19 November 2007, Prof. Alejandro Rey

abstract and short biography

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. I will discuss the progress and challenges of modeling in three 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 spider silk fiber spinning process.

(3) Chiral self-assembly, defect textures, and wetting in DNA solutions. Multiscale modeling and simulation shed some light on how concentrated DNA solutions form chiral liquid crystals, how phase ordering leads to characteristic defect textures, and how flow effects during wetting leads to orientational transitions.

Alejandro Rey received his B.S. in chemical engineering from the City College of New York and earned his Ph.D. In chemical engineering at the University of California, Berkeley. 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 257 refereed papers and book chapters, and given 68 invited talks. Professor Rey's accomplishments have been recognized through several profes­sional awards, including the 20th Olaf Hougen Professorship at the University of Wisconsin, 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.