Accueil >
Production scientifique
(144) Production(s) de IN M.
|
|
Enhanced active motion of Janus Colloids at the water surface
Auteur(s): Wang X., In M., Blanc C., Nobili M., Stocco A.
Conference: 23e Congres general de la Societe Francaise de Physique (Strasbourg, FR, 2015-08-24)
Ref HAL: hal-01257720_v1
Exporter : BibTex | endNote
Résumé: Active colloids are an emerging and promising class of colloidal particles, which are designed to perform autonomous motion as biological microswimmers by transforming chemical or other form of energies into work and propulsion. When the particle size is about a micrometer or smaller, the directional propulsion competes with the translational and rotational Brownian motion. Here we explore the possibility of enhancing the directional motion of self-propelled Janus colloids by slowing down their rotational diffusion.We have investigated the active motion of self-propelled colloids confined at the air-water interface. The two dimensional motion of micron-sized Silica-Platinum Janus colloids has been experimentally measured by particle tracking video-microscopy under increasing concentration of the catalytic fuel, i.e. H2O2. Comparing to the motion in bulk, a dramatic enhancement of both the persistence length of trajectories and the speed has been observed. The interplay of colloid self-propulsion, due to an asymmetric catalytic reaction occurring on the colloid, and interfacial frictions controls the enhancement of the directional movement. The slowing down of the rotational diffusion at the interface, also measured experimentally, plays a pivotal role in the control and enhancement of active motion.
|
|
|
Drug-Polymer Electrostatic Complexes as New Structuring Agents for the Formation of Drug-Loaded Ordered Mesoporous Silica
Auteur(s): Molina Emilie, Warnant Jerome, Mathonnat M., Bathfield Mael, In M., Laurencin Danielle, Jérôme Christine, Lacroix-Desmazes Patrick, Marcotte Nathalie, Gerardin Corine
(Article) Publié:
Langmuir, vol. 31 p.12839-12844 (2015)
Ref HAL: hal-01257693_v1
DOI: 10.1021/acs.langmuir.5b03221
WoS: WOS:000365930900001
Exporter : BibTex | endNote
20 Citations
Résumé: Using aminoglycoside antibiotics as drug models, it was shown that electrostatic complexes between hydrophilic drugs and oppositely charged double-hydrophilic block copolymers can form ordered mesophases. This phase behavior was evidenced by using poly(acrylic acid)-block-poly(ethylene oxide) block copolymers in the presence of silica precursors, and this allowed preparing drug-loaded mesoporous silica directly from the drug-polymer complexes. The novel synthetic strategy of the hybrid materials is highly efficient, avoiding waste and multistep processes; it also ensures optimal drug loading and provides pH-dependence of the drug release from the materials.
|
|
|
Enhanced active motion of Janus colloids at the water surface
Auteur(s): Wang X., In M., Blanc C., Nobili M., Stocco A.
(Article) Publié:
Soft Matter, vol. 11 p.7376-7384 (2015)
Texte intégral en Openaccess :
Ref HAL: hal-01216307_v1
DOI: 10.1039/c5sm01111f
WoS: WOS:000361550000018
Exporter : BibTex | endNote
51 Citations
Résumé: We have investigated the active motion of self-propelled colloids confined at the air–water interface and explored the possibility of enhancing the directional motion of self-propelled Janus colloids by slowing down their rotational diffusion. The two dimensional motion of micron-sized silica–platinum Janus colloids has been experimentally measured by particle tracking video-microscopy at increasing concentrations of the catalytic fuel, i.e. H2O2. Compared to the motion in the bulk, a dramatic enhancement of both the persistence length of trajectories and the speed has been observed. The interplay of colloid self-propulsion, due to an asymmetric catalytic reaction occurring on the colloid, surface properties and interfacial frictions controls the enhancement of the directional movement. The slowing down of the rotational diffusion at the interface, also measured experimentally, plays a pivotal role in the control and enhancement of active motion.
|
|
|
Brownian diffusion of a partially wetted colloid
Auteur(s): Boniello G., Blanc C., Fedorenko D., Medfai Mayssa, Ben Mbarek Nadia, In M., Gross M., Stocco A., Nobili M.
