Jerome Pulpytel - Academia.edu (original) (raw)

Papers by Jerome Pulpytel

HAL (Le Centre pour la Communication Scientifique Directe), Sep 17, 2018

Polypropylene (PP) particles are used for various purposes, however, the good mechanical properti... more Polypropylene (PP) particles are used for various purposes, however, the good mechanical properties of PP are counterbalanced by a poor wettability. The wettability of PP particles was therefore improved by an atmospheric pressure blown-arc air plasma jet treatment in a new designed homemade Wurster fluidized bed reactor (Wurster-FBR). This reactor, was used to treat 200 g of particles per batch. The surface free energy of PP particles determined by the Zisman method showed an increase from 30.7 to 38.6 mN m −1 after 120 s of treatment. XPS results showed a 5% increase of the atomic concentration of oxygen on the surface of the treated particles. In order to describe the process, a 2D axisymmetric nonisothermal k-ε turbulent model was used to determine the velocity field, pressure, and temperature profile of the gas phase inside the reactor. Furthermore an Eulerian-Eulerian multiphasic CFD model was added to determine the dynamics of the particles inside the reactor, and the results were compared with fast imaging, thermocouple, and anemometry measurements. These investigations are very important to monitor the homogeneity of the particle treatments, to determine the average effective treatment time for each particle and to avoid overheating of thermally sensitive PP. K E Y W O R D S atmospheric pressure plasma, CFD modeling, polymer surface treatment and coating technology, Wurster fluidised-bed reactor 1 | INTRODUCTION The use of polymer materials has several advantages as compared to metals such as reduced weight and ease of machinability. However, the inert character of the material results in poor adhesion characteristics with other materials as well as poor paintability and printability. In order to improve these properties without changing the bulk properties of the Abbreviations: APPFB, atmospheric pressure plasma fluidized bed; APPJ, atmospheric pressure plasma jet; CFD, computational fluid dynamics; CVD, chemical vapor deposition; DBD, dielectric barrier discharge; DEM, discrete element method; FBR, fluidized bed reactor; FTIR, fourier-transform infrared spectroscopy; HDPE, high density polyethylene; HMDSO, hexamethyldisiloxane; LMWOM, low molecular weight oxidized material; PCFBR, plasma circulating fluidized bed reactor; PE, polyethylene; PP, polypropylene; SEM, scanning electron microscope; RANS, reynolds-averaged navier-stocks equations; XPS, X-ray photoelectron spectrometry; UHMW PE, ultra-high molecular weight polyethylene; WFBR, wurster fluidized bed reactor.

Journal of Physics D, Apr 22, 2005

C 2 H, C 3 and C 3 H radicals and the C 4 H 2 molecule are measured by threshold ionization mass ... more C 2 H, C 3 and C 3 H radicals and the C 4 H 2 molecule are measured by threshold ionization mass spectrometry in a remote Ar/C 2 H 2 expanding thermal plasma used for deposition of hydrogenated amorphous carbon films. Radical densities are calibrated and their fluxes towards the substrate are compared to the film growth rate. C 2 H has marginal contribution to the growth due to its fast gas phase reaction with C 2 H 2 resulting in a low C 2 H density. The C 3 and C 3 H resonantly stabilized radicals behave differently due to their ultra low reactivity with C 2 H 2 and are proposed to be significant growth precursors in plasma processes involving C 2 H 2 .

HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2018

HAL (Le Centre pour la Communication Scientifique Directe), Sep 17, 2018

In the present study, low surface energy perfluorodecyl acrylate (PFDA) coatings and their copoly... more In the present study, low surface energy perfluorodecyl acrylate (PFDA) coatings and their copolymer coatings with diethylene glycol dimethyl ether (DEGDME) (i.e. PFDA-co-DEGDME) have been deposited through plasma enhanced chemical vapor deposition (PECVD) onto thermanox coverslips in a low pressure tubular inductively coupled RF plasma reactor. The influence of plasma parameters on surface chemical properties of the coatings were investigated by using fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS) and water contact angle (WCA). The protein repellent properties of the plasma polymer coatings have been investigated using quartz crystal microbalance (QCM).

