On phenomena in ionized gases
References [1] D. Mariotti, R.M. Sankaran, J. Phys. D 43
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- Bu sahifa navigatsiya:
- Atmospheric pressure plasmas for agriculture, medicine and surface technology
- 1. Introduction and experimental set-up
- 2. Results and conclusions
- 3. References [1] M. Janda, V. Martišovitš, K. Hensel, Z. Machala, Plasma Chem. Plasma Proc., 36
- Electron interactions for plasma diagnostics and modelling
- 4. References
- Gas-liquid interfacial plasmas for novel gene transfer systems
- Pulsed Laser and Sputtering Deposition of Optical Materials
References [1] D. Mariotti, R.M. Sankaran, J. Phys. D 43 (2010) 323001. [2] N. Shirai, S. Uchida, F. Tochikubo, Jpn. J. Appl. Phys. 53 (2014) 046202.
10 Fig.1. Model for glow discharge electrolysis.
0
20 30 10 13 10 14 10 15 10 16 10 17 10 18 10 19 10 20 10 21 Distance from electrode (nm) Conc ent
ra tion (c
m -3 ) H + (x100) OH - (x100) Cl - Na + 2000
1000 0 10 13 10 14 10 15 10 16 10 17 10 18 10 19 10 20 10 21 Na + Cl - OH - (x100) H + (x1000) e aq Distance from interface (nm) Conc ent
ra tion (c
m -3 ) (a) (b)
Fig. 2. Spatial distribution of ion species in the liquid in front of (a) metal anode and (b) glow discharge cathode.
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XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Atmospheric pressure plasmas for agriculture, medicine and surface technology
J. Pawłat P 1 , U P. Terebun P 1
, M. Kwiatkowski 1 P , K. Hensel 2 Z. Machala 2 , Z. Kovalova 2 , K. Kučerová 2 , B. Tarabová 2 , M. Janda 2 A. Starek 3 , M. Budzen 3 , A. Sujak 3
1 Institute of Electrical Engineering and Electrotechnologies, Lublin University of Technology, Poland 2 Faculty of Mathematics, Physics and Informatics,Comenius University, Bratislava, Slovakia 3
An atmospheric pressure plasma jet and glidarc reactors were used to enhance the seed germination, disinfect non-heat resistant surfaces and to increase wettability of selected polymeric materials. Selected reactive oxygen and nitrogen species (RONS) were measured for plasma generators operating in different modes: Transient Spark, Mini Glide-arc and Dielectric Barrier Discharge Jet to find optimal operational conditions for selected biomedical and agricultural applications. E. coli was selected as a model microorganism for biodecontamination comparative tests.
Different types of discharges could be taken into account for biomedical, material and agricultural applications. This work summarizes selected experimental results in above fields, obtained with Mini Glide-arc (GA), Dielectric Barrier Discharge Jet (BDB), radio frequency (RF) plasma jet and Transient Spark (TS) [1-4].
Paper is primary choice for antibiotic sensitivity tests (disc diffusion method). Radio frequency plasma jet with central electrode inside the nozzle, working with mixtures of oxygen, nitrogen, air with helium or argon was tested to decrease the surface contact angle of cellulose based paper platform using Kruss DSA25E goniometer. The highest change: decrease of surface contact angle from 96 o
o after 60 s treatment was observed using mixture of helium and nitrogen. Experiments confirmed significant influence of the distance between the treated sample and reactor nozzle, especially for treatment times larger than 15 s. After 30s application of DBD plasma jet working with helium gas and admixture of air caused average decrease of the contact angle for acrylonitrile- butadiene-styrene from 75 o to 42
o , for polypropylene homopolymer from 82 o to 45 o , and for high impact polystyrene from 90 o to 48 o o, respectively. GA reactor was used for pre-sowing stimulation of
characterized by a different exposition times (1, 2, 5, 10 and 15 minutes) as well as untreated control were used. The highest germination parameters were obtained for seeds stimulated with plasma for the exposition times of 2 and 5 min. Control GA plasma treatment - 2 min
thuringiaca L., zoom 500x.
