Multicomponent polymeric materials are widely used in various modern technologies and will have even broader applications in future technologies, from lightweight materials, to solar cells and electrical energy storage to biomedical technologies. Yet, our fundamental understanding of the processes and interactions that control macroscopic properties in these materials remains limited. The overarching goal of the research is to develop a fundamental understanding of how interfacial properties and interactions affect structure, morphology, dynamics, and macroscopic properties of multicomponent polymeric systems, in both the liquid and solid states. The research focuses on two themes. The first seeks to correlate structure-property relationships in polymer-nanoparticle mixtures to the nanoparticle structure and interfacial interactions, while the second involves the correlation of molecular architecture, electrostatic interactions and external fields to the morphology of multiblock copolymer materials, including both neat block copolymers and those containing discrete nanoparticles. To fully understand the underlying processes and mechanisms, we will pursue a comprehensive interdisciplinary approach lead by advanced theory and simulations, precise synthesis with nano-scale control and state-of-the-artcharacterization (with special emphasis on neutron scattering). The fundamental knowledge developed in this program will contribute to the scientific foundation for the rational design of multicomponent polymer based materials with superior properties and function that can address many DOE challenges such as organic photovoltaics, fuel cell membranes, and stronger light-weight materials that result in energy savings.