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  1. Article ; Online: Influence of Surfactant Concentration on Spontaneous Emulsification Kinetics.

    Toor, Ritu / Denoyel, Renaud / Liggieri, Libero / Schmitt, Murielle / Antoni, Mickaël

    Langmuir : the ACS journal of surfaces and colloids

    2022  Volume 38, Issue 38, Page(s) 11521–11528

    Abstract: The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two ... ...

    Abstract The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two water-soluble surfactants (CTAB and SDS) is investigated. As time runs, the drop interface turns opaque due to the formation of microstructures associated with spontaneous emulsification. The time evolution of this phenomenon is shown to depend upon temperature and surfactant concentration, which leads to an overall shrinkage due to gradual water uptake and transport into paraffin oil. Spontaneous emulsification kinetics depends upon the chemical composition. Higher concentrations of Span 80 and CTAB (resp. SDS) are shown to promote (resp. hinder) water transport. This work provides new insights into the understanding of spontaneous emulsification when combining the properties of non-ionic and ionic surfactants.
    Language English
    Publishing date 2022-09-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.1c03443
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Influence of Surfactant Concentration on Spontaneous Emulsification Kinetics

    Toor, Ritu / Denoyel, Renaud / Liggieri, Libero / Schmitt, Murielle / Antoni, Mickaël

    Langmuir. 2022 Sept. 12, v. 38, no. 38

    2022  

    Abstract: The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two ... ...

    Abstract The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two water-soluble surfactants (CTAB and SDS) is investigated. As time runs, the drop interface turns opaque due to the formation of microstructures associated with spontaneous emulsification. The time evolution of this phenomenon is shown to depend upon temperature and surfactant concentration, which leads to an overall shrinkage due to gradual water uptake and transport into paraffin oil. Spontaneous emulsification kinetics depends upon the chemical composition. Higher concentrations of Span 80 and CTAB (resp. SDS) are shown to promote (resp. hinder) water transport. This work provides new insights into the understanding of spontaneous emulsification when combining the properties of non-ionic and ionic surfactants.
    Keywords chemical composition ; emulsifying ; light microscopy ; lipophilicity ; oils ; shrinkage ; surfactants ; temperature ; water solubility ; water uptake
    Language English
    Dates of publication 2022-0912
    Size p. 11521-11528.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.1c03443
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: In memoriam: Professor Albert Sanfeld (1932-2015).

    Sefiane, Khellil / Antoni, Mickael

    Advances in colloid and interface science

    2016  Volume 234, Page(s) 1–2

    Language English
    Publishing date 2016-05-02
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 210507-x
    ISSN 1873-3727 ; 0001-8686
    ISSN (online) 1873-3727
    ISSN 0001-8686
    DOI 10.1016/j.cis.2016.03.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2716: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  4. Article ; Online: Microstructure Formation in Freezing Nanosuspension Droplets.

    Nespoulous, Mathieu / Denoyel, Renaud / Antoni, Mickaël

    The journal of physical chemistry letters

    2018  Volume 9, Issue 10, Page(s) 2714–2719

    Abstract: The structural evolution of suspensions upon freezing is studied with optical microscopy in a suspended droplet configuration. Droplets are of millimeter size and consist of an aqueous mixture of silica particles, while the surrounding phase is hexane. ... ...

    Abstract The structural evolution of suspensions upon freezing is studied with optical microscopy in a suspended droplet configuration. Droplets are of millimeter size and consist of an aqueous mixture of silica particles, while the surrounding phase is hexane. Freeze-thaw cycles are applied to this system, and a two-step freezing mechanism is evidenced. A fast adiabatic growth of dendrites that invade the full droplets is first observed and occurs within a few milliseconds. Then, a slow process lasts for several seconds and corresponds to the release of solidification latent heat into the hexane phase. The striking feature of this work is to evidence that after the first freeze-thaw cycle flocculated microstructures are generated. When a second cycle is performed, microstructures further flocculate and generate, for dense silica suspensions, stable porous spheres of the size of the droplets. A phenomenological description based on repulsion or engulfment of particles by solidifying ice fronts is proposed.
    Language English
    Publishing date 2018-05-17
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.8b00984
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Spontaneous Microstructure Formation at Water/Paraffin Oil Interfaces.

