الفهرس 
Introduction and Literature SurveyOnly 14 pages are availabe for public view
 |  | from | 157 |  |  |
| | | from | 157 | | |
Abstract
Chitosan/polycaprolactone (Ch/PCL) semi-natural polymeric blend containing gradient concentrations of CdSe quantum dots (QDs) dopant were synthesized via hot injection method. Synthesized samples containing different concentration of CdSe QDs were characterized by X-ray diffraction and FTIR absorption spectroscopy. FTIR experimental data of synthesized samples shows the maintenance of characteristic vibrational band with a marginal variation in both intensity and position related to the increase in dopant concentration. XRD patterns reveals amorphous nature of prepared virgin blend and blend samples that contain small amount of QDs. Samples with higher QDs concentration, namely (0.008, 0.016) wt.% shows appearance of crystalline bands related to the (1 1 1) reflection plane and in agreement with JCPDS card no. 19-0191. Scanning electron microscopy (SEM) indicates that morphology of synthesized biocomposites is critically affected by addition of CdSe QDs. Antibacterial tests reveals different inhibition zone related to increasing concentration of CdSe QDs and type of bacteria under investigation. Evaluation of The activity index % were also studied. A blend of chitosan, which has low conductivity, and poly (ϵ - caprolactone), PCL, which has fast ionic motion for facilitating ionic conduction. Semiconductor CdSe quantum dot’s was embedded in the polymer blend matrix to be used in biological CdSe Qd’s. The dielectric constant, ϵ ’ , of polymer composite was constant with respect to temperatures. This explained as a decrease of charge carriers and their mobility. The hopping mechanism governs both the transport of charge carriers and their relaxation. At low frequencies, the loss tangent, tan δ, increases to a maximum value with increasing frequency and then decreases again at higher frequency. Semicircles were observed in Cole- Cole diagram at temperature 20oC with their center blow the X- axis, M’, and this indicate that ther are dielectric relaxation over a wide range.