J. Houdkova

Deposition of hard thin films from HMDSO in atmospheric pressure dielectric barrier discharge

An atmospheric pressure dielectric barrier discharge burning in nitrogen with a small admixture of hexamethyldisiloxane (HMDSO) was used for the deposition of thin organosilicon films. The thin films were deposited on glass, silicon and polycarbonate substrates, and the substrate temperature during the deposition process was increased up to values within the range 25 - 150 C in order to obtain hard SiOx-like thin films.

Adhesion and differentiation of Saos-2 osteoblast-like cells on chromium-doped diamond-like carbon coatings

Diamond-like carbon (DLC) thin films are promising for use in coating orthopaedic, dental and cardiovascular implants. The problem of DLC layers lies in their weak layer adhesion to metal implants. Chromium is used as a dopant for improving the adhesion of DLC films. Cr-DLC layers were prepared by a hybrid technology, using a combination of pulsed laser deposition (PLD) from a graphite target and magnetron sputtering. Depending on the deposition conditions, the concentration of Cr in the DLC layers moved from zero to 10.0 at.%. The effect of DLC layers with 0.0, 0.9, 1.8, 7.3, 7.7 and 10.0 at.% Cr content on the adhesion and osteogenic differentiation of human osteoblast-like Saos-2 cells was assessed in vitro. The DLC samples that contained 7.7 and 10.0 at.% of Cr supported cell spreading on day 1 after seeding. On day three after seeding, the most apparent vinculin-containing focal adhesion plaques were also found on samples with higher concentrations of chromium. On the other hand, the expression of type I collagen and alkaline phosphatase at the mRNA and protein level was the highest on Cr-DLC samples with a lower concentration of Cr (0−1.8 at.%). We can conclude that higher concentrations of chromium supported cell adhesion; however DLC and DLC doped with a lower concentration of chromium supported osteogenic cell differentiation.Graphical Abstract

Hydrogen at Polymer Surfaces

We present a relatively simple method for analyzing H content on surfaces of selected commercially available polymers, i.e. polyethylene, polypropylene, polystyrene, and poly(methylphenylsilylene). The applied method, i.e. the Elastic Peak Electron Spectroscopy (EPES), is based on quasi‐elastic scattering of primary beam electrons with atoms of solid sample constituents. Electron energy, scattering angle and difference between electron mass and atomic mass of sample constituents induces an electron recoil energy loss. Recoil effect results of splitting the elastic peak into components, by their energy shifting and broadening. For above‐mentioned polymers, the EPES method indicates the surface H content close to the nominal composition. Sampling depth of the method does not exceed inelastic mean free path of electrons used in the scattering experiment. Therefore, the technique is useful to monitor H surface content during or after various surface modifications as UV, electron and ion beam modification of p...