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2018

Polypropylene (PP) particles are used for various purposes, however, the good mechanical properti... more Polypropylene (PP) particles are used for various purposes, however, the good mechanical properties of PP are counterbalanced by a poor wettability. The wettability of PP particles was therefore improved by an atmospheric pressure blown-arc air plasma jet treatment in a new designed homemade Wurster fluidized bed reactor (Wurster-FBR). This reactor, was used to treat 200 g of particles per batch. The surface free energy of PP particles determined by the Zisman method showed an increase from 30.7 to 38.6 mN m −1 after 120 s of treatment. XPS results showed a 5% increase of the atomic concentration of oxygen on the surface of the treated particles. In order to describe the process, a 2D axisymmetric nonisothermal k-ε turbulent model was used to determine the velocity field, pressure, and temperature profile of the gas phase inside the reactor. Furthermore an Eulerian-Eulerian multiphasic CFD model was added to determine the dynamics of the particles inside the reactor, and the results were compared with fast imaging, thermocouple, and anemometry measurements. These investigations are very important to monitor the homogeneity of the particle treatments, to determine the average effective treatment time for each particle and to avoid overheating of thermally sensitive PP. K E Y W O R D S atmospheric pressure plasma, CFD modeling, polymer surface treatment and coating technology, Wurster fluidised-bed reactor 1 | INTRODUCTION The use of polymer materials has several advantages as compared to metals such as reduced weight and ease of machinability. However, the inert character of the material results in poor adhesion characteristics with other materials as well as poor paintability and printability. In order to improve these properties without changing the bulk properties of the Abbreviations: APPFB, atmospheric pressure plasma fluidized bed; APPJ, atmospheric pressure plasma jet; CFD, computational fluid dynamics; CVD, chemical vapor deposition; DBD, dielectric barrier discharge; DEM, discrete element method; FBR, fluidized bed reactor; FTIR, fourier-transform infrared spectroscopy; HDPE, high density polyethylene; HMDSO, hexamethyldisiloxane; LMWOM, low molecular weight oxidized material; PCFBR, plasma circulating fluidized bed reactor; PE, polyethylene; PP, polypropylene; SEM, scanning electron microscope; RANS, reynolds-averaged navier-stocks equations; XPS, X-ray photoelectron spectrometry; UHMW PE, ultra-high molecular weight polyethylene; WFBR, wurster fluidized bed reactor.

Plasma Processes and Polymers, 2011

Plasma-related effects are shown to lead to large differences in the temperatures of catalyst nan... more Plasma-related effects are shown to lead to large differences in the temperatures of catalyst nanoparticles and of the substrate heating stage and therefore lead to much higher nanofiber growth rates than those in conventional thermal growth processes. Further details can be found in the article by H. Mehdipour, K. Ostrikov, A. E. Rider,* and Z. J. Han on page 386

HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2019

Surfaces and Interfaces

Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a... more Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a dielectric barrier discharge at atmospheric pressure. Commercially available GNs were incorporated into HMDSO precursor at different concentrations up to 2 wt%. The nanocomposite coatings were analyzed using scanning electron microscopy (SEM) and nanoindentation test. Based on SEM images, it was found that the GNs were well distributed and dispersed in the plasma polymerized hexamethyldisiloxane (ppHMDSO) matrix with no significant agglomeration. The results of nanoindentation tests performed with the continuous stiffness measurements mode showed an increase in the hardness and reduced Young's modulus with the increase of graphene nanosheets percentage. The maximum increase was two orders of magnitude for 2% GNs/ppHMDSO nanocomposite coatings compared to the homopolymer ppHMDSO. Furthermore, the creep compliance analysis showed that the nanocomposite coatings exhibited a viscoelastic behavior compared to the plasma polymer homopolymer.

