Закономерности формирования Pd-Bi наночастиц, полученных нанесением металлоорганических предшественников на Al2O3

В настоящей работе мы провели синтез палладий-висмутовых катализаторов, нанесенных на оксид алюминия, и исследовали процессы, протекающие при взаимодействии предшественников иPd(acac)2 и Bi(ac)3 с оксидом алюминия

Plasma-assisted deposition of dielectric conformal coating using hexamethyldisiloxane as precursor

Plasma polymerization is a rapidly growing field of plasma technology. Using this method, it is possible to solve applied problems, for example, the deposition of conformal dielectric coatings to protect electrical circuit boards operating in outer space. In this paper, we study the vapor deposition of hexamethyldisiloxane using low-pressure plasma. The morphology, dielectric strength under plasma, and chemical composition of the deposited coating are studied. It was established that the coating has a lamellar structure, which, together with the data of IR spectroscopy, indirectly prove the formation of a polymer coating. The dielectric strength of the coating under plasma was 650 V

Effect of silver ion implantation on surface physicochemical properties of composite materials based on polylactic acid and hydroxyapatite

The investigation of surface physicochemical and biological properties of polylactic acid and hydroxyapatite and composite materials based on them modified by Ag 1×1015 ion/cm2 and 1×1016 ion/cm2 40 keV ion implantation is presented. X-ray analysis reveals that ion implantation of the above mentioned materials leads to crystallite size and degree of crystallinity increase. The intensity of -С=О line is found by IR-spectroscopy to be decreased that is associated with surface layer carbonization processes of PLA during ion implantation. Silver ion introducing is established to enhance hydrophobic properties of the materials; this process is accompanied by free surface energy decreasing. It is shown that cell viability of non-implanted PLA is comparable with a control sample and ion implantation negatively affects to cell viability. The investigated materials can be promising for biomedical application

Effect of carbon-ion implantation on the surface physical and chemical properties of polylactic acid, hydroxyapatite and a composite based on them

The results of investigation of the surface physical and chemical properties of polylactic acid, hydroxyapatite and a composite material based on them taken in the ratio of components 80/20, modified by carbon ions with exposure doses of 1 × 10 15 and 1 × 10 16 ion/cm 2 at an accelerating voltage of 20 kV are presented. The surface chemical composition of the samples is studied by Fourier transform infrared spectroscopy. The elemental composition of the surface is studied by X-ray photoelectron spectroscopy. According to the obtained results, the simultaneous processes of destruction and cross linking of polylactic acid and polymer macromolecules are established. To assess the wettability of the untreated and modified surface of materials, contact-angle measurements and surface energy calculations are performed. It is established that carbon-ion implantation leads to improvement in the hydrophobic properties of materials; this process is accompanied by a decrease in the free surface energy

Chemical state and morphology of Zn and Mg ion-implanted polyvinyl alcohol

The investigations of the surface physicochemical properties of polyvinyl alcohol modified by magnesium and zinc ion implantation to doses of 1∙10^15 and 1∙10^16 ion/cm^2 and energies of 24 keV (for Zn1.2+) and 30 keV (for Mg1.5+) are described. The effects of the ion beam exceed the projective range of ions by the TRIDYN method; therefore, in the conditions of ion implantation, the long-range effect arises due to radiation diffusion and thermal restructuring of the material. X-ray photoelectron spectroscopy reveals that after ion beam treatment of polyvinyl alcohol, magnesium and zinc are in both metallic and oxidized states. Ion implantation leads to an essential change in the chemical state of the polyvinyl alcohol surface. The surface chemistry modification is assumed to be caused by thermal and radiation effects on the material. The evolution of changes in the surface structure is presented and shown to be independent of the type of implanted metal ion. Restructuring of polyvinyl alcohol is accompanied by an increase in the degree of crystallinity and, as a result, a change in mechanical properties. A change in surface morphology leads to the increase of free surface energy

Characterization of hexamethyldisiloxane plasma polymerization in a DC glow discharge in an argon flow

This work aims to study hexamethyldisiloxane (HMDSO) plasma polymerization in a low-pressure glow discharge in a gas flow. HMDSO was activated in a plasma-chemical reactor with a DC glow discharge in an argon flow. The argon flow (the mass flow rate was 230 mg/min) was injected in the direction of the anode from the cathode. HMDSO vapors were injected into the plasma-chemical reactor either through the hollow cathode or through the inlet located between the cathode and the anode. Polymer coatings were deposited on the substrates located in a vacuum chamber. Plasma polymerization was characterized based on the mass of coatings deposited under varying external conditions: the HMDSO mass flow rate (1–10 mg/min), the average discharge current (6–60 mA), and the discharge power (6–30 W). The operation modes of the plasma-chemical system were determined. The chemical structure of the coatings was analyzed using the infrared spectroscopy. The processes occurring in different regions of the glow discharge and at the interface near the substrate surface are proposed. A DC glow discharge in a gas flow can be used for local deposition of polymer coatings on the surface of dielectric or conductive materials

Low-temperature plasma treatment of polylactic acid and PLA/HA composite material

Investigations of the surface physicochemical properties of polylactic acid and polylactic acid/hydroxyapatite composite in a 70/30 ratio modified by atmospheric pressure low-temperature glow discharge argon plasma with the pulse duration of 1 μs and 5 μs and repetition rate of 100 kHz are described. Plasma modification of such materials may significantly affect physicochemical properties of surface. The polymerization of l-lactide was carried out at a temperature of 155 °C for 6 h. X-ray diffraction analysis shows that the degree of crystallinity of polylactic acid and composites based on polylactic acid/hydroxyapatite composite increases after plasma treatment due to polymer chain disruption. Infrared spectroscopy indicates that the –C=O absorption band intensity increases with plasma pulse duration, in turn indicating oxidation processes occurring in the polylactic acid surface layers. The wettability characteristics of the materials are improved by the plasma treatment, resulting in decreased water, glycerol, and ethylene glycol contact angle, and enhanced free surface energy

Surface property modification of biocompatible material based on polylactic acid by ion implantation

The investigations of the surface physicochemical and biological properties of polylactic acid modified by silver, argon and carbon ion implantation to doses of 1 × 10^14, 1 × 10^15 and 1 × 10^16 ion/cm^2 and energies of 20 keV (for C^+ and Ar^+) and 40 keV (for Ag^2+) are described. X-ray photoelectron spectroscopy revealed that chemical bond ratio in polylactic acid is alternated indicating that different chemical processes take place depending on the implanted ion kind. Chemical reactions that occur during ion implantation of polylactic acid are proposed. X-ray diffraction analysis shows the degree of crystallinity decrease for all the ion types that leads to microhardness and elastic modulus decreasing. Silver is established to form metal nanoparticle into subsurface layer of polylactic acid with the average size of 2-3 nm. It was shown by atomic force microscopy that the higher irradiation doses the lower the surface roughness of polylactic acid that results in hydrophilicity improvement. The cytotoxicity investigation on three individual donor macrophages shows that Ag-implanted polylactic acid has no negative impact on the immune system cells and can be very promising material for biomedical application