Despite their natural abundance and wide industrial applications, such as red blood cells and clay, disks are the least studied colloidal systems compared to geometries like spheres and rods. We have established methods to fabricate and control the size, aspect ratio, and polydispersity of disks and systematically investigate their effects on discotic liquid crystal phase transitions. This talk will focus on surface controlled shape design of discotic microparticles using phase changing emulsions and the observation of the discotic smectic phase using nanoplates with identical thickness. Recent results such as discotic liquid crystals emulsions, gelation via ionic exchange, depletion attraction induced liquid crystal phase transition, iridescence from layered structure, and nematic hydrogels will briefly presented. Comprehensive understanding of the colloidal discotics in terms of complex fluids behaviors and liquid crystal transitions will help establish theory for model atomic liquid crystals and develop industrial applications.
Professor Cheng obtained his PhD degree from the Physics Department of Princeton University in 1999. He has his MS degree from the Institute of High Energy Physics (Beijing) in 1993 and BS degree from the Modern Physics Department of University of Science and Technology of China in 1990. He was a postdoctoral fellow of ExxonMobil Research and Engineering Company (Annandale, New Jersey, USA), and Harvard University (with Prof. Dave Weitz). He joined Texas A&M University as an Assistant professor in the Artie McFerrin Department of Chemical Engineering in August 2004 and was promoted to Associate professor in 2010. He is also a faculty member of the Materials Science and Engineering Program and the Professional Program in Biotechnology of TAMU. Professor Cheng’s expertise is in the area of complex fluids and soft condensed matter physics. He has published over 60 papers in journals including Nature, Science, and Physical Review Letters.