Basic Physics of Plasmas/Discharges: Production of Active Species

Ricard, A.

doi:10.1007/978-94-009-1946-4_1

Cited by 2 publications

(4 citation statements)

References 17 publications

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“…A more complex situation holds for the singlet state, because there is the possibility of radiative de-excitation of all n 1 P levels both the ground state and to the 2 1 S metastable state. For the above-mentioned reasons, the He 2 3 S metastable states are found to be more important in surface modifications in the discharge than are the He 2 1 S metastable states [20].…”

Section: Optical Emission Spectroscopy Investigationsmentioning

confidence: 98%

“…The metastable species-metastable species collision has a cross section of about σ m−m = 1.4 × 10 −14 cm 2 and also generates energetic electrons [21]. Ionic states could be produced by the Penning ionization process in the helium-diatomic molecules gas mixtures; the rate coefficients of about 10 −11 cm 3 s −1 for such processes indicate a reaction with medium efficiency [20]. It must also be pointed out that, insofar as the triplet state He 2 3 S is concerned, the optical transition to the ground state being forbidden, all the radiative cascades from the higher levels bring the atom into the 2 3 S metastable state.…”

Section: Optical Emission Spectroscopy Investigationsmentioning

confidence: 99%

“…The electron temperature T e can be obtained from the ratio between the emission intensities of a singlet and a triplet line. For the plasma region (negative light emission) the following relation holds [20,23]:…”

Section: Experiments Without Pet In the Dischargementioning

confidence: 99%

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Surface cross linking and functionalization of poly(ethylene terephthalate) in a helium discharge

Gheorghiu

Aréfï

Amouroux

et al. 1997

Plasma Sources Sci. Technol.

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Films of poly(ethylene terephthalate) (PET) have been subjected to a low frequency (70 kHz) helium discharge, with a non-symmetrical configuration of electrodes, in order to study the treatment conditions for which the 'ageing' effect is slowed down. Treatments were made for different gas flow rates (40, 70 and 100 sccm) and different exposure times (1, 10 and 30 s). Emission spectroscopy and mass spectrometry were used to characterize the discharge plasma. The resulting modifications to the polymer surface were analysed via contact angle measurements and the XPS technique. It is pointed out that treatments on an He discharge induce both a functionalization and a cross linking of the uppermost layers of the polymer film. The residual oxygen, which partially originates within the polymer, induces surface oxidation. The cross-linked content critically depends on the residence time and concentration of implicated species. It seems that a change in the surface work function takes place as a result of a surface restructuring in the earliest stages of the reactions. This could involve an increase in the rate constant for the surface de-excitation of the helium metastables in the presence of the polymer. A contribution to the understanding of the competitive processes of cross linking and functionalization, as a function of the helium flow rate, is accomplished.

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Section: Optical Emission Spectroscopy Investigationsmentioning

confidence: 98%

Section: Optical Emission Spectroscopy Investigationsmentioning

confidence: 99%

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Surface cross linking and functionalization of poly(ethylene terephthalate) in a helium discharge

Gheorghiu

Aréfï

Amouroux

et al. 1997

Plasma Sources Sci. Technol.

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“…Modification with radiofrequency plasma is able to solve a wide range of problems: removal of residual stresses, changing the surface roughness, removal of relief and fractured layers, increasing corrosion resistance, activating the surface of the material for finishing, increasing water absorption, etc. In a number of works [12][13][14][15][16][17][18][19][20][21], many authors have studied the effects of plasma on polymers, finding that significant changes occur in the polymer structure itself when exposed to low-temperature plasma.…”

Section: Introductionmentioning

confidence: 99%

Improving the Physical and Mechanical Performance of Laminated Wooden Structures by Low-Temperature Plasma Treatment

et al. 2021

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This paper considers the effect of RF plasma on wood in improving the adhesion of binders to wood by increasing its surface wettability. Our study reveals that radiofrequency (RF) plasma treatment causes a greater than threefold decrease in the marginal wetting angle of wood. The greatest effect is achieved in RF plasma treatment in argon, which is on average 5% greater than that of RF plasma treatment in air or in propane/nitrogen mixture. In addition, the power of the RF plasma torch has the greatest influence, and the main influence comes from the voltage applied to the RF plasma torch; current does not have such a significant effect. To achieve a significant effect, the duration of exposure should be at least 5 min, with a total power of 4.05 kW.Studies have been conducted to determine the adhesive strength of wood. An increase in the strength of laminated beams made from RF-treated bars in relation to control samples was found. The greatest impact on the adhesion strength was revealed when using PVA-based glue, compared with the use of polyurethane-based adhesives and urea-formaldehyde resin.

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Basic Physics of Plasmas/Discharges: Production of Active Species

Cited by 2 publications

References 17 publications

Surface cross linking and functionalization of poly(ethylene terephthalate) in a helium discharge

Surface cross linking and functionalization of poly(ethylene terephthalate) in a helium discharge

Improving the Physical and Mechanical Performance of Laminated Wooden Structures by Low-Temperature Plasma Treatment

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