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El Haitami A, Resmerita AM, Ursu LE, Asandulesa M, Cantin S, Farcas A. Novel Insight into the Photophysical Properties and 2D Supramolecular Organization of Poly(3,4-ethylenedioxythiophene)/Permodified Cyclodextrins Polyrotaxanes at the Air-Water Interface. Materials (Basel) 2023; 16:4757. [PMID: 37445070 DOI: 10.3390/ma16134757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Two poly(3,4-ethylenedioxythiophene) polyrotaxanes (PEDOT∙TMe-βCD and PEDOT∙TMe-γCD) end-capped by pyrene (Py) were synthesized by oxidative polymerization of EDOT encapsulated into TMe-βCD or TMe-γCD cavities with iron (III) chloride (FeCl3) in water and chemically characterized. The effect of TMe-βCD or TMe-γCD encapsulation of PEDOT backbones on the molecular weight, thermal stability, and solubility were investigated in depth. UV-vis absorption, fluorescence (FL), phosphorescence (PH), quantum efficiencies, and lifetimes in water and acetonitrile were also explored, together with their surface morphology and electrical properties. Furthermore, dynamic light scattering was used to study the hydrodynamic diameter (DH) and z-potential (ZP-ζ) of the water soluble fractions of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD. PEDOT∙TMe-βCD and PEDOT∙TMe-γCD exhibited a sharp monodisperse peak with a DH of 55 ± 15 nm and 122 ± 32 nm, respectively. The ZP-ζ value decreased from -31.23 mV for PEDOT∙TMe-βCD to -20.38 mV for PEDOT∙TMe-γCD, indicating that a negatively charged layer covers their surfaces. Surface pressure-area isotherms and Brewster angle microscopy (BAM) studies revealed the capability of the investigated compounds to organize into sizeable and homogeneous 2D supramolecular assemblies at the air-water interface. The control of the 2D monolayer organization through the thermodynamic parameters of PEDOT∙TMe-βCD and PEDOT∙TMe-γCD suggests potential for a wide range of optoelectronic applications.
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Affiliation(s)
- Alae El Haitami
- Laboratory of Physical Chemistry of Polymers and Interfaces, CY Cergy Paris Université, F95000 Cergy, France
| | - Ana-Maria Resmerita
- "Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania
| | - Laura Elena Ursu
- "Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania
| | - Mihai Asandulesa
- "Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania
| | - Sophie Cantin
- Laboratory of Physical Chemistry of Polymers and Interfaces, CY Cergy Paris Université, F95000 Cergy, France
| | - Aurica Farcas
- "Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania
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Bourque C, Dumont E, Martisella M, Daoust L, Cantin S, Levasseur MC, de Steur Q, Duval M, Marquis MA, Sultan S. L’expérience à long terme des parents endeuillés en oncologie pédiatrique : une étude rétrospective de 2 à 18 ans après le décès d’un enfant. PSYCHO-ONCOLOGIE 2023. [DOI: 10.3166/pson-2022-0222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Objectifs : Cette étude rétrospective et transversale vise à comprendre l’expérience à long terme des parents endeuillés en oncologie pédiatrique et les différences du deuil parental en fonction du genre.
Matériel et méthodes : Un questionnaire multisectionnel coconstruit avec des cliniciens et intervenants en suivi de deuil a été tenu en ligne en 2018 et 2019. Les participants au sondage étaient des parents dont l’enfant était décédé au service d’hématologie-oncologie du CHU Sainte-Justine 2 à 18 ans auparavant. Des sections spécifiques sur les réactions, les changements et les souvenirs ont fait l’objet d’analyses descriptives.
Résultats : Les réponses de 48 parents ont été analysées. Les résultats indiquent que les mères ont tendance à modifier certaines de leurs activités sociales, alors que les pères cherchent plutôt à retrouver leurs habitudes. Les réactions initialement fortes des parents s’atténuent au fil du temps sans disparaître, en particulier la tristesse et les troubles du sommeil. Les parents ont des souvenirs apaisants des interactions et des soins reçus des intervenants en milieux clinique et communautaire même plusieurs années après le décès de leur enfant.
Conclusion : L’offre de soutien psychosocial communautaire et professionnel à long terme est pertinente, de même aux besoins des couples et aux besoins individuels des parents en fonction du genre.
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Vaillard AS, El Haitami A, Dreier LB, Fontaine P, Cousin F, Gutfreund P, Goldmann M, Backus EHG, Cantin S. Vertically Heterogeneous 2D Semi-Interpenetrating Networks Based on Cellulose Acetate and Cross-Linked Polybutadiene. Langmuir 2022; 38:2538-2549. [PMID: 35171621 DOI: 10.1021/acs.langmuir.1c03084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This work reports the feasibility of polybutadiene (PB) cross-linking under UV irradiation in the presence of a linear polymer, cellulose acetate (CA), to form semi-interpenetrating polymer networks at the air-water interface. The thermodynamic properties and the morphology of two-dimensional (2D) CA/PB blends are investigated after UV irradiation and for a wide range of CA volume fractions. A contraction of the mixed Langmuir films is observed independent of the composition, in agreement with that recorded for the individual PB monolayer after cross-linking. The PB network formation is demonstrated by in situ sum-frequency generation spectroscopy on the equivolumic CA/PB mixed film. From Brewster angle microscopy observations, the PB network synthesis does not induce any morphology change at the mesoscopic scale, and all of the mixed films remain homogeneous laterally. In situ neutron reflectometry is used to probe the effect of PB cross-linking on the vertical structure of CA/PB mixed films. For all studied compositions, significant thickening of the films is evidenced, consistent with their contraction ratio. This thickening is accompanied by a partial expulsion of the PB toward the film-air interface, which is attributed to the hydrophobic character of the PB. This phenomenon is stronger for films rich in PB. In particular, the structure of the PB-rich film undergoes a transition from vertically homogeneous to inhomogeneous along the depth. 2D semi-interpenetrating polymer networks can thus be synthesized at the air-water interface with a morphology that is strongly influenced by the polymer-polymer and polymer-environment interactions.