Germination capacity reached
60% and
germination energy was 54.5% comparing to 36.25% and 30% for control, respectively. SEM photos (Fig. 1) indicated visible changes of the seeds’ surface, however, distinguishing changes in the water contact angle measurement on the surface of the seeds were not observed. Measurements of RONS were performed in gas and liquid phase for selected plasma generators operating in different modes
[1] M. Janda, V. Martišovitš, K. Hensel, Z. Machala, Plasma Chem. Plasma Proc., 36 (2016) 767. [2] J. Pawłat, EPJAP 61(2) (2013) 1-11. [3] J. Pawłat, M. Kwiatkowski, P. Terebun, T. Murakami, IEEE Trans. Plasma Sci., 99, (2015) 1-7. [4] J. Pawłat, M. Kwiatkowski, P. Terebun, J. Diatczyk. J. Phys. D 49 (2016) 374001.
and Development Agency APVV-0134-12, Slovak grant agency VEGA 1/0918/15, KONNECT CATPLAS, and LUT research found. Topic number 17, 14 37
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Electron interactions for plasma diagnostics and modelling
P. Papp P P , J. Országh, Š. Matejčík P
P
The role of low-energy and high-energy electrons in discharges and plasma is well known. In the Electron Plasma Processes Laboratories (EPPL) at the Comenius University in Bratislava we are studying the low-energy processes on atoms, molecules and clusters in gas-phase. Electron ionisations, excitations and corresponding dissociative processes are measured by the means of mass spectrometry and optical emission spectroscopy, as well as a theoretical interpretation of results with quantum chemical calculations is being done. Most recently Plasma-Enhanced Chemical Vapour Deposition (PECVD) and Focused Electron Beam Induced Deposition (FEBID) precursors were studied using crossed electron/molecular beams techniques and theory.
The EPPL at the Comenius University in Bratislava are dealing with mass spectrometric studies of electron e ionisation and dissociative ionisation reactions of molecules M and clusters: e + M → M + + 2e
(1) e + M → X + (M-X) + + 2e
(2) electron attachment and dissociative electron attachment studies to the molecules and clusters: e + M → [M - ] # + 2e
(3) e + M → [M - ] # → X + (M-X) - + 2e (4)
electron induced fluorescence studies via excitation of atoms and molecules and in dissociative excitation of the molecules:
(6) where X, (M-X) represent neutral fragments of the molecule, M*, X* represent excited states of molecules or fragments in different electronic states. These studies (1-4) cover measurements of the ionisation functions of the molecules (partial cross sections), determination of the reaction threshold for the
reactions and
the corresponding bond dissociation energies, mainly on molecular targets relevant to plasma technology, nano technology and radiation chemistry (metal-organic compounds, alkenes, halogenated compounds, amino acids) [1]. The non elastic interactions (5-6) of electrons with atoms and molecules produce emission spectra of atoms, molecules recorded at different electron energies and absolute excitation-emission cross sections, being analyzed by UV/VIS optical spectrometer [2].
Last few years a great effort of EPPL has been applied to understand the elementary processes of low-energy electron interactions with precursor molecules relevant to nano-technology [1-5]. We have studied several precursors available for deposition of Fe, Co, Cu, Zn, Ni, Si or W layers. The most extensive studies have been performed with the Fe(CO)
5 precursor; with electron induced ionisation (1,2) and dissociative electron attachment (3,4) to understand the fragmentation of ionised Fe(CO) 5 and
its decomposition to Fe + and Fe - respectively; with electron induced
fluorescence the
excitation thresholds and Fe and CO emission bands. Most recently the gas-phase experiments were upgraded to cluster measurements of this compound to reveal the behaviour of electron ionisation and electron attachment of a precursor in larger environment.
Financing of this work was by the Slovak Grant Agency VEGA 1/0417/15. This work was supported by the Slovak Research and Development Agency, project Nr. APVV-15-0580. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 692335.
