Search

Your search keyword '"Rosa, Luis G."' showing total 45 results
Start Over Author "Rosa, Luis G."
45 results on '"Rosa, Luis G."'

6. Crystalline ice grown on the surface of the ferroelectric polymer poly(vinylidene fluoride) (70%) and trifluoroethylene (30%)

Author

Rosa, Luis G., Xiao C. Zeng, Jie Xiao, Dowben, Peter A., Losovyj, Yaroslav B., Yi Gao, and Yakovkin, Ivan N.

Subjects
Polymers -- Electric properties, Polymers -- Chemical properties, Polyvinylidene fluoride -- Electric properties, Polyvinylidene fluoride -- Chemical properties, Ethylene -- Electric properties, Ethylene -- Chemical properties, Chemistry
Abstract

Water ice is observed at the copolymer ferroelectric poly(vinylidene difluoride-trifluoroethylene P(VDF-TrFe 70:30) surface and the growth of crystalline thin films of water on these polymer surfaces implicates water to polymer dipole interactions. The occurrence of these interactions enables water to act as a spectator to surface ferroelectric transitions in the system.

Published
2005

7. Water adsorption on and desorption from crystalline copolymers of vinylidene fluoride with trifluoroethylene

Author

Rosa, Luis G., Jacobson, P.A., and Dowben, P.A.

Subjects
Thermal desorption -- Usage, Ethylene -- Chemical properties, Ethylene -- Thermal properties, Chemicals, plastics and rubber industries
Abstract

The study examined water adsorption on crystalline polyvinylidene fluoride with 30% trifluoroethylene, P(VDF-TrFE, 70:30) by thermal desorption spectroscopy. It identified two distinctly different water desorption, one adsorbed species that resembles ice and another species that interacts more strongly with the polymer thin film.

Published
2005

9. Evidence for an influence of local dipole excitations in thermal desorption

Author

Rosa, Luis G., Jacobson, P.A., and Dowben, P.A.

Subjects
Ferroelectric crystals -- Chemical properties, Ferroelectric crystals -- Atomic properties, Dielectric films -- Chemical properties, Dielectric films -- Atomic properties, Thin films -- Chemical properties, Thin films -- Atomic properties, Electron configuration -- Analysis, Chemicals, plastics and rubber industries
Abstract

Ferroelectric crystalline copolymer films of vinylidene fluoride with trifluoroethylene strongly interact with the dipoles of adsorbed and absorbed water molecules. The electronic structure of the ferroelectric copolymer films of vinylidene fluoride with trifluoroethylene films is locally altered with incident UV radiation suggesting metastable excited states that may involve dipole reorientation

Published
2006

10. H/D isotopic exchange in water interactions with the ferroelectric copolymer: Poly(vinylidene fluoride-trifluoroethylene) (70%:30%)

Author

Rosa, Luis G., Yakovkin, I.N., and Dowben, P.A.

Subjects
Crystalline polymers -- Structure, Water -- Properties, Water -- Structure, Adsorption -- Analysis, Chemicals, plastics and rubber industries
Abstract

Two distinctly different adsorption sites are identified by thermal desorption spectroscopy for both water and heavy water adsorption and adsorption on crystalline poly(vinylidene fluoride with trifluorethylene (30%)), P(VDF-TrFE 70:30). It is found that there is H/D exchange between the water or heavy water molecules and the ferroelectric polymer (largely-(CH2-CF2)-), particularly at the polymer surface.

Published
2005

11. Vibrionic coupling in the valence band photoemission of the ferroelectric copolymer: Poly(vinylidene fluoride) (70%) and trifluoroethylene (30%)

Author

Rosa, Luis G., Losovyj, Ya B., Choi, Jaewu, and Dowben, P.A.

Subjects
Electrochemistry -- Research, Photoemission -- Research, Chemicals, plastics and rubber industries
Abstract

Two different vibrational contributions to the photoemission fine structure of the ferroelectric copolymer poly(vinylidene fluoride) with trifluoro [CH(sub 2)-CF(sub 2):CHF-CF(sub 2), 70%:30%] are identified. It was found that the contribution of one of vibrational mode to the photoemission fine structure decreases with decreasing temperature.

Published
2005

12. Nanoscale Fabrication of the Ferroelectric Polymer Poly(vinylidene Fluoride with Trifluoroethylene) P(VDF-TrFE) 75:25 Thin Films by Atomic Force Microscope Nanolithography

Author

Vega, Omar, Delgado, David, Wong, Freddy, Gonzalez, Rosette, and Rosa, Luis G.