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Affiliation(s)
| | | | - Lisa B Dreier
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Philippe Fontaine
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - Fabrice Cousin
- Laboratoire Léon Brillouin, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | | | - Michel Goldmann
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif sur Yvette Cedex, France
- Institut des NanoSciences de Paris, Sorbonne Université, 75252 Paris Cedex 05, France
- Faculté des Sciences Fondamentales et Biomédicales, Université de Paris, 75006 Paris, France
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department of Physical Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
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El Haitami A, Resmerita AM, Fichet O, Cantin S, Aubert PH, Farcas A. Synthesis, Photophysics, and Langmuir Films of Polyfluorene/Permodified Cyclodextrin Polyrotaxanes. Langmuir 2021; 37:11406-11413. [PMID: 34528811 DOI: 10.1021/acs.langmuir.1c02014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In the present study, we investigated the effect of permodified 2,3,6-tri-O-trimethylsilyl β- and γ-cyclodextrin (TMS·β-CD, TMS·γ-CD) encapsulation on the optical, electrochemical, morphological, and supramolecular arrangements of a poly[2,7'-(9,9-dioctylfluorene-alt-2',7-fluorene)] PF copolymer. For this purpose, the photophysical properties and Langmuir monolayer formation of PF·TMS·β-CD and PF·TMS·γ-CD polyrotaxanes were investigated and compared with those of the reference PF. Surface pressure-area isotherms and Brewster angle microscopy studies indicated the capability of both polyrotaxanes to organize into larger and homogeneous 2D supramolecular assemblies at the air-water interface. The obtained results suggest that the presence of the surrounding TMS·β-CD and TMS·γ-CD macrocycles on the PF backbones leads to changes in the conformation and hydrophobicity of the film surfaces. Our investigation offers a method to assess the impact of TMS-CD encapsulation on the control of 2D monolayer formation, with particular attention on the generation of stable PF monolayers for organic electronic devices.
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Affiliation(s)
| | | | | | | | | | - Aurica Farcas
- "Petru Poni" Institute of Macromolecular Chemistry, 700487 Iasi, Romania
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Vaillard AS, El Haitami A, Fontaine P, Cousin F, Gutfreund P, Goldmann M, Cantin S. Surface Pressure-Induced Interdiffused Structure Evidenced by Neutron Reflectometry in Cellulose Acetate/Polybutadiene Langmuir Films. Langmuir 2021; 37:5717-5730. [PMID: 33905653 DOI: 10.1021/acs.langmuir.1c00745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Binary blends of water-insoluble polymers are a versatile strategy to obtain nanostructured films at the air-water interface. However, there are few reported structural studies of such systems in the literature. Depending on the compatibility of the polymers and the role of the air-water interface, one can expect various morphologies. In that context, we probed Langmuir monolayers of cellulose acetate (CA), of deuterated and postoxidized polybutadiene (PBd) and three mixtures of CA/PBd at various concentrations by coupling surface pressure-area isotherms, Brewster angle microscopy (BAM), and neutron reflectometry at the air-water interface to determine their thermodynamic and structural properties. The homogeneity of the films in the vertical direction, averaged laterally over the spatial coherence length of the neutron beam (∼5 μm), was assessed by neutron reflectometry measurements using D2O/H2O subphases contrast-matched to the mixed films. At 5 mN/m, the whole mixed films can be described by a single slightly hydrated thin layer. However, at 15 mN/m, the fit of the reflectivity curves requires a two-layer model consisting of a CA/PBd blend layer in contact with the water, interdiffused with a PBd layer at the interface with air. At intermediate surface pressure (10 mN/m), the determined structure was between those obtained at 5 and 15 mN/m depending on film composition. This PBd enrichment at the air-film interface at high surface pressure, which leads to the PBd depletion in the blend monolayer at the water surface, is attributed to the hydrophobic character of this polymer compared with the predominantly hydrophilic CA.
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Affiliation(s)
| | | | - Philippe Fontaine
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP48, 91192 Gif sur Yvette Cedex, France
| | - Fabrice Cousin
- Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS UMR 12, F-91191 Gif-sur-Yvette, France
| | - Philipp Gutfreund
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Michel Goldmann
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP48, 91192 Gif sur Yvette Cedex, France
- Institut des NanoSciences de Paris, Sorbonne Université, 4 Place Jussieu, 75252 Paris Cedex 05, France
- Faculté des Sciences Fondamentales et Biomédicales, Université de Paris, 45 rue des Sts-Pères, 75006 Paris, France
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Haroun F, El Haitami A, Ober P, Backus EHG, Cantin S. Poly(ethylene glycol)- block-poly(propylene glycol)- block-poly(ethylene glycol) Copolymer 2D Single Network at the Air-Water Interface. Langmuir 2020; 36:9142-9152. [PMID: 32686418 DOI: 10.1021/acs.langmuir.0c01398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this work, Langmuir monolayers based on poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG) triblock copolymer were in situ stabilized at the air-water interface in the presence of a cross-linking agent, benzene-1,3,5-tricarboxaldehyde (BTC), in the aqueous subphase. The reaction takes place through acid-catalyzed acetalization between the terminal hydroxyl groups of the copolymer and aldehyde functions of the BTC molecules. Mean area per repeat unit measurements as a function of the reaction time show a significant monolayer contraction associated with an increase in its compressibility modulus. In addition, Brewster angle microscopy observations indicate the appearance of higher-density two-dimensional domains, irreversibly formed at constant surface pressure. This is also confirmed on a smaller scale by atomic force microscopy (AFM). These arguments, consistent with copolymer monolayer cross-linking in acidic medium, are supported in situ at the air-water interface by sum-frequency generation (SFG) spectroscopy. Furthermore, PEG-PPG-PEG monolayer cross-linking is not evidenced in alkaline medium, in coherence with the interfacial acid-catalyzed acetalization.
