Papers by Keyword: Film

Abstract: Silk fibroin (SF) / pearl powder (PP) blend films with glycerol as a crosslinker were prepared by adding PP into SF solution and casting the SF solution onto the polystyrene disks at room temperature. The effects of amount of PP on surface morphology, structure, mechanical properties and water-solubility of films were investigated in this study. The surface morphology was observed with scanning electron microscope. The structure of films was investigated by X-ray diffraction. The dissolution rates of SF in films were measured by ultraviolet spectroscopy and mass loss percentages of the films were examined by weighing method. The elongation at break and the tensile strength of the films were measured on a universal testing machine. The results showed that surface of films without PP was smooth, particles rose increasingly obviously on the surface of films with PP with the increase of amount of PP. The condensed structure of SF in the films without PP was mainly silk I crystals. When the addition of PP was more than 5%, it had obvious effects on the crystal formation of SF in the films. Apart from silk I crystals, silk II crystals formed in the condensed structure of SF containing PP. The mass loss rate of films decreased with the increase of PP and the corresponding dissolution rate of SF was between 0.29% and 0.48% when the proportion of PP was in the range of 0% to 15%. The elongation at break was significantly affected by the addition of PP, but there were no significant effects on the tensile strength. When the proportion of PP was more than 5%, the elongation at break of the films dropped significantly.

Abstract: LaNiO₃ (LNO) is known as a candidate for oxide electrodes with perovskite type crystal structure which is suitable for lattice matching with conventional perovskite ferroelectrics, Pb (Zr,Ti)O₃ (PZT), BaTiO₃ (BTO), etc. We have been investigating thermal expansion effects of the LNO film with PZT/LNO/Si and BTO/LNO/Si structures, where ferroelectric and piezoelectric properties are enhanced by a compressive thermals stress impressed from the LNO layer to the ferrelectric films. The ferroelectric films also shows high [00 orientation owing to [100] orientation of the LNO film. In the present study, further investigation of the LNO films prepared on Si substrates by CSD method is made by transmission electron microscopy (TEM) in order to understand self-orientation along [100] perpendicular to the film plane which effectively leads orientation of PZT films prepared on the LNO film. The results obviously indicates that the 1 layer deposited LNO film has almost no orientation, whereas it shows tendency of orientation of [100] perpendicular to the film plane when the layer number increased.

Abstract: High-quality La_0.84Sr_0.16Ga_0.26Mg_0.74O_3-δ (LSGM) epitaxial thin films were successfully grown on (100)-SrTiO₃ (STO) substrates at a temperature of 800 °C by a pulsed laser deposition (PLD) method with KrF excimer laser pulses at an ozone pressure of 1.3 × 10³ Pa. X-ray diffraction rocking curve measurements showed that the LSGM films had a full-width at half-maximum (FWHM) value of 0.11 °for out-of-plane 002 reflection, which was smaller than that reported for LaGaO₃ films grown by atomic layer deposition methods (0.18 ^o). The reciprocal spaces mapping of 103 refraction showed that the LSGM films had a slightly larger lattice parameter a (out-of-plane) of 0.393 nm than a_// (in-plane) of 0.391 nm.

Abstract: nanoSiO₂/cellulose composite films were prepared via ionic liquids 1-ethyl-3-methylimidazolium acetate (EMIMAc) solution containing cotton pulp cellulose. The as-prepared composite films were characterized by means of scanning electron microscope (SEM) and thermogravimetric analysis (TGA). It was indicated that the surface structure of obtained films was dense and compact, which was composed of nanoSiO₂ particles. The modified nanoSiO₂ composite film showed a good thermal stability with decomposition temperature up to 692°C when the weight residue of the film was 50%. The tensile strength and elongation at break increased by 50% and 35% than that of original cellulose film without SiO₂. The film containing 0.5% SiO₂ showed a water flux of 249.8L.m².h^-1 and the retention of BSA by 97%.

Abstract: Here a simple method was developed to fabricate hydrophilic Polyethersulphone film via a sol-gel process. The correspondent hydrophilicity was evaluated by infrared spectral analysis, X-ray photoelectron spectroscopy, the contact angle measurement, atomic force microscope and scanning electron microscope analysis, respectively. Both FTIR and XPS analysis indicated that the film surfaces have a relatively dense sol layer, which favors to become hydrophilic. AFM analysis demonstrated that the higher hydrophilicity was mainly attributed to the surface roughness, while SEM images show that the micro/nanometer crater-like protrusions appears on the film surfaces, whereas the spongy structures & the finger-like structures appear in cortex and intermediate layer respectively. This leads to the hydrophilic film forming after film being treated by sol-gel method.

