The Experts below are selected from a list of 4485 Experts worldwide ranked by ideXlab platform
Rony Snyders - One of the best experts on this subject based on the ideXlab platform.
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Surface Engineering of Bromine-Based Plasma Polymer Films: A Step toward High Thiol Density Containing Organic Coatings
2018Co-Authors: Damien Thiry, Matthias Pouyanne, Damien Cossement, Axel Hemberg, Rony SnydersAbstract:Nowadays, the development of synthetic methods regarding the fabrication of −SH containing organic coatings continues to attract a considerable attention. Among the potential techniques, the Plasma Polymerization appears as one of the most promising method but the difficulty to control the chemical composition of the layers is highly limiting. In this context, in this work, we report on an original method combining dry and wet chemistry approaches in view of selectively incorporating −SH functions in organic coatings. Our strategy is based on the (i) synthesis of a bromine-containing Plasma Polymer Film, followed by (ii) a selective grafting of dithiol-based molecule on C–Br bond. Investigating the Plasma Polymerization process has revealed that, in our experimental window, the load of energy in the discharge has little influence on the chemical composition as well as on the cross-linking degree of the layers. This behavior is explained by considering the concomitant influence of the gas-phase reactions and the supply of energy to the growing Film through ion bombardment. With regard to the functionalization strategy, based on comparative X-ray photoelectron spectroscopy measurements, it has been unambiguously demonstrated that a selective reaction between propanedithiol and the C–Br bond acting as the reactive center takes place resulting in the removing of the bromine atom and the incorporation of −SH groups in the PPF. Depending on the grafting reaction duration, the relative proportion of carbon bearing the −SH group is found to evolve from 4 to 6%. On the other hand, the dissolution of unbounded bromine-based species in the liquid medium during the grafting procedure is also evidenced. The whole set of our results clearly demonstrates the attractiveness of our strategy paving the way for new development in the fabrication of −SH-rich-containing organic thin Films
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combining mass spectrometry diagnostic and density functional theory calculations for a better understanding of the Plasma Polymerization of ethyl lactate
Journal of Physical Chemistry B, 2014Co-Authors: Sylvie Ligot, Damien Thiry, Maxime Guillaume, Pascal Gerbaux, Fabian Renaux, Jerome Cornil, Philippe Dubois, Rony SnydersAbstract:The focus of this work is on the growth mechanism of ethyl lactate-based Plasma Polymer Film (ELPPF) that could be used as barrier coatings. In such an application, the ester density of the Plasma Polymer has to be controlled to tune the degradation rate of the material. Our strategy consists of correlating the Plasma chemistry evaluated by RGA mass spectrometry and understanding, via DFT calculations, the chemistry of the synthesized thin Films. The theoretical calculations helped us to understand the Plasma chemistry in Plasma ON and OFF conditions. From these data it is unambiguously shown that the signal m/z 75 can directly be correlated with the precursor density in the Plasma phase. The combination of XPS and chemical derivatization experiments reveal that the ester content in the ELPFF can be tailored from 2 to 18 at. % by decreasing the RF power, which is perfectly correlated with the evolution of the Plasma chemistry. Our results also highlight that the ELPPF chemistry, especially the ester content, is affected by the Plasma mode of operation (continuous or pulsed discharge, at similar injected mean power) for similar ester content in the Plasma. This could be related to different energy conditions at the interface of the growing Films that could affect the sticking coefficient of the ester-bearing fragments.
