Polymeric materials are at the core of novel applications and state-of-the-art technologies, affecting all aspects of modern life. The lengthy list of applications ranges from membrane and barrier technologies in energy and environmental engineering (such as in gas separations and water purification) to biomedical engineering and packaging. Through this activity we aim develop new modeling methodologies and tools for a) the relaxation of complex polymer melts by introducing novel approaches able to equilibrate rigid parts of the chains, and b) the systematic study of gas diffusion and sorption in polymers up to high pressures.