Glenn Fredrickson

Glenn H. Fredrickson, Ph.D.
Mitsubishi Chemical Professor, University of California, Santa Barbara
Chemical Engineering
Fredrickson Research Group

Abstract: Modeling asymmetric polymer membrane formation processes: NIPS, SNIPS and all that
Porous polymer membranes play an important role in gas and liquid separation technologies, and as separators and reactive manifolds in electrochemical devices. An important class of membranes are asymmetric, having a gradient of pore size across the membrane and allowing for favorable combinations of high selectivity and high permeability. Many such membranes are manufactured by a process of non-solvent induced phase separation (NIPS) in which a non-solvent bath is used to precipitate a polymer film containing polymer and a good solvent. A recent innovation replaces the polymer with a block copolymer that can self-assemble to form highly uniform 10 nm scale pores at the surface of the film, further enhancing membrane selectivity (SNIPS). While NIPS is practiced commercially and SNIPS is under active development, both processes are poorly understood and the final membrane structure is dictated by a complex interplay of convective and diffusive transport, macro and micro-phase separation in multicomponent systems, thermal agitation, and structural arrest by vitrification.

This talk will summarize our recent progress in developing dynamic phase-field models of the NIPS and SNIPS processes, driven by thermodynamic forces that faithfully describe the rich thermodynamic landscape of the film and bath environments. We have identified the essential ingredients for achieving asymmetric pores in NIPS, and are beginning to understand the interplay of solvent selectivity and volatility, block copolymer architecture, and dry annealing on the membrane morphology in SNIPS.

Biography:
Glenn H. Fredrickson is a soft matter theorist recognized for his work on self-assembling polymers, especially block copolymers. He pioneered a “field-theoretic simulation” technique involving a direct numerical attack on field theory models that has been widely deployed to assess the structure and phase behavior of complex, multiphase polymer systems. Fredrickson was born in Washington, D.C., and grew up in Indialantic, Florida. He graduated from the University of Florida with a B.S. degree in chemical engineering and received M.S. and Ph.D. degrees in the same discipline from Stanford University. In 1984, he joined AT&T Bell Laboratories as a Member of Technical Staff, and moved to the University of California, Santa Barbara (UCSB) in 1990 as a Professor of Chemical Engineering and Materials. Fredrickson is currently a Distinguished Professor at UCSB and a Member of the Board of Mitsubishi Chemical Holdings Corporation, where he was previously Chief Technology Officer. He is a member of both the National Academy of Sciences and the National Academy of Engineering.