Abstract: The combination of carbon nanotubes (CNT) and conducting polymers offers an attractive route for the production of novel compounds that can be used in a variety of applications such as sensors, actuators, and molecular scale electronic devices. In this work, functionalized multiwall carbon nanotubes (f-MWCNTs) were added in different load ratios (3 wt%, 5 wt% and 10 wt%) to thiophen (PTh) polymer to procedure PTh/CNTs nanocomposite and deposited on porous silicon substrate by electropolarization. Photoconductive detectors were fabricated using PTh/f-MWCNTs matrix to work in the near region and middle IR regions. These detectors were illuminated by semiconductor laser diode wavelength of 808(nm) and Nd-YAG laser of wavelength 1064 (nm) to study the I-V characteristics and figures of merit. FTIR spectra assignments verify that the thiophene groups were successfully introduced into the carbon nanotubes. SEM images reflect that the electro polymerization process gives well coating for the CNTs by PTh. The conductivity of PTh as a function of temperature increased about 30 times due to addition of f-MWCNTs. Figures of merit reflect a good IR radiation sensitivity and photo response. The specific detectivity was in order of 108 (cm.Hz1/2/W) for both IR regions. The rise and fall times of the output signal are about of 192 (μs) and 121 (μs) respectively for load ratio 5wt% of CNT, which consider good values for these types of detectors.
Abstract: The physical and chemical characterize of quantum dots (QDs) extensively depend upon the optical and morphological factors such as size and shape. The zinc selenide (ZnSe) quantum dots (QDs) have been prepared by chemical method and used to fabricate quantum dot hybrid junction devices with different types of organics polymers. The optical studies illustrate that the band gap value from the photoluminescence (PL) with high intensity of these QDs is found about 3.1 eV.
The electroluminescence's (EL) hybrid devices were demonstrated by room temperature PL and electroluminescence (EL). Current-voltage (I–V) characteristics indicate that the output current is good compared to the few voltages (5.5 V) used which gives good results to get a generation of white light. The EL spectrum reveals a broad emission band covering the range from 350 - 700 nm. The emissions producing this white luminescence were recognized depending on the chromaticity coordinates (CIE 1931). The correlated color temperature (CCT) was found to be about 5759, 3500 and 3498 K for ITO/TPD/ZnSe, ITO/PPV/ZnSe and ITO/PEDOT/ZnSe QDs respectively. Fabrication of EL- hybrid devices from semiconductors materials (ZnSe QDs) with holes injection organic polymer (TPD, PPV and PEDOT) was effective in white light generation.
Abstract: A new amphiphilic bio-organic material was developed by conjugating the xanthine oxidase inhibitor, 2-amino-6-hydroxy-8-mercaptopurine (AMHP) with the naturally occurring polyphenol coumaric acid (CA). The formed product, AMHP-CA was allowed to self-assemble at a pH range of 4 through 8. Nanospheres or fibrous assemblies ranging upto micrometers in length were formed, depending upon growth conditions. Furthermore, it was found that the assemblies biomimetically formed gold nanoparticles on its surfaces resulting in AMHP-CA-AuNP hybrids. The DNA sensing ability of the AuNP bound AMHP-CA assemblies was investigated at varying concentrations by studying the changes in conformations of salmon milt DNA by CD spectroscopy and by examining live binding with surface plasmon resonance (SPR) analysis. AuNP bound AMHP-CA assemblies had significantly increased DNA sensing ability and SPR signal compared to binding interactions in the absence of AuNPs. Thus, in this study it was found that AMHP-CA-AuNP assemblies may function as biosensors for DNA detection.
Abstract: In this study, Polylactic acid and Hydroxypropyl cellulose (PLA-HPC) fibers were fabricated by electrospinning. Methylene blue (MEB), as a model hydrophilic drug was embedded into PLA-HPC fibrous membranes. SEM results depicted that fibers are smooth, cylindrical, uniform and it confirmed the incorporation of MEB in PLA fibers alter the fibers morphology. Studies show the on-demand release of drug from PLA-HPC fibrous membranes under temperature stimuli which were absent in membranes manufactured out of PLA. This can be attributed to reversible volume phase transitions of HPC molecules in response to applied external temperature. This study may provide more efficient strategies for developing materials with on-demand drug release capability.
Abstract: Zinc layered hydroxides (ZLHs) can be used as host materials for drug-ZLH host–guest structures. Aspirin with 0.1 and 0.4 M were intercalated into zinc layered hydroxides to form aspirin nanocomposites; ASPN1 and ASPN4, respectively. From XRD and software, the interlayer spacing of ASPN1 and ASPN4 was 15.2 Å. The result coupled with molecular geometry calculation indicates that the spatial orientation of the drug in the ZLH was monolayer for ASPN1 and ASPN4 nanocomposites. The release of the aspirin from ASPN4 nanocomposite at pH 6.8 is 35%, compared to 98% at pH 1.2, and followed Hixson model and Korsmeyer model for ASPN4 at pH 6.8 and pH 1.2, respectively. This result indicates sustained release of the drugs from their respective nanocomposites, and therefore these nanocomposites have good potential to be used as controlled-release formulation of the aspirin. The ASPN4 nanocomposite was highly effective to Escherichia coli compared to free aspirin, where the ASPN4 given 1.37 inhibition zone compared to aspirin which given 1.17 cm inhibition zone.