This GOALI project is a collaboration between academia and industry. Its objective is to prototype a new paradigm for materials research based on the synergistic application of molecular level simulation and experimental testing, to identify the essential relationships between molecular structure, morphology and performance. In the program proposed here, this paradigm will be realized through the discovery and development of additives (e.g. nucleating agents, clarifiers) that alter the morphology and properties of plastics. Molecular simulations will be used to survey existing and hypothetical additives, to demonstrate speed-up and to identify sensible trends in crystallization kinetics. In-depth evaluation of selected additives will be used to demonstrate refinement of the process of discovery and to identify the precision with which current simulations can distinguish the effects of different additives. Experimental rheological and structural characterization will be used to validate heuristics and to establish the connection between crystallization kinetics and ultimate morphologies and properties.