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Characterisation of the surface structure and bioactivity of glass and glass ceramics using surface topography

100%

Lutišanová G., Palou M., Mikula M., Kozánková J.

Open Chemistry

2012

vol. 10

issue 6

1890-1898

The present paper reports the results of the relationship between the surface topography, microstructure and the in vitro bioactivity of samples with and without fluorapatite content in simulated body fluid. Glasses and glass ceramics belonging to the Li2O-SiO2-CaO-P2O5-CaF2 system were prepared by using conventional melting technique following by heat treatment to obtain glass ceramics. This current study demonstrates the benefits of combining two microscopic methods for better investigation of the surface structure. The formation of apatite layer on the surface and the increase in surface roughness proved that the glasses and glass ceramics with bioactive fluorapatite content could satisfy to the requirements for biomaterial applications. The results also showed that the roughness of apatite layer formed after immersion in body fluid on the surface of glasses with fluorapatite was more pronounced than that of equivalent glass ceramic samples cured under the same conditions. [...]

Multilayer coatings for flexible high-barrier materials

88%

VaÅ¡ko K., Noller K., Mikula M., Amberg-Schwab S., Weber U.

Open Physics

2009

vol. 7

issue 2

371-378

A multilayer, flexible, and transparent high-barrier system based on flexible plastic foils, polyethyleneterephthalate (PET) and ethylene-tetrafluoroethylene-copolymer (ETFE), combined with vacuum-deposited, inorganic SiOx layers and hybrid ORMOCERÂ® varnish layers were prepared in different orders on a semiproduction level. Barrier properties of prepared systems, as water vapour transmission (WVTR) and oxygen transmission (OTR), were measured and studied in connection with surface energy, surface topography, and water vapour adsorption properties. Correlations among layers sequence, barrier properties, and other parameters are presented, including some basic principles of permeation of substances through multilayer barrier systems. A combination of several inorganic and hybrid varnish layers is necessary to achieve the technological demands from a barrier standpoint. It is easier to suppress the oxygen transport than the water transport, due to the additional active penetration of water through hydrogen bonds and silanol creations at oxide interfaces, capillary condensation, and swelling with high internal pressure, leading to new defects.

On the topographic and optical properties of SiC/SiO2 surfaces

76%

Jureckova S., Jureckova M., Chovanec F., Kobayashi H., Takahashi M., Mikula M., Pina E.

Open Physics

2009

vol. 7

issue 2

321-326

The roughness of the semiconductor surface substantially influences properties of the whole structure, especially when thin films are created. In our work 3C SiC, 4H SiC and Si/a-SiC:H/SiO2 structures treated by various oxidation a passivation procedures are studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). Surface roughness properties are studied by fractal geometry methods. The complexity of the analysed surface is sensitive to the oxidation and passivation steps and the proposed fractal complexity measure values enable quantification of the fine surface changes. We also determined the optical properties of oxidized and passivated samples by using visual modelling and stochastic optimization.

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2 Open Physics

1 Open Chemistry

1 2012

2 2009

3 Mikula M.

1 Amberg-Schwab S.

1 Chovanec F.

1 Jureckova M.

1 Jureckova S.

1 Kobayashi H.

1 Kozánková J.

1 Lutišanová G.

1 Noller K.

1 Palou M.

1 Pina E.

1 Takahashi M.

1 VaÅ¡ko K.

1 Weber U.

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Characterisation of the surface structure and bioactivity of glass and glass ceramics using surface topography

Multilayer coatings for flexible high-barrier materials

On the topographic and optical properties of SiC/SiO2 surfaces