Preparation and characterization of TiO2 coated Fe nanofibers for electromagnetic wave absorber

Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer.     

Effect of UV/ozone treatment on interactions between ink-jet printed Cu patterns and polyimide substrates

In this study, we apply UV/ozone treatment to modify the surface properties of polyimide substrate and investigate the effects of UV/ozone treatment on surface properties of polyimide and the morphologies of ink-jet printed Cu patterns. Wettability of polyimide surface is enhanced by UV/ozone treatment as confirmed by contact angle analysis and XPS results. The change in wettability affected droplet sizes and morphologies of ink-jet-printed lines. The average droplet size increased from 26.8 μm on untreated polyimide to 42.5 μm after UV/ozone treatment. Furthermore, irregular patterns of coexisting beads and short lines were observed in untreated polyimide film, despite minimal overlap of dots. In contrast, patterns that were ink-jet printed on polyimide film that was modified by UV/ozone for 1 h showed continuous lines with straight edges.     

Antitumor activity of sorafenib-incorporated nanoparticles of dextran/poly(dl-lactide-<Emphasis Type="Italic">co</Emphasis>-glycolide) block copolymer

Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly(DL-lactide-co-glycolide) [DexbLG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated DexbLG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated DexbLG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated DexbLG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated DexbLG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated DexbLG nanoparticles are promising candidates as vehicles for antitumor drug targeting.