Seminar: Dr. Jaime GRUNLAN, Texas A&M, Polymer NanoComposites Laboratory
Professor Jaime Grunlan will give a talk entitled « Nanobrick Walls for Gas Barrier and Flame Suppression and Polymer Nanocomposites for Thermoelectric Energy Conversion« , Tuesday 10th of July, 9:00am (room Sci1 009)
Abstract:The first part of this talk involves making multifunctional thin films, using layer-by-layer (LbL) assembly, within the Polymer NanoComposites (PNC) Laboratory (http://nanocomposites.tamu.edu/).
LbL deposition involves exposing a substrate (e.g., plastic film, fabric, glass, etc.) to solutions of oppositely charged ingredients. Each anionic (e.g., clay) and cationic (e.g., polyethylenimine) layer is 1 – 100 nm thick depending on a variety of deposition conditions. We are producing nanocomposite films, with 10 – 80 wt% clay, that are completely transparent and exhibit oxygen transmission rates below 0.005 cm3/m2•day at a film thickness below 100 nm. These same “nano brick wall” assemblies are very conformal and able to impart flame resistance to foam and fabric by uniformly coating them three-dimensionally. In the case of cotton fabric, each 10 μm fiber is individually coated to create a nano brick wall shield. On foam, these coatings can cut the heat release rate (HRR) in half, relative to uncoated foam, and eliminate melt dripping.
If there is time, I’ll describe segregated network (latex-based) composites containing carbon nanotubes (used to produce electricity from a thermal gradient). Thermoelectric materials harvest electricity from waste heat (or any temperature gradient in the environment). Nanotube-filled polymer composites can be viable for energy conversion. By combining double-walled carbon nanotubes (DWNT), stabilized with poly(3,4- ethylenedioxythiophene): poly(styrene sulfonate) in water, an electrical conductivity (σ) near 2000 S/cm is achieved in a poly(vinyl acetate) latex-based matrix. When combined with a Seebeck coefficient (S) above 40 μV/K, a power factor (S2σ) above 370 μW/m·K2 is achieved at room temperature. All of the materials described are water-based and processing occurs under ambient conditions in most cases. Our work in these areas has been featured numerous times in C&EN and also highlighted in Nature, ScienceNews and various other scientific news outlets.
