Publications by authors named "David Carrière"

17 Publications

  • Page 1 of 1

Toward a Chemical Control of Colloidal YVO Nanoparticles Microstructure.

Langmuir 2020 Aug 30;36(31):9124-9131. Epub 2020 Jul 30.

Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay, Route de Saclay, 91128 Palaiseau Cedex, France.

Rare-earth-doped oxides are a class of compounds that have been largely studied in the context of the development of luminescent nanocrystals for various applications including fluorescent labels for bioimaging, MRI contrast agents, luminescent nanocomposite coatings, etc. Elaboration of colloidal suspensions is usually achieved through coprecipitation. Particles exhibit emission properties that are similar to the bulk counterparts, although altered by crystalline defects or surface quenching species. Focusing on YVO:Eu, one of the first reported systems, the aim of this work is to revisit the elaboration of nanoparticles obtained through a simple aqueous coprecipitation route. The objective is more precisely to get a better understanding of the parameters affecting the particles' