the induction

period of polymerizations.

Oxidized aminocarbazoles:

(commercially available)

(previous work)

Instituto de Carboquímica (CSIC), Dept. of NanotechnologyMiguel Luesma Castán 4, E-50018 Zaragoza, Spain

*e-mail: pablojm@icb.csic.es

pH=

2pH

= 5

UV-Vis Excitation spectra Emission spectra

em= 450 nm

em= 450 nm

exc= 313 nm

exc= 400 nm

Oxidativepolymerization in

acidic media (HCl 1M)

440 460 480 500 5200

1x105

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)Acknowledgements

200:1100:166:13:1

aniline:DAC ratio

Fluorescence in copolymer aqueousdispersions increases with ‘carbazole’

content, and it depends strongly on the pH

PANI-DAC/MWNTs

PANI-DAC

NH

HN

NH

HN

n

NH

HN

NH

HN

n

‘polaron’ form

‘bipolaron’ form

*Polyaniline, in emeraldine salt state:

1 Jiménez, P.; Maser, W. K.; Castell, P.; Martínez, M. T.; Benito, A. M. Macromolecular Rapid Communications 2009, 30 (6), 418-422

Zn, HCl

MeOH

Zn, HCl

MeOH

Zn, HCl

MeOH

1. Cu(NO3)2, Ac2O/AcOH

2. NaOH(aq)

Cu(NO 3) 2

Ac 2O/AcOH

Cu(NO 3

) 2Ac 2O

/AcO

H

445 nm

λ λ

λ

λ

Spanish MICINN under projects MAT2006-13167-C02-02 and MAT2007-66927-C02-01).Aragon Consolidated Group Programme DGA-T66 CNN and Aragon Project DGA-PI086/08.P. Jiménez acknowledges Fundación Ramón Areces for his PhD grant

Thorough washing of materials with organic solventsleaves pure PANI-ES and removes all fluorescence