Papers by Keyword: Optical Absorption Spectroscopy

Abstract: A Polymer blends compose of Poly (3,4-ethylenedioxythiophene):Poly (styrene sulphonic acid)(PEDOT:PSS) and Polyaniline (PANi) have been prepared using drop casting technique. Optical parameters such as refractive index (n), extinction coefficient (k), reflectance, and optical dielectric were determined in this study. It is found that reflectance spectra increase as the PANi concentration decreases in the sample of small photon energy. The refractive index of the sample shows significant effect with the PEDOT:PSS concentration. As the concentration of PEDOT:PSS increases, the refractive index shows a normal dispersion behavior. Extinction coefficient decrease as the wavelength increase within the range of 300 nm to 350 nm that may contribute to the loss fraction of light due to scattering and the decreasing of absorbance at this range. However, the extinction coefficient increases from 350 nm to the maximum wavelength of 800 nm since the absorbance is also increasing. Both the real and imaginary part of the dielectric constant decreases when the photon energy increases. This revealed that the compositions of PEDOT:PSS influence the optical properties of hybrid PEDOT-PSS:PANi thin film.

Abstract: Thin film conducting polymer thiophene based that is poly(3,4-ethylenedioxythiophene): poly(styrene sulphonic acid) (PEDOT:PSS) blended with Polyaniline (PANi) have been prepared with different composition by using drop casting technique. The optical characterization has been done by analyzing the absorbance spectra in the wavelength 300 to 800 nm. The electronic parameters were calculated by using Tauc/Davis-Mott Model. The results obtained showed that the absorbance, optical energy and Urbach energy were dependence on the ratio of PEDOT: PSS to PANi compositions.

Abstract: Ag-Cu nanoparticles/silicate glass composites are synthesized by twice ion-exchange and reduction treatment. The as-produced glass slides were characterized by UV–Vis spectroscopy, electron probe microanalysis (EPM) and high resolution transmission electron microscopy (HRTEM). The studies show that Ag-Cu nanoparticles aggregate on the surface of the silicate glass, which size is from 2 nm to 8 nm. The copper layer on the surface of glass matrix is about 20 m by compared to Ag layer (120 m), indicating that it is more difficult for copper ions to enter into the interior. Ag-Cu migration in glass matrix cannot be simply ascribed to a direct interaction with hydrogen, but to a more complex process involving a charge balancing mechanism during hydrogen-sodium ion-exchange.

Abstract: Potential application of Carbon Nanotubes as a drug delivery system is limited by their hydrophobity and their natural tendency to aggregate in the bundles. Dispersion and solubility of Singlewall Carbon Nanotubes (SWCNT) in Phosphate Buffered Saline (PBS) solution via non covalent and covalent interactions was investigated. Galactosyl-β1-Sphyngosine (glycolipid precursor of cerebrosides, structured with a hydrophobic chain, a hydrophilic head and an amine group between them) was used. Pristine SWCNTs were wrapped with Galactosyl-β1-Sphyngosine (Gal-Sphy), whereas the carboxylic groups of the functionalized CNTs were activated in order to interact with amine groups of Galactosylsphyngosine and render the coating stronger. Samples dispersion was characterized by optical absorption spectroscopy (OAS). The comparison and efficiency of the dispersion stability of the functionalized material in respect to the pristine SWCNTs will be presented. We exploited Raman Spectroscopy to evaluate relative purity of the samples, and the Infrared analysis to characterize the presence of the functional groups on the tubes surface. The morphology of the samples was studied using high resolution transmission electron microscopy (HR-TEM).