Issues : Control of chain organization, alignment

1. N N Si Y N Polymer Quantum Dots Computational Nanochemistry optical characterization by emission pattern imaging: MEH-PPV nanoparticles act like single (z-oriented) atoms! - signature of quantum dot behavior synthetic methodology: nanoparticle generation of semiconducting polymers (MEH-PPV) from microdroplets of dilute of solution - 3-D confinement should produce rod-shaped nanocrystalline particles • For both the pyrolysis and polymerization reactions, the reaction kinetics are inhibited in the interior of the carbon nanotube • This effect is much larger in the polymerization reaction Goal: To make polymer analogues of inorganic semiconductor quantum dots without specialized synthetic chemistry Typical conformation of C20H42 inside a (7,7) carbon nanotube and in vacuum • Issues: • Control of chain organization, alignment • Optical signature of ‘artificial atom’ behavior in polymer nanoparticles? • Questions: • Choice/range of materials? • How might polymer q-dots differ from inorganic dots (morphology, orientation, etc.)? • Applications: • Nanophotonics - tunable optical interface to nanoworld • Molecular wires for nanoscale computing • Bioconjugate (fluorescent marker) applications Weight-averaged molecular weight for the polymerization of polyethylene in various geometries at 3200K. The reaction proceeds much more slowly in the nanotube. Temperature dependence of the kinetics for polymeriza-tion of ethylene in various geometries. The kinetics are faster by more than an order of magnitude in the bulk. Polymer Normal Modes Ceramic Properties Is it possible to simulate properties of experimentally designed complex polymer structures? Correlation between measured aspect ratios and the energycalculated in local density formalism. Polymer structures involve tens of thousands of monomer units. Dynamic studies involve coupled motions of thousands of bodies. Normal modes involve generation and processing of extremely large, sparse matrices. Applications include modeling properties of designed polymer structures Funding Sources High impact work, recently featured in such places as The Journal of Physical Chemistry Schematic of the contrasting intergranular film segregation behavior of Lu and La in SiO2-rich glassy triple pockets, according to proposed theoretical model. Strong Y-N bonding is consistent with an observed increase in fracture toughness