    Schmitt, Murielle / Toor, Ritu / Denoyel, Renaud / Antoni, Mickaël

    Langmuir : the ACS journal of surfaces and colloids

    2017  Volume 33, Issue 49, Page(s) 14011–14019

    Abstract: An experimental investigation of spontaneous emulsification is proposed with a water drop pendant in a paraffin oil (PO) solution loaded with a surfactant (SPAN80). Optical microscopy in a transmission mode is employed for high-spatial-resolution image ... ...

    Abstract An experimental investigation of spontaneous emulsification is proposed with a water drop pendant in a paraffin oil (PO) solution loaded with a surfactant (SPAN80). Optical microscopy in a transmission mode is employed for high-spatial-resolution image recording. The kinetics of spontaneous emulsification is studied. It is shown to generate a darkening of the drops because of interface modification with a characteristic time that depends upon the SPAN80 concentration. For low concentrations, spontaneous emulsification is slow and produces micrometer-sized droplets, whereas for large concentrations, it is fast and bush-like microstructures are observed. These microstructures increase in size and progressively invade the complete water/PO interfaces, detach, and finally migrate into the PO phase. This transport phenomenon withdraws water from the drops and leads to a gradual shrinking of their volume. At the end of this process, they appear as deformed objects surrounded by a loose membrane.
    Language English
    Publishing date 2017--12
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.7b02549
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: A numerical investigation on the drainage of a surfactant-modified water droplet in paraffin oil.

    Lekhlifi, Adil / Fanzar, Abdelaziz / Antoni, Mickaël

    Advances in colloid and interface science

    2015  Volume 222, Page(s) 446–460

    Abstract: A volume of fluid approach is used in numerical simulations of the settling motion of a surfactant modified water droplet in a continuous paraffin oil phase. The droplet is millimeter-sized and confined in a square two dimensional domain. The surfactant ... ...

    Abstract A volume of fluid approach is used in numerical simulations of the settling motion of a surfactant modified water droplet in a continuous paraffin oil phase. The droplet is millimeter-sized and confined in a square two dimensional domain. The surfactant interfacial and bulk concentration-equations are solved together with the incompressible Navier-Stokes equation. The role of boundary walls in the overall settling dynamics is described. As the droplet moves downwards the interfacial shear creates non-homogeneous interfacial surfactant concentrations and Marangoni driven phenomena come into play. A decrease of the drainage velocity is then evidenced indicating that buoyancy forces are counter balanced by Marangoni induced lift-forces. The lateral migration of the droplet due to boundary wall proximity is discussed. It is shown to increase with wall proximity and to decrease when increasing the interfacial concentration. Finally, a simplified model is used to investigate the evolution of the bulk concentration assuming the surfactant is insoluble in paraffin oil and poorly soluble in water.
    Language English
    Publishing date 2015-08
    Publishing country Netherlands
    Document type Journal Article ; Review
    ZDB-ID 210507-x
    ISSN 1873-3727 ; 0001-8686
    ISSN (online) 1873-3727
    ISSN 0001-8686
    DOI 10.1016/j.cis.2015.02.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 2716: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  7. Article: Influence of substrate heating on the evaporation dynamics of pinned water droplets.

    Girard, Fabien / Antoni, Mickaël

    Langmuir : the ACS journal of surfaces and colloids

    2008  Volume 24, Issue 20, Page(s) 11342–11345

    Abstract: The dynamics of evaporating water droplets deposited on a heated substrate is investigated numerically. Droplets are pinned with a contact line radius of R = 1 mm. Evaporative mass flow and convection occurring inside the droplets are studied for ... ...

    Abstract The dynamics of evaporating water droplets deposited on a heated substrate is investigated numerically. Droplets are pinned with a contact line radius of R = 1 mm. Evaporative mass flow and convection occurring inside the droplets are studied for different heating substrate sizes L S and heating temperatures T S. A simplified model neglecting hydrodynamics in air and evaporative cooling and assuming droplets to be spherical caps is simulated with a finite element method. A toruslike convective cell appears inside the droplets as evaporation takes place. For L S/ R > 1, the contact line is warmer than the apex of the droplets, and convection generates a downstream flow in the vicinity of the symmetry axis of the droplets. For L S/ R < 1, it is the apex that is warmer. Convection then generates an upstream flow. The overall evaporation time is described. It slows when L S/ R > 1.
    Language English
    Publishing date 2008-10-21
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/la8012206
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  8. Article ; Online: Use of IR thermography to investigate heated droplet evaporation and contact line dynamics.

