Kivanc Sel

Synthesis and characterization of new microgel from tris(2-aminoethyl)amine and glycerol diglycidyl ether as poly(TAEA-co-GDE)

Here, we report a new microgel preparation from tris(2-aminoethyl)amine (TAEA) and glycerol diglycidyl ether (GDE) as p(TAEA-co-GDE) via simple microemulsion polymerization/crosslinking by using L-α lecithin as surfactant and gasoline as organic phase. The p(TAEA-co-GDE) microgels were visualized using optical microscopy and scanning electron microscopy (SEM) with size ranges <10 μm. The prepared particles were found to be positively charged, 23.61 ± 1.2 mV at pH~4.5, according to zeta-potential measurements, and the charge of particles decreased with increase in pH of the medium and become negatively charged after pH 10. The microgel particles were protonated (quaternized) or deprotanated by HCl and NaOH treatments, changing their zeta potential to 33 ± 1.3 mV and 14.53 ± 1.8 mV, respectively. Thermal properties of the prepared particles were observed by TG analysis before and after quaternization, and also after Co(II), Cu(II) and Cd(II) metal ion absorption. Here, we also demonstrated in situ CdS quantum dot (Q-dots) preparation within p(TAEA-co-GDE) microgels. The peak energy of 2.5 eV was observed in the fluorescence spectrum of p(TAEA-co-GDE)-CdS microgel by applying an excitation wavelength of 300 nm. Furthermore, the prepared p(TAEA-co-GDE) particles showed antibacterial characteristics against common bacteria such as Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633 and Pseudomonas aeruginosa ATCC 10145 and have great potential for biomedical use. Additionally, p(TAEA-co-GDE) particles are found to be biocompatible against L929 Fibroblast cells.

Determination of the refractive index of a dielectric film continuously by the generalized S-transform

The generalized S-transform was improved as a method to determine the refractive index of a dielectric film continuously by using the transmittance spectrum, and the applicability of the method was demonstrated on mica. The result determined from the generalized S-transform method was compared with the results determined from the S-transform and the fringe counting methods and published values. The advantage of the proposed method was explained, and the absolute error of the presented method was also calculated.

Refractive index and extinction coefficient determination of an absorbing thin film by using the continuous wavelet transform method.

We present the continuous wavelet transform (CWT) method for determining the dispersion curves of the refractive index and extinction coefficient of absorbing thin films by using the transmittance spectrum in the visible and near infrared regions at room temperature. The CWT method is performed on the transmittance spectrum of an a - Si(1-x)C(x):H film, and the refractive index and extinction coefficient of the film are continuously determined and compared with the results of the envelope and fringe counting methods. Also the noise filter property of the method is depicted on a theoretically generated noisy signal. Finally, the error analyses of the CWT, envelope, and fringe counting methods are performed.