Researchers must find a sustainable way of providing the power our modern lifestyles demand.

Building better batteries

http://nathan.instras.com/ResearchProposalDB/doc-109.pdf

A review on polymer nanofibers by electrospinning and their applications in nanocomposites

The large-scale practical application of fuel cells will be difficult to realize if the expensive platinum-based electrocatalysts for oxygen reduction reactions (ORRs) cannot be replaced by other efficient, low-cost, and stable electrodes. Here, we report that vertically aligned nitrogen-containing carbon nanotubes (VA-NCNTs) can act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, and tolerance to crossover effect than platinum for oxygen reduction in alkaline fuel cells. In air-saturated 0.1 molar potassium hydroxide, we observed a steady-state output potential of –80 millivolts and a current density of 4.1 milliamps per square centimeter at –0.22 volts, compared with –85 millivolts and 1.1 milliamps per square centimeter at –0.20 volts for a platinum-carbon electrode. The incorporation of electron-accepting nitrogen atoms in the conjugated nanotube carbon plane appears to impart a relatively high positive charge density on adjacent carbon atoms. This effect, coupled with aligning the NCNTs, provides a four-electron pathway for the ORR on VA-NCNTs with a superb performance.

http://science.sciencemag.org/content/sci/323/5915/760.full.pdf

Nitrogen-doped carbon nanotube arrays with high electrocatalytic activity for oxygen reduction.

Research in the use of organic polymers as the active semiconductors in light-emitting diodes has advanced rapidly, and prototype devices now meet realistic specifications for applications. These achievements have provided insight into many aspects of the background science, from design and synthesis of materials, through materials fabrication issues, to the semiconductor physics of these polymers.

Electroluminescence in conjugated polymers

A general all-atom force field for atomistic simulation of common organic molecules, inorganic small molecules, and polymers was developed using state-of-the-art ab initio and empirical parametrization techniques. The valence parameters and atomic partial charges were derived by fitting to ab initio data, and the van der Waals (vdW) parameters were derived by conducting MD simulations of molecular liquids and fitting the simulated cohesive energies and equilibrium densities to experimental data. The combined parametrization procedure significantly improves the quality of a general force field. Validation studies based on large number of isolated molecules, molecular liquids and molecular crystals, representing 28 molecular classes, show that the present force field enables accurate and simultaneous prediction of structural, conformational, vibrational, and thermophysical properties for a broad range of molecules in isolation and in condensed phases. Detailed results of the parametrization and validation f...

COMPASS: An ab Initio Force-Field Optimized for Condensed-Phase ApplicationsOverview with Details on Alkane and Benzene Compounds

We present in this paper the results of a detailed neutron scattering investigation at various temperatures of the dynamical properties of the linear-mercury-chain compound ${\mathrm{Hg}}_{3\ensuremath{-}\ensuremath{\delta}} \mathrm{As}{\mathrm{F}}_{6}$. The main emphasis has been put on the nature of the response function of the Hg chains at higher temperatures ($T\ensuremath{\gtrsim}150$ K). The results are analyzed and discussed in terms of new theoretical results obtained by Emery and Axe, and it is found that the behavior of the Hg chains in this temperature region is one-dimensional liquidlike, in accordance with theoretical predictions. Below ${T}_{c}=120$ K where three-dimensional long-range order is established among the Hg ions, the transverse phononlike excitations in the Hg chains with displacement along the chain develop a small (\ensuremath{\sim} 0.1 meV) energy gap at finite wave vector. This feature makes it straightforward to demonstrate the absence of elastic scattering in the sheets of scattering from the Hg chains. We have measured at room temperature acoustic As${\mathrm{F}}_{6}$ sublattice phonons in the $\ensuremath{\Delta}(\ensuremath{\zeta}00)$ and the $\ensuremath{\Lambda}(00\ensuremath{\zeta})$ directions. The observed dispersion slope of the transverse branch along $\ensuremath{\Delta}$ polarized along $\ensuremath{\Lambda}$ is about 25% smaller than that of the transverse branch along $\ensuremath{\Lambda}$ polarized along $\ensuremath{\Delta}$, in apparent disagreement with elasticity theory which predicts both modes to be governed by ${C}_{44}$. We show that this behavior can be qualitatively explained by the anisotropic coupling between Hg chains and the host lattice, leading to a much smaller elastic regime in the $\ensuremath{\Lambda}$ direction than in the $\ensuremath{\Delta}$ direction.

Neutron investigation of the dynamical properties of the mercury-chain compound Hg/sub 3delta/ AsF/sub 6/

Sensors using octaaniline for volatile organic compounds

Trans-polyacetylene, (CH)x, can be p-doped (oxidized) to the metallic regime by gaseous oxygen in the presence of an aqueous solution of a non-oxidizing acid such as HBF4. The oxygen oxidizes the (CH)x to (CHy+)x while the HBF4 supplies a stable fluoroborate counter-anion to give a species such as [CHy+A–y]x(y≈ 0.02; A–= fluoroborate). The doping process is consistent with the reduction potentials of (CH)x and O2 in acid solution. In the absence of the acid, oxygen reacts irreversibly with the semiconducting (CH)x to destroy its conductivity. The [CHy+A–y]x formed above may be connected to a lead anode in a HBF4 electrolyte whereupon it is reduced to (CH)x with concomitant production of an electric current. If oxygen is bubbled over the (CH)x during this process it is continuously electrochemically reduced by the lead as rapidly as it is oxidized chemically by the oxygen. The (CH)x therefore acts as a catalyst electrode: a ‘fuel-cell’ electrode for the room-temperature reduction of O2 to H2O at atmospheric pressure. The overall reaction does not occur to any significant extent in the absence of the (CH)x.

Alan G. MacDiarmid

Papers

Neutron investigation of the dynamical properties of the mercury-chain compound Hg/sub 3delta/ AsF/sub 6/

Sensors using octaaniline for volatile organic compounds

p-Doping of (CH)x to the metallic regime with gaseous oxygen. Application to oxygen fuel-cell-type electrodes

Ring-rotational defects in polyaniline

A solid-state NMR investigation of the structure and dynamics of polyanilines