    Fabien, Girard / Antoni, Mickaël / Sefiane, Khellil

    Langmuir : the ACS journal of surfaces and colloids

    2011  Volume 27, Issue 11, Page(s) 6744–6752

    Abstract: In this paper we present the results of an experimental study investigating interfacial properties during the evaporation of sessile water droplets on a heated substrate. This study uses infrared thermography to map the droplet interfacial temperature. ... ...

    Abstract In this paper we present the results of an experimental study investigating interfacial properties during the evaporation of sessile water droplets on a heated substrate. This study uses infrared thermography to map the droplet interfacial temperature. The measurements evidence nonuniform temperature and gradients that evolve in time during the evaporation process. A general scaling law for the interfacial temperature is deduced from the experimental observations. A theoretical analysis is performed to predict the local evaporation rates and their evolution in time. The use of energy conservation laws enabled us to deduce a general expression for the interfacial temperature. The comparison between the theory and experiments shows good agreement and allows us to rationalize the experimental observations. The thermography analysis also enabled the detection of the three-phase contact line location and its dynamics. To our knowledge, such measurements are performed for the first time using thermography.
    Language English
    Publishing date 2011-06-07
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/la104962m
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Infrared thermography investigation of an evaporating sessile water droplet on heated substrates.

    Girard, Fabien / Antoni, Mickaël / Sefiane, Khellil

    Langmuir : the ACS journal of surfaces and colloids

    2010  Volume 26, Issue 7, Page(s) 4576–4580

    Abstract: The present study is an experimental investigation of the thermal evolution of millimeter-sized sessile water droplets deposited on heated substrates. Infrared thermography is used to record temperature profiles on the droplet interface in time as ... ...

    Abstract The present study is an experimental investigation of the thermal evolution of millimeter-sized sessile water droplets deposited on heated substrates. Infrared thermography is used to record temperature profiles on the droplet interface in time as evaporation takes place. The local measurements of the interface temperature allowed us to deduce the local evaporation rate and its evolution in time. To our knowledge, this is the first time that such measurements have been performed. The deduced evaporation rate using thermography data has been validated with optical measurements. Temperature evolution is used to reveal the contact line location and transient temperature fields. Temperature differences between the apex of the droplet and the contact line are shown to decrease in time. The rate of local temperature increase at the interface is found to behave linearly with time. The slope of this linear increase turns out to be more pronounced as the substrate temperature is increased. A generalized linear trend, using dimensionless properties for the interface temperature rise, is deduced from the measurements.
    Language English
    Publishing date 2010-04-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/la9048659
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Evaporation and Marangoni driven convection in small heated water droplets.

    Girard, Fabien / Antoni, Mickaël / Faure, Sylvain / Steinchen, Annie

    Langmuir : the ACS journal of surfaces and colloids

    2006  Volume 22, Issue 26, Page(s) 11085–11091

    Abstract: Evaporation dynamics of small sessile water droplets under microgravity conditions is investigated numerically. The water-air interface is free, and the surrounding air is assumed to be quasisteady. The droplet is described by Navier-Stokes and heat ... ...

    Abstract Evaporation dynamics of small sessile water droplets under microgravity conditions is investigated numerically. The water-air interface is free, and the surrounding air is assumed to be quasisteady. The droplet is described by Navier-Stokes and heat equations and its surrounding water/air gaseous phase with Laplace equation. In the thermodynamic conditions of the simulations presented herein, the evaporative mass flow is nonlinear. It shows a minimum that indicates the existence of qualitative changes in the evaporative regimes although the droplet is sessile. Due to temperature gradients on the free interface, Marangoni motion occurs and generates inside the droplet convection cells that furthermore exhibit small fluctuating motion as evaporation goes on.
    Language English
    Publishing date 2006-12-19
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/la061572l
    Database MEDical Literature Analysis and Retrieval System OnLINE

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