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Combining Mass Spectrometry Diagnostic and Density Functional Theory Calculations for a Better Understanding of the Plasma Polymerization of Ethyl Lactate
2014Co-Authors: Sylvie Ligot, Damien Thiry, Maxime Guillaume, Pascal Gerbaux, Fabian Renaux, Jerome Cornil, Philippe Dubois, Rony SnydersAbstract:The focus of this work is on the growth mechanism of ethyl lactate-based Plasma Polymer Film (ELPPF) that could be used as barrier coatings. In such an application, the ester density of the Plasma Polymer has to be controlled to tune the degradation rate of the material. Our strategy consists of correlating the Plasma chemistry evaluated by RGA mass spectrometry and understanding, via DFT calculations, the chemistry of the synthesized thin Films. The theoretical calculations helped us to understand the Plasma chemistry in Plasma ON and OFF conditions. From these data it is unambiguously shown that the signal m/z 75 can directly be correlated with the precursor density in the Plasma phase. The combination of XPS and chemical derivatization experiments reveal that the ester content in the ELPFF can be tailored from 2 to 18 at. % by decreasing the RF power, which is perfectly correlated with the evolution of the Plasma chemistry. Our results also highlight that the ELPPF chemistry, especially the ester content, is affected by the Plasma mode of operation (continuous or pulsed discharge, at similar injected mean power) for similar ester content in the Plasma. This could be related to different energy conditions at the interface of the growing Films that could affect the sticking coefficient of the ester-bearing fragments
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derivatization of free radicals in an isopropanol Plasma Polymer Film the first step toward Polymer grafting
ACS Applied Materials & Interfaces, 2013Co-Authors: Sergey Ershov, Philippe Dubois, Farid Khelifa, Rony SnydersAbstract:Plasma-Polymerized Films (PPF) synthesized by Plasma-enhanced chemical vapor deposition (PECVD) find increasing applications in biomedicine and differ in many ways from conventional Polymers. One of the most specific properties of the PPF is the high reactivity of its free-radical-rich surface, arising from the deposition mechanism. Although generally considered as a disadvantage leading to the aging of the PPF, reactivity of the Plasma-treated Polymers and PPF surfaces can be beneficially employed, for example, for grafting of a specific chemical functionality or short Polymer chains. The quantitative evaluation of the surface radical density of the PPF is thus considered as the necessary preparatory step toward any subsequent grafting reaction. In the present study, the surface radical density of an isopropanol-based PPF was quantitatively determined by a combination of NO chemical derivatization and X-ray photoelectron spectroscopy (XPS). Once the derivatization conditions were optimized, the radical d...
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towards the understanding of Plasma Polymer Film behaviour in ethanol a multi technique investigation
Progress in Organic Coatings, 2011Co-Authors: Laurent Denis, Damien Thiry, Damien Cossement, Pascal Gerbaux, Fabiola Brusciotti, Isabel Van De Keere, V Goossens, Herman Terryn, M Hecq, Rony SnydersAbstract:Abstract Plasma Polymer Films (PPFs) of allylamine are prepared varying the mean power injected in the Plasma ( P mean ). The PPF behaviour in ethanol is studied through the analysis of the PPF physico-chemistry and the composition of the resulting ethanol solutions. By Visible light Spectroscopic Ellipsometry (VISSE), it is observed that the well-known decrease of the PPF thickness (Δ d ) upon immersion decreases as a function of P mean . This behaviour is attributed to an increase of the PPF cross-linking density ( χ ). By means of time-of-flight secondary ion mass spectrometry (ToF-SIMS) and further statistical processing of the data by principal component analysis (PCA), we propose a method to discriminate the samples according to χ . A significant increase in the PPF oxygen content is also observed after immersion which is ascribed to reaction between ethanol molecules and trapped radicals of the PPF network. On the other hand, taking into account the specificities of the gas chromatography–mass spectrometry (GC–MS) method, the resulting ethanol solutions are demonstrated to be free of chemical species containing a number of carbon atoms ranging from 7 to 40. However, Δ d (accounting for PPF restructuring) might come with the dissolution of PPF materials having less than 7 carbon atoms.
Jürgen Brieger - One of the best experts on this subject based on the ideXlab platform.
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the effect of extracellular matrix proteins on the cellular response of huvecs and hobs after covalent immobilization onto titanium
Journal of Biomedical Materials Research Part A, 2015Co-Authors: Martin Heller, Renate Forch, Peer W. Kämmerer, Marie‐anne Luszpinski, Bilal Alnawas, Jürgen BriegerAbstract:Biomimetic surface modifications are regarded as promising approach to stimulate cellular behavior at the interface of implant materials. Aim of the study was an evaluation of the cellular response of human umbilical cord cells (HUVECS) and human osteoblasts (HOBS) on titanium covalently coated with the extracellular matrix (ECM) proteins fibrinogen, collagen, laminin, and osteopontin. For the surface modification, titanium discs were first amino-functionalized by Plasma Polymerization of allylamine. The ECM protein conjugation was performed using the linker molecule α, ω-bis-N-hydroxysuccinimide polyethylene glycol (Di-NHS linker). For surface characterization, infrared spectroscopy and fluorescein isothiocyanate staining (FITC) were used to evaluate the presence and distribution of primary amines in the Plasma Polymer Film. Real-time analyses of the respective protein conjugation processes were performed via surface plasmon resonance kinetic measurements. All ECM proteins were immobilized successfully. Furthermore, the biological functionality of the conjugated factors fibronectin and collagen could be proven as they led to a distinct stimulation of cell adhesion of HUVECS and HOBS when compared to the control group. The highest cell coverage of HUVECS was observed on fibronectin-modified surfaces with approximately 35% and on collagen with 33% after 24 h (PT: 9.4%). For laminin, no additional effect was observed, and for osteopontin, only a slight enhancement of cell adhesion was found. A similar, cell-stimulating tendency of fibronectin and collagen was seen as well after 3 and 7 days. Biomimetic surface modification via Plasma Polymerization is a powerful method for biomolecule conjugation with a high retention of biological functionality and offer promising clinical perspectives. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2035–2044, 2015.
