Molecular simulation in polymer science: Understanding experiments better

New techniques and applications of atomistic molecular simulation methods a re reported. Their aim is to provide a better understanding of the molecula r basis of experimental results. To this end, calculations are performed of experimentally measurable observables. These are then compared to experime ntal results, thus validating the computational models and procedures. Fina lly, the simulations are analysed for the atomistic structural and dynamica l properties that give rise to the experimental observation. In this way, t he model assumptions commonly used in interpreting experimental raw data ar e avoided. Two examples are given: the free volume in polymers probed by po sitron-annihilation spectroscopy and the local alignment of polymer chains inferred from NMR measurements.