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Full-Text Articles in Polymer Science
Poly(Meta-Phenylene Isophthalamide) Nanofibers: Coating And Post Processing, Wenxia Liu, Mathew Graham, Edward A. Evans, Darrell Hyson Reneker
Poly(Meta-Phenylene Isophthalamide) Nanofibers: Coating And Post Processing, Wenxia Liu, Mathew Graham, Edward A. Evans, Darrell Hyson Reneker
College of Polymer Science and Polymer Engineering
Electrospun nanofibers have applications in the areas of filtration, composites; biomaterials, and electronics. Controlling the surface properties of these nanofibers is important for many applications. Nanofibers can also be used as unique substrates for observing the growth of deposited films and creating nanoscale structures. In this work, electrospun poly(meta-phenylene isophthalamide) (MPD-I) nanofibers were used as substrates for creating nanoscale structures out of carbon-based materials and metals. MPD-I was used because it can be electrospun into nanofibers with diameters smaller than 10 nm and it has good thermal stability. MPD-I nanofibers were coated with carbon, copper, and aluminum using plasma enhanced …
A Device For Surface Study Of Confined Micron Thin Films In A Total Internal Reflection Geometry, Sergey Mamedov, Alexander D. Schwab, Ali Dhinojwala
A Device For Surface Study Of Confined Micron Thin Films In A Total Internal Reflection Geometry, Sergey Mamedov, Alexander D. Schwab, Ali Dhinojwala
College of Polymer Science and Polymer Engineering
A device to probe the molecular structure of materials next to a solid interface in a thin film geometry has been developed. The device can produce controlled thicknesses as small as 1 mum with parallelity better than 0.003degrees. We have shown that the thickness and the parallelity of the film produced between two optical surfaces can be quantified using white light and monochromatic light interferometry, respectively. In addition, this apparatus allows the study of these films in a static state or under shear using spectroscopic techniques involving transmission or reflection measurements. (C) 2002 American Institute of Physics.
Melting At Alkyl Side Chain Comb Polymer Interfaces, K. S. Gautam, Ali Dhinojwala
Melting At Alkyl Side Chain Comb Polymer Interfaces, K. S. Gautam, Ali Dhinojwala
College of Polymer Science and Polymer Engineering
Infrared visible sum frequency generation (SFG) spectroscopy has been used to study structure and melting transition temperatures of alkyl-side chain-acrylate comb polymers at air and solid interfaces. At the air interface, the SFG spectra show methyl bands and two transitions are observed: the first, near the bulk melting temperature, T-m, and the second 10-20degreesC higher than T-m. The shorter the alkyl side chain, the larger the difference between the two transition temperatures. In contrast, methylene bands are observed at sapphire interface with a single transition near T-m (C18).
Motion Of Droplets Along Thin Fibers With Temperature Gradient, Alexander L. Yarin, Wenxia Liu, Darrell Hyson Reneker
Motion Of Droplets Along Thin Fibers With Temperature Gradient, Alexander L. Yarin, Wenxia Liu, Darrell Hyson Reneker
College of Polymer Science and Polymer Engineering
Liquid n-decane, n-undecane, n-dodecane, and n-hexadecane formed tiny symmetrical droplets on a partially wettable cylindrical fiber. When a temperature gradient was created along the fiber, the droplets began to move along the fiber toward the cold region. An explanation of the phenomenon is related to the thermocapillary motion. Other possible mechanisms were ruled out. The theoretical results and experimental data agree reasonably well. (C) 2002 American Institute of Physics.
Two-Photon-Excited Green Emission And Its Dichroic Shift Of Oriented Thin-Film Cds On Glass Formed By Laser Deposition, B. Ullrich, R. Schroeder, H. Sakai, A. Zhang, Stephen Z. D. Cheng
Two-Photon-Excited Green Emission And Its Dichroic Shift Of Oriented Thin-Film Cds On Glass Formed By Laser Deposition, B. Ullrich, R. Schroeder, H. Sakai, A. Zhang, Stephen Z. D. Cheng
College of Polymer Science and Polymer Engineering
The photoluminescence of oriented thin-film CdS on glass formed by laser deposition was investigated employing 200 fs, 1.54 eV laser pulses at room temperature. The ultrafast excitation caused a two-photon absorption process, which results in purely green emission at the band gap. The spectra are fitted very well by the application of the van Roosbroeck-Shockley relation, density of states, and Urbach's rule demonstrating the intrinsic character of the radiative recombination. It is further shown that the energy position of the emission peak depends on the polarization of the impinging laser beam due to the dichroism of the highly oriented films. …