Alejandro D. Rey, McGill University

Modeling liquid crystal materials and processes in biological systems

Friday January 18th, 4pm, Phillips 332
(refreshments served in Phillips 330 starting at 3:30)

Abstract: Liquid crystal phases are found in DNA, proteins, lipids and polysaccharides. Frozen-in, chiral liquid crystal ordering also occurs in solid biocomposites such as insect cuticle, muscle, plant cell walls and collagen, where the helicoid structure is believed to arise by self-assembly processes. Spinning of silk fibers by spiders is another biological polymer process that relies on liquid crystal self-assembly. After discussing models of biological liquid crystal self assembly, thermodynamics, interfaces, defects and spreading flow, I will present the progress and challenges of modeling in two applications:

(1) Biological helicoids form by directed self-assembly. Theory and computer simulation of chiral phase ordering show that the directed self-assembly process reproduces the natural structures. The computational results shed light on the role of chiral ordering on the formation of helicoidal monodomains.

(2) Spinning of spider silk involves a complex sequence of phase transitions that includes nematic phase ordering in the duct section of the spinning apparatus. Simulation of phase ordering under capillary confinement replicates the observed structures found in Nephila clavipes and other orb-weavers. The computational results shed light on the role of defect textures in the fiber spinning process.

ALEJANDRO D. REY
Department of Chemical Engineering
McGill University
Montreal, Quebec, Canada H3A2B2
e-mail:alejandro.rey@mcgill.ca
phone:514-398-4196

ALEJANDRO D. REY received his B.S. in chemical engineering from the City College of New York in 1985, where he was salutatorian of the college. He earned his Ph.D. in chemical engineering at the University of California, Berkeley under the supervision of Professor Morton Denn in 1988. Dr. Rey has been a faculty member at McGill University since 1988 and is now professor of chemical engineering and executive member of the McGill Advanced Materials Institute. He is a member of the McGill Center for Nonlinear Dynamics in Physiology and Medicine, the McGill Center for Self-Assembled Chemical Structures, the NSF-Engineering Research Center for Advanced Fibers and Films at Clemson University, and serves on the editorial board of Design and Nature. He has authored over 240 refereed papers and book chapters, and given close to 50 invited talks.

Professor Rey’s accomplishments have been recognized through several professional awards, including the James McGill Chair in Chemical Engineering, and the 1993 Class of ’51 Outstanding Teacher Award from McGill’s Faculty of Engineering. Five of his former graduate students and postdoctoral fellows are engineering academics in Japan, South Korea, Brazil, and Canada.