Plasma Chemistry and Plasma Processing, 2020

In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred... more In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred hydrophilic functional groups onto the surface, which lead to enhanced bioactivity of UHMWPE without affecting the biocompatibility of the polymer. The latter was checked by increased adhesion of fibroblast cells to the polymer. The effects of the He/2% O 2 DBD plasma was compared for the first time to a rotating blown arc atmospheric pressure plasma jet (r-APPJ) in air. The results show a better functionalization as well as stability of the surface properties of the films treated with the DBD. The surface modified UHMWPE once immersed in a Simulated Body Fluid induced the formation of nucleus of hydroxyapatite (calcium phosphate) leading to the growth of a thick apatite coating which was followed up to 14 days, which can be expected to be highly bioactive. Surface characterization techniques also showed different chemical moieties in the case of the two different atmospheric discharges. DBD discharge in He/2% O 2 , leading to more stable polar functions grafted to a crosslinked polymer surface, proved to be more bioactive than UHM-WPE treated by a r-APPJ in air. The latter treatment lead to grafting of less oxygen containing groups to the surface as well as to LMWOM created on r-APPJ treated UHMWPE which are unstable in aqueous media used both in SBF and fibroblasts in DMEM. Keywords DBD (dielectrc barrier discharge) • APPJ (atmospheric pressure plasma jet) • Simulated body fluid (SBF) • Hydroxyapatite (ha) • Surface treatment • UHMWPE (ultrahigh molecular weight polyethylene)

Poly (e-caprolactone)-poly (ethylene glycol) (PCL-PEG) copolymers have great potential applicatio... more Poly (e-caprolactone)-poly (ethylene glycol) (PCL-PEG) copolymers have great potential applications in the fields of tissue engineering, pharmaceutics and medicinal chemistry. In the present work we have developed, amphiphilic biodegradable PCL-PEG copolymer coatings by catalyst free ROP of e-caprolactone (e-CL), in presence of 2-Methoxyethylether (DEGME). A low pressure inductively excited RF (13.56MHz) plasma reactor, designed for the deposition of copolymers [1], [2], was operating in the pulsed mode with Argon as the carrier gas. Experiments were performed at different e-CL/PEG monomer feed ratio and effective power. Cellular adhesion tests have been performed using 3 different cell types: human ovarian carcinoma cell line (NIH:OVCAR-3), human bone marrow endothelial cells and human fibroblast (3T3) (see. Fig. 1). Cells were cultured in the RPMI-1640, which was supplemented with 1% (v/v) antibiotics (10,000 U/ml penicillin-G sodium, 10mg/ml streptomycin), 2mM Lglutamine and 10% ...

Applied Surface Science, 2021

Abstract An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionaliza... more Abstract An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionalization of graphite using two consecutive plasma treatments before immobilization of laccase as a biocatalyst to perform oxygen reduction reaction (ORR) by direct electron transfer ((DET). Nano-structuration of graphite surfaces by synthesis of vertical graphen-like carbon nanowalls (CNWs) was performed by microwave excited plasma enhanced chemical vapor deposition (PECVD). Atmospheric pressure plasma jet (APPJ) system was then used to functionalize chemically the CNWs surface via a rapid and dry route. A partial fractional design evidenced two significant parameters of the APPJ treatment in terms of ORR current density: the treatment time and the inter-distance between the plasma jet and the surface of the carbon material. With the optimized APPJ treatment parameters, a four-fold enhancement of the ORR current density (-440 ± 70 µA/cm2) could be obtained on CNWs, compared to graphite electrodes. The maximal current density obtained was about -1 mA/cm2 with oxidized laccase covalently immobilized on the electrode without any agitation of the solution, confirming the main importance of enzyme orientation on the electrode surface for efficient DET transfer, the relevance of electrode nanostructuration and the advantage of covalent linking of the protein on the electrode surface.

Plasma Processes and Polymers, 2017

In this work, the surface modification of ultra-high-molecular-weight polyethylene (UHMWPE), a li... more In this work, the surface modification of ultra-high-molecular-weight polyethylene (UHMWPE), a linear polymer, by a helium transporting discharge at atmospheric pressure was investigated by means of FTIR, AFM, XPS, ToF-SIMS, and contact angle measurements. Two types of discharge configurations, that is, jet and glow of the transporting discharge for the surface treatment of polymer substrates were studied. The results show that the position of the UHMWPE polymer substrates plays an important role in the surface modification and stability of the treatment. The polymer substrates placed inside the transporting discharge tube present more stable wettability and surface modification. In addition, the transporting discharge was used to modify the inner surface of the high density polyethylene tube.