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Affiliation(s)
- Ferhat Haroun
- LPPI, CY Cergy Paris Université, F95000 Cergy, France
| | | | - Patrick Ober
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department of Physical Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Sophie Cantin
- LPPI, CY Cergy Paris Université, F95000 Cergy, France
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Vaillard AS, El Haitami A, Dreier LB, Backus EHG, Cantin S. Correction to "Confinement and Cross-Linking of 1,2-Polybutadiene in 2D at the Air-Water Interface". Langmuir 2020; 36:2741. [PMID: 32134678 DOI: 10.1021/acs.langmuir.0c00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
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Vaillard AS, El Haitami A, Dreier LB, Backus EHG, Cantin S. Confinement and Cross-Linking of 1,2-Polybutadiene in Two Dimensions at the Air-Water Interface. Langmuir 2020; 36:862-871. [PMID: 31935102 DOI: 10.1021/acs.langmuir.9b03297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Langmuir monolayers of 1,2-polybutadiene (PB) were investigated by means of surface pressure-area isotherms, Brewster angle microscopy (BAM) observations, and sum-frequency generation (SFG) spectroscopy. A homogeneous and stable monolayer is formed 1.5 h after PB spreading provided that both light and oxygen are present. This was attributed to a slight oxidation of the PB at the air-water interface. The cross-linking of PB under UV photoirradiation was then studied. SFG spectroscopy demonstrates the in situ formation of a two-dimensional network. From surface pressure-area characterizations and BAM experiments, the cross-linked PB monolayer appears significantly denser and more rigid than the non-irradiated monolayer. Atomic force microscopy images reveal an increase by a factor of three in the root-mean-square roughness of the irradiated monolayers compared with the non-irradiated ones.
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Affiliation(s)
- Anne-Sophie Vaillard
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528) , Institut des Matériaux, CY Cergy Paris Université , 5 mail Gay-Lussac Neuville/Oise , Cergy-Pontoise Cedex 95031 , France
| | - Alae El Haitami
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528) , Institut des Matériaux, CY Cergy Paris Université , 5 mail Gay-Lussac Neuville/Oise , Cergy-Pontoise Cedex 95031 , France
| | - Lisa B Dreier
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz 55128 , Germany
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz 55128 , Germany
- Department of Physical Chemistry , Währinger Strasse 42 , Vienna A-1090 , Austria
| | - Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528) , Institut des Matériaux, CY Cergy Paris Université , 5 mail Gay-Lussac Neuville/Oise , Cergy-Pontoise Cedex 95031 , France
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Royaux A, El Haitami A, Fichet O, Cantin S. Surface free-energy determination of copper wire using a large range of model liquids. SN Appl Sci 2020. [DOI: 10.1007/s42452-019-1828-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Ji X, Liu X, Cacucciolo V, Imboden M, Civet Y, El Haitami A, Cantin S, Perriard Y, Shea H. An autonomous untethered fast soft robotic insect driven by low-voltage dielectric elastomer actuators. Sci Robot 2019; 4:4/37/eaaz6451. [PMID: 33137720 DOI: 10.1126/scirobotics.aaz6451] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/20/2019] [Indexed: 01/19/2023]
Abstract
Insects are a constant source of inspiration for roboticists. Their compliant bodies allow them to squeeze through small openings and be highly resilient to impacts. However, making subgram autonomous soft robots untethered and capable of responding intelligently to the environment is a long-standing challenge. One obstacle is the low power density of soft actuators, leading to small robots unable to carry their sense and control electronics and a power supply. Dielectric elastomer actuators (DEAs), a class of electrostatic electroactive polymers, allow for kilohertz operation with high power density but require typically several kilovolts to reach full strain. The mass of kilovolt supplies has limited DEA robot speed and performance. In this work, we report low-voltage stacked DEAs (LVSDEAs) with an operating voltage below 450 volts and used them to propel an insect-sized (40 millimeters long) soft untethered and autonomous legged robot. The DEAnsect body, with three LVSDEAs to drive its three legs, weighs 190 milligrams and can carry a 950-milligram payload (five times its body weight). The unloaded DEAnsect moves at 30 millimeters/second and is very robust by virtue of its compliance. The sub-500-volt operation voltage enabled us to develop 780-milligram drive electronics, including optical sensors, a microcontroller, and a battery, for two channels to output 450 volts with frequencies up to 1 kilohertz. By integrating this flexible printed circuit board with the DEAnsect, we developed a subgram robot capable of autonomous navigation, independently following printed paths. This work paves the way for new generations of resilient soft and fast untethered robots.
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Affiliation(s)
- Xiaobin Ji
- Soft Transducers Laboratory (LMTS), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Xinchang Liu
- Integrated Actuators Laboratory (LAI), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Vito Cacucciolo
- Soft Transducers Laboratory (LMTS), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Matthias Imboden
- Soft Transducers Laboratory (LMTS), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Yoan Civet
- Integrated Actuators Laboratory (LAI), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Alae El Haitami
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 Mail Gay Lussac, 95031 Cergy-Pontoise, France
| | - Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 Mail Gay Lussac, 95031 Cergy-Pontoise, France
| | - Yves Perriard
- Integrated Actuators Laboratory (LAI), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland
| | - Herbert Shea
- Soft Transducers Laboratory (LMTS), École Polytechnique Fédérale de Lausanne (EPFL), Rue de la Maladière 71B, Neuchâtel 2000, Switzerland.
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Royaux A, Fabre-Francke I, Balcar N, Barabant G, Bollard C, Lavédrine B, Cantin S. Long-term effect of silk paper used for wrapping of plasticized PVC objects: Comparison between ancient and model PVC. Polym Degrad Stab 2018. [DOI: 10.1016/j.polymdegradstab.2018.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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El Haitami A, Goldmann M, Fontaine P, Fauré MC, Cantin S. Inorganic mixed phase templated by a fatty acid monolayer at the air-water interface: the Mn and Mg case. Phys Chem Chem Phys 2018; 20:6629-6637. [PMID: 29457172 DOI: 10.1039/c8cp00308d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We studied by means of Grazing Incidence X-ray Diffraction (GIXD) coupled with X-ray fluorescence spectroscopy the structure of a behenic acid monolayer spread at the surface of Mg2+/Mn2+ mixed aqueous solutions. For the pure Mg2+ and Mn2+ aqueous solutions, the cations induce at the surface different 2D lattice superstructures of the organic monolayer. These superstructures correspond to an inorganic organized monolayer anchored to the hydrophilic group of the ordered behenic acid monolayer. Among the various diffraction peaks, we focused on those characteristics of the behenic acid oblique cell. As the Mg2+ mole fraction x increases in the Mg2+/Mn2+ mixed subphase, a continuous evolution of the oblique cell parameters is observed indicating the insertion of Mg2+ cations in the Mn2+ ordered monolayer. Then, a further increase leads to the appearance of a coexistence between two oblique surface phases. The cell parameters of both phases evolve continuously along the x range of the transition until a single Mg-rich ordered phase is detected. However, although the intensities of the peaks in the coexistence region are in agreement with a first-order phase transition, the cell parameters evolve simultaneously. Considering a thermodynamics analysis, this evidences that, apart from the concentration, another unidentified intensive parameter is varying. We suggest that it is the ionic strength, which appears to be strongly related to the concentrations.
