Levich Institute Seminar Announcement, 02/26/2008
Tuesday, 02/26/2008
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Dr. Shahab Shojaei-Zadeh
City College of CUNY
Levich Institute

"Confinement and Flow of Microscopic Defects in Layered Liquids"


ABSTRACT


The term layered liquids applies to a broad range of materials containing anisotropic molecules that arrange themselves in parallel stacks. Examples are concentrated surfactant solutions, block copolymers, bio-membranes, liquid crystalline polymers, and liquid crystals. Due to the solid-like nature of these materials, microscopic defects form when their parallel layer structure is disturbed by external forces, surface interactions, or geometrical confinement. Unlike in solid crystals, defects formed here can flow and we show that the presence of defects change flow characteristics of these materials. In this talk, different methods for controlling the size and ordering of a particular class of defects known as focal conics are presented. The flow behavior of these defects in microchannels is then examined. A microfluidic network is designed and developed to enable a precise control over the pressure driven flow. Driving flow within this micro fluidic network enables simultaneous visualization of the defect texture evolution and measurement of the pressure gradient - flow rate relationship.

BRIEF ACADEMIC/EMPLOYMENT BACKGROUND:

Shahab Shojaei-Zadeh is originally from Isfahan, Iran. He received his B.S. and M.S. in Mechanical Engineering, from Isfahan University of Technology and Sharif University of Technology respectively. He then joined Prof. Shelley Anna's Micro Complex Fluids Laboratory at Carnegie Mellon and obtained his PhD in 2007. He is currently a Levich Fellow in the Benjamin Levich Institute. His research interests include microfluidics, interfacial fluid mechanics, self-organizing systems, and bio-MEMS.