Subjects
Article
Abstract

Thin films of an organic ferroelectric system, poly(vinylidene fluoride with trifluoroethylene) P(VDF-TrFE, Kureha Corporation, Tokyo, Japan) 75:25 layers, have been deposited on highly ordered pyrolytic graphite and silicon dioxide by the horizontal Schaefer method of Langmuir-Blodgett techniques. It is possible to "shave" or mechanically displace small regions of the polymer film by using atomic force microscope nanolithography techniques such as nanoshaving, leaving swaths of the surface cut to a depth of 4 nm and 12 nm exposing the substrate. The results of fabricating stripes by nanoshaving two holes close to each other show a limit to the material "stripe" widths of an average of 153.29 nm and 177.67 nm that can be produced. Due to the lack of adhesion between the substrates and the polymer P(VDF-TrFE) film, smaller "stripes" of P(VDF-TrFE) cannot be produced, and it can be shown by the sequencing of nanoshaved regions that "stripes" of thin films can be removed.

Published
2012

21. Back Cover: Approaching an organic semimetal: Electron pockets at the Fermi level for a p -benzoquinonemonoimine zwitterion (Phys. Status Solidi B 8/2012)

Author

Rosa, Luis G., primary, Velev, Julian, additional, Zhang, Zhengzheng, additional, Alvira, Jose, additional, Vega, Omar, additional, Diaz, Gerson, additional, Routaboul, Lucie, additional, Braunstein, Pierre, additional, Doudin, Bernard, additional, Losovyj, Yaroslav B., additional, and Dowben, Peter A., additional

Published
2012
Full Text
View/download PDF

28. The interface bonding and orientation of a quinonoid zwitterion

Author

Xiao, Jie, primary, Zhang, Zhengzheng, additional, Wu, Dong, additional, Routaboul, Lucie, additional, Braunstein, Pierre, additional, Doudin, Bernard, additional, Losovyj, Yaroslav B., additional, Kizilkaya, Orhan, additional, Rosa, Luis G., additional, Borca, Camelia N., additional, Gruverman, Alexei, additional, and Dowben, Peter A., additional

Published
2010
Full Text
View/download PDF

37. Electronic structure and vibrational spectra ofC2B10-based clusters and films

Author

Park, Kyungwha, primary, Pederson, M. R., additional, Boyer, L. L., additional, Mei, W. N., additional, Sabirianov, R. F., additional, Zeng, X. C., additional, Bulusu, S., additional, Curran, Seamus, additional, Dewald, James, additional, Day, Ellen, additional, Adenwalla, Shireen, additional, Diaz, Manuel, additional, Rosa, Luis G., additional, Balaz, S., additional, and Dowben, P. A., additional

Published
2006
Full Text
View/download PDF

43. Franck−Condon Coupling in Anthracene Isomer Self-Assembled Layers and Symmetry Effects on the High Resolution Ultraviolet Photoemission Spectra

Author

Rosa, Luis G., Jiang, Jinyue, Wong, Freddy Li, Xiao, Jie, Utreras, Emmanuel, Lima, Ocelio V., Alvira, Jose, Losovyj, Ya. B., and Tan, Li

Abstract

Franck−Condon coupling to the electronic structure of anthracene silane isomer complexes self-assembled on a silicon oxide surface has been measured by high-resolution photoelectron emission spectroscopy. Our results are in strong agreement with theoretical semiempirical calculations and gas phase measurements. The Franck−Condon vibronic fine structure observed in the high resolution photoemission spectra exhibits a strong dependence on the isomer, in particular, the anthracene functional group orientation with respect to the surface normal.

Published
2010
Full Text
View/download PDF

44. The elimination of the influence of ambient environmental effects on the structure of 'inert' polymers.

Author

Rosa, Luis G., Jacobson, P. A., Lemoine, Raymond, and Dowben, P. A.

Subjects
*POLYMERS, *THIN films, *X-ray diffraction, *VACUUM, *CRYSTALLOGRAPHY, *SURFACES (Technology)
Abstract

The construction and use of a vacuum chamber suitable for conventional X-ray diffraction has revealed the influence of the ambient environment, including moisture, on the bulk structure of very thin polymer films. It is concluded that studies of thin film organic systems, even those thought not to be perturbed by ambient water vapor and other contaminants, may benefit from undertaking some studies in such small sample vacuum chambers. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

45. Approaching an organic semimetal: Electron pockets at the Fermi level for a p -benzoquinonemonoimine zwitterion.

Author

Rosa LG, Velev J, Zhang Z, Alvira J, Vega O, Diaz G, Routaboul L, Braunstein P, Doudin B, Losovyj YB, and Dowben PA

Abstract

There is compelling evidence of electron pockets, at the Fermi level, in the band structure for an organic zwitterion molecule of the p -benzoquinonemonoimine type. The electronic structure of the zwitterion molecular film has a definite, although small, density of states evident at the Fermi level as well as a nonzero inner potential and thus is very different from a true insulator. In spite of a small Brillouin zone, significant band width is observed in the intermolecular band dispersion. The results demonstrate that Bloch's theorem applies to the wave vector dependence of the electronic band structure formed from the molecular orbitals of adjacent molecules in a molecular thin film of a p -benzoquinonemonoimine type zwitterion.

Published
2012
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results