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Affiliation(s)
- Alae El Haitami
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95031 Cergy-Pontoise Cedex, France.
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Royaux A, Fabre-Francke I, Balcar N, Barabant G, Bollard C, Lavédrine B, Cantin S. Aging of plasticized polyvinyl chloride in heritage collections: The impact of conditioning and cleaning treatments. Polym Degrad Stab 2017. [DOI: 10.1016/j.polymdegradstab.2017.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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El Haitami A, Goldmann M, Cousin F, Dosseh G, Cantin S. From Homogeneous to Segregated Structure of Poly(dimethylsiloxane)/Cellulose Derivative Mixed Langmuir Films Depending on Composition: An in Situ Neutron Reflectivity Study. Langmuir 2015; 31:6395-6403. [PMID: 26017847 DOI: 10.1021/acs.langmuir.5b01197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The mixing behavior of deuterated polydimethylsiloxane (PDMSd) and cellulose acetate butyrate (CAB) spread as Langmuir films at the air-water interface was studied by means of surface pressure-area isotherms, Brewster angle microscopy (BAM) observations, and in situ neutron reflectivity. The contrast variation method was used with different D2O/H2O mixtures as subphase, allowing contrast matching to either CAB, PDMSd, or PDMSd/CAB mixed film if homogeneous. At PDMSd volume fractions Φ lower than 0.6, the mixed film is a homogeneous monolayer throughout the film compression, in agreement with the monophasic film observed by BAM and the attractive interactions between PDMSd and CAB evidenced from the isotherm measurements. In contrast, at PDMSd volume fractions Φ higher than 0.6, a vertically segregated structure of the mixed film is highlighted. Indeed, whatever the surface pressure, a bilayer structure is observed with a PDMSd layer in contact with the air over a thin CAB layer in contact with the subphase. These results show that the structure of the film is mainly driven by the PDMSd volume fraction which allows obtaining either a homogeneous membrane which composition can be tuned or a vertically segregated system. In contrast, only the thickness of the layers varies with the surface pressure while the structure of the film is not affected.
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Affiliation(s)
- Alae El Haitami
- †Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, Cergy-Pontoise Cedex 95000, France
| | - Michel Goldmann
- ‡Institut des Nanosciences de Paris (INSP, UMR 7588), Université Pierre et Marie Curie, 4 place Jussieu, Paris 75252 Cedex 05, France
- §UFR Biomédicale des Saints-Pères, Université Paris Descartes, 45 rue des St pères, 75006 Paris, France
| | - Fabrice Cousin
- ∥Laboratoire Léon Brillouin (LLB), CEA-CNRS, Saclay, Gif-sur-Yvette Cedex 91191, France
| | - Gilberte Dosseh
- †Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, Cergy-Pontoise Cedex 95000, France
| | - Sophie Cantin
- †Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, Cergy-Pontoise Cedex 95000, France
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Farcas A, Resmerita AM, Aubert PH, Ghosh I, Cantin S, Nau WM. Synthesis, Photophysical, and Morphological Properties of Azomethine-Persylilated α-Cyclodextrin Main-Chain Polyrotaxane. MACROMOL CHEM PHYS 2015. [DOI: 10.1002/macp.201400543] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Aurica Farcas
- “P. Poni” Institute of Macromolecular Chemistry; 41A Gr. Ghica Voda Alley Iasi 700487 Romania
| | - Ana-Maria Resmerita
- “P. Poni” Institute of Macromolecular Chemistry; 41A Gr. Ghica Voda Alley Iasi 700487 Romania
| | - Pierre-Henri Aubert
- Laboratoire de Physicochimie des Polymères et des Interfaces; Institut des Matériaux; Université de Cergy-Pontoise; 5 Mail Gay Lussac Neuville sur Oise 95031 Cergy-Pontoise Cedex France
| | - Indrajit Ghosh
- Jacobs University; School of Engineering and Science; D-28759 Bremen Germany
| | - Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces; Institut des Matériaux; Université de Cergy-Pontoise; 5 Mail Gay Lussac Neuville sur Oise 95031 Cergy-Pontoise Cedex France
| | - Werner M. Nau
- Jacobs University; School of Engineering and Science; D-28759 Bremen Germany
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Farcas A, Aubert PH, Mohanty J, Lazar AI, Cantin S, Nau WM. Molecular wire formation from poly[2,7-(9,9-dioctylfluorene)-alt-(5,5′-bithiophene/cucurbit[7]uril)] polyrotaxane copolymer. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2014.11.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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El Haitami A, Backus EHG, Cantin S. Synthesis at the air-water interface of a two-dimensional semi-interpenetrating network based on poly(dimethylsiloxane) and cellulose acetate butyrate. Langmuir 2014; 30:11919-11927. [PMID: 25238044 DOI: 10.1021/la502514e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The UV-induced cross-linking of methacryloxypropyl-terminated poly(dimethylsiloxane) oligomers was studied at the air-water interface either in pure PDMS Langmuir monolayers or in mixed films containing cellulose acetate butyrate. Surface pressure-area isotherms, area measurement at constant surface pressure, Brewster angle microscopy observations, and infrared-visible sum frequency generation (SFG) spectroscopy were combined to follow the evolution of the monolayers upon in situ UV photoirradiation. For both systems, the mean area per repeat unit decreases with irradiation time reflecting the monolayer contraction. In addition, SFG measurements evidence the conversion of the methacrylate groups into unconjugated poly(methacrylate) ones. These results demonstrate PDMS cross-linking, leading to the formation of either a single PDMS network or a PDMS network entrapped in a CAB matrix. The network formation is accompanied by morphology changes as shown by atomic force microscopy on the transferred monolayer. Indeed, filamentous structures appear on both pure and mixed preirradiated monolayers.
