Increase In Film Roughness Research Articles

Electrostimulable polymeric films with hyaluronic acid and lipid nanoparticles for simultaneous topical delivery of macromolecules and lipophilic drugs.

This study focused on developing electrically stimulable hyaluronic acid (HA) films incorporating lipid nanoparticles (NPs) designed for the topical administration of lipophilic drugs and macromolecules. Based on beeswax and medium-chain triglycerides, NPs were successfully integrated into silk fibroin/chitosan films containing HA (NP-HA films) at a density of approximately 1011 NP/cm2, ensuring a uniform distribution. This integration resulted in a 40% increase in film roughness, a twofold decrease in Young's modulus, and enhanced film flexibility and bioadhesion work. The NP-HA films, featuring Ag/AgCl electrodes, demonstrated the capability to conduct a constant electrical current of 0.2mA/cm2 without inducing toxicity in keratinocytes and fibroblasts during a 15-min application. Moreover, the NPs facilitated the homogeneous distribution of lipophilic drugs within the film, effectively transporting them to the skin and uniformly distributing them in the stratum corneum upon film administration. The sustained release of HA from the films, following Higuchi kinetics, did not alter the macroscopic characteristics of the film. Although anodic iontophoresis did not noticeably affect the release of HA, it did enhance its penetration into the skin. This enhancement facilitated the permeation of HA with a molecular weight (MW) of up to 2 × 105 through intercellular and transcellular routes. Confocal Raman spectroscopy provided evidence of an approximate 100% increase in the presence of HA with a MW in the range of 1.5-1.8 × 106 in the viable epidermis of human skin after only 15min of iontophoresis applied to the films. Combining iontophoresis with NP-HA films exhibits substantial potential for noninvasive treatments focused on skin rejuvenation and wound healing.

Synthetic versus Natural Precursor Layer: A Study on the Properties of Biocompatible Chitosan/Carboxymethyl Cellulose Nanofilms.

Polyelectrolyte multilayers are nanofilms with vast applications in numerous areas such as medicine and food industry. Recently, they have been getting a lot of attention as potential food coatings for the prevention of fruit decay during transportation and storage, and therefore the coatings need to be biocompatible. In this study, we fabricated thin films made of biocompatible polyelectrolytes, positively charged polysaccharide chitosan, and negatively charged carboxymethyl cellulose on a model silica surface. Typically, to enhance the properties of the prepared nanofilms, the first layer (precursor layer) of poly(ethyleneimine) is used. However, for the construction of completely biocompatible coatings, this could be problematic due to potential toxicity. This study offers an option for a viable candidate as a replacement precursor layer: chitosan itself was adsorbed from a more concentrated solution. In the case of chitosan/carboxymethyl cellulose films, using chitosan over poly(ethyleneimine) as a precursor layer has shown a twofold increase in film thickness, as well as an increase in film roughness. In addition, these properties can be tuned by the presence of a biocompatible background salt (e.g., sodium chloride) in the deposition solution that has proven to change the film thickness and surface roughness depending on the salt concentration. Such a straightforward way of tuning the properties of these films combined with their biocompatibility makes this precursor material a prime candidate for use as a potential food coating.

Oxygen mediated defect evolution in RF sputtered Ga2O3 thin films on p-Si substrate

Impact of oxygen concentration in governing the structural and optical properties of RF sputter Ga 2 O 3 thin film deposited on p-Si at 500 o C by controlling the oxygen flow rate (OFR) has been demonstrated in this work. To maintain the oxygen rich and oxygen poor condition, the argon (Ar) to oxygen (O 2 ) ratio systematically varied from 1:1, 1:2, to 1:0, 2:1 and, 3:1 respectively. Such OFR reliant change in crystalline quality of the grown Ga 2 O 3 thin film is investigated by X-ray Diffraction (XRD) study. The atomic force microscopy results further illustrate an increase in film roughness owing to the inevitable introducing of defects/ oxygen vacancy ( V O ) during deposition with higher OFR. The modification in material stoichiometry via generation of V O and defects in surplus of oxygen is further supported with XPS analysis. Moreover, a rising trend of optical bandgap (Eg) due to transformation from oxygen rich to oxygen poor condition was revealed by spectroscopic ellipsometery study and further correlated with the improved crystallinity of the film. A maximum Eg of 4.44 eV was obtained for the Ga 2 O 3 thin film deposited with 3:1 Ar to O 2 ratio. Finally, the photoluminescence (PL) investigation confirms a strong correlation between defects/ V O generation with OFR variation. Where, the decrease in blue band contribution in lower oxygen concentration was correlated with reduced Vo concentration via its active participation in gallium vacancy V Ga and Vo pair (V Ga +Vo) formation. Finally, the impact of OFR on the Ga 2 O 3 /Si heterojunction device property is also investigated by utilizing the current–voltage (I-V) measurements, which shows a superior device performance for film grown in oxygen poor condition owing to the presence of lower defect concentration, surface roughness, and interface states. • Oxygen mediated structural, chemical and optical transformation of Ga 2 O 3 thin film deposited on p-Si substrate at 500 o C temperature by RF sputtering. • Impact of oxygen extremes on the defect evolution of Ga 2 O 3 thin film by photoluminescence study. • The heterojunction properties of β-Ga 2 O 3 /Si are studied electrically and such heterojunctions exhibit relatively superior rectification properties. • 3:1 is the optimum Ar to O 2 ratio to achieve high quality, defect-free Ga 2 O 3 film on Si.

