Author : June Q. Sun
Release : 1996
Genre : Ion bombardment
Kind : eBook
Book Rating : 209/5 ( reviews)
Book Synopsis Surface Modification of Polymers Using OH Radicals and Energetic Neutrals [microform] by : June Q. Sun
Download or read book Surface Modification of Polymers Using OH Radicals and Energetic Neutrals [microform] written by June Q. Sun. This book was released on 1996. Available in PDF, EPUB and Kindle. Book excerpt: A special vacuum process has been developed for adding functional groups onto polymer surfaces with different reactivities. In this novel technique, polymer surfaces were exposed, in a vacuum chamber, to OH radicals generated by the dissociation of water vapour on hot rhenium wires. Laser-induced fluorescence spectroscopy was used to confirm the existence of the OH radicals in the reactor. It was found by X-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy that about half a monolayer equivalent of the C-OH group could be generated on a relatively reactive polymer like polystyrene with a 20 seconds exposure at a water pressure of $1\times 10\sp{-3}$ Torr. Further exposure of the polymer leads to the formation of other functional groups like the C-O-C, C=O and COOH on the surface. For surface engineering of more stable polymers, energetic neutrals were used to activate the polymer surfaces. In this process, the hot rhenium wires were used as thermionic emitter for gas phase electron impact ionization. The ions were subsequently accelerated with an electric field, and were then used to generate energetic neutrals by ion-molecule collisions. The energetic neutrals for activating an electrically insulating surface were controlled by the ion formation, ion acceleration, gas pressure (the mean-free path), and the separation between the ionization zone and the sample surface. With a filament temperature of 1600$\sp\circ$C, an accelerating voltage of 50 eV, a water pressure of $1\times 10\sp{-3}$ Torr (collision mean free path being about 5 cm), and an ion drifting distance of 12 cm, about 0.15 monolayer equivalent of the COH were added to teflon and 0.35 to polyethylene in 30 seconds.
