Teresa Dib Zambon AtvarsInstituto de Química
Universidade Estadual de CampinasCampinas, São Paulo, Brasil
E-mail: [email protected]
Some Some applicationsapplications of of photoluminescencephotoluminescence for for probingprobing polymerpolymer relaxationrelaxation processesprocesses
Summer School - Stereochemical Aspects of Novel Materials, UCSB, august 14-27, 2005
Part 2 p1
Slide 1
p1 roprpg, 7/2/2005
outline
Polymer systems and morphologyPolymer motions, phase transitions and polymer relaxation processesPhotoluminescence spectroscopy and polymer relaxation processes
fluorescencephosphorescencequenching processes time resolved spectroscopy
Luminescence in polymers Non-fluorescent polymers (host-guest systems)Polymers modified with luminescent groupsIntrinsically luminescent polymersConjugated luminescent polymersElectroluminescence and photoluminescence
Summer School - Stereochemical Aspects of Novel Materials, UCSB, august 14-27, 2005
Types of luminescent polymers : 1. non-fluorescent polymers (host-guest systems)
Amorphous materials
Semicrystalline polymers
How the guest interacts with the polymer?Which site is the guest sensing?
Guest in semicrystalline polymers
Amorphous region
Surface of a lamellae
Interfase between amorfous and
crystalline phase
Probing orientation in stretched materials
Molecules changes from one site to other
and can be preferentially oriented in the stretching direction
They can sense the new environment
Relaxation processes in oriented polymers
Talhavini et al. Polymer, 1986
Talhavini, et al, Polymer 1986
Relaxation processes associatedwith the interface crystalline
amorphous interface are more defined
There is a larger population ofanthracene molecules located
in the interface comparedwith non-stretched material
α-relaxation process
How important is the distance for a guest sensor?
Pyrene in LDPEand some coplolymers
with vinyl acetate (EVA)
II/IIII ratio changes
Lifetimes also change
Linear correlation with lifetime and II/IIII ratio
because the random distribution of the polar groups
1st (open) and 2nd run (dark) Yamaki, Eur. Polym. J., 2002
First (dark) and second (open) scans
Naylons = condensation of an amide a carboxylic acid
Naylon-6
Poly(caprolactone)
Naylon-11
Naylon-6,6
Naylon-6,9
Naylon-6,10
Naylon-6,12
constant
Photophysical properties of pyrene in naylons
310 ns1.29Naylon-6,12
296 ns1.30Naylon-6,10
276 ns1.31Naylon-6,9
250 ns1.44Naylon-6,6
276 ns1.27Naylon-11
260 ns1.41Naylon-6
265 ns1.15Poly(caprolactam)
Decrease of the polarity
Polymers modified with luminescent groups
Will sense the environment around the molecule
More sensivity to the motions involving the segments where they were bonded
Selective attachment should enhance the sensitivity and coupled motions can be analyzed.
Weiss, et al., 1992
Polyethylene and vinyl acetate copolymers modified with pyrenyl groups
Not observed
Yamaki, et al., Photochem. Photobiol. Sci. 2002.
Relaxation processeswill be associated with
these groups
Selective attachment
3 8 0 4 0 0 4 2 0 4 4 0 4 6 00
2 0 0 0
4 0 0 0
6 0 0 0
8 0 0 0 a .
4 1 0 K
3 0 K
Rela
tive
inte
nsity
(a.u
.)
W a v e le n g th ( n m )
3 6 0 3 8 0 4 0 0 4 2 0 4 4 0 4 6 0
0
3 0 0 0
6 0 0 0
9 0 0 0
1 2 0 0 0 b .
4 1 0 K
3 0 K
Rela
tive
inte
nsity
(a.u
.)
W ave len g th (n m )
pyrenyl attached to LDPE
Pyrene as a guest in LDPE
0 100 200 300 4000,0
0,2
0,4
0,6
0,8
1,0
Tm
Tα
Tg (β)Tγ
a.
Nor
mal
ized
inte
nsity
Temperatura (K)
Normalized and integrated fluorescence intensities versus temperature for pyrene (n) and 1-pyrenyl groups ( ) in (a) LDPE and (b) PVAC.
0 100 200 300 400
0,0
0,2
0,4
0,6
0,8
1,0
Tβ
Tg
Tβ́
b.
Nor
mal
ized
inte
nsity
T ( K )
Schur, Weiss et al., Macromolecules, 2003
Weiss et al., Macromolecules, 2003
Intrinsically luminescent polymers: poly(2-vinyl naphthalene)
Poly(2-vinyl naphthalene)
Cruz, et al. J. Appl. Polym. Sci. 2001
Intrinsically luminescent polymers:
Deus, Akcelrud, et al. Chem. Phys. 2004
Deus, Akcelrud, et al. Chem. Phys. 2004
Deus, Akcelrud, et al. Macromolecules 2004
Conjugated luminescent polymers
O
O
*
*n
Poly(2-methoxy-5-(2-ethylhexyloxy)-p-phenylene vinylene)
MEH-PPV
Steady-statefluorescenceemission
Blue shift
Increase of intensity
Cossiello, et al. Macromolecules 2005
DMTA dataArrhenius plots
Relaxation processes
T = 320 ± 10 KT = 220 ± 10 KFluorescence
T = 310 ± 10 K
Ea = 62.4 kJ mol-1 K-1
T = 210 ± 10 K
Ea = 22.5 kJ mol-1 K-1TSC
T = 330 ± 10 K
Ea = 85.4 kJ mol-1 K-1
T = 210 ± 10 K
Ea = 29.1 kJ mol-1 K-1DMTA
α-relaxationβ-relaxationTechniques
Cossiello et al. Macromolecules, 2005
Molecular Motions by 13C NMR
Bloise, et. al. Phys. Rev. B. 2005
Bloise et al. Phys. Rev. B, 2005
Conclusions from 13C RMN
Carbons 11, 12, 13, 14, 15, 16, and 17 gain mobility after the β-relaxation process
Implications of the relaxation processes on the electroluminescence properties
Electroluminescence and photoluminescence
poly(9,9-(di-n,n-octyl-fluorene))
Winokur et al. Phys. Rev. B. 2003
Spectral profiles and condensed medium
Spectral profiles and condensed medium
Spectral profiles and condensed medium
Relaxation process and spectral broadening
Brown, et.al. J. Polum Sci. Polym. Phys. Ed. 2004
Martins, et. Al. J. Phochem. Photobiol. A Chem. 2002
Thank you!
Summer School - Stereochemical Aspects of Novel Materials, UCSB, august 14-27, 2005
Fred
Miguel
Jennifer
