The Observation of Plasma Structures in Electrolyte Solution

Maximov, A. I.; Kuz’micheva, L. A.; Nikiforov, Alexander Y.; Titova, J. V.

doi:10.1007/s11090-006-9015-5

Cited by 9 publications

(9 citation statements)

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“…Under these conditions, the electric characteristics of face discharge became very close to those of the discharge in dielectric tubes filled electrolyte solution, as previously described by us [4]. This type of discharge was shown to be effective toward the oxidative modification of native cellulose- containing TABLE II RESIDUAL LIGNIN IN BAST FIBERS AFTER TWO-STAGE PROCESS materials, and the application of face discharge for the delignification of bast fibers is rather reasonable.…”

Section: Resultssupporting

confidence: 82%

“…In this case, the plasma zone is shunted by the thin surface layer of the electrolyte. This type of discharge is similar to a diaphragm one [4], and the mechanisms of discharge interaction with electrolyte solution are also close. Solution activation takes place under the action of the primary active articles H, OH, and e solv (products of nonequilibrium dissociation and ionization of water molecules).…”

Section: Introductionmentioning

confidence: 59%

“…Under these conditions, the direct plasma action on the material under treatment may be joined with the action of solution, which is activated by a plasma. Several types of plasma-solution systems with underwater discharges as well as some of their physical properties and chemical effects were described in [2]- [4].…”

Section: Introductionmentioning

confidence: 99%

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Application of Underwater Discharge for Modification of Cellulose Materials

Titova¹,

Stokozenko

Maximov³

2010

IEEE Trans. Plasma Sci.

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The electric parameters of "face" underwater discharges were under study. Oscillograms of current and voltage were obtained for various conditions of discharge ignition, and dynamic current-voltage characteristics were obtained. The application of this type of discharge for delignification processes of rough bast fibers (flax, hemp, and jute) in different solutions was investigated. The residual lignin was determined after plasmasolution treatment and after a shorter chemical treatment with reduced alkalinity. Such two-stage treatment was shown to be effective considerably as far as the delignification degree was 68% for flax, 64% for hemp, and 39% for jute, which are higher than those of lignin removal by traditional chemical technologies.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 59%

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Application of Underwater Discharge for Modification of Cellulose Materials

Titova¹,

Stokozenko

Maximov³

2010

IEEE Trans. Plasma Sci.

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“…Moreover, the underwater plasma is a source of different reaction species, solvated electrons, ozone, UV-radiation, shock waves, etc. and the energies of these plasma species are at least in the same order or are higher than C-C and C-H dissociation energies [2,7,8]. Thus, all functionalization reactions at polyolefin surfaces are accompanied by partial polymer degradation because of C-C bond dissociation.…”

Section: Introductionmentioning

confidence: 96%

“…[1][2][3][4]. A densely functionalized polyolefin surface with preferably monotype functional groups is needed to graft molecules chemically for producing special surface properties as necessary for biochips, sensors, anti-fouling layers, etc.…”

Section: Introductionmentioning

confidence: 99%

Role of Hydrogen Peroxide in Selective OH Group Functionalization of Polypropylene Surfaces using Underwater Capillary Discharge

Joshi

Friedrich

Wagner

2011

Journal of Adhesion Science and Technology

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Plasma chemical methods are well suited for introducing functional groups to the surfaces of chemically inert polymers such as polyolefins. However, a broad variety of functional groups are often formed. Unfortunately, for further chemical processing such as grafting of molecules for advanced applications a highly dense monotype functionalized polyolefin surface is needed. Therefore, the main task was to develop a selective surface functionalization process, which formed preferably only a single type of functional groups at the surface in high concentration. Amongst the novel plasma methods, the underwater plasma process (UWP) is one of most attractive options to solve the problem of monotype functionalization. Such plasma is an efficient source of ions, electrons, UV-radiation, high-frequency shock waves, radicals such as hydroxyl radical, and reactive neutral molecules such as hydrogen peroxide.In contrast to established gas phase glow discharge processes, the water phase limits the particle and radiation energies and thus the energy input into the polymer. By virtue of the liquid water environment, which moderates highly energetic plasma species, extensive oxidation, degradation, cross-linking and radical formation on the polymer are more limited as compared to gas plasma exposure. The variety of plasma produced species in the water phase is also much smaller because of the limited reaction possibilities of the plasma with water. The possibility to admix a broad variety of chemical additives makes underwater plasma even more attractive.Hydrogen peroxide and the catalyst (Fe-ZSM5) should influence and increase the equilibrium concentration of OH radicals in the underwater plasma process. It was found that these radicals played a very important role in OH functionalization of polyolefin surfaces. Hydrogen peroxide was identified to be the most prominent precursor for OH group formation in the UWP. The catalyst would affect the steady state of OH radical formation and its reaction with the substrate surface and thus accelerates the functionalization process.

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Selective Surface Modification of Polypropylene using Underwater Plasma Technique or Underwater Capillary Discharge

Joshi¹,

Schulze²,

Meyer‐Plath³

et al. 2009

Plasma Processes & Polymers

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Among new types of plasma processes, the underwater plasma is one of the most attractive methods for functionalization of polymer surfaces. The interesting features of plasma solution system are that the material surfaces to be modified remain in contact with the plasma‐moderated solution. The role of plasma‐moderated liquids, allows the reach of the reactive species through solution onto the geometrically hindered sites. The UV radiation produced in plasma formation helps in generating additional excited, ionized, and dissociated molecules and species in the reaction solution. An interesting feature of the technique is its flexibility to use a wide variety of additives as or in solution system. This allows us to create a selective or monotype functionalization of material surfaces. Such system was studied for the selective hydroxyl functionalization of polypropylene surface. The oxidation of polymer surfaces and the introduction of O‐containing functional groups by underwater plasma was found to exceed concentrations typically achieved in oxygen low‐pressure gas discharge plasmas up‐to two‐folds (maximal 56 O/100 C). The fraction of OH groups among all O‐containing moieties amounts from 25 to 40% in comparison to that in the gas plasma of about 10% OH groups. Addition of hydrogen peroxide into this same system increases the fraction of CO bonds up to 75% (27‐OH/100 O). A study was focused to optimize the role of hydrogen peroxide on the efficiency of oxidation and selectivity with chemical derivatization with respect to the formation of mono‐sort hydroxyl functionalities, calculated using a chemical derivatization technique.

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The Observation of Plasma Structures in Electrolyte Solution

Cited by 9 publications

References 0 publications

Application of Underwater Discharge for Modification of Cellulose Materials

Application of Underwater Discharge for Modification of Cellulose Materials

Role of Hydrogen Peroxide in Selective OH Group Functionalization of Polypropylene Surfaces using Underwater Capillary Discharge

Selective Surface Modification of Polypropylene using Underwater Plasma Technique or Underwater Capillary Discharge

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