Polymer scientist recognized for work ranging from superconductors, to polymer mechanical behavior, to templated self-assembly. Pioneered the use of sophisticated characterization tools (e.g., Rutherford backscattering, holographic interferometry, and neutron reflectivity) to make state-of-the-art measurements on microstructure and dynamic behavior with unsurpassed temporal and spatial resolution. Work permitted critical testing of many essential concepts: for example, the reptation theory of diffusion of entangled chains. Work on mechanical properties, on control of microstructure formation, and on phase-transition problems in thin films has led to fundamental and applied discoveries, including demonstration of vastly improved fracture toughening by cross-linking and sequestration of block polymers to polymer-polymer interfaces. Authored nearly 500 research papers, organized more than a dozen symposia, and has served extensively as an advisor to universities and the government. Honors include a Guggenheim Fellowship and a Humboldt Senior Scientist Award.