1. Department of Chemical Engineering, Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway, Statoil Research Centre, N-7005 Trondheim, Norway, Department of Hydrocarbon Process Chemistry, SINTEF Materials and Chemistry, P. O. Box 124, Blindern, N-0314 Oslo, Norway, Department of Polymer Technology, Helsinki University of Technology, P.O. Box 6100, FIN-02015 HUT, Finland