Browsing by Subject "Plastic films"
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Item Open Access Doping of 2-Cl-PANI/PVC films by exposure to UV, γ-rays and e-beams(Elsevier Sequoia SA, Lausanne, Switzerland, 2000) Sevil, U. A.; Güven, O.; Birer, Ö.; Süzer, Ş.2-Chloro-polyaniline (2-Cl-PANI) is chemically prepared in its non-conducting (Emeraldine Base, EB) form and dissolved together with polyvinylchloride (PVC) in THF for casting into thin (10-50 μm) composite films. The electrical conductivity of these films increases by more than four orders of magnitude (from 10-6 to 10-2 S/cm) when they are exposed to UV, γ-rays and e-beams. This is attributed to the dehydrochlorination (loss of HCl) of PVC by exposure to energetic particles and subsequent doping of the 2-Cl-PANI (i.e., conversion to Emeraldine Salt, ES) by the in-situ-created HCl. The doped films can also be returned to their undoped form by further exposure to NH3 vapours. The UV (or other particles)-induced doping/NH3 undoping cycles can be repeated several times until almost total dehydrochlorination of the PVC matrix. UV-Vis-NIR, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopic (XPS) techniques are employed to follow the changes in the composite films upon doping by exposure to these energetic particles.Item Open Access Platinum-palladium loaded polypyrrole film electrodes for the electrooxidation of D-glucose in neutral media(Elsevier Sequoia SA, Lausanne, Switzerland, 1999) Becerik, İ.; Süzer, Ş.; Kadirgan, F.Modified polymer films with metal particles incorporated into the films by electrodeposition are known as possible electrocatalysts for various electrode reactions such as fuel cell applications. This work presents some results concerning the electrooxidation of D-glucose at modified polymer film electrodes prepared on a platinum substrate. This reaction has a great deal of interest in view of its applications to detection systems (glucose sensor), fuel cells (pacemakers) and electroorganic systhesis. The modified polymer film electrodes contain platinum and/or palladium particles dispersed in the polypyrrole film by electrodeposition in neutral media. Addition of palladium to platinum modifies the electrocatalytic behaviour of the electrode drastically. The modification is thought to involve minimization of the poisoning of the catalyst, hence increasing its electrode activity.Item Open Access UV-induced acid-base chemistry within the PVC matrix: Wavelength selectivity(ACS, Washington, DC, United States, 2000) Süzer, Şefik; Birer O.The dehydrochlorination of polyvinyl chlorides (PVC) is investigated by using it as an in-situ Bronsted acid source, in blends with pH indicators for optical changes, and with basic forms of conducting polymers to determine the electrical conductivity changes. The in-situ created HCl was responsible for the optical and electrical conductivity changes in pH indicator+PVC and nonconducting electroactive polymer (PANI) or PANI+PVC systems. It was possible to sensitized PVC and trigger polyene formation at higher wavelengths. The nature of polyene formation was strongly dependent on the wavelength of irradiation as well as the amount of energy transferred to the matrix from the sensitizer.Item Open Access XPS and water contact angle measurements on aged and corona-treated PP(John Wiley & Sons, Inc., 1999) Süzer, S.; Argun, A.; Vatansever, O.; Aral, O.Effects of corona treatment and aging on commercially produced corona discharged polypropylene (PP) films were followed via surface sensitive roughness analysis by atomic force microscopy (AFM), water contact angle (WCA), and X-ray photoelectron spectroscopic (XPS) measurements. Roughness analysis by AFM gave similar results for both untreated and corona-treated samples. The measured water contact angle decreased after corona treatment but increased with aging. XPS findings revealed that corona treatment caused an increase in the O-containing species on the surface of the films, but the measured O/C atomic ratio decreased with aging. The angle dependence of the observed XPS O/C atomic ratio further revealed that surface modifications by the corona treatment were buried into the polymer away from the surface as a function of aging. This is attributed to a surface rearrangement of the macromolecules in agreement with the findings of Garbassi et al. on oxygen-plasma-treated polypropylene.