Abstract: The hybrid guest-host nanocomposite films based on poly (ethylene oxide) (PEO) and molybdenum doped vanadium pentoxide (V_0.975Mo_0.025)₂O₅nH₂O were prepared by sol-gel and hydrothermal reaction via a two-part process. The electrical properties along and across V-O layers have been evaluated. The results indicate that the proper amount of PEO can increase the electrical conductivity of the films. The electrochromism of the films were investigated by cyclic voltammetry, the ex-situ transmission spectra and photographs. The films display a reversible multichromism (orangegreenbluebrown) upon Li⁺ ion insertion/extraction.

Abstract: To investigate the effects of sol pH value and water content on photocatalytic activity of TiO₂ prepared with sol-gel auto-igniting synthesis (SAS) method, TiO(NO₃)₂ was prepared with TiCl₄ as raw material and used as precursor of TiO₂. By changing sol pH value and water content, different TiO₂ powders were prepared and characterized with XRD, SEM and photodegradation of methylene blue (MB). Results indicated that TiO₂ presented the highest photocatalytic activity while sol pH value and mass fraction of water were adjusted to 7 and 50% respectively while the mole ratio of n (TiCl₄): n (citric acid): n (ammonium nitrate) was fixed as 1: 1: 3. The TiO₂ powders were confirmed as loose and porous anatase type with particle size of 15 nm by SEM and XRD.

Abstract: Titanium dioxide (TiO₂) was prepared by Sol-Gel technique that was coated on the grade 304-stainless steel. Effect of dip coated speed, number of coated cycles and annealed temperature on films properties were investigated. The optimum condition for film preparation was at dip coated speed of 0.12 cm/s, number of coated cycles of 20 cycles and annealed temperature of 500 °C. TiO₂ film was crystal structure in anatase phase that had the main plane (101). Surface morphology of the TiO₂ films formed grain that look like knobby shape. nanograin sizes were slightly difference that showed in the range of 10-50 nm. Under optimum condition, TiO₂ film was used as photocatalyst to treat domestic wastewater. TiO₂ film was coated on the paddles of water wheel and 24 paddles were used to create water wheel. Films surface area were contact to wastewater and the light around 0.504 m² under working volume and working area of 0.0135 m³ and 0.09 m², respectively. Under irradiation of the near UV with average intensity of 0.89 mW/cm² over 24 hrs., and rotational speed of 17 rev/min. that were controlled by microcontroller box set. To compare treatment efficiency, uncoated TiO₂ - water wheel (UTWW) was run in the same condition of coated TiO₂ - water wheel (CTWW). The result showed that the CTWW had higher treatment efficiency than the UTWW. Especially for COD, TS, TDS and PO₄^3-, CTWW had greater treatment efficiency than the UTWW that percentage difference were greater than 90%.

Abstract: Stimulating cell proliferation is a challenge in the field of silk fibroin-based biomaterials. In this study, silk fibroin/hyaluronic acid blend films were prepared by a casting method using carbodiimide as a cross-linking agent. Carbodiimide induced silk fibroin to form Silk I crystal structure which was not affected by the presence of hyaluronic acid. The films showed high water resistance. In vitro, the performance of these films was assessed by seeding L929 cells. The results indicated that the silk fibroin/hyaluronic acid blend films with the blend ratio of 80/20 and 60/40 promoted cell proliferation compared with the pure silk fibroin or hyaluronic acid film. These results suggest that silk fibroin/hyaluronic acid blend films are water stable and cytocompatible materials which are expected to be useful in biomedical applications.

Abstract: Recently, there has been renews interest in chitosan as materials in producing of biocomposite films. The chitosan (CS)/corn cob (CC) biocomposite films were prepared by solvent casting method. The effect of CC content on tensile properties of CS/CC biocomposite films was studied. The tensile strength and elongation at break of CS/CC biocomposite films decreased as increasing of CC content. However, the increasing of CC content was increased the tensile modulus of CS/CC biocomposite films. Scanning electron microscopy (SEM) was indicated that the deceasing of tensile properties was due to the poor interfacial adhesion between CC filler and CS matrix.