458775 Understanding and Engineering Heterogeneous Materials at the Molecular Level

Wednesday, November 16, 2016: 8:40 AM
Imperial A (Hilton San Francisco Union Square)
Bradley F. Chmelka, Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA

Self-assembly or crystallization from solutions, melts, or solids involve complicated thermodynamic, kinetic, and mass transport effects that are challenging to elucidate and control, even more so in the presence of functional solute species. Such processes are central to the syntheses and resulting properties of diverse inorganic, organic, and inorganic-organic hybrid materials, the understandings of which are often elusive because of their heterogeneous, multicomponent, and/or non-equilibrium characters. The challenges are exacerbated by the complex order and disorder that additionally result from distributions of functional species and environments or the roles of surfaces, which can have large influences on macroscopic material properties and device performances. This is the case for many heterogeneous materials with important engineering applications, such as catalysts for hydrocarbon conversion or pollution abatement, advanced structural solids, membrane materials for electrochemical devices, and materials for harnessing solar energy. By using a combination of spectroscopic, scattering, and bulk property measurements, such materials can be probed over multiple length and time scales to correlate their compositions and structures with their macroscopic properties and functions. In particular, advancements in solid-state nuclear magnetic resonance spectroscopy, especially the availability of ultrahigh magnetic fields and dynamic-nuclear-polarization-enhancement techniques, enable new insights to be obtained on the local environments, interactions, and distributions of functional species in bulk solids or near surfaces. Recent results will be presented on the molecular-level properties of self-assembled or semi-crystalline inorganic, organic, and hybrid materials, which provide new understanding to guide their rational design and syntheses for chemical engineering applications.

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