Surface and Coatings Technology, 2019

The present study proposes an alternative eco-friendly method to prepare a thin composite coating... more The present study proposes an alternative eco-friendly method to prepare a thin composite coating based on graphene embedded in siloxane polymers which can be used as application for the corrosion protection of steel. The nanocomposite coatings were elaborated by a dielectric barrier discharge using a nebulized colloidal suspension of graphene nanosheets (GNs) dispersed in hexamethyldisiloxane (HMDSO) used as the precursor for the polymer matrix. After obtaining a stable colloidal solution, it was nebulized into the plasma reactor to form a plasma polymer (pp) coating from HMDSO (ppHMDSO) in which GNs were incorporated (GN@ppHMDSO) on the mild steel substrate. The chemical structure of the hybrid coatings was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry. Raman spectra of GNs and GN@ppHMDSO coatings suggest the existence of charge transfer between the GNs and the HMDSO matrix. Furthermore, scanning electron microscopy confirms the synthesis of micro/nanocomposite with a fairly homogeneous dispersion of the GNs in the polymer matrix. The corrosion resistance of the samples was evaluated by electrochemical impedance spectroscopy which showed that the hybrid coatings GN@ppHMDSO deposited by a one-step atmospheric pressure plasma process, presented excellent anticorrosion performance with 99.99% of protection efficiency.

Plasma Chemistry and Plasma Processing, 2019

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Cell repellent coatings on inner walls of tubes by means of transporting discharge in atmospheric pressure.

Journal of Physics D: Applied Physics, 2016

The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmosphe... more The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmospheric pressure rotating plasma jet (APPJ) and the surface modifications were studied to assess its hydrophilicity and adhesion to acrylic adhesive tape intended for medical applications. Furthermore, the extent of hydrophobic recovery under different storage conditions was studied. The surface treatment of PDMS with the APPJ under optimal conditions noticeably increased the oxygen content and most of the surface silicon species were fully oxidized. A brittle silica-like layer on the outermost surface was created showing changes in topography due to the formation of grooves and cracks. A huge improvement in T-peel and the shear adhesive strength of the APPJ-treated PDMS surface/acrylic tape joints was obtained. On the other hand, the hydrophilicity of the PDMS surface increased noticeably after the APPJ treatment, but 24 h after treatment almost 80% hydrophobicity was recovered and the adhesive strength was markedly reduced with time after the APPJ treatment. However, the application of an acrylic adhesive layer on the just-APPJ-treated PDMS surface retained the adhesive strength, limiting the extent of hydrophobic recovery.

Polymer, 2016

Calcium Phosphates (CaPs) have excellent bone regeneration capacity, and their combination with s... more Calcium Phosphates (CaPs) have excellent bone regeneration capacity, and their combination with specific drugs is of interest because it allows adding new functionalities. In CaPs, drug release is mainly driven by diffusion, which is strongly affected by the porosity of the matrix and the drug-material interaction. Therefore, it is very difficult to tune their drug release properties beyond their intrinsic properties. Furthermore, when the CaPs are designed as scaffolds, the increased complexity of the macrostructure further complicates the issue. This work investigates for the first time the use of biocompatible plasma-polymers to provide a tool to control drug release from drug-loaded CaP scaffolds with complex surfaces and intricate 3D structure. Two different CaPs were selected displaying great differences in microstructure: low-temperature CaPs (Calcium-deficient hydroxyapatite cements, CDHA) and sintered CaP ceramics (β-Tricalcium Phosphate, β-TCP). The deposition of PCL-co-PEG (1:4) copolymers on CaPs was achieved by a low pressure plasma process, which allowed coating the inner regions of the scaffolds up to a certain depth. The coating covered the micro and nanopores of the CaPs surface and produced complex geometries presenting a nano and micro rough morphology which lead to low wettability despite the hydrophilicity of the copolymer. Plasma coating with PCL-co-PEG on scaffolds loaded with Simvastatin acid (potentially osteogenic and angiogenic) allowed delaying and modulating the drug release from the bone scaffolds depending on the thickness of the layer deposited, which, in turn depends on the initial specific surface area of the CaP.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 17, 2018

