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William B Euler

Publications and source records attributed to William B Euler.

6 recordsLinked to original sources
PubMed2006

Photoactuation from a carbon nanotube-nafion bilayer composite.

A bilayer composite of single walled carbon nanotubes (SWNTs) deposited onto Nafion exhibits substantial mechanical motion upon exposure to visible or near-infrared light. The magnitude of the actuation parallels the absorption spectrum of the SWNTs in the near-infrared, but the actuation diminishes in the visible and disappears in the UV portions of the spectrum. In the near-infrared region, the photoactuation is linear with respect to the light intensity. The photoactuation also appears to be associated with a photocurrent across the nanotube/Nafion interface. The proposed mechanism for the actuation is that band bending of the semiconducting SWNTs induces polarization of mobile hydrogen ions at the Nafion interface, which then causes swelling of the polymer.

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PubMed2005

Bis(phosphine imide)s: easily tunable organic electron donors.

[graph: see text] The electrochemical, structural, and spectroscopic properties of bis(phosphine imide)s have been investigated. p-Phenylenebis(phosphine imide)s Ar3PNC6H4NPAr3 (1a-d) have two reversible single-electron oxidations. The first oxidation potentials can be varied from -0.05 to 0.15 V (versus SCE) by modification of the substituents on phosphorus (Ar). Electron-donating substituents lower the oxidation potential, while electron-withdrawing substituents increase the oxidation potential. The difference between the first and second oxidation potential (deltaE, 0.41-0.50) and the electronic coupling (Hab, 1.1 eV) are similar for 1a-d. Computational (DFT) and UV-visible-NIR spectroscopic investigations of 1a-d suggest that the first oxidation leads to a delocalized radical cation 1a*+ while the second oxidation leads to a quinonoidal dicationic state 1a2+. The aromatic linker between phosphine imides has also been modified. Upon oxidation, N,N'-4,4'-biphenylene(bis(triphenyl)phosphine imide) (3) forms radical cationic and a dicationic species similar to 1a-d. While deltaE (0.18 V) and Hab (0.63 eV) are smaller, suggesting weaker electronic communication between the two P=N units in the radical cationic state, the presence of NIR absorptions with vibrational fine structure (768, 861, and 983 nm) supports the formation of delocalized radical cation for 3*+.

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PubMed2004

Electromechanical actuation of composite material from carbon nanotubes and ionomeric polymer.

An actuating system composed of nafion ionomeric polymer coated with single-walled carbon nanotubes electrodes was studied as an electromechanical actuator. The actuator gives a sizable mechanical response to low voltages (turn-on voltage of approximately 2.5 V) under open-air conditions, i.e., in the absence of a surrounding supporting electrolyte. The actuator is active under both dc and ac bias and has a strong resonance at low frequencies which is dependent upon the size of the actuator. The actuator was studied using Fourier transform infrared and vis-NIR spectroscopies, cyclic voltammetry, and by the current-time response under an applied step voltage. An analytical model is proposed to understand the electrical behavior, which is consistent with the spectroscopic results.

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PubMed2003

Synthesis and solution characterization of [Ru(bpy)2]2+ modified polyazines.

A series of [Ru(bpy)(2)](2+) complexes linked by a controlled number of azine units (one to seven) were synthesized and studied in the solution phase. Polymers and dimer model compounds were examined by cyclic voltammetry and IR, NMR, and visible-NIR spectroscopies. The NMR spectra and the cyclic voltammograms indicated that the Ru(2+) sites influenced the main chain properties at least 15 A from the metal site. The first oxidation in each material was assigned to a ligand-centered process, but DFT calculations suggested that the Ru(2+) has an important influence. The first oxidized state of the polymers has a spectroscopic band that is consistent with an intervalence transfer (IT) transition, but this absorption is not seen in the dimer model compounds. Thus, the IT feature is assigned to a ligand-ligand transition that spans several repeat units in the polymer.

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