[1] M. Lacko, P. Papp, K. Wnorowski, Š. Matejčík, Eur. Phys. J. D 69 (2015) 84. [2] A. Ribar, M. Danko, J. Országh, J.F.F. da Silva, I. Utke, Š. Matejčík, Eur. Phys. J. D 69 (2015) 117.
[3] S. Engmann, M. Stano, P. Papp, M. J. Brunger, Š. Matejčík, O. Ogólfsson, J. Chem. Phys. 138 (2013) 044305. [4] P. Papp, S. Engmann, M. Kučera, M. Stano, Š. Matejčík, O. Ogólfsson, Int. J. Mass. Spectrom.
[5] S. Engmann, M. Stano, Š. Matejčík, O. Ogólfsson, Angew. Chem. Int. Ed. 50 (2011), 9475. Topic number 1 38
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Gas-liquid interfacial plasmas for novel gene transfer systems
T. Kaneko 1 P , S. Sasaki P 1 P , K. Takashima 1 P , T. Sato 2 P , M. Kanzaki 3 P
P
P
P
minimally-invasive gene transfer systems, where the various kinds of plasma-induced stimulations could affect the transfer efficiency. In an attempt to identify the dominant factors for enhancing the gene transfer, we focus on reactive species and measure the concentration and distribution of the plasma-produced reactive species in liquid using two types of plasmas; “plasma jet in contact with liquid” and “micro plasma in liquid (in-liquid plasma)”. We have revealed a positive correlation between the transfer efficiency and concentration of the short-lived reactive species such as • OH
. Furthermore, it is found that the duration of • OH
production by the in-liquid plasma is longer than that by the plasma jet, and accordingly, the higher transfer efficiency is realized by the in-liquid plasma compared with the plasma jet irradiation.
Non-equilibrium atmospheric-pressure plasmas (APPs) in liquid or in contact with liquid, i.e., gas-liquid interfacial atmospheric-pressure plasmas (GLI-APPs), have attracted much attention as a novel technology, which provides new physical and chemical effects on the surface of the liquid and the exotic reactions are expected in the liquid. Using the GLI-APPs, several applications have been developed in material science such as nanoparticle synthesis, surface treatment of nanomaterials, while in life science such as medicine, agriculture, and biology. Recently, GLI-APPs are medically utilized for highly-efficient and minimally-invasive gene transfer systems [1-3], where the various kinds of plasma-induced stimulations could affect the transfer efficiency. In an attempt to identify the dominant factors for enhancing the gene transfer, we focus on reactive species, which are classified into three categories in terms of the life-span: long-lived (e.g. H 2 O 2 ) and short-lived (e.g. • OH, O
2 •- ) reactive species, and investigate the functions of the plasma-produced reactive species in liquid on the cell activity such as cell-membrane permeability [4,5] using two types of plasmas; “plasma jet in contact with liquid” and “micro plasma in liquid (in-liquid plasma)”.
First, we developed a plasma jet whose plume is in contact liquid using low frequency (frequency: 8-10 kHz, voltage: 5-12 kV) with Helium gas flow, which was exposed to the biological buffer at a controlled thickness. To evaluate the spatial mapping of liquid phase OH radicals ( • OH aq ) and
plasma-induced effect on the gene transfer, the gelling reagent containing terephtalic acid (TA) and adherent cells with gene-simulated fluorescent dye (YOYO-1) are prepared, respectively. It is found that • OH
which reaches to gelling reagent decreases with an increase in liquid thickness (<1 mm), and the plasma-induced YOYO-1 transfer is found to decay markedly with liquid thickness. Furthermore, the center-localized distribution of • OH aq , which is resulting from the center-peaked • OH distribution in the gas phase region, corresponds with the distribution of the transferred cells by plasma irradiation. Second, we generated in-liquid plasma by applying a pulse power (voltage: 1.5 kV, pulse width: 10-100 μs, current:0.2-2.8 A) to micro-scale thin electrode in the biological buffer. Here, indirect plasma irradiation (IPI) method was employed to eliminate factors except for products in liquid for a clarification of cell response mechanism. The transfer efficiency using in-liquid plasma is found to be much higher than that using plasma jet. Furthermore, it is observed that the duration of • OH aq
production by the in-liquid plasma is longer than that by the plasma jet. These results suggest that short-lived reactive species such as • OH aq is likely one of the dominant factors responsible for the plasma-induced YOYO-1 transfer, and the higher transfer efficiency is relevant to the longer duration of • OH aq production using the in-liquid plasma compared with the plasma jet irradiation.
