Ion beam analysis of a-C:H films on alloy steel substrate

An a-C:H thin film deposited by plasma immersion ion implantation and deposition on alloy steel (16MnCr5) was analyzed using a self-consistent ion beam analysis technique.In the self-consistent analysis, the results of each individual technique are combined in a unique model, increasing confidence and reducing simulation errors.Self-consistent analysis, then, is able to improve the regular ion beam analysis since several analyses commonly used to process ion beam data still rely on handling each spectrum independently.The sample was analyzed by particle-induced x-ray emission (for trace elements), elastic backscattering spectrometry (for carbon), forward recoil spectrometry (for hydrogen) and Rutherford backscattering spectrometry (for film morphology).The self-consistent analysis provided reliable chemical information about the film, despite its heavy substrate.As a result, we could determine precisely the H/C ratio, contaminant concentration and some morphological characteristics of the film, such as roughness and discontinuities.© 2013 Elsevier B.V.All rights reserved.

Aging of plasma-activated copper and gold surfaces and its hydrophilic recovery after water immersion

A significant increase of surface hydrophilicity of copper and gold surfaces was obtained after atmospheric pressure plasma treatment using the surface dielectric barrier discharge with specific electrode geometry, the so-called diffuse coplanar surface barrier discharge. Surface wettability was estimated using the sessile drop method with further calculation of the surface free energy. After the plasma treatments, it was observed that the treated surfaces exhibited hydrophobic recovery (or aging effect). The aging effect was studied in different storage environments, such as air, low and high vacuum. The role of plasma and the reasons of the following aging effect are discussed with respect to the observed hydrophilic recovery after immersing the aged surfaces into deionized water. The changes in the surface morphology, composition and bond structure are presented and discussed as well. (C) 2013 Elsevier B. V. All rights reserved.

Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and optical properties of Cu2O crystalline electrodeposited films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Supramolecular organization-electrical properties relation in nanometric organic films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dispositivos flexíveis de monitoramento de pH e de deflexão mecânica à base de polianilina

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Film based on Y2O3: Eu3+ (5 mol% of Eu3+) for flat panel display

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal inkjet printing of polyaniline on paper

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vortex dynamics in mesoscopic superconducting square of variable surface

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural and optical properties of chlorinated plasma polymers

Amorphous hydrogenated chlorinated carbon (a-C:H:Cl) films were produced by the plasma polymerization of chloroform-acetylene-argon mixtures in a radiofrequency plasma enhanced chemical vapor deposition system. The main parameter of interest was the proportion of chloroform in the feed, R(C), which was varied from 0 to 80%. Deposition rates of 80 nm min (1) were typical for the chlorinated films. Infrared reflection-absorption spectroscopy revealed the presence of C-Cl groups in all the films produced with chloroform in the feed. X-ray photoelectron spectroscopy confirmed this finding, and revealed a saturation of the chlorine content at similar to 47 at.% for R(C)>= 40%. The refractive index and optical gap, E(04), of the films were roughly in the 1.6 to 1.7, and the 2.8 to 3.7 eV range. These values were calculated from transmission ultraviolet-visible-near infrared spectra. Chlorination leads to an increase in the water surface contact angle from similar to 40 degrees to similar to 77 degrees. (C) 2011 Elsevier B.V. All rights reserved.

Development of amorphous carbon protective coatings on poly(vinyl)chloride

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Wettability, optical properties and molecular structure of plasma polymerized diethylene glycol dimethyl ether

Modern industry has frequently employed ethylene glycol ethers as monomers in plasma polymerization process to produce different types of coatings. In this work we used a stainless steel plasma reactor to grow thin polymeric films from low pressure RF excited plasma of diethylene glycol dimethyl ether. Plasmas were generated at 5W RF power in the range of 16 Pa to 60 Pa. The molecular structure of plasma polymerized films and their optical properties were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and UltravioletVisible Spectroscopy, respectively. The IR spectra show C-H stretching at 3000-2900 cm(-1), C=O stretching at 1730-1650 cm(-1), C-H bending at 1440-1380 cm(-1), C-O and C-O-C stretching at 1200-1000 cm(-1). The refraction index was around 1.5 and the optical gap calculated from absorption coefficient presented value near 3.8 eV. Water contact angle of the films ranged from 40 degrees to 35 degrees with corresponding surface energy from 66 to 73x10(-7) J. Because of its favorable optical and hydrophilic characteristics these films can be used in ophthalmic industries as glass lenses coatings.

Erbium-activated silica-zirconia planar waveguides prepared by sol-gel route

Er(3+) doped (100-x)SiO(2)-xZrO(2) planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er(3+) ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 mu m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er(3+) ion. (c) 2007 Elsevier B.V. All rights reserved.

Fabrication and testing of a poly(vinylidene fluoride) (PVDF) microvalve for gas flow control

A microactuator made from poly(vinylidene fluoride) (PVDF), a piezoelectric polymer, was fabricated to control the gas flow rate through a glass micronozzle. The actuator was formed by gluing together two PVDF sheets with opposite polarization directions. The sheets were covered with thin conducting films on one side, that were then used as electrodes to apply an electric field to move the valve. The actuator has a rectangular shape, 3 mm x 6 mm. The device was incorporated with a micronozzle fabricated by a powder blasting technique. Upon applying a DC voltage across the actuator electrodes, one sheet expands while the other contracts, generating an opening motion. A voltage of +300 V DC was used to open the device by moving the actuator 30 mu m, and a voltage of -200 V DC was used to close the device by moving the actuator 20 mu m lower than the relaxed position. Flow measurements were performed in a low-pressure vacuum system, maintaining the microvalve inlet pressure constant at 266 Pa. Tests carried out with the actuator in the open position and with a pressure ratio (inlet pressure divided by outlet pressure) of 0.5, indicated a flow rate of 0.36 sccm. In the closed position, and with a pressure ratio of 0.2, a flow rate of 0.32 sccm was measured.

AN ACTINOMETRIC STUDY OF C2H2 PLASMA POLYMERIZATION AND FILM PROPERTIES

Thin polymer films were grown in radio frequency discharges containing C2H2. Actinometry revealed the trend in the plasma concentration of the CH species as a function of the operating pressure. The C-H bond density in the films, revealed by infrared analysis, was found to increase with the pressure of C2H2 in a similar way to that of the concentration of the CH species in the discharge. From transmission ultraviolet-visible spectroscopy data, optical parameters of the polymers, namely, the refractive index and the optical gap, were calculated. For the range of pressure studied, the refractive index decreased from 1.73 to 1.63 and the optical gap increased from 2.4 to 3.3 eV. Finally, measurements of the residual stress of the polymer films were carried out by the bending beam method, using a He-Ne laser, yielding values from 0.05 to 0.3 GPa. (C) 1995 American Vacuum Society.