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Spectroscopic studies of poly(vinyl alcohol) films filled with a lanthanum/ N ‐ethylmorpholine complex
Author(s) -
ElKader Kamal M. Abd,
Anwar Zeinab
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26756
Subject(s) - vinyl alcohol , lanthanum , materials science , absorption spectroscopy , band gap , absorption (acoustics) , analytical chemistry (journal) , polymer , doping , activation energy , chemistry , inorganic chemistry , composite material , organic chemistry , optics , physics , optoelectronics
Poly(vinyl alcohol) (PVA) films with different concentrations of lanthanum ions were prepared with a casting technique. The thickness of the prepared samples was 0.25 mm. Optical absorption and transmission measurements were performed for thesesamples. The ultraviolet–visible absorption spectra of pure PVA showed absorption bands at 200, 275, and 325 nm, which were assigned to the presence of carbonyl groups. The absorption spectra of doped PVA films showed an observable change in the band position with the filling levels. This was due to the link between the lanthanum metal ion and the polymer OH groups. The dependence of the absorption coefficient on the photon energy was determined, and the band tails and energy gaps were calculated. The band tail increased, whereas the optical gaps decreased, as the concentration of lanthanum ions increased. X‐ray diffraction was used to characterize the prepared films. The results indicated the appearance of several new bands not existing for the lanthanum ions or PVA. Direct current/voltage characterization curves were measured for PVA–lanthanum films with different concentrations, and they showed remarkable increases in the conduction current of about 3 orders of magnitude in comparison with that of the pure PVA film. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007