Université PSL



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Cyclic Olefin Copolymer Plasma millireactors
Schelcher G, Guyon C, Ognier S, Cavadias S, Martinez E, Taniga V, Malaquin L, Tabeling P and Tatoulian M
Lab. Chip - 14(16) 3037-42 - DOI: 10.1039/c4lc00423j - 2013
The novelty of this paper lies in the development of a multistep process for the manufacturing of plasma millireactors operating at atmospheric pressure. The fabrication process relies on the integration of metallic electrodes over a cyclic olefin copolymer chip by a combination of photopatterning and sputtering. The developed plasma millireactors were successfully tested by creating air discharges in the gas volume of the millichannel. A sputtered silica layer was deposited on the channel walls to provide a barrier between the plasma and the polymer in order to prevent the alteration of polymer surfaces during the plasma treatment. Interest in this process of employing plasma millireactor as a high reactive environment is demonstrated here by the degradation of a volatile organic compound (acetaldehyde) in ambient air. In this miniaturized device, we obtained a high acetaldehyde conversion (98%) for a specific input energy lower than 200 J L(-1).
Surface functionalization of COC microfluidic materials by plasma and click chemistry processes
Y. Ladner, F. D’orlye, C. Perrard, B. Da Silva, C. Guyon, M. Tatoulian, S. Griveau, F. Bedioui & A. Varenne
Plasma Process - 10(11) :959-69 - DOI:10.1002/ppap.201300066 - 2013
A robust method for COC surfaces functionalization was developed for the first time by plasma polymerization. 1-bromopropane in the vapor phase allowed the formation of a brominated deposit on COC surfaces, which stability, homogeneity and chemical nature were evaluated for different experimental conditions. The analysis of vapor phase was achieved by mass spectrometry to control brominated precursor fragmentation. Following nucleophilic exchange in the presence of NaN3 to convert the brominated surface to azide-bearing surface, these modified COC were further functionalized with a fluorescent alkyne, via the copper-catalyzed azide–alkyne cycloaddition reaction, i.e. “click” reaction. Surface modifications were characterized by water contact angle measurement, ellipsometry, electrochemical microscopy, XPS, IR and fluorescence microscopy. This new process was proved to be efficient and stable in time up to 7 days.
Catkin liked nano-Co3O4 catalyst built-in organic microreactor by PEMOCVD method for trace CO oxidation at room temperature
G. L. Chen,C. Guyon,Z. X. Zhang,B. Da Silva,P. Da Costa,S. Ognier,D. Bonn,M. Tatoulian
Microfluidics and Nanofluidics - 16(1-2) :141-148 - DOI:10.10.1007/s10404-013-1220-y - 2013
In this paper, tricobalt tetraoxide (Co3O4) catalyst was coated on the polydimethylsiloxane microchannel by the plasma-enhanced metal-organic chemical vapor deposition technology. The obtained Co3O4 film was characterized by SEM, XRD, XPS, and TEM, and the results show that the as-deposited Co3O4 film was initially composed of many cauliflowers-shaped microclusters. Also, the microcauliflower was transformed from an amorphous phase to a crystal phase when the Co3O4 film was treated by Ar and O2 plasma for more than 20 min, and the crystal lattice line occurred on the surface of nano-sized-Co3O4 particles. Meanwhile, the interface of Co3O4 particles with diameter between 3 and 12 nm became obvious and some nano-catkin structures were also formed on the Co3O4 film. The ratio of Co3+/Co2+ in the spinel-type Co3O4 was nearly 2, and the nano-particles predominantly expose their {311}, {111}, and {220} planes. These morphologies and structure characteristics were found to be ideal for increasing the catalytic activity efficiency of Co3O4 for CO oxidation, and the catalytic stability of Co3O4 coated on the organic microreactor lasted nearly 85 h for trace CO oxidation at room temperature.
