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Controlled structuring of self-assembled polystyrene microsphere arrays by two different plasma systems
Domonkos, Mária ; Ižák, Tibor ; Stolcova, L. ; Proška, J. ; Kromka, Alexander
In this study we present a successful manipulation of microspheres by reactive ion etching (RIE). A self-assembled monolayer close-packed array of monodisperse polystyrene microspheres (PM) with diameter of 471 nm was used as the primary template. The PM templates were processed in two different RIE systems: (i) capacitively coupled radiofrequency plasma (CCP) and (ii) dual plasma system which combines CCP and pulsed linear-antenna microwave plasma (PLAMWP). The influence of process conditions on the PM geometry was systematically studied by scanning electron microscopy (SEM). It was found out that choosing optimal parameters results in a tunable diameter of PM with various shapes (from spheres to pyramid-like structures) while keeping their periodic hexagonal ordering.
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Comparative study on functionalization of NCD films with amine groups
Artemenko, Anna ; Kozak, Halyna ; Stuchlík, Jiří ; Biederman, H. ; Kromka, Alexander
Two plasma-based processes for functionalization of oxygen or hydrogen terminated NCD surfaces with amino groups were compared. The first process was based on deposition of thin (8 nm) amine containing plasma polymer by RF magnetron sputtering of Nylon target in Ar/N-2 working gas mixture. RF plasma treatment in NH3 for 10 minutes was used in the second process. The properties of NCD films before and after amination were characterized by scanning electron microscopy (SEM), wettability measurements, spectral ellipsometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and current-voltage (I-V) measurements. The presence of nitrogen (and thus amino groups) on the surface was confirmed by XPS measurements in both cases. The obtained results indicated that NCD surface functionalization from amine containing plasma polymer by RF magnetron sputtering is an alternative technological solution for successful functionalization of diamond surfaces for biosensor applications.
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Influence of incorporated nanodiamond particles on mechanical properties of composite material based on multi-layer PVA nanofiber textiles
Prošek, Zdeněk ; Indrová, K. ; Rácová, Z. ; Ryparová, Pavla ; Nežerka, V. ; Topič, J. ; Tesárek, Pavel ; Kromka, Alexander
The present study investigates the influence of NDP on mechanical properties of multi-layer PVA nanofiber textiles. The particles of a diameter equal to 5 nm were incorporated into double- and triple-layer textiles, while the single-layer samples were prepared as the reference. The diameter of PVA nanofibers varied from 100 to 300 nm. We characterized the tensile strength, stiffness and ductility of fabricated nanofibers by using a conventional method – a tensile test. We found that the NDP-enriched nanofibers reveal antibacterial character. However, none or negligible influence of NDP additions on the tested mechanical properties was observed.
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Controlled structuring of self–assembled polystyrene microsphere arrays by two different plasma systems
Domonkos, Mária ; Ižák, Tibor ; Štolcová, L. ; Proška, J. ; Kromka, Alexander
In this study we present a successful manipulation of microspheres by reactive ion etching (RIE). A self-assembled monolayer close-packed array of monodisperse polystyrene microspheres (PM) with diameter of 471 nm was used as the primary template. The PM templates were processed in two different RIE systems: (i) capacitively coupled radiofrequency plasma (CCP) and (ii) dual plasma system which combines CCP and pulsed linear-antenna microwave plasma (PLAMWP). The influence of process conditions on the PM geometry was systematically studied by scanning electron microscopy (SEM). The process conditions were controlled by varying radiofrequency (RF) power, gas mixture (O2:CF4 ratio) and process duration.
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Comparativ study on functionalization of NCD films with amine groups
Artemenko, Anna ; Kozak, Halyna ; Stuchlík, Jiří ; Biederman, H. ; Kromka, Alexander
Nanocrystalline diamond (NCD) films are considered as highly attractive material for biosensing due to its unique semiconducting properties. This can be achieved by modification of NCD films surface on molecular level. Typically chemical immobilization of biomoleculs requires the presence of active functional groups on the diamond surface. This was achieved by attachment of -NH2 functional groups on the surface of H- or O-terminated NCD surface via two plasma-based processes. The first process, deposition of thin amine containing polymer by RF magnetron sputtering of Nylon target in Ar/N2 gas mixture. The second process employs RF plasma treatment in NH3 for 10 minutes. Chemical derivatization (CD) XPS analysis revealed that polymeric coating exhibits a higher amount of amino groups than the diamond surface treated in NH3 RF plasma. Results of I-V measurements showed that surface conductivity of H-terminated NCD films was preserved only after the RF sputtering.
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Growth of diamond thin films: a review
Kromka, Alexander ; Potocký, Štěpán ; Rezek, Bohuslav
Diamond is shown as an extraordinary material which offers promising solution for variety of fundamental studies and industrial uses. Here, growth of synthetic diamond films at low pressures (1 atm) and low temperatures (<1000°C) from carbon consisting gas mixtures is discussed. Variety of chemical vapor deposition techniques are reviewed, their advantages and disadvantages are pointed out too.
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Structuring of diamond films by reactive ion plasma etching
Domonkos, M. ; Ižák, Tibor ; Proška, J. ; Kromka, Alexander
In this study, two common strategies of diamond film structuring are described. Main focus is on the comparison of top-down and the bottom-up strategies. The top-down strategy is primary related to dry reactive ion etching through masking materials (or even without mask), while bottom-up strategy is based on selective area deposition of diamond film. Several methods of both strategies are demonstrated in details in the article, regarding to their properties and basic principles.
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