4 research outputs found
The antimicrobial activity of lapachol and its thiosemicarbazone and semicarbazone derivatives
Structural and optical properties of amorphous hydrogenated fluorinated carbon films produced by PECVD
Fluorinated films were deposited from radiofrequency discharges of toluene/trifluorotoluene and toluene/sulfur hexafluoride mixtures. Actinometric optical emission spectroscopy was used to determine trends in the concentrations of the plasma species H, CH, and F as a function of the partial pressure of trifluorotoluene or sulfur hexafluoride present (expressed as a percentage of the total chamber pressure) designated R-T and R-s, respectively. Transmission infrared spectrophotometry and electron spectroscopy for chemical analysis revealed that the films contain various fluorine-containing functionalities and that the degree of fluorination increases as R-T or R-s is increased. Ultraviolet-visible spectrophotometry of films deposited at various values of R-T and of R-s allowed the determination of the absorption coefficients ct of the films. From plots of ct as a function of photon energy it was possible to calculate the optical gap (E-04). An intriguing result was a decline and subsequent rise in E-04 as R-s was increased. Molecular modelling using ZINDO/PM3 calculations provided a semi-quantitative explanation of the dependence of E-04 on R-s. (C) 1997 Elsevier Science S.A.3044167114915