Addition of nanosized inorganic materials in a polymeric matrix results to nanohybrids with optimized properties with respect to the initial components. On the other hand, the behaviour of polymers when they are restricted in space or when they are close to surfaces can be very different from that in the bulk. In this work, we investigate the morphology, crystallization and dynamics of a hydrophilic, semi-crystalline polymer, poly(ethylene oxide), PEO, when mixed with silica, SiO2, nanoparticles in a broad range of compositions. The good dispersion of the nanoparticles was verified by Transmission Electron Microscopy (TEM), whereas the morphology and crystallization behaviour of the hybrids were investigated with X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). All techniques show a gradual decrease of polymer crystallinity with increasing the amount of nanoparticles; nevertheless, polymer crystallization is observed for all silica loadings. Moreover, DSC measurements showed the existence of two melting and crystallization transitions in hybrids with polymer content lower than 50wt%, indicating that the polymer crystallizes differently than the bulk near the silica surface.

1. PEO CRYSTALLIZATION AND CHAIN
CONFORMATION
CLOSE TO SIO2 SURFACES
H. Papananou,1,2 K. Chrissopoulou,1 K. S. Andrikopoulos3,
G. A. Voyiatzis3, and S. H. Anastasiadis 1,2
1Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas,
Heraklion Crete, Greece
2Department of Chemistry, University of Crete, 710 03 Heraklion Crete, Greece
3Institute of Chemical Engineering Sciences, Foundation for Research and Technology-Hellas, Patras,
Greece

2. Understanding of the behavior of polymers
under confinement.
Motivation
 In the past we have worked with planar
geometry confining the polymer between
clay galleries of 1nm.
 The polymer was not able to crystallize
under this severe confinement
 We needed control of confining length
 Poly(ethylene oxide) Mw=100.000
 SiO2 nanoparticles R=6 nm

3. X-Ray Diffraction
 Crystallinity gradually decreases
 Increase of the amorphous halo
due to both increase of the
amorphous polymer and the
presence of the nanoparticles
5 10 15 20 25 30
80%
20%
30%
35%
40%
32%
0%
38%
50%
60%
70%
90%
100%
Peo
Content
 (
o
)

4. Differential Scanning Calorimetry
 Crystallinity gradually decreases
 A second melting (and crystallization)
peak appears for hybrids with less than
50% PEO
 The new melting transition shows a
composition dependent Tm
 For hybrids with low polymer content
it is the new transition that prevails-100 -50 0 50 100
Temperature (
o
C)
30%
32%
35%
100%
40%
38%
60%
70%
20%
50%
80%
90%
PEO content

5. FTIR-ATR Spectroscopy
 CH2 wagging vibration
 Pure polymer exhibits either
the crystalline band or the
melt one
 Region that a crystalline and a
melt state coexist for the
nanocomposite
 This temperature region
coincides with the region seen
in DSC
1300 1320 1340 1360 1380 1400
Wavenumbers (cm
-1
)
Absorbance(a.u.)
T=120
o
C
100% PEOTm
=68.5
o
C
T=40
o
C
T=110
o
C
T=100
o
C
T=90
o
C
T=50
o
C
T=60
o
C
T=80
o
C
T=70
o
C
T=22
o
C
1300 1320 1340 1360 1380 1400
Wavenumbers (cm
-1
)
Absorbance(a.u.)
T=120
o
C
T=100
o
C
T=90
o
C
T=30
o
C
T=70
o
C
T=60
o
C
T=58
o
C
T=54
o
C
T=50
o
C
T=34
o
C
T=38
o
C
T=44
o
C
T=48
o
C
T=40
o
C
maximum=49
o
C
30% PEO
Tm2
=38.7
o
C
Tm1
=55.4
o
C
T=27
o
C

6. FTIR-ATR Spectroscopy
 CH2 wagging vibration region
 Increase in the gauche
population for hybrids with high
SiO2 content
 Confining length is 5-10 nm
while in clays 1nm
1200 1250 1300 1350 1400
0,1
0,2
Wavenumbers (cm
-1
)
C-C trans
100% PEO
80% PEO
30% PEO
T=90
o
C
C-C gauche
70 80 90 100 110 120
0,4
0,5
0,6
0,7
0,8
0,9
1,0
Temperature (
o
C)
I
gauce
/I
total
100% PEO
80% PEO
30% PEO
20% PEO

7. Further Understanding
 PEO-SiO2 hybrids with nanoparticles of R~15 nm and R~70 nm
 PEO-SiO2 hybrids with combination of nanoparticles of R~6nm
and R~70 nm
 Raman
 Broadband Dielectric Spectroscopy
 Kinetics (DSC, POM)

8. Acknowledgements
 Action KRIPIS, PROENYL research project, MIS-448305
(2013SE01380034), funded by the General Secretariat for Research and
Technology, Ministry of Education, Greece and the European
Regional Development Fund (Sectoral Operational Programme:
Competitiveness and Entrepreneurship, NSRF 2007-2013)/ European
Commission and

9. Thank you