Development and Characterization of Silk Fibroin-based Oral Films Containing Turmeric Extract as Dietary Supplement

Dietary supplements have extreme importance. Due to the easily degradable nature of these supplements, the development and application of carrier systems in food technologies seem to be extremely important. Today, oral film technologies have gained importance due to their rapid and high absorption properties. This study chose silk fibroin (SF) as the main component due to its high biocompatibility. Turmeric extract has been added to the oral films as an active agent. The prepared films were analyzed with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to reveal their morphological properties, and at the same time, the film thickness was measured. It has been found that the increase in extract amount is a factor that causes an increase in film roughness while causing a decrease in phase separation. It was observed that the film roughness increased twice with the addition of extract. The roughness of the films formed with 15% extract was measured as 28.5. The average roughness of the films formed without the use of extracts was observed as 15.7 mm. It was also observed that the Trolox equivalent antioxidant capacity (TEAC) was doubled for films containing 15% turmeric extract after one hour of release. The films exhibited different weight loss profiles after release as the amount of turmeric extract was changed. Disc diffusion experiments revealed that films containing turmeric extract exhibited antimicrobial effects.

Alzheimer's disease diagnosis based on detection of autoantibodies against Aβ using Aβ40 peptide in liposomes

BackgroundAlzheimer’s disease (AD) is the most common form of dementia and affect more than 50 million people worldwide. Thus, there is a high demand by non-invasive methods for an early diagnosis. This work explores the AD diagnostic using the amyloid beta 1–40 (Aβ40) peptide encapsulated into dipalmitoyl phosphatidyl glycerol (DPPG) liposomes and immobilized on polyethylene imine previously deposited on screen-printed carbon electrodes to detect autoantibodies against Aβ40, a potential biomarker found in plasma samples. MethodsThe immunosensor assembly was accompanied by atomic force microscopy (AFM) images that showed globular aggregates from 20 to 200 nm corresponding liposomes and by cyclic voltammetry (CV) through increase of the voltammogram area each material deposited. After building the immunosensor, when it was exposed to antibody anti-Aβ40, there was an increase in film roughness of approximately 9 nm, indicating the formation of the immunocomplex. ResultsIn the detection by CV, the presence of specific antibody, in the range of 0.1 to 10 μg/ml, resulted in an increase in the voltammograms area and current in 0.45 V reaching 3.2 µA.V and 5.7 μA, respectively, in comparison with the control system, which remained almost unchanged from 0.1 μg/ml. In patient samples, both cerebrospinal fluid (CSF) and plasma, was possible separated among positive and negative samples for AD using CV profile and area, with a difference of 0.1 μA.V from the upper error bar of healthy samples for CSF sample and 0.6 μA.V for plasma sample. ConclusionsThese results showed the feasibility of the method employed for the non-invasive diagnostic of Alzheimer’s disease detecting natural autoantibodies that circulate in plasma through a simple and easy-to-interpret method.

Ambipolar SnOx thin-film transistors achieved at high sputtering power

SnO is the only oxide semiconductor to date that has exhibited ambipolar behavior in thin-film transistors (TFTs). In this work, ambipolar behavior was observed in SnOx TFTs fabricated at a high sputtering power of 200 W and post-annealed at 150–250 °C in ambient air. X-ray-diffraction patterns showed polycrystallisation of SnO and Sn in the annealed SnOx films. Scanning-electron-microscopy images revealed that microgrooves appeared after the films were annealed. Clusters subsequently segregated along the microgrooves, and our experiments suggest that they were most likely Sn clusters. Atomic force microscopy images indicate an abrupt increase in film roughness due to the cluster segregations. An important implication of this work is that excess Sn in the film, which has generally been thought to be detrimental to the film quality, may promote the ambipolar conduction when it is segregated from the film to enhance the stoichiometric balance.

Solution-derived ZnO nanoflowers based photoelectrodes for dye-sensitized solar cells

Flower-like ZnO nanostructures, composed of hexagonal nanorods were manipulated, via a low temperature hydrothermal method from an aqueous solution using polyethyleneimine (PEI) as a surfactant in the seed sole. It was found that the PEI in the seed sole not only affected the geometrical shape of ZnO flowers but also changed the length and spacing of the petals. These flower-like nanostructures were used as photoelectrodes in dye-sensitized solar cells. Compared to rod-like flowers (sample X1), the blade-like flowers (sample X2) nanostructures demonstrate increased power conversion efficiency (η) of about 106%. Meanwhile, short-circuits current density (JSC), open-circuit voltage (VOC), and fill factor (FF) are all substantially improved. The enhancement of η, VOC and FF in the blade-like-flower photoelectrodes were mainly ascribed to the enlargement of internal surface area between the blades for higher dye loading and the improved light harvesting from efficient light scattering. The band gap energies were 3.31eV and 3.27eV for rod-like flowers and blade-like flowers respectively. The decrease in the optical band gap with the increase of film roughness was due to decrease of lattice defects.