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Affiliation(s)
- Alae El Haitami
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise , 5 mail Gay-Lussac Neuville/Oise, 95031 Cergy-Pontoise, Cedex, France
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Martino A, Krainik A, Pasteris C, Hoffmann D, Chabardes S, Berger F, Le Bas JF, Cantin S, Attye A, Grand S. Neurological imaging of brain damages after radiotherapy and/or chimiotherapy. J Neuroradiol 2014; 41:52-70. [PMID: 24439107 DOI: 10.1016/j.neurad.2013.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 07/22/2013] [Accepted: 07/30/2013] [Indexed: 11/16/2022]
Abstract
Radiotherapy and chemotherapy may induce neurological toxicities with different appearances on CT and MRI scans. While optimized radiotherapy techniques have reduced some complications, new unwanted effects have occurred on account of therapeutic protocols involving the simultaneous use of radiotherapy and chemotherapy. Advances in radio-surgery, innovative anti-angiogenic therapies, as well as prolonged patient survival have led to the emergence of new deleterious side effects. In this report, we describe the early, semi-delayed, and late encephalic complications, while specifying how to identify the morphological lesions depending on the therapeutic protocol.
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Affiliation(s)
- A Martino
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France
| | - A Krainik
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France
| | - C Pasteris
- Clinique de Radiothérapie, CHU de Grenoble, Grenoble, France
| | - D Hoffmann
- Clinique de Neurochirurgie, CHU de Grenoble, Grenoble, France
| | - S Chabardes
- Clinique de Neurochirurgie, CHU de Grenoble, Grenoble, France
| | - F Berger
- Grenoble Institut de Neurosciences, équipe 7, 38043 Grenoble, France
| | - J F Le Bas
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France
| | - S Cantin
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France
| | - A Attye
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France
| | - S Grand
- Clinique Universitaire de Neuroradiologie et Imagerie, CHU de Grenoble, Grenoble, France.
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20
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Cantin S, Fauré MC, Perrot F, Goldmann M. Structure and kinetics of fatty acid Langmuir monolayers on zinc salt solutions. J Phys Chem B 2013; 117:16275-82. [PMID: 24283749 DOI: 10.1021/jp407047a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The adsorption of zinc cations under behenic acid Langmuir monolayers was investigated by means of isotherm measurements, grazing incidence X-ray diffraction and Brewster angle microscopy. The structure of the films was characterized as a function of Zn(2+) concentration, for three different counterions (chloride, iodide, bromide) and at two subphase pHs (5.5 and 7.5). At pH 5.5 and in the studied concentration range, Zn(2+) adsorption leads to a condensation of the fatty acid monolayer with the same phase transitions as over pure water. In contrast, at higher pH the organic X-phase is evidenced immediately above a concentration threshold without any ion organization. Even though Cu(2+) and Zn(2+)cations induce both the fatty acid X-phase, the kinetics of its formation appears strongly different. Indeed, as for Mg(2+) and Cd(2+), the intermediate new I-structure is evidenced in the course of Zn(2+) adsorption although superstructures are observed only for Mg(2+) and Cd(2+). However, for Zn(2+), the I-phase evolves to the final state through a new structure called X' and a continuous X'-X transition. Finally, any effect of the counterion is evidenced neither during the kinetic process nor in the final state.
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Affiliation(s)
- Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise , 5 mail Gay-Lussac Neuville/Oise, 95031 Cergy-Pontoise Cedex, France
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Cantin S, Perrot F, Fontaine P, Goldmann M. Limited propagation of lattice distortion in trilayer Langmuir-Blodgett films: correlation with mesoscopic structure. Langmuir 2013; 29:11046-11054. [PMID: 23927021 DOI: 10.1021/la401860j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The structure of trilayer Langmuir-Blodgett (LB) films on oxidized silicon wafers has been investigated using grazing incidence X-ray diffraction at various incidence angles and atomic force microscopy (AFM). These films are formed by two behenic acid (BA) layers and a third monolayer of amphiphilic molecules having different architectures. These molecules have the same polar head and differ from each other by the chain, either saturated or unsaturated hydrogenated or semi-fluorinated. The structure of the first BA monolayer appears as unchanged in all cases, whereas a condensation of the second BA monolayer is evidenced when the third layer is not formed with the saturated hydrogenated chain. We interpret this condensation as resulting from the mismatch between the lattices of the second BA layer and the external monolayer, possibly associated with the formation of a new monolayer-air interface creating line tension effects. Line tension estimation has also been made from the size of the holes observed in the different LB films.
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Affiliation(s)
- Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 Mail Gay-Lussac Neuville/Oise, 95031 Cergy-Pontoise Cedex, France.
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Abrakhi S, Péralta S, Fichet O, Teyssié D, Cantin S. Poly(azobenzene acrylate-co-fluorinated acrylate) spin-coated films: influence of the composition on the photo-controlled wettability. Langmuir 2013; 29:9499-9509. [PMID: 23805895 DOI: 10.1021/la400938j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The wetting properties of spin-coated films of copolymers based on azobenzene and fluorinated units have been investigated. The copolymers, denoted as poly(Azo-co-AcRf6), have been synthesized by free-radical polymerization of different proportions of acrylate monomers bearing either an azobenzene group or a semifluorinated side chain. The UV-visible spectroscopy analysis of the different spin-coating films through a cycle of UV and visible light irradiation indicates the reversible trans-cis isomerization of azobenzene groups. Simultaneously, atomic force microscopy shows that surface roughness does not exceed 1 nm. Advancing and receding contact angles of water and diiodomethane have been measured before and after UV photoirradiation of the different surfaces. In particular, a decrease in the advancing contact angles has been observed upon trans-cis isomerization of azobenzene groups. Switching variations up to 50° have been evidenced without any introduction of surface nanoroughness. Surface free-energy evaluations have been deduced from these measurements, including dispersive and polar components. The results show that, through surface composition and UV photoirradiation, a large range of surface free-energies can be obtained, from 7 to 46 mN·m(-1).
