Note: Coffee and snacks will precede the seminar at 3 p.m. in the Ford ES&T first-floor atrium

Monirosadat (Sanaz) Sadati, Assistant Professor, University of South Carolina

"3D Printing-guided Chiral Self-assembly in Cellulose-based Constructs"

Abstract: The emergence of three-dimensional (3D) printing has advanced the fabrication of on-demand architectures for various applications, from functional devices to organs. However, 3D printing is limited to feature size and lacks the nanoscale design of the constituents vital for functional devices. In this talk, I will present how combining the "bottom-up" molecular self-assembly with a "top-down" manufacturing strategy can be exploited to program nanoscale chiral arrangements in cellulose-based constructs. The chiral or helical arrangement, in which layers of nanoparticles/fibers are slightly twisted by a fixed angle relative to the neighboring layers, is known as the origin of the superior fracture resistance of the mineralized chitin in the "smasher-type" mantis shrimp's dactyl club and the vivid metallic colors in beetles. We design our chiral inks based on cellulose nanocrystals and ether variants of cellulose to imprint nano- and microscales chiral self-assembly with controlled helical pitch length. We exploit the flow-induced alignment intrinsic to the printing process to direct hierarchical chiral self-assembly in the printed constructs. By tuning the ink formulation, its rheological properties, and printing parameters, we have been able to print architectures with the organized built-in chiral nanostructure. Our biomimetic concept will open the path to developing materials with new optical (dynamic color and photonic properties) and mechanical (toughness, strength) properties, naturally emerging from their nanostructure and transferred into the larger scale printed architectures, expanding 3D printing material technologies well beyond what has been conceived and attempted so far, into a new generation of composite and process design.

Bio: Dr. Monirosadat (Sanaz) Sadati has served as an Assistant Professor in the Department of Chemical Engineering at the University of South Carolina since 2019. She earned her doctorate in Materials Science and Polymer Physics from ETH Zürich in Switzerland, where she studied the complex flow of polymer melts under the guidance of Prof. Hans Christian Oettinger. Dr. Sadati was honored with two Swiss National Science Foundation Postdoctoral Fellowship awards, allowing her to conduct research at Harvard. She then moved to the University of Chicago, where she worked with Prof. Juan de Pablo focusing on liquid crystals. Her current research focuses on the emerging area of and guided self-assembly of anisotropic materials and bio-inspired structured materials design using 3D printing technologies for applications in photonics, sensing, tissue engineering and energy. She received NSF CAREER award in 2021 to study chiral liquid crystalline materials and develop a fundamental understanding of their crystallization and optical behavior within curved confinement.