(Article) Publié:
Nature Materials, vol. 14 p.908 (2015)
Ref HAL: hal-01202128_v1
DOI: 10.1038/NMAT4348
WoS: 000360192000024
Exporter : BibTex | endNote
74 Citations
Résumé: The dynamics of colloidal particles at interfaces between two fluids plays a central role in microrheology, encapsulation, emulsification, biofilm formation, water remediation and the interface-driven assembly of materials. Common intuition corroborated by hydrodynamic theories, suggests that such dynamics is governed by a viscous force lower than that observed in the more viscous fluid. Here, we show experimentally that a particle straddling an air/water interface feels a large viscous drag that is unexpectedly larger than that measured in the bulk. We suggest that such a result arises from thermally activated fluctuations of the interface at the solid/air/liquid triple line and their coupling to the particle drag through the fluctuation–dissipation theorem. Our findings should inform approaches for improved control of the kinetically driven assembly of anisotropic particles with a large triple-line-length/particle-size ratio, and help to understand the formation and structure of such arrested materials.
|
|
|
Enhanced active motion of Janus Colloids at the water surface
Auteur(s): Stocco A., Wang X., Nobili M., Blanc C., In M.
Conference: MICROSWIMMERS - FROM BULK TO INTERFACES (Bordeaux, FR, 2015-04-13)
Ref HAL: hal-01163595_v1
Exporter : BibTex | endNote
Résumé: Active colloids are an emerging and promising class of colloidal particles, which are designed to perform autonomous motion by transforming chemical or other form of energies into work and propulsion.Here, we have investigated the active motion of self-propelled colloids confined at the air-water interface. The two dimensional motion of micron-sized Silica-Platinum Janus colloids has been experimentally measured by particle tracking video-microscopy under increasing concentration of the catalytic fuel, i.e. H2O2. Comparing to the motion in bulk, a dramatic enhancement of both the persistence length of trajectories and the speed has been observed. The interplay of colloid self-propulsion, due to an asymmetric catalytic reaction occurring on the colloid, and interfacial frictions controls the enhancement of the directional movement. The slowing down of the rotational diffusion at the interface, also measured experimentally, plays a pivotal role in the control and enhancement of active motion.
|
|
|
Electrostatic Interaction between Nonuniformly Charged Colloids: Experimental and Numerical Study
Auteur(s): Derot Claire, Porcar Lionel, Lee Yongjin, Pincus Phillip A., Jho Yongseok, In M.
(Article) Publié:
Langmuir, vol. 31 p.1649 (2015)
Ref HAL: hal-01148771_v1
PMID 25587999
DOI: 10.1021/la504579c
WoS: 000349575200007
Exporter : BibTex | endNote
1 Citation
Résumé: The influence of the surface charge distribution on the interaction between nanosized particles in water is reported. The distribution of charges at the surface of initially neutral microemulsion droplets has been modulated by additions of various oligomeric cationic surfactants. The osmotic compressibility of the doped microemulsions was measured by light and small-angle neutrons scattering and reveals that the overall effective interaction induced by the ionic groups is repulsive. However, particular charge distributions decrease the osmotic compressibility much less than others. Independent measurements of the activity of the bromide counterions with specific electrodes evidence a significant decrease in the effective charge, which, however, cannot account for the osmotic compressibility in the framework of the primitive model. The q dependence of the structure factor reveals an attractive contribution over a short distance. Numerical studies assign this attractive contribution to the overlap of hydration shells that are extended as a result of the charge localization.
|
|
|
'Continuous Droplet Interface Crossing Encapsulation (cDICE): artificial cells and capsules
Auteur(s): Loiseau E., Claudet C., In M., Abkarian M., Massiera G.
(Affiches/Poster)
Liquid Matter Conference (Lisbon, PT), 2014-07-21
Ref HAL: hal-02070599_v1
Exporter : BibTex | endNote
Résumé: The Continuous Droplet Interface Crossing Encapsulation (cDICE) is an easy and robust method for producing, at high yield, monodisperse lipid vesicles with a controlled content as well as capsules with a designed shell. It consists in forcing a droplet through an interface between two imiscible fluids, using an external force such as centrifugation. At high inertia, the droplet entrain fluid that will constitute the shell of the capsule. At low inertia, the presence of amphiphile and the deformable interface interactions lead to monolayers zipping and formation of an amphiphile bilayer around the droplet. We will discuss the physical mechanisms involved in the production of both cDICE vesicles (low droplets inertia) and capsules (at high inertia), and the potential applications of this method. This method founds indeed many applications in biomimetics as it allows to encapsulate various biological solutions (biopolymers, hemoglobin, colloids, polymeric gels, cells. . . ) in membranes that can be composite and/or assymetric, or polymeric, and in the field of microencapsulation.
|