[1]
S. Sasaki, et al., Appl. Phys. Express 7 (2014) 026202. [2]
[3]
S. Sasaki, et al., Sci. Rep. 6 (2016) 25728. [4]
S. Sasaki, et al., J. Phys. D: Appl. Phys. 49 (2016) 334002. [5]
T. Kaneko et al., J. Clin. Biochem. Nutr. 60 (2017) 3. 17 39
XXXIII ICPIG, July 9-14, 2017, Estoril/Lisbon, Portugal
Pulsed Laser and Sputtering Deposition of Optical Materials
M. Chaker P 1 P
P 1 P
P
We used Pulsed Laser Deposition and Sputtering to synthesize advanced materials in the form of thin films with tailored properties. In this presentation, we will mainly focus on two materials, namely calcium-barium niobate (CBN) that show excellent electro-optical properties and vanadium dioxide (VO 2 ) that presents a reversible insulator-to-metal transition. Capitalizing on our in-depth characterization of such films, we were able to optimize their properties and to explore their use for various applications, including high performance electro-optical waveguide modulators based on CBN films and smart radiator device (SRD) based on VO 2 films for the passive thermal control of microsatellites.
Innovation in materials science and engineering resides in our ability to design new materials with tailored properties (electrical, optical, magnetic, etc.) by controlling their microstructure. One of the most powerful means to uniquely arrange matter at such scale is to use plasmas due to their unique ability to provide simultaneously a variety of particles such as ions, neutral atoms and radicals. In this presentation, we will focus on the synthesis of two specific materials in the form of thin films, namely calcium-barium niobate (CBN) and vanadium dioxide (VO 2 ) using Pulsed Laser Deposition (PLD) and sputtering.
Calcium barium niobate (Ca x Ba 1-x Nb 2 O 6 ) in the form of thin film is a promising material for integrated electro-optical (EO) device applications, due to its unique EO properties (EO coefficient of 130 pm/V) and high Curie temperature (above 250°C). We successfully used PLD to grow high quality CBN epitaxial thin films on various substrates (MgO and NSTO). These films show both low surface roughness and out-of-plane lattice parameters comparable to that of CBN bulk material. An advanced patterning method using a nickel hard mask and a chlorine inductively coupled plasma was also developed. Combining PLD grown films and patterning, waveguides with smooth and nearly vertical sidewalls were fabricated and characterized. In addition, highly (001)-oriented CBN thin films were grown on MgO by Radio- Frequency magnetron sputtering. Close-to-bulk film stoichiometry (Ca 0.28 Ba
Nb 2 O 6 ) was obtained for an O 2
the annealing temperature of 1000 o C, (001) oriented thin films were achieved with lattice parameter in the c-direction and a chemical composition very close to that of the bulk. The refractive index of the films is 2.21 at λ = 630 nm and a strong second harmonic signal can be generated nonlinearly in the films [1]. This overall work represents a significant step towards the integration and the potential use of CBN films for high performance electro-optical waveguide modulators. Vanadium dioxide (VO 2 ) is a “smart” material that undergoes a reversible insulator-to-metal transition (IMT), characterized by a dramatic increase of both its conductivity and reflectivity in infrared and terahertz (THz) ranges of wavelengths when the temperature is increased above 68°C. In a series of studies, our group has investigated the physics governing the IMT of VO 2 thin films [2] and explored new application opportunities [3-4]. For example, we demonstrated that by incorporating VO 2
was possible to achieve VO 2 -based smart coatings responding to the temperature by adapting their thermal emittance to radiate more heat at high temperature and less at low temperature. This behavior is quite interesting for application as smart radiator device (SRD) for the passive thermal control of microsatellites.
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