The aim of the thesis was to elucidate the effect of confinement of amorphous phase of apolymer above its glass transition temperature being in contact with another polymer in a rigid state.Confinement is unavoidably connected with surfaces enforcing confinement. It is very difficult to separate theeffect of confinement from the effect of interfaces because both effects arise parallel and coincide. Multilayeredfilms were chosen as the base material for the studies because they contain multifold number of confined layerand response from confinement and interfaces is multifold increased. Hoping that some of experimentaltechniques are more sensitive to interfaces while others to confinement we selected the following:microcalorimetry, SSNMR, direlectrical spectroscopy and dynamic shear rheology. We have searched for theinfluence of PS on dynamics of phenyl rings of PC for PC/PS film with ratio 70/30 in the temperature rangefrom 296 K to 393 K employing PILGRIM pulse sequence. .We show that above the glass transition temperatureof PS, the PC component became more flexible. It is at the first glance the effect of the interface because there isno significant confinement of thicker PC layers. Dielectric relaxation spectroscopy measurements in our studyclearly provide evidence for deviations from a simple 2-phase structure in multilayered films PC/PS that is worthto be analyzed more in the future. The dielectric response of the multilayer samples was also modeled andcompared with experimental results. We obtained again discrepancies between the simulated spectra and themeasured spectra for multilayer films. Knowing the exact composition and viscoelastic behaviour of eachcomponent, the theoretical viscoelastic behavior of composites has been predicted numerically. Then,rheological tests have been made, and confronted with numerical predictions, to detect the confinement effect.The upper limit of thickness beyond which PS in confined layers at rubbery state becomes stiffer than in bulk isabout 150/200 nm. It appeared that the shear modulus of the thinnest PS layers (10 nm) is nearly 2.5 times largerthan that for bulk PS sample. We can note that Tg of PS layers also begins to increase beyond this upper limit ofthickness.. None of the experiment could clearly deliver the information about the effect of confinement orinterface on the behavior of PS layers alone. The results obtained here point out that separation of the effects ofconfinement and interfaces remains very difficult.

Le but de la thèse était de comprendre l’effet du confinement en épaisseur nanométrique sur lespropriétés d’un polymère amorphe au-dessus de sa transition vitreuse. Le confinement est inévitablement lié auxeffets de surface générant le confinement et on imagine immédiatement la difficulté qu’il y a à séparer les effetsde confinement et d’interfaces. Des films multi-nanocouches alternées de PS et PC obtenus par un procédéspécifique d’extrusion ont été choisis pour l’étude car l’effet du confinement comme celui des interfaces sontmultipliés et plus facilement détectable. En espérant que des techniques expérimentales soient plus sensibles àl’un des effets, nous avons plus particulièrement sélectionné la calorimétrie, la RMN, la spectroscopiediélectrique et la rhéologie dynamique en cisaillement. En RMN du solide, nous avons pu montrer que lamobilité des cycles phénoliques du PC augmente dans des films PC/PS en proportions respectives 70/30 pourdes températures supérieures à la température de transition vitreuse du PS. Cet effet peut être plutôt attribué àl’interface sachant que l’épaisseur des couches de PC est plus importante. Les essais de relaxation diélectriquemontre clairement un écart entre les réponses des films multi-couches et ceux pour les structures bi-composants.Ces résultats ont été confirmés par les écarts obtenus entre la réponse diélectrique simulée des films multi-couches obtenue à partir des réponses propres du PC et PS et celle mesurée. Ces résultats sont très prometteurs,mais demandent des études supplémentaires pour une analyse en profondeur. Connaissant le comportementrhéologique dynamique en cisaillement des matériaux PS et PC, celui des films multi-couches a été prédit. Ilapparait que le module élastique du PS augmente significativement lorsque l’épaisseur des couches de PSdescend en dessous d’un seuil plutôt élevée : 150 à 200 nm. En dessous de ce seuil, la transition vitreuse du PSmesurée par calorimétrie augmente également sensiblement. Aucune des modélisations proposées ne permetd’expliquer avec suffisamment de fidélité les résultats expérimentaux. / The aim of the thesis was to elucidate the effect of confinement of amorphous phase of apolymer above its glass transition temperature being in contact with another polymer in a rigid state.Confinement is unavoidably connected with surfaces enforcing confinement. It is very difficult to separate theeffect of confinement from the effect of interfaces because both effects arise parallel and coincide. Multilayeredfilms were chosen as the base material for the studies because they contain multifold number of confined layerand response from confinement and interfaces is multifold increased. Hoping that some of experimentaltechniques are more sensitive to interfaces while others to confinement we selected the following:microcalorimetry, SSNMR, direlectrical spectroscopy and dynamic shear rheology. We have searched for theinfluence of PS on dynamics of phenyl rings of PC for PC/PS film with ratio 70/30 in the temperature rangefrom 296 K to 393 K employing PILGRIM pulse sequence. .We show that above the glass transition temperatureof PS, the PC component became more flexible. It is at the first glance the effect of the interface because there isno significant confinement of thicker PC layers. Dielectric relaxation spectroscopy measurements in our studyclearly provide evidence for deviations from a simple 2-phase structure in multilayered films PC/PS that is worthto be analyzed more in the future. The dielectric response of the multilayer samples was also modeled andcompared with experimental results. We obtained again discrepancies between the simulated spectra and themeasured spectra for multilayer films. Knowing the exact composition and viscoelastic behaviour of eachcomponent, the theoretical viscoelastic behavior of composites has been predicted numerically. Then,rheological tests have been made, and confronted with numerical predictions, to detect the confinement effect.The upper limit of thickness beyond which PS in confined layers at rubbery state becomes stiffer than in bulk isabout 150/200 nm. It appeared that the shear modulus of the thinnest PS layers (10 nm) is nearly 2.5 times largerthan that for bulk PS sample. We can note that Tg of PS layers also begins to increase beyond this upper limit ofthickness.. None of the experiment could clearly deliver the information about the effect of confinement orinterface on the behavior of PS layers alone. The results obtained here point out that separation of the effects ofconfinement and interfaces remains very difficult.