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Affiliation(s)
- Sanae Abrakhi
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
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Villien M, Chipon E, Troprès I, Bouvier J, Cantin S, Chechin D, Le Bas JF, Krainik A, Warnking JM. Per-subject characterization of bolus width in pulsed arterial spin labeling using bolus turbo sampling. Magn Reson Med 2012; 69:1677-82. [PMID: 22829470 DOI: 10.1002/mrm.24412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/05/2012] [Accepted: 06/21/2012] [Indexed: 11/11/2022]
Abstract
Quantification of cerebral blood flow using QUIPSSII pulsed arterial spin labeling requires that the QUIPSS saturation delay TI1 is shorter than the natural temporal bolus width. Yet the duration of the bolus of tagged spins entering the region of interest varies during vasoactive stimuli such as gaseous challenges or across subjects due to differences in blood velocity or vessel geometry. A new technique, bolus turbo sampling, to rapidly measure the duration of the inflowing bolus is presented. It allows to optimize the arterial spin labeling acquisition to ensure reliable quantification of perfusion while maximizing the arterial spin labeling signal by avoiding the use of unnecessarily short label durations. The average bolus width measured in the right and left middle cerebral artery territories using the bolus turbo sampling technique has a repeatability coefficient of 75 ms and correlates significantly with the TI1,max determined from a novel multi-TI1 protocol (R=0.65, P<0.05). The possibility to measure the bolus width under hypercapnia is demonstrated.
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Backus EHG, Abrakhi S, Péralta S, Teyssié D, Fichet O, Cantin S. Sum-Frequency Generation Spectroscopy of Cinnamate Modified Cellulosic Polymer at the Air–Water Interface. J Phys Chem B 2012; 116:6041-9. [DOI: 10.1021/jp301844b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Ellen H. G. Backus
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam,
The Netherlands, and Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, 55128
Mainz, Germany
| | - Sanae Abrakhi
- Laboratoire
de Physico-Chimie
des Polymères et des Interfaces (LPPI, EA 2528), Institut des
Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
| | - Sébastien Péralta
- Laboratoire
de Physico-Chimie
des Polymères et des Interfaces (LPPI, EA 2528), Institut des
Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
| | - Dominique Teyssié
- Laboratoire
de Physico-Chimie
des Polymères et des Interfaces (LPPI, EA 2528), Institut des
Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
| | - Odile Fichet
- Laboratoire
de Physico-Chimie
des Polymères et des Interfaces (LPPI, EA 2528), Institut des
Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
| | - Sophie Cantin
- Laboratoire
de Physico-Chimie
des Polymères et des Interfaces (LPPI, EA 2528), Institut des
Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
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Abstract
We report a combined vibrational sum-frequency generation (SFG) spectroscopy, Brewster angle microscopy (BAM), and ellipsometry study of different surfactants on water as a function of surfactant density. Vibrational SFG spectra of surfactants on the water surface in a Langmuir trough have been measured in both the surfactant CH and the water OH stretch regions. At low densities, the SFG signal generated at the surface in the presence of the surfactant is indistinguishable from the SFG signal generated at the clean water-air interface. When the surfactant density increases, i.e., upon compressing the monolayer, a very sudden increase in the SFG signal in both the CH and OH spectral regions is observed. For higher laser fluences, this stepwise increase occurs at increasingly higher surfactant densities. Since BAM shows that surfactant molecules are clearly present at these low densities, we conclude that at low surfactant density the laser beam displaces relatively high-density domains with surfactants in the liquid expanded phase out of the region of the laser focus. This is a consequence of the thermal gradient induced by local heating of the water phase with the monolayer on top due to repetitive laser excitation at 1 kHz. It can be circumvented by using a rotating trough. In this manner, the sampled surface area can be refreshed, allowing artifact-free vibrational SFG spectra to be measured down to the very lowest surfactant densities. In ellipsometry experiments, a similar step can be noticed, which, however, is of a different nature; i.e., it is not related to heating (the laser fluence is very low and the light nonresonant) but to a molecular transition. The occurrence of the step in ellipsometry as a function of area per molecule depends critically on the preparation of the monolayer. By giving the molecules time and space to relax during the preparation of the monolayer, this step could also be eliminated.
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Affiliation(s)
- Ellen H G Backus
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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Abrakhi S, Péralta S, Cantin S, Fichet O, Teyssié D. Synthesis and characterization of photosensitive cinnamate-modified cellulose acetate butyrate spin-coated or network derivatives. Colloid Polym Sci 2011. [DOI: 10.1007/s00396-011-2559-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bouteau M, Cantin S, Fichet O, Perrot F, Teyssié D. Contribution toward comprehension of contact angle values on single polydimethylsiloxane and poly(ethylene oxide) polymer networks. Langmuir 2010; 26:17427-17434. [PMID: 20919692 DOI: 10.1021/la102384s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The large application ranges of polydimethylsiloxane (PDMS) and poly(ethylene oxide) (PEO) based materials justify the importance of controlling polymer surface properties including morphology and wettability behavior. However, it appears that the reported contact angle values of PDMS surfaces show significant scattering which cannot always be interpreted in terms of sole chemical data. In addition, few values are reported concerning pure PEO surfaces, since the polymer generally swells in the presence of water. Thus, in order to correlate surface properties with sample preparation, several single PDMS and PEO polymer networks were synthesized with varying cross-linkers and different cross-linking densities. First, the sample surface topography was systematically analyzed by atomic force microscopy (AFM). It was proven that the removal process of the polymer film from the mold plays a significant role in surface topography according to the vitreous or rubbery state of the given polymer network at room temperature irrespective of mold surface treatment. AFM-scale smooth surfaces can be obtained for all the samples by removing them systematically from the mold at a temperature below the α-relaxation temperature. Dynamic water contact angles were then measured and the values analyzed as a function of cross-linker nature and cross-linking density.