Polypropylene (PP) particles are used for various purposes, however, the good mechanical properti... more Polypropylene (PP) particles are used for various purposes, however, the good mechanical properties of PP are counterbalanced by a poor wettability. The wettability of PP particles was therefore improved by an atmospheric pressure blown-arc air plasma jet treatment in a new designed homemade Wurster fluidized bed reactor (Wurster-FBR). This reactor, was used to treat 200 g of particles per batch. The surface free energy of PP particles determined by the Zisman method showed an increase from 30.7 to 38.6 mN m −1 after 120 s of treatment. XPS results showed a 5% increase of the atomic concentration of oxygen on the surface of the treated particles. In order to describe the process, a 2D axisymmetric nonisothermal k-ε turbulent model was used to determine the velocity field, pressure, and temperature profile of the gas phase inside the reactor. Furthermore an Eulerian-Eulerian multiphasic CFD model was added to determine the dynamics of the particles inside the reactor, and the results were compared with fast imaging, thermocouple, and anemometry measurements. These investigations are very important to monitor the homogeneity of the particle treatments, to determine the average effective treatment time for each particle and to avoid overheating of thermally sensitive PP. K E Y W O R D S atmospheric pressure plasma, CFD modeling, polymer surface treatment and coating technology, Wurster fluidised-bed reactor 1 | INTRODUCTION The use of polymer materials has several advantages as compared to metals such as reduced weight and ease of machinability. However, the inert character of the material results in poor adhesion characteristics with other materials as well as poor paintability and printability. In order to improve these properties without changing the bulk properties of the Abbreviations: APPFB, atmospheric pressure plasma fluidized bed; APPJ, atmospheric pressure plasma jet; CFD, computational fluid dynamics; CVD, chemical vapor deposition; DBD, dielectric barrier discharge; DEM, discrete element method; FBR, fluidized bed reactor; FTIR, fourier-transform infrared spectroscopy; HDPE, high density polyethylene; HMDSO, hexamethyldisiloxane; LMWOM, low molecular weight oxidized material; PCFBR, plasma circulating fluidized bed reactor; PE, polyethylene; PP, polypropylene; SEM, scanning electron microscope; RANS, reynolds-averaged navier-stocks equations; XPS, X-ray photoelectron spectrometry; UHMW PE, ultra-high molecular weight polyethylene; WFBR, wurster fluidized bed reactor.

Journal of Physics D, Apr 22, 2005

C 2 H, C 3 and C 3 H radicals and the C 4 H 2 molecule are measured by threshold ionization mass ... more C 2 H, C 3 and C 3 H radicals and the C 4 H 2 molecule are measured by threshold ionization mass spectrometry in a remote Ar/C 2 H 2 expanding thermal plasma used for deposition of hydrogenated amorphous carbon films. Radical densities are calibrated and their fluxes towards the substrate are compared to the film growth rate. C 2 H has marginal contribution to the growth due to its fast gas phase reaction with C 2 H 2 resulting in a low C 2 H density. The C 3 and C 3 H resonantly stabilized radicals behave differently due to their ultra low reactivity with C 2 H 2 and are proposed to be significant growth precursors in plasma processes involving C 2 H 2 .

HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2018

HAL (Le Centre pour la Communication Scientifique Directe), Sep 17, 2018

In the present study, low surface energy perfluorodecyl acrylate (PFDA) coatings and their copoly... more In the present study, low surface energy perfluorodecyl acrylate (PFDA) coatings and their copolymer coatings with diethylene glycol dimethyl ether (DEGDME) (i.e. PFDA-co-DEGDME) have been deposited through plasma enhanced chemical vapor deposition (PECVD) onto thermanox coverslips in a low pressure tubular inductively coupled RF plasma reactor. The influence of plasma parameters on surface chemical properties of the coatings were investigated by using fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS) and water contact angle (WCA). The protein repellent properties of the plasma polymer coatings have been investigated using quartz crystal microbalance (QCM).

HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2018

Polypropylene (PP) particles are used for various purposes, however, the good mechanical properti... more Polypropylene (PP) particles are used for various purposes, however, the good mechanical properties of PP are counterbalanced by a poor wettability. The wettability of PP particles was therefore improved by an atmospheric pressure blown-arc air plasma jet treatment in a new designed homemade Wurster fluidized bed reactor (Wurster-FBR). This reactor, was used to treat 200 g of particles per batch. The surface free energy of PP particles determined by the Zisman method showed an increase from 30.7 to 38.6 mN m −1 after 120 s of treatment. XPS results showed a 5% increase of the atomic concentration of oxygen on the surface of the treated particles. In order to describe the process, a 2D axisymmetric nonisothermal k-ε turbulent model was used to determine the velocity field, pressure, and temperature profile of the gas phase inside the reactor. Furthermore an Eulerian-Eulerian multiphasic CFD model was added to determine the dynamics of the particles inside the reactor, and the results were compared with fast imaging, thermocouple, and anemometry measurements. These investigations are very important to monitor the homogeneity of the particle treatments, to determine the average effective treatment time for each particle and to avoid overheating of thermally sensitive PP. K E Y W O R D S atmospheric pressure plasma, CFD modeling, polymer surface treatment and coating technology, Wurster fluidised-bed reactor 1 | INTRODUCTION The use of polymer materials has several advantages as compared to metals such as reduced weight and ease of machinability. However, the inert character of the material results in poor adhesion characteristics with other materials as well as poor paintability and printability. In order to improve these properties without changing the bulk properties of the Abbreviations: APPFB, atmospheric pressure plasma fluidized bed; APPJ, atmospheric pressure plasma jet; CFD, computational fluid dynamics; CVD, chemical vapor deposition; DBD, dielectric barrier discharge; DEM, discrete element method; FBR, fluidized bed reactor; FTIR, fourier-transform infrared spectroscopy; HDPE, high density polyethylene; HMDSO, hexamethyldisiloxane; LMWOM, low molecular weight oxidized material; PCFBR, plasma circulating fluidized bed reactor; PE, polyethylene; PP, polypropylene; SEM, scanning electron microscope; RANS, reynolds-averaged navier-stocks equations; XPS, X-ray photoelectron spectrometry; UHMW PE, ultra-high molecular weight polyethylene; WFBR, wurster fluidized bed reactor.

Plasma Processes and Polymers, 2011

Plasma-related effects are shown to lead to large differences in the temperatures of catalyst nan... more Plasma-related effects are shown to lead to large differences in the temperatures of catalyst nanoparticles and of the substrate heating stage and therefore lead to much higher nanofiber growth rates than those in conventional thermal growth processes. Further details can be found in the article by H. Mehdipour, K. Ostrikov, A. E. Rider,* and Z. J. Han on page 386

HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2019

Surfaces and Interfaces

Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a... more Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a dielectric barrier discharge at atmospheric pressure. Commercially available GNs were incorporated into HMDSO precursor at different concentrations up to 2 wt%. The nanocomposite coatings were analyzed using scanning electron microscopy (SEM) and nanoindentation test. Based on SEM images, it was found that the GNs were well distributed and dispersed in the plasma polymerized hexamethyldisiloxane (ppHMDSO) matrix with no significant agglomeration. The results of nanoindentation tests performed with the continuous stiffness measurements mode showed an increase in the hardness and reduced Young's modulus with the increase of graphene nanosheets percentage. The maximum increase was two orders of magnitude for 2% GNs/ppHMDSO nanocomposite coatings compared to the homopolymer ppHMDSO. Furthermore, the creep compliance analysis showed that the nanocomposite coatings exhibited a viscoelastic behavior compared to the plasma polymer homopolymer.