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The effect of extracellular matrix proteins on the cellular response of HUVECS and HOBS after covalent immobilization onto titanium
Journal of biomedical materials research. Part A, 2014Co-Authors: Martin Heller, Renate Forch, Peer W. Kämmerer, Bilal Al-nawas, Marie‐anne Luszpinski, Jürgen BriegerAbstract:Biomimetic surface modifications are regarded as promising approach to stimulate cellular behavior at the interface of implant materials. Aim of the study was an evaluation of the cellular response of human umbilical cord cells (HUVECS) and human osteoblasts (HOBS) on titanium covalently coated with the extracellular matrix (ECM) proteins fibrinogen, collagen, laminin, and osteopontin. For the surface modification, titanium discs were first amino-functionalized by Plasma Polymerization of allylamine. The ECM protein conjugation was performed using the linker molecule α, ω-bis-N-hydroxysuccinimide polyethylene glycol (Di-NHS linker). For surface characterization, infrared spectroscopy and fluorescein isothiocyanate staining (FITC) were used to evaluate the presence and distribution of primary amines in the Plasma Polymer Film. Real-time analyses of the respective protein conjugation processes were performed via surface plasmon resonance kinetic measurements. All ECM proteins were immobilized successfully. Furthermore, the biological functionality of the conjugated factors fibronectin and collagen could be proven as they led to a distinct stimulation of cell adhesion of HUVECS and HOBS when compared to the control group. The highest cell coverage of HUVECS was observed on fibronectin-modified surfaces with approximately 35% and on collagen with 33% after 24 h (PT: 9.4%). For laminin, no additional effect was observed, and for osteopontin, only a slight enhancement of cell adhesion was found. A similar, cell-stimulating tendency of fibronectin and collagen was seen as well after 3 and 7 days. Biomimetic surface modification via Plasma Polymerization is a powerful method for biomolecule conjugation with a high retention of biological functionality and offer promising clinical perspectives.
Hiroki Kuwano - One of the best experts on this subject based on the ideXlab platform.
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application of Plasma Polymer Film coated sensors to gas identification using linear filters
Sensors and Actuators B-chemical, 1996Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki KuwanoAbstract:Abstract A chemical sensing system that uses a new type of sensor Film and digital signal processing of sensor dynamic responses is described. It consists of quartz-crystal microbalances coated with Plasma-Polymer Films. The sensor dynamic responses include information about the target gases, and are described by linear filters the coefficients of which reflect the sensor's dynamics and which can extract the dynamic parameters, even when the gas concentrations change, using multiple sensors with different dynamic characteristics. This method is applicable to various uses under practical conditions. The application of the proposed method to a fire-alarm system is described. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards, Finally, some simulation results indicate that it is significant for these sensors to have different dynamic properties when the sensors' outputs are greatly disturbed by noise.
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application of Plasma Polymer Film coated sensors to gas identification using linear filters
Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95, 1995Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki KuwanoAbstract:A chemical sensing system that uses a new type of sensor Film and digital signal processing of sensor dynamic responses is described. This system consists of quartz crystal microbalances coated with Plasma Polymer Films. The sensor dynamic responses include information about the target gases, and linear filters can extract the dynamic parameters even when the gas concentrations change. An application to a fire alarm system is described based on the proposed method. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards.
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chemical sensing by analysing dynamics of Plasma Polymer Film coated sensors
Sensors and Actuators B-chemical, 1994Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki Kuwano, Robert LemosAbstract:Abstract A chemical sensing system that incorporates unique sensor Films and uses pattern recgonition of their dynamic responses is presented. This system consists of a sensor array of quartz-crystal microbalances coated with Plasma Polymer Films. The Films, synthesized by radio-frequency sputtering, are useful because of their high density of radical sites and unsaturated bonds. When this sensor array is exposed to a gas, the adsorption and desorption of the target gas causes a dynamic frequency response in each piezoelectric sensor. The sensor response is analysed by an autoregressive model typically to estimate the parameters of dynamic systems. This model's coefficients reflect the sensor dynamics, providing pattern vectors that characterize the target gas. Based on this model, classification maps for single gases can be created with these pattern vectors. Thesse maps show that the dynamic sensor response provides useful information for gas classification. This model also confirms that our sensing system can identify the components of a gas mixture.
