Description:

Abstract: Single crystals and bespoke textures in self-assembled soft materials

We examine strategies for directing self-assembly in nanostructured soft materials to create single crystals and bespoke textures. Our work elucidates physical processes that are relevant for such directed self-assembly, in part by leveraging in situ scattering tools, with an overall goal of exploiting fundamental understanding to create useful materials or devices. In particular, we consider the use of magnetic fields and confinement effects for directed self-assembly of soft mesophases of block copolymers and discotic liquid crystals. The ability to produce highly ordered functional materials over macroscopic length scales is demonstrated. We explore the role of alignment and connectivity in creating materials with highly anisotropic ion transport, and in creating highly selective nanofiltration membranes with uniformly aligned nanopores produced by molecular self-assembly. Application of orthogonal fields, and field processing across sequential phase transitions enables a novel realization of macroscopic single crystals of self-assembled mesophases with precisely specified texture. Recent progress on low field (sub-1 T) alignment and the associated potential to develop bespoke textures in block copolymers using local field screening are presented.

Bio: Prof. Osuji received his B.S. in Materials Science and Engineering from Cornell University with a senior thesis on the use of random copolymers for polymer interface reinforcement supervised by Prof. Edward J. Kramer. He received his PhD in Materials Science and Engineering from MIT in 2003 for studies of structure-property relationships and self-assembly of liquid crystalline block copolymers, supervised by Prof. Edwin L. Thomas. After MIT he spent 2 1/2 years as a Senior Scientist at a start-up company, Surface Logix Inc., where he conducted research on the use of soft lithography, microfluidics and surface patterning for fabricating cell-based assays, planar waveguides and other devices. Prof. Osuji conducted post-doctoral work on shear induced structure formation and dynamics of colloidal gels with Prof. David A. Weitz in Applied Physics at Harvard from 2005-2007. In 2007 he joined the faculty at Yale University and is currently an Associate Professor in the Department of Chemical and Environmental Engineering. In July 2018 he will join the faculty as a Professor of Chemical and Biomolecular Engineering at the University of Pennsylvania. He leads an experimental research group focused on structure and dynamics of soft matter and complex fluids. Topics of interest include structure-property relationships in ordered soft materials, directed self-assembly of block copolymers and other soft mesophases, and rheology and slow dynamics of disordered systems.
Prof. Osuji is the recipient of a CAREER award from the National Science Foundation (2008) and the 2010 Arthur Greer award of Yale College. He received an Office of Naval Research's Young Investigator award and a 3M Nontenured Faculty award in 2012. He is the 2015 recipient of the Dillon Medal of the American Physical Society and the 2015 Hendrick C. Van Ness Award.