Plasma Chemistry and Plasma Processing, 2020

In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred... more In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred hydrophilic functional groups onto the surface, which lead to enhanced bioactivity of UHMWPE without affecting the biocompatibility of the polymer. The latter was checked by increased adhesion of fibroblast cells to the polymer. The effects of the He/2% O 2 DBD plasma was compared for the first time to a rotating blown arc atmospheric pressure plasma jet (r-APPJ) in air. The results show a better functionalization as well as stability of the surface properties of the films treated with the DBD. The surface modified UHMWPE once immersed in a Simulated Body Fluid induced the formation of nucleus of hydroxyapatite (calcium phosphate) leading to the growth of a thick apatite coating which was followed up to 14 days, which can be expected to be highly bioactive. Surface characterization techniques also showed different chemical moieties in the case of the two different atmospheric discharges. DBD discharge in He/2% O 2 , leading to more stable polar functions grafted to a crosslinked polymer surface, proved to be more bioactive than UHM-WPE treated by a r-APPJ in air. The latter treatment lead to grafting of less oxygen containing groups to the surface as well as to LMWOM created on r-APPJ treated UHMWPE which are unstable in aqueous media used both in SBF and fibroblasts in DMEM. Keywords DBD (dielectrc barrier discharge) • APPJ (atmospheric pressure plasma jet) • Simulated body fluid (SBF) • Hydroxyapatite (ha) • Surface treatment • UHMWPE (ultrahigh molecular weight polyethylene)

Poly (e-caprolactone)-poly (ethylene glycol) (PCL-PEG) copolymers have great potential applicatio... more Poly (e-caprolactone)-poly (ethylene glycol) (PCL-PEG) copolymers have great potential applications in the fields of tissue engineering, pharmaceutics and medicinal chemistry. In the present work we have developed, amphiphilic biodegradable PCL-PEG copolymer coatings by catalyst free ROP of e-caprolactone (e-CL), in presence of 2-Methoxyethylether (DEGME). A low pressure inductively excited RF (13.56MHz) plasma reactor, designed for the deposition of copolymers [1], [2], was operating in the pulsed mode with Argon as the carrier gas. Experiments were performed at different e-CL/PEG monomer feed ratio and effective power. Cellular adhesion tests have been performed using 3 different cell types: human ovarian carcinoma cell line (NIH:OVCAR-3), human bone marrow endothelial cells and human fibroblast (3T3) (see. Fig. 1). Cells were cultured in the RPMI-1640, which was supplemented with 1% (v/v) antibiotics (10,000 U/ml penicillin-G sodium, 10mg/ml streptomycin), 2mM Lglutamine and 10% ...

Applied Surface Science, 2021

Abstract An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionaliza... more Abstract An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionalization of graphite using two consecutive plasma treatments before immobilization of laccase as a biocatalyst to perform oxygen reduction reaction (ORR) by direct electron transfer ((DET). Nano-structuration of graphite surfaces by synthesis of vertical graphen-like carbon nanowalls (CNWs) was performed by microwave excited plasma enhanced chemical vapor deposition (PECVD). Atmospheric pressure plasma jet (APPJ) system was then used to functionalize chemically the CNWs surface via a rapid and dry route. A partial fractional design evidenced two significant parameters of the APPJ treatment in terms of ORR current density: the treatment time and the inter-distance between the plasma jet and the surface of the carbon material. With the optimized APPJ treatment parameters, a four-fold enhancement of the ORR current density (-440 ± 70 µA/cm2) could be obtained on CNWs, compared to graphite electrodes. The maximal current density obtained was about -1 mA/cm2 with oxidized laccase covalently immobilized on the electrode without any agitation of the solution, confirming the main importance of enzyme orientation on the electrode surface for efficient DET transfer, the relevance of electrode nanostructuration and the advantage of covalent linking of the protein on the electrode surface.

Plasma Processes and Polymers, 2017

In this work, the surface modification of ultra-high-molecular-weight polyethylene (UHMWPE), a li... more In this work, the surface modification of ultra-high-molecular-weight polyethylene (UHMWPE), a linear polymer, by a helium transporting discharge at atmospheric pressure was investigated by means of FTIR, AFM, XPS, ToF-SIMS, and contact angle measurements. Two types of discharge configurations, that is, jet and glow of the transporting discharge for the surface treatment of polymer substrates were studied. The results show that the position of the UHMWPE polymer substrates plays an important role in the surface modification and stability of the treatment. The polymer substrates placed inside the transporting discharge tube present more stable wettability and surface modification. In addition, the transporting discharge was used to modify the inner surface of the high density polyethylene tube.