Masayuki Nakamura - One of the best experts on this subject based on the ideXlab platform.
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application of Plasma Polymer Film coated sensors to gas identification using linear filters
Sensors and Actuators B-chemical, 1996Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki KuwanoAbstract:Abstract A chemical sensing system that uses a new type of sensor Film and digital signal processing of sensor dynamic responses is described. It consists of quartz-crystal microbalances coated with Plasma-Polymer Films. The sensor dynamic responses include information about the target gases, and are described by linear filters the coefficients of which reflect the sensor's dynamics and which can extract the dynamic parameters, even when the gas concentrations change, using multiple sensors with different dynamic characteristics. This method is applicable to various uses under practical conditions. The application of the proposed method to a fire-alarm system is described. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards, Finally, some simulation results indicate that it is significant for these sensors to have different dynamic properties when the sensors' outputs are greatly disturbed by noise.
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application of Plasma Polymer Film coated sensors to gas identification using linear filters
Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95, 1995Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki KuwanoAbstract:A chemical sensing system that uses a new type of sensor Film and digital signal processing of sensor dynamic responses is described. This system consists of quartz crystal microbalances coated with Plasma Polymer Films. The sensor dynamic responses include information about the target gases, and linear filters can extract the dynamic parameters even when the gas concentrations change. An application to a fire alarm system is described based on the proposed method. This system can discriminate between the gases from burning polyvinyl chloride (PVC) cables and circuit boards.
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chemical sensing by analysing dynamics of Plasma Polymer Film coated sensors
Sensors and Actuators B-chemical, 1994Co-Authors: Masayuki Nakamura, Iwao Sugimoto, Hiroki Kuwano, Robert LemosAbstract:Abstract A chemical sensing system that incorporates unique sensor Films and uses pattern recgonition of their dynamic responses is presented. This system consists of a sensor array of quartz-crystal microbalances coated with Plasma Polymer Films. The Films, synthesized by radio-frequency sputtering, are useful because of their high density of radical sites and unsaturated bonds. When this sensor array is exposed to a gas, the adsorption and desorption of the target gas causes a dynamic frequency response in each piezoelectric sensor. The sensor response is analysed by an autoregressive model typically to estimate the parameters of dynamic systems. This model's coefficients reflect the sensor dynamics, providing pattern vectors that characterize the target gas. Based on this model, classification maps for single gases can be created with these pattern vectors. Thesse maps show that the dynamic sensor response provides useful information for gas classification. This model also confirms that our sensing system can identify the components of a gas mixture.
Damien Thiry - One of the best experts on this subject based on the ideXlab platform.
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Surface Engineering of Bromine-Based Plasma Polymer Films: A Step toward High Thiol Density Containing Organic Coatings
2018Co-Authors: Damien Thiry, Matthias Pouyanne, Damien Cossement, Axel Hemberg, Rony SnydersAbstract:Nowadays, the development of synthetic methods regarding the fabrication of −SH containing organic coatings continues to attract a considerable attention. Among the potential techniques, the Plasma Polymerization appears as one of the most promising method but the difficulty to control the chemical composition of the layers is highly limiting. In this context, in this work, we report on an original method combining dry and wet chemistry approaches in view of selectively incorporating −SH functions in organic coatings. Our strategy is based on the (i) synthesis of a bromine-containing Plasma Polymer Film, followed by (ii) a selective grafting of dithiol-based molecule on C–Br bond. Investigating the Plasma Polymerization process has revealed that, in our experimental window, the load of energy in the discharge has little influence on the chemical composition as well as on the cross-linking degree of the layers. This behavior is explained by considering the concomitant influence of the gas-phase reactions and the supply of energy to the growing Film through ion bombardment. With regard to the functionalization strategy, based on comparative X-ray photoelectron spectroscopy measurements, it has been unambiguously demonstrated that a selective reaction between propanedithiol and the C–Br bond acting as the reactive center takes place resulting in the removing of the bromine atom and the incorporation of −SH groups in the PPF. Depending on the grafting reaction duration, the relative proportion of carbon bearing the −SH group is found to evolve from 4 to 6%. On the other hand, the dissolution of unbounded bromine-based species in the liquid medium during the grafting procedure is also evidenced. The whole set of our results clearly demonstrates the attractiveness of our strategy paving the way for new development in the fabrication of −SH-rich-containing organic thin Films
