Microwave Plasma Research Papers - Academia.edu (original) (raw)
In this review, microwave plasma gas-phase synthesis of inorganic materials and material groups is discussed from the application-oriented perspective of a materials scientist: why and how microwave plasmas are applied for the synthesis... more
In this review, microwave plasma gas-phase synthesis of inorganic materials and material groups is discussed from the application-oriented perspective of a materials scientist: why and how microwave plasmas are applied for the synthesis of materials? First, key players in this research field will be identified, and a brief overview on publication history on this topic is given. The fundamental basics, necessary to understand the processes ongoing in particle synthesis—one of the main applications of microwave plasma processes—and the influence of the relevant experimental parameters on the resulting particles and their properties will be addressed. The benefit of using microwave plasma instead of conventional gas phase processes with respect to chemical reactivity and crystallite nucleation will be reviewed. The criteria, how to choose an appropriate precursor to synthesize a specific material with an intended application is discussed. A tabular overview on all type of materials synthesized in microwave plasmas and other plasma methods will be given, including relevant citations. Finally, property examples of three groups of nanomaterials synthesized with microwave plasma methods, bare Fe 2 O 3 nanoparticles, different core/shell ceramic/organic shell nanoparticles, and Sn-based nanocomposites, will be described exemplarily, comprising perspectives of applications.
A waveguide-based microwave plasma system was built using a resonant cavity and a quartz tube. 2.45 GHz 850 W magnetron was used to obtain helium discharge without an igniter. The temporal images of discharge were recorded on microsecond... more
A waveguide-based microwave plasma system was built using a resonant cavity and a quartz tube. 2.45 GHz 850 W magnetron was used to obtain helium discharge without an igniter. The temporal images of discharge were recorded on microsecond time scales using an intensified charge-coupled device camera. The excitation temperature was calculated as 3385 K using the helium lines, which were obtained from emission spectrum of the discharge. The gas temperature was measured as 1208 K by a thermocouple.
- by Ondřej Jašek and +1
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- Engineering, Nanoparticles, CHEMICAL SCIENCES, Mossbauer Spectroscopy
Titanium surfaces were equipped with positively and negatively charged chemical functional groups by plasma polymerization. Their capability to influence the adhesion of human mesenchymal stem cells (hMSCs) and inflammation processes was... more
Titanium surfaces were equipped with positively and negatively charged chemical functional groups by plasma polymerization. Their capability to influence the adhesion of human mesenchymal stem cells (hMSCs) and inflammation processes was investigated on titanium substrates, which are representative of real implant surfaces. For these purposes, titanium samples were coated with plasma polymers from allylamine (PPAAm) and acrylic acid (PPAAc). The process development was accompanied by physicochemical surface analysis using XPS, FT-IR and contact angle measurements. Very thin plasma polymer coatings were created, which are resistant to hydrolysis and delamination. Positively charged amino groups improve considerably the initial adhesion and spreading steps of hMSCs. PPAAm and PPAAc surfaces have an effect on the differentiation of hMSCs, e.g., the expression of osteogenic markers in dependence on culturing conditions. Acrylic acid groups appear to stimulate early mRNA differentiation markers (ALP, COL, Runx2) under basal conditions, whereas positively and negatively charged groups both stimulate late differentiation markers, like BSP and OCN, after 3 days of osteogenic stimulation. Long-term intramuscular implantation in rats revealed that PPAAc surfaces caused significantly stronger reactions by macrophages and antigen-presenting cells compared to untreated control (polished titanium) samples, while PPAAm films did not show a negative influence on the inflammatory reaction after implantation.