he different structure characteristics of nanosized Co3O 4 film crystallized by the annealing and plasma techniques
G.L. Chen, C. Guyon, Z.X., Zhang, S. Ognier, J. Beem, M.Tatoulian
Microfluidics and Nanofluidics - 107 :1111 – 114 - DOI:10.1016/j.matlet.2013.05.071 - 2013
In this study, we deposited nano-Co3O4 film on silicon substrate using plasma-enhanced metal—organic chemical vapor deposition (PEMOCVD), and the structure difference of Co3O4 crystallized by the annealing and the Ar/O2 plasma techniques were explored by SEM, TEM, XRD, and XPS. Compared to the net morphology of Co3O4 film treated with high calcinations temperature, the cauliflowers-shaped micro-clusters were changed to nano-catkin when the sample was treated with Ar and O2 plasma for 40 min. Additionally, both samples (annealed and plasma-treated) showed the formation of both the {311} and {220} planes. The surface richness of active Co3+ sites on the exposed {220} plane indicated that the as-deposited nano-Co3O4 films have potential catalytic properties for CO and hydrocarbon oxidation.
Carbamazepine removal from water by dielectric barrier discharge : comparison of ex situ and in situ discharge on water
Y. Liu, S. Mei, D. Iya-Sou, S. Cavadias, S. Ognier
Chemical Engineering And Processing - 56 :10-18 - DOI:10.1016/j.cep.2012.03.003 - 2012
Dielectric barrier discharges (DBD) were used for the degradation of carbamazepine (CBZ) in aqueous solution. The electric discharge was generated either ex situ or in situ directly on the water surface. To maintain the same ozone concentration of 40 ppm in both instances, the power injected was 0.7 W in the ex situ discharge and 12 W in the in situ discharge. The results showed 100% CBZ removal after 3 min of treatment with the ex situ discharge, while the in situ discharge only removed 81% of the CBZ after 60 min. According to measurements of UV absorbance at 285 nm and 254 nm, and of total organic carbon, the ex situ discharge system also proved to be more effective than the in situ system. The measurement of nitrogen oxides in both gaseous and liquid phases indicated that high energy in situ discharges produced a large amount of NOx. These species contributed to decreased pH and significantly slowed the CBZ oxidation rate, due to their competition with ozone. Production of NOx should be avoided when using the DBD technique for wastewater treatment.
Atmospheric Pressure Deposition of Thin Functional Coatings: Polymer Surface Patterning by DBD and Post-Discharge Polymerization of Liquid Vinyl Monomer from Surface Radicals
J.P. Borra, A. Valt, F. Arefi-Khonsari, M. Tatoulian
Plasma Process - 9(11-12) :1104-15 - DOI:10.1002/ppap.201100210 - 2012
We present a route for grafting polyacid and polyether coatings on polymers by post-discharge polymerization of liquid vinyl monomer. Surface modifications of polymer films by Micro-Discharges in air Dielectric Barrier Discharge (MD, DBD) are depicted with sub-micrometer craters homogeneously distributed. Both the energy per MD and the power density are critical to avoid thermal film deformation. Homogeneous surface composition is related to the DBD energy density. The polymerization mechanism is depicted from yields versus DBD energy density and time of exposure to air between DBD and monomer deposition. Both parameters control the surface density of radicals and peroxides, triggering the post-DBD polymerization with 80 and 73% of monomer functionality remaining in acid and ether coatings, respectively. The effect of deposition conditions on coatings properties is shown as well as the stability of coatings upon washing.
Fabrication Of Metallic Patterns On PDMS Using Transfer Technology: Application To MRI Microcoils
M. Couty, S. Nazeer, C. Jelita, E. Martincic, M. Woytasik, J.C. Ginefri, L. Darrasse, M. Tatoulian, E. Dufour-Gergam
MICRO & NANO LETTERS - 7(6) :519-22 - DOI:10.1049/mnl.2012.0271 - 2012
Despite the large use of this material in the microsystem field, fabrication of metallic patterns on polydimethylsiloxane (PDMS) still remains a challenge. In this Letter, we present a new process based on the transfer principle and report its application to MRI microcoils. These double-side structures are well aligned and the transfer yield is higher than 90%. The limit of the working range for these flexible coils is a bending radius of 2 mm, similar to the radius of the coil. The developed process opens a wide range of further applications for flexible devices.