Surface and Coatings Technology, 2019

The present study proposes an alternative eco-friendly method to prepare a thin composite coating... more The present study proposes an alternative eco-friendly method to prepare a thin composite coating based on graphene embedded in siloxane polymers which can be used as application for the corrosion protection of steel. The nanocomposite coatings were elaborated by a dielectric barrier discharge using a nebulized colloidal suspension of graphene nanosheets (GNs) dispersed in hexamethyldisiloxane (HMDSO) used as the precursor for the polymer matrix. After obtaining a stable colloidal solution, it was nebulized into the plasma reactor to form a plasma polymer (pp) coating from HMDSO (ppHMDSO) in which GNs were incorporated (GN@ppHMDSO) on the mild steel substrate. The chemical structure of the hybrid coatings was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry. Raman spectra of GNs and GN@ppHMDSO coatings suggest the existence of charge transfer between the GNs and the HMDSO matrix. Furthermore, scanning electron microscopy confirms the synthesis of micro/nanocomposite with a fairly homogeneous dispersion of the GNs in the polymer matrix. The corrosion resistance of the samples was evaluated by electrochemical impedance spectroscopy which showed that the hybrid coatings GN@ppHMDSO deposited by a one-step atmospheric pressure plasma process, presented excellent anticorrosion performance with 99.99% of protection efficiency.

Plasma Chemistry and Plasma Processing, 2019

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Cell repellent coatings on inner walls of tubes by means of transporting discharge in atmospheric pressure.

Journal of Physics D: Applied Physics, 2016

The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmosphe... more The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmospheric pressure rotating plasma jet (APPJ) and the surface modifications were studied to assess its hydrophilicity and adhesion to acrylic adhesive tape intended for medical applications. Furthermore, the extent of hydrophobic recovery under different storage conditions was studied. The surface treatment of PDMS with the APPJ under optimal conditions noticeably increased the oxygen content and most of the surface silicon species were fully oxidized. A brittle silica-like layer on the outermost surface was created showing changes in topography due to the formation of grooves and cracks. A huge improvement in T-peel and the shear adhesive strength of the APPJ-treated PDMS surface/acrylic tape joints was obtained. On the other hand, the hydrophilicity of the PDMS surface increased noticeably after the APPJ treatment, but 24 h after treatment almost 80% hydrophobicity was recovered and the adhesive strength was markedly reduced with time after the APPJ treatment. However, the application of an acrylic adhesive layer on the just-APPJ-treated PDMS surface retained the adhesive strength, limiting the extent of hydrophobic recovery.

Polymer, 2016

Calcium Phosphates (CaPs) have excellent bone regeneration capacity, and their combination with s... more Calcium Phosphates (CaPs) have excellent bone regeneration capacity, and their combination with specific drugs is of interest because it allows adding new functionalities. In CaPs, drug release is mainly driven by diffusion, which is strongly affected by the porosity of the matrix and the drug-material interaction. Therefore, it is very difficult to tune their drug release properties beyond their intrinsic properties. Furthermore, when the CaPs are designed as scaffolds, the increased complexity of the macrostructure further complicates the issue. This work investigates for the first time the use of biocompatible plasma-polymers to provide a tool to control drug release from drug-loaded CaP scaffolds with complex surfaces and intricate 3D structure. Two different CaPs were selected displaying great differences in microstructure: low-temperature CaPs (Calcium-deficient hydroxyapatite cements, CDHA) and sintered CaP ceramics (β-Tricalcium Phosphate, β-TCP). The deposition of PCL-co-PEG (1:4) copolymers on CaPs was achieved by a low pressure plasma process, which allowed coating the inner regions of the scaffolds up to a certain depth. The coating covered the micro and nanopores of the CaPs surface and produced complex geometries presenting a nano and micro rough morphology which lead to low wettability despite the hydrophilicity of the copolymer. Plasma coating with PCL-co-PEG on scaffolds loaded with Simvastatin acid (potentially osteogenic and angiogenic) allowed delaying and modulating the drug release from the bone scaffolds depending on the thickness of the layer deposited, which, in turn depends on the initial specific surface area of the CaP.