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combining mass spectrometry diagnostic and density functional theory calculations for a better understanding of the Plasma Polymerization of ethyl lactate
Journal of Physical Chemistry B, 2014Co-Authors: Sylvie Ligot, Damien Thiry, Maxime Guillaume, Pascal Gerbaux, Fabian Renaux, Jerome Cornil, Philippe Dubois, Rony SnydersAbstract:The focus of this work is on the growth mechanism of ethyl lactate-based Plasma Polymer Film (ELPPF) that could be used as barrier coatings. In such an application, the ester density of the Plasma Polymer has to be controlled to tune the degradation rate of the material. Our strategy consists of correlating the Plasma chemistry evaluated by RGA mass spectrometry and understanding, via DFT calculations, the chemistry of the synthesized thin Films. The theoretical calculations helped us to understand the Plasma chemistry in Plasma ON and OFF conditions. From these data it is unambiguously shown that the signal m/z 75 can directly be correlated with the precursor density in the Plasma phase. The combination of XPS and chemical derivatization experiments reveal that the ester content in the ELPFF can be tailored from 2 to 18 at. % by decreasing the RF power, which is perfectly correlated with the evolution of the Plasma chemistry. Our results also highlight that the ELPPF chemistry, especially the ester content, is affected by the Plasma mode of operation (continuous or pulsed discharge, at similar injected mean power) for similar ester content in the Plasma. This could be related to different energy conditions at the interface of the growing Films that could affect the sticking coefficient of the ester-bearing fragments.
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Combining Mass Spectrometry Diagnostic and Density Functional Theory Calculations for a Better Understanding of the Plasma Polymerization of Ethyl Lactate
2014Co-Authors: Sylvie Ligot, Damien Thiry, Maxime Guillaume, Pascal Gerbaux, Fabian Renaux, Jerome Cornil, Philippe Dubois, Rony SnydersAbstract:The focus of this work is on the growth mechanism of ethyl lactate-based Plasma Polymer Film (ELPPF) that could be used as barrier coatings. In such an application, the ester density of the Plasma Polymer has to be controlled to tune the degradation rate of the material. Our strategy consists of correlating the Plasma chemistry evaluated by RGA mass spectrometry and understanding, via DFT calculations, the chemistry of the synthesized thin Films. The theoretical calculations helped us to understand the Plasma chemistry in Plasma ON and OFF conditions. From these data it is unambiguously shown that the signal m/z 75 can directly be correlated with the precursor density in the Plasma phase. The combination of XPS and chemical derivatization experiments reveal that the ester content in the ELPFF can be tailored from 2 to 18 at. % by decreasing the RF power, which is perfectly correlated with the evolution of the Plasma chemistry. Our results also highlight that the ELPPF chemistry, especially the ester content, is affected by the Plasma mode of operation (continuous or pulsed discharge, at similar injected mean power) for similar ester content in the Plasma. This could be related to different energy conditions at the interface of the growing Films that could affect the sticking coefficient of the ester-bearing fragments
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towards the understanding of Plasma Polymer Film behaviour in ethanol a multi technique investigation
Progress in Organic Coatings, 2011Co-Authors: Laurent Denis, Damien Thiry, Damien Cossement, Pascal Gerbaux, Fabiola Brusciotti, Isabel Van De Keere, V Goossens, Herman Terryn, M Hecq, Rony SnydersAbstract:Abstract Plasma Polymer Films (PPFs) of allylamine are prepared varying the mean power injected in the Plasma ( P mean ). The PPF behaviour in ethanol is studied through the analysis of the PPF physico-chemistry and the composition of the resulting ethanol solutions. By Visible light Spectroscopic Ellipsometry (VISSE), it is observed that the well-known decrease of the PPF thickness (Δ d ) upon immersion decreases as a function of P mean . This behaviour is attributed to an increase of the PPF cross-linking density ( χ ). By means of time-of-flight secondary ion mass spectrometry (ToF-SIMS) and further statistical processing of the data by principal component analysis (PCA), we propose a method to discriminate the samples according to χ . A significant increase in the PPF oxygen content is also observed after immersion which is ascribed to reaction between ethanol molecules and trapped radicals of the PPF network. On the other hand, taking into account the specificities of the gas chromatography–mass spectrometry (GC–MS) method, the resulting ethanol solutions are demonstrated to be free of chemical species containing a number of carbon atoms ranging from 7 to 40. However, Δ d (accounting for PPF restructuring) might come with the dissolution of PPF materials having less than 7 carbon atoms.