Stable modification of PDMS surface properties by plasma polymerization: Innovative process of allylamine PECVD deposition and microfluidic devices sealing
S. Massey, A. Duboin, D. Mantovani, P. Tabeling, M. Tatoulian
Surface & Coatings Technology - 206(19-20) :4303-9 - DOI:10.1016/j.surfcoat.2012.04.047 - 2012
This paper presents a new and innovative process of modification of wetting of open micro-channels involving a method to seal the microfluidic devices. Allylamine was polymerized on poly(dimethylsiloxane) (PDMS) by plasma-enhanced chemical vapour deposition (PECVD) to modify the wetting properties of open micro-channels. The sealing of the devices was done by thermal pressing. All the steps of the process were characterized by different analysis techniques to understand the mechanisms of the process and to assess the performance of the technique. Physicochemical analysis of the polymerized allylamine coatings (X-ray photoelectron spectroscopy and static water contact angle) showed that the coatings were resistant to the thermal pressing and were stable in ambient air and underwater up to 14 days of ageing, even if the water contact angle decreased during the underwater ageing. Parallel tests were undergone in microfluidic devices and the stability of ageing was tested by the production of the simple oil-in-water emulsions. All the experiments showed that this new PECVD/thermal press process is an effective way to modify the wetting properties of an open microfluidic device and includes a technique to seal effectively the system afterwards.
Fluidized bed plasma for pre-treatment of Co-ferrierite catalysts: An approach to NOx abatement
R. Bartolomeu, M. Foix, A. Fernandes, M. Tatoulian, M.F. Ribeiro, C. Henriques, P. Da Costa
CATALYSIS TODAY - 176(1) :234-8 - DOI:10.1016/j.cattod.2010.12.051 - 2011
Replacement of calcination procedures used during catalyst preparation, by a plasma treatment, was studied over a Co-ferrierite (Co-FER) catalyst. The catalyst was tested in the NOx selective catalytic reduction reaction. A combination of UV–Vis spectroscopy and TG analysis revealed the presence of ammonium ions on the untreated and plasma Co-FER samples but not on the calcined one. Therefore, it can be concluded that the plasma treatment was not able to replace the thermal calcination step. The evaluation of catalyst behaviour was performed both under temperature programmed surface reaction (TPSR) and under steady-state conditions at different temperatures. NO oxidation tests showed that, during TPSR runs, calcined catalyst produces more NO2 than plasma catalyst. NOx consumption during TPSR of plasma catalyst confirms that precursors used on the ion-exchange procedure are still present on the catalyst even after the plasma treatment, reacting with NO to produce R-NOx, N2O and N2. Concerning deNOx tests using ethanol as reducing agent, TPSR tests showed higher NOx conversions over untreated and plasma catalysts due to the presence of ammonium and acetate precursors on these catalysts. Untreated, plasma and calcined catalysts present the same NOx and COx conversions in isothermal tests.
Deposition of Cobalt Oxide thin films by PECVD for catalysis application
C. Guyon, A. Barkallah, F. Rousseau, K. Giffard, D. Morvan, M. Tatoulian
Surface & Coatings Technology - 206(7) :1673-9 - DOI:10.1016/j.surfcoat.2011.09.060 - 2011
Plasma-enhanced chemical vapour deposition (PECVD) was used to prepare thin films of cobalt oxide. Cobalt oxide-based (CoO and Co3O4) catalysts were chosen due to their efficiency in mineralisation of organic pollutants achieved by catalytic ozonation. In this work, two types of PECVD processes were used for the production of cobalt oxide thin films. In the first one, a solution of nitrate salt of cobalt was sprayed into a RF low pressure plasma discharge (40 MHz, 600 Pa, 200 W) to obtain CoxOy layers. In the second MOPECVD (metal organic plasma-enhanced chemical vapour deposition) process, cobalt oxide thin films were deposited using a capacitive coupled external electrodes RF plasma reactor (13.56 MHz, 100 Pa, 200 W) with cobalt carbonyl Co2(CO)8 dissolved in hexene as precursor sprayed in a gas carrier (argon and oxygen). In the case of coatings produced from a solution of cobalt nitrate salt, a layer of 1 µm of Co3O4 in crystalline form was obtained after annealing. Considering the thin films obtained from cobalt carbonyl precursor, analyses confirmed the presence of cobalt oxide in a polymeric layer on the surface of the substrate. XRD investigation showed the presence of a crystalline phase of Co3O4 (crystallite size of about 40 nm).

14 publications.