The 320th MANA Special Seminar
Prof. Naoki Toshima & Prof. Jaime C. Grunlan
| Date | March 13, Wednesday |
| Time | 15:30-17:00 |
| Place | Auditorium, 1F, WPI - MANA Building, Namiki Site, NIMS |
Download PDF file for seminar info.
15:30-16:15
Metal Nanoparticles for Conversion of Material and Energy
Material and energy can control all the world of material. Thus, their conversion is a target of recent science and technology. Here we demonstrate metal nanoparticles play an important role as catalysts for material conversion and as components of organic thermoelectric materials for energy conversion. For fabrication of active catalysts, the structure of bimetallic nanoparticles was controlled to produce a core/shell structure and crown jewel structure. The catalyst with the latter structure, in which catalytically active Au atoms are located only at the top positions of a catalytically inactive Pd cluster, was extremely active for glucose oxidation. As for energy conversion between thermal energy and electricity, the hybridization of metal nanoparticles with conducting polymers was found to improve not only the electrical conductivity but also the Seebeck coefficient of the organic thermoelectric materials.
Speaker
Prof. Naoki Toshima, Dept of Applied Chemistry & Advanced Materials Institute, Tokyo University of Science Yamaguch, Japan
Chair
Dr. Katsuhiko Ariga, MANA PI, MANA, NIMS
16:15-17:00
Polyelectrolyte-Silicate Nanobrick Wall Thin Films for Flame Suppression, Gas Barrier and So Much More…
Layer-by-layer (LbL) assembly is wide-reaching conformal coating “platform” technology capable of imparting a multiplicity of functionalities on nearly any type of surface in a relatively environmentally friendly way. At its core, LbL is a solution deposition technique in which layers of cationic and anionic materials (e.g. colloidal or nano-particles, polymers, metal ions, and even biological molecules) are built up via electrostatic attractions in an alternating fashion while controlling process variables such as pH, coating time, and concentration. Using this technique, films having precise optical, electrical, biomedical, flammability, antimicrobial, and barrier properties have been demonstrated to date.
At the Polymer NanoComposites (PNC) Laboratory at Texas A&M we are producing nanocomposite films having 10 – 96 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 highly flammable foam and fabric by uniformly coating the complex three-dimensional geometries. In the case of cotton fabric, each 10 mm fiber is individually coated to create a nano brick wall shield. On foam, these coatings can simultaneously cut the heat release rate (HRR) in half, relative to uncoated foam, and eliminate melt dripping without adding halogenated flame retardants. We’ve also developed intumescent recipes that do not require clay, but rather rely on the foaming action of phosphorus and nitrogen-rich molecules. I’ll also describe how the LbL process can produce carbon nanotube films with low sheet resistance (< 100 W/sq) and visible light transmission above 85%. 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 several times in Chemical & Engineering News as well as highlighted in Nature, ScienceNews and various other scientific news outlets.
Speaker
Prof. Jaime C. Grunlan, Dept of Mechanical Engineering and Dept of Chemical Engineering & Materials Science and Engineering Program, Texas A&M University, USA
Chair
Dr. Katsuhiko Ariga, MANA PI, MANA, NIMS