NTUA
Profile and Background
NTUA is one of the major research organizations in Greece. The Dielectrics Group at NTUA consists of 4 staff members, 2 post-doctoral researchers and (at present) 4
PhD students. The Group has contributed to over 250 journal papers and conference contributions on the structure-property relationships in polymers, biopolymers and composites. Research into that field has been proceeding for more than 15 years in
Athens in close cooperation with several universities and research centers worldwide, in particular in Europe. In the last 2-3 years the Group is intensively involved in the investigation of nanostructured polymer-based materials, such as polymeric nanocomposites, hybrid rigid/flexible networks and molecular composites. The Group employs dielectric techniques to study local dynamics and charge transport in various materials. In addition, thermal transitions, as well as mechanical and thermomechanical properties and performance, are investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and mechanical tests, in close collaboration with the Polymers Group at NTUA (2 staff members and
2 PhD students). Polymer-water interactions are intensively investigated in the Group by using gravimetric water sorption/diffusion measurements and by dielectric measurements at various levels of relative humidity/water content.
Research interests
The research interests of the Group related to the Network include:
 the investigation of the structure-properties relationships in various polymer-based nanostructured materials
 the development of methodologies for using dielectric techniques for structural and morphological characterisation in nanostructured materials
 measurements and modeling of electrical conductivity in nanocomposites consisting of conducting and insulating regions
 the investigation of effects on the structure and local dynamics of polymers and glass-forming liquids induced by confinement in small volumes of nanometer size
 the investigation of the hydration properties of polymers, composites and nanostructured polymer-based materials including both the various forms of organisation of water in these materials and the effects of water on the structure and local dynamics of the matrix material
 relaxation phenomena of glassy polymers and composites
 yield and post-yield behaviour of amorphous and semicrystalline polymersconstitutive equations
Laboratory facilities
1.
Equipment for broadband dielectric spectroscopy covering a broad frequency (10
-2
-10
9
Hz) and temperature range (77-650 K), consisting of 1 frequency response analyzer, 2 impedance analyzers, 1 LCR-meter and 1 bridge
2.
Equipment for thermally stimulated depolarization currents (TSDC) and for isothermal charging-discharging current measurements

3.
Equipment for equilibrium and dynamic water sorption measurements
4.
Standard mechanical testing in tension and compression with an Instron 1121 tester, at various crosshead speeds and head sensitivities, including also impact tests
5.
Non-contact measurement of deformation with a Model Laser extensometer, for accurate measurement of longitudinal and transverse elongation, and the variation of rate of deformation in real time of experiment
6.
Dynamic mechanical spectroscopy of materials at various frequency ranges and temperatures
7.
Differential scanning calorimetry (DSC) and thermal expansion coefficient
(TMA) apparatus
8.
UV accelerating aging system (SUNTEST)
Education and training activities
1) Staff members of the Dielectrics Group (and of the Polymers Group) are intensively involved in teaching activities (courses and practical exercise) in the field of materials science at undergraduate and postgraduate level at NTUA.
2) Prof. P. Pissis and Assoc. Prof. E. Kontou give courses in the MSc programme
“Polymer Science and Applications” at the University of Athens.
3) We are starting in September at the Physics Department of NTUA a new MSc and
PhD programme in Nanotechnologies and Microsystems.
4) Prof. P. Pissis supervises every year 5-7 under- and postgraduate foreign
(european) students coming to the lab within Erasmus/Socrates and other european programmes.
5) Training is provided for foreign young scientists (mostly from east-european countries) coming to the lab for a longer period (normally 2-6 months) within individual fellowship programmes (INTAS, NATO, greek programmes), 2-4 scientists every year.
Selected recent publications related to the Network
1. V. A. Bershtein, L. M. Egorova, P. N. Yakushev, O. Meszaros, P. Sysel, L. David,
E. Duval. A. Kanapitsas and P. Pissis,
Nanostructure and molecular dynamics in rod-like polyimide / flexible-chain polyimide molecular composites,
J. Macromol. Sci.- Phys. B41, 419 – 450 (2002).
2. A. Kanapitsas, P. Pissis, R. Kotsilkova,
Dielectric studies of molecular mobility and phase morphology in polymer – layered silicate nanocomposites,
J. Non-Cryst. Solids 305, 204 – 211 (2002).
3. V. A. Bershtein, L. M. Egorova, P. N. Yakushev, P. Pissis, P. Sysel, L. Brozova,
Molecular dynamics in nanostructured polyimide silica hybrid materials and their thermal stability,
J. Polym. Sci. Part B Polym. Phys. 40, 1056 – 1069 (2002).

4.
A. Kanapitsas, P. Pissis, C.G. Delides, P. Sysel, V. Sindelar, V.A. Bershtein,
Poly(imide-amide) – poly(ethylene adipate) hybrid networks. II. Dielectric studies,
Polymer 43, 6955 – 6963 (2002).
5.
S. Kripotou, P. Pissis, V.A. Bershtein, P. Sysel, R. Hobzova,
Dielectric studies of molecular mobility in hybrid polyimide-poly(dimethylsiloxane) networks,
Polymer, in press.