Grant Supported Activities for the first year has resulted in two publications, one paper accepted to Nature Materials and two oral presentations.

It was shown, that the structure properties of a polymer chain immersed in solution of similar polymer chains (melt) can not be treated as a classical random walk. Following Flory's ideality hypothesis, chains in the melt adopt Gaussian configurations, and their form factor is supposed to be given by Debye's formula. At striking variance to this, we obtain noticeable (up to 20%) non-monotonic deviations which can be traced back to the incompressibility of dense polymer solutions beyond a local scale. The Kratky plot (q²F(q) vs wave vector q) does not exhibit the plateau expected for Gaussian chains in the intermediate q range. One rather finds a significant decrease according to the correction in F^-1(q) as  q³/32ρ that only depends on the concentration ρ of the solution, but neither on the persistence length or the interaction strength. The non-analyticity of the above q³ correction is linked to the existence of long-range correlations for collective density fluctuations that survive screening. Finite-chain size effects are found to decay with chain length N as 1/√N. These deviations from ideality should be measurable by neutron scattering experiments. An experimental verification would be of great fundamental interest; it could also delineate the conditions where the predicted corrections to ideality can be observed in real polymer systems and must be considered in understanding their structure, phase behavior, and dynamics. Such an impact on structure and dynamics is expected theoretically, for the bulk and also for thin polymer films.

We studied the static and dynamic properties of a polymer melt in a confined geometry -- nanopores whose diameter was comparable with the size of a polymer coil. It was shown that the non ideal corrections are amplified due to confinement. The dynamics undergoes dramatic change. The Poiseuille's description of flow of polymer melt in a capillary and new picture is introduced, based on individual reptation dynamics of a single polymer.