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Application of RBS and NRA in the fabrication of carbon based devices

Description: We have used Nuclear Reaction Analysis (NRA) and Rutherford Backscattering Spectrometry (RBS) as well as resonant backscattering as analytical tools in fabricating carbon based drug delivery bio-implants, electrodes for batteries, and devices to entrap or filter specific toxins. Precursor is resol C{sub 7}H{sub 8}O{sub 2} liquid, which converts to fully cured phenolic resin C{sub 7}H{sub 6}O (sp gr 1.25) on heating at 170 C. This resin further transforms with no change in shape to glassy carbon (sp gr 1.45) on heating to 1000 C. Final product consists of long ribbon-like molecules of sp2 carbon atoms aggregated locally to form subcrystalline domains arranged randomly in space. RBS and NRA were used in measuring the porosity before and after activation, in concentration profiling of stored drugs before and after leaching, in detecting low level light element impurities, and in detecting changes in the structure of the device due to fabrication.
Date: June 1, 1995
Creator: Ila, D.; Zimmerman, R.L.; Maleki, H.; Evelyn, A.L. & Poker, D.B.
Partner: UNT Libraries Government Documents Department

Ion beam modification of PVDC and PE polymers

Description: Electronic and nuclear stopping effects produced by MeV ion bombardment in polyvinylidine chloride and polyethylene are separated by stacking thin films of the polymers. Resulting multi-layer laminates of each polymer were bombarded with 3.5-MeV alpha particles. Energy of the incident ions was selected using the TRIM code so that the first layers experienced most of the effects of the electronic energy deposited and the last layers received most of the effects of the nuclear stopping power. Changes in conductance and chemical structure of each layer were measured by direct resistivity measurements and Raman microprobe analysis.
Date: December 31, 1995
Creator: Evelyn, A.L.; Ila, D.; Fisher, J. & Poker, D.B.
Partner: UNT Libraries Government Documents Department

Effects of MeV Ions on PE and PVDC

Description: We studied the effects of 3.5 and 5.0 MeV alpha bombardment on polyethylene and polyvinylidene chloride both of which have simple chemical structures. Using a thin polymer film stacking technique, we were able to map the effects of the MeV alpha particles in their track. The first layer of the thin polymer film stack experienced most of the effects of the electronic energy deposited and the last layer received most of the effects of the nuclear stopping. Using Raman microprobe analysis and measuring the ratio of the formation of graphene structures (G-line) to the disordered (amorphous) carbon line (D-line), we were able to separate the severed bond effects in the end of the alpha particles` track in the last polymer film layers from the effects of the electronic energy deposited in the first polymer film layers. The results are in agreement with our other measurements of each polymer film using FTIR, RBS and resistance measurements.
Date: December 1997
Creator: Evelyn, A. L.; Ila, D.; Zimmerman, R. L.; Bhat, K.; Poker, D.B. & Hensley, D. K.
Partner: UNT Libraries Government Documents Department