30 likes | 148 Views
Shape and Aggregation Control of Nanoparticles: Not Shaken, Not Stirred. P.I.: Richard B. Kaner, UCLA Program Director: Dr. Andrew J. Lovinger NSF DMR-0507294. with stirring. no stirring.
E N D
Shape and Aggregation Control of Nanoparticles: Not Shaken, Not Stirred P.I.: Richard B. Kaner, UCLA Program Director: Dr. Andrew J. Lovinger NSF DMR-0507294 with stirring no stirring Rapid stirring during synthesis leads to homogeneous nucleation and the growth of more nanofibers, while stirring leads to heterogeneous nucleation and produces large aggregates as shown for polyaniline. Although counter intuitive (consider shaking orange juice to break up aggregation) this finding may be quite general for nanoparticle synthesis as poly(m-toluidine) and silica nanostructures also aggregate when stirred during their synthesis.* *D. Li and R.B. Kaner J. Am. Chem. Soc., 128, 968-975, 2006. Most-Accessed J. Am. Chem. Soc. Article: January-March, 2006 See: http://pubs.acs.org/journals/jacsat/promo/most_accessed/index.html
The Intrinsic Nanofibrillar Morphology of PolyanilineP.I.: Richard B. Kaner, UCLA Program Director: Dr. Andrew J. Lovinger NSF DMR-0507294 We have discovered that nanofibers appear to be the intrinsic morphology of polyaniline when synthesized in water. During conventional synthesis, as oxidant is slowly added into a solution of monomer, secondary growth occurs which leads to agglomerated particles as seen in the TEM images presented in the Chemical Communications cover (on the left). We have developed two new synthetic approaches to suppress aggregation—1) interfacial polymerization and 2) rapid mixing (shown above). J. Huang and R.B. Kaner, Chem. Comm., 2006, 367-376.
Periodic Table of the Toys P.I.: Richard B. Kaner, UCLA Program Director: Dr. Andrew J. Lovinger NSF DMR-0507294 A just synthesized, warm polyurethane foam “milkshake” is passed around a special education class at Thomas Edison Middle School by PI Ric Kaner (below). The students each painted an element, e.g. Se for seal, to create a “Periodic Table of the Toys.” This 5’ X 8’ mural designed by Carol Salame, the president of the UCLA student affiliates chapter of the Am. Chem. Soc. now hangs permanently in the first floor corridor of Edison Middle School as an inspiration to future generations of budding scientists.