Effect of Zn and Ti mole ratio on microstructure and photocatalytic properties of magnetron sputtered TiO2–ZnO heterogeneous composite film

Series of TiO2–ZnO heterojunction composite films with different n(Zn)/n(Ti) ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n(Zn)/n(Ti) on the microstructures of TiO2–ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n(Zn)/n(Ti) typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n(Zn)/n(Ti) leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2–ZnO films reach the maximum and minimum at n(Zn)/n(Ti) of 1/9.3, respectively. The n(Zn)/n(Ti) shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n(Zn)/n(Ti) has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n(Zn)/n(Ti), the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n(Zn)/n(Ti) but rather on the microstructures of the TiO2–ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n(Zn)/n(Ti)=1:9.3.

EFFECTS OF HYDROGEN GAS FLOW RATIO ON THE QUALITY OF NANO-DIAMOND FILMS

In this paper, we studied the effects of hydrogen gas flow ratio of [H2]/[N2 + CH4 + H2] on the quality of nanometer diamond (nano-diamond) films prepared by microwave plasma enhanced chemical vapor deposition method. Nano-diamond films were deposited on the silicon substrates from a gaseous mixture of nitrogen, methane and hydrogen. The experimental results show that if only using a gaseous mixture of nitrogen and methane, although we can obtain nano-diamond films with a grain size of about 5nm, the diamond films contain much non-diamond components. With hydrogen addition, and with increasing the hydrogen gas flow ratio from 1 to 10%, the non-diamond components in the films are significantly reduced and the grain size of the films increases from 5nm to 60nm. However optical transmittance of the films increases with increasing hydrogen gas flow ratio from 1 to 7% because of an improvement of film quality, and then decreases with further increasing hydrogen gas flow ratio owing to the increase of film roughness.

Phase and microstructural evolution during the interaction between bismuth oxide films and ptlti/SiO2/Si substrates

The interactions between metalogranically derived bismuth oxide films and Pt/Ti/SiO2/Si substrates have been investigated in this study. The diffusion of bismuth species to the substrate and that of titanium species to the film surface occur during the heating processes, and pluralistic Bi-Ti-O phases are formed. With an increase in the heating temperature, the diffusion of titanium species is enhanced, thereby forming the compounds with a high Ti/Bi ratio in films. Based on analysis of SEM and AFM, the microstructure of films are significantly varied by the diffusion of titanium species, which results in the formation of large grains on film surface and causes a significant increase in roughness of films. The above results imply that the interface between bismuth-layered perovskite films and Pt/Ti/SiO2/Si substrates would be influenced by the interdiffusion of bismuth and titanium species.

Characterizing the gloss properties of hydrocolloid films

Hydrocolloid films were prepared by two methods, namely dehydration of thin layers of gels and of gum solutions. Gelatin gel films containing greater amounts of dry matter than all other prepared films provided by far the highest gloss values. Increase in gelatin concentration in the gels resulted in an increase in the mean gloss of the dry films in a linear fashion. Roughness measurements and scanning electron microscope (SEM) micrographs indicated that the gelatin films possessed very smooth surfaces. Similar to gelatin, increase in concentration of gellan resulted in an increase in gloss of resultant films. In direct contrast, mean gloss of both agar and agarose gel films decreased with increasing gel concentration. These trends may be due to the increase in roughness of films with increasing gel concentration, which in the case of agar was also noticeable in the SEM micrographs. Xanthan films provided the most glossy appearance of those prepared by drying of gum solutions, followed closely by alginate. Both exhibited the same trend of mean gloss increasing with gum concentration, similar to gelatin. In both instances, this behaviour could not be related to roughness, which also increased with gum concentration.

Surface roughness and height-height correlations dependence on thickness of YBaCuO thin films

For high T c superconducting multilayer applications, smooth interfaces between the individual layers are required. However, in general, e.g., YBaCuO grows in a 3D screw-dislocation or island nucleation growth mode, introducing a surface roughness. In this contribution we study the surface layer roughness as a function of different deposition techniques as well as deposition parameters. Special attention will be paid to the increase in film roughness with increasing film thickness. For these studies we used scanning probe microscopy. From these experiments, we obtained an island density decreasing with a square root dependence on the film thickness. Furthermore, height-height correlations indicate that the film growth can be described by a ballistic growth process, with very limited effective surface diffusion. The correlation lengths ξ are on the order of the island size, inferring that the island size forms the mean diffusion barrier. This results in a representation of non-correlated islands, which can be considered as autonomous systems.