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Affiliation(s)
- Murielle Bouteau
- Laboratoire de Physico-Chimie des Polymères et des Interfaces (LPPI, EA 2528), Institut des Matériaux, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95000 Cergy-Pontoise Cedex, France
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Cantin S, Péralta S, Fontaine P, Goldmann M, Perrot F. Evolution toward the X phase of fatty acid Langmuir monolayers on a divalent cation solution. Langmuir 2010; 26:830-837. [PMID: 19719160 DOI: 10.1021/la9022823] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The structure of docosanoic acid monolayers spread over chloride salt solutions of copper was investigated by means of isotherm measurements, grazing incidence X-ray diffraction, and Brewster angle microscopy, as a function of the ion concentration and at two subphase pHs (5.5 and 7.5). The X phase is evidenced immediately above a concentration threshold which depends on the pH. The sequence of phases leading to this rigid phase involves two different processes depending on the pH. The initial L(2h) phase evolves toward an X-like phase through a phase transition which is first order at pH 7.5 while it is second order at pH 5.5. The transition is then followed by a continuous evolution toward the X phase.
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Affiliation(s)
- Sophie Cantin
- Laboratoire de Physico-Chimie des Polymères et des Interfaces (LPPI, EA 2528), Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95031 Cergy-Pontoise Cedex, France.
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Pichon BP, Cantin S, Smulders MMJ, Vos MRJ, Chebotareva N, Popescu DC, van Asselen O, Perrot F, Sijbesma R, Sommerdijk NAJM. Molecular recognition controls the organization of mixed self-organized bis-urea-based mineralization templates for CaCO(3). Langmuir 2007; 23:12655-12662. [PMID: 17973513 DOI: 10.1021/la7026225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
To investigate the role and importance of nondirectional electrostatic interactions in mineralization, we explored the use of Langmuir monolayers in which the charge density can be tuned using supramolecular interactions. It is demonstrated that, in mixed Langmuir monolayers of bis-ureido surfactants containing oligo(ethylene oxide) and ammonium head groups associated with matching or nonmatching spacers between the two urea groups, the organization is controlled by molecular recognition. These different organizations of the molecules lead to different nucleation behavior in the mineralization of calcium carbonate. The formation of modified calcite and vaterite crystals was induced selectively by different phases of mixed monolayers, and they were characterized by SEM, TEM, and SAED. To understand the influence of the mixed Langmuir monolayers on the crystallization process, we studied the mixtures by means of (pi-A) isotherms and Brewster angle microscopy observations. Infrared reflection-absorption spectroscopy experiments were also performed on Langmuir-Schaefer films. From these results, we conclude that the local organization of the two systems discussed here gives rise to differences in both charge density and flexibility that together determine not only polymorph selection and the nucleation face but also the morphology of the resulting crystals.
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Affiliation(s)
- Benoît P Pichon
- Laboratory of Macromolecular and Organic Chemistry and Department of Polymer Technology, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
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Cantin S, Fichet O, Perrot F, Teyssié D. Spontaneous polymerization at the air-water interface: a Brewster angle microscopy study. Langmuir 2007; 23:12243-12248. [PMID: 17949021 DOI: 10.1021/la7020534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
When a dioctadecyldimethylammonium bromide (DODA) monolayer is spread onto a styrene sulfonate (SSt) aqueous solution, this monomer undergoes a spontaneous polymerization process [Fichet, O; Teyssié, D. Macromolecules 2002, 35, 5352]. However, the polymer synthesized in this monolayer cannot be investigated by classical characterization techniques. Brewster angle microscopy has thus been used as a complementary method in order to study this spontaneous polymerization. From these measurements, the threshold concentration above which the spontaneous polymerization occurs has been determined more precisely; the monomer adsorption under the DODA monolayer has been evidenced as being very fast, as supposed previously; moreover, sodium bicarbonate is confirmed as an inhibitor of the polymerization. Also, the replacement of SSt by toluene sulfonate (TSt) confirms the SSt spontaneous polymerization. Finally, the molecular weight and/or the structure of the polymer synthesized in the monolayer seems to be different from those synthesized in solution.
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Affiliation(s)
- Sophie Cantin
- Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI, EA 2528), Université de Cergy-Pontoise-5, mail Gay-Lussac, Neuville-sur-Oise, Cergy-Pontoise Cedex, France.
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Bouteau M, Cantin S, Benhabib F, Perrot F. Sliding behavior of liquid droplets on tilted Langmuir-Blodgett surfaces. J Colloid Interface Sci 2007; 317:247-54. [PMID: 17935726 DOI: 10.1016/j.jcis.2007.09.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 09/02/2007] [Accepted: 09/08/2007] [Indexed: 12/01/2022]
Abstract
The sliding behavior of liquid droplets on inclined Langmuir-Blodgett surfaces was investigated. The critical sliding angle defined as the tilt angle of the surface at which the drop slides down as well as the advancing and receding contact angles was measured for five different liquids on five surfaces. In addition, the contact line geometry was analyzed at critical sliding angle. The experimental relationship between the surface tension forces resulting from contact angle hysteresis and the weight of the drop was compared to theoretical predictions. Even though the shape of the drop bases was found as skewed ellipses, a model assuming parallel-sided elongated drops is shown to describe reasonably the experimental values. This result probably indicates the main influence of the capillary forces at the rear and front edges of the drop with respect to that exerted on the lateral sides.
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Affiliation(s)
- Murielle Bouteau
- Laboratoire de Physico-Chimie des Polymères et des Interfaces (LPPI, EA 2528), Université de Cergy-Pontoise, Neuville sur Oise, 95 031 Cergy-Pontoise Cedex, France
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Pignat J, Cantin S, Liu RCW, Goldmann M, Fontaine P, Daillant J, Perrot F. pH-dependent kinetics of MgCl2 adsorption under a fatty-acid Langmuir film. Eur Phys J E Soft Matter 2006; 20:387-94. [PMID: 16927026 DOI: 10.1140/epje/i2006-10027-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 07/28/2006] [Indexed: 05/11/2023]
Abstract
The effect of subphase pH (5.5 and 10.5) on the structure of behenic-acid monolayers was investigated during Mg(2+) adsorption by means of Grazing Incidence X-ray Diffraction (GIXD) and Brewster Angle Microscopy (BAM). The final phase corresponding to an ion superlattice commensurate to the behenic-acid cell is pH-independent. In contrast, the sequence of phases evidenced from the initial L(2)-phase to this final state presents at pH 10.5 an additional stage associated to a film condensation toward the L' (2)-phase. The structures of the intermediate states preceding the superstructure nucleation are slightly different, both with a short-range fatty-acid order. Finally, a laser light effect that could result from visible light absorption by the inorganic complexes is evidenced in the final state as well as in the intermediate phases.
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Affiliation(s)
- J Pignat
- LPPI, Université de Cergy-Pontoise, 5 mail Gay-Lussac Neuville/Oise, 95031, Cergy-Pontoise Cedex, France
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Cantin S, Bouteau M, Benhabib F, Perrot F. Surface free energy evaluation of well-ordered Langmuir–Blodgett surfaces. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2005.10.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Liu RCW, Cantin S, Perrot F, Winnik FM. Effects of polymer architecture and composition on the interfacial properties of temperature-responsive hydrophobically-modified poly(N-isopropylacrylamides). POLYM ADVAN TECHNOL 2006. [DOI: 10.1002/pat.823] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Cantin S, Pignat J, Perrot F, Fontaine P, Goldmann M. Observation of a two-step mechanism in the formation of a superstructure of cadmium-behenic acid Langmuir monolayer: evidence of an intermediate structure. Phys Rev E Stat Nonlin Soft Matter Phys 2004; 70:050601. [PMID: 15600579 DOI: 10.1103/physreve.70.050601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Indexed: 05/24/2023]
Abstract
By means of grazing incidence x-ray diffraction, the structure of a behenic acid monolayer spread over chloride salt solutions of cadmium is observed to evolve from the tilted L2 phase to the superstructure (corresponding to an organized monolayer of ions in addition to the ordered organic film), through an intermediate phase. The studied salt concentrations are below the so-called "threshold" needed for the formation of this superstructure. This kinetic process involving two first-order phase transitions is confirmed by Brewster angle microscopy experiments and surface pressure-area isotherms measured at different times after monolayer deposition.
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Affiliation(s)
- S Cantin
- LPPI (EA 528), Université de Cergy-Pontoise, Neuville sur Oise, 95 031 Cergy-Pontoise Cedex, France
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Dupres V, Cantin S, Benhabib F, Perrot F, Fontaine P, Goldmann M. Variation of the in-plane structure with depth revealed by grazing incidence x-ray diffraction in a thin Langmuir-Blodgett film. ACTA ACUST UNITED AC 2002; 66:012701. [PMID: 12241399 DOI: 10.1103/physreve.66.012701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2002] [Indexed: 11/07/2022]
Abstract
Grazing incidence x-ray diffraction is used to characterize the molecular arrangement of ultrathin Langmuir-Blodgett (LB) multilayers. Using two angles of incidence of the beam allowing its penetration either throughout the complete depth of the film or only through the external layers, we show that it is possible to discriminate between the molecular packing of the deeper monolayers and that of the external monolayers of the LB film.
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Affiliation(s)
- V Dupres
- Laboratoire de Physique des Matériaux et des Surfaces, Université de Cergy-Pontoise, Neuville sur Oise, 95 031 Cergy-Pontoise Cedex, France
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Dupres V, Cantin S, Perrot F, Fontaine P, Goldmann M. Evidence of a tilted and herringbone structure in cadmium behenate Langmuir–Blodgett ultrathin films: Comparison with Langmuir monolayers. J Chem Phys 2002. [DOI: 10.1063/1.1447909] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Raynal C, Cantin S, Confavreux C, Dumouchel H, Steineur M, Charhon A, Broussolle C. Fièvre au long cours et BOOP (bronchiolitis obliterans organizing pneumonia) postradique. Rev Med Interne 2001. [DOI: 10.1016/s0248-8663(01)83550-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Séguin L, Pimont M, Rinfret-Raynor M, Cantin S. [Conjugal violence during pregnancy: a literature review.]. Sante Ment Que 2000; 25:288-312. [PMID: 18253581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Conjugal violence is a complicated issue which scope and consequences are increasingly documented. Among the many facets of the phenomenon, its occurrence during pregnancy is particularly worrisome. This article reviews the scientific literature pertaining to this issue. After establishing the prevalence of conjugal violence during pregnancy, the authors examine the major studies analyzing factors associated with this violence as well as its consequences for the mother and the infant. The article concludes that the current informations, although partial, are sufficient to justify early detection of conjugal violence in order to help future mothers efficiently.
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Cantin S, Laroche C, Lavallée P, Lessard JM. [Patellectomy: results of a long-term follow-up]. Can J Surg 1993; 36:461-3. [PMID: 8221403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The authors are in disagreement with the literature on the results of patellectomy after comminuted fracture of the patella. They assessed retrospectively 17 patients who underwent unilateral total patellectomy between 1955 and 1980. Subjective and objective (clinical examination, radiologic examination and Cibex II studies) assessment was carried out for each patient using the contralateral healthy knee as a control. The results demonstrated 88% patient satisfaction, no ligamentous instability and no early arthrosis but a decrease in extensor muscle strength to 75% of normal. The authors conclude that total patellectomy is better tolerated and causes less morbidity than suggested in the literature.
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Affiliation(s)
- S Cantin
- Du département de chirurgie orthopédique, Hôpital de l'Enfant-Jésus, Université Laval, Québec
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Kinnard P, Cantin S. The Akin procedure in hallux valgus. Can J Surg 1991; 34:491-3. [PMID: 1913397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A retrospective study of 28 Akin procedures was undertaken to assess their results. Patient satisfaction, clinical findings and roentgenographic measurements were evaluated after follow-up periods of 12 to 42 months. The outcome was excellent in nearly 60% of the patients, especially those whose discomfort was related to the laterally deviated great toe and to the prominence of the first metatarsal head.
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Affiliation(s)
- P Kinnard
- Department of Orthopaedic Surgery, Centre Hospitalier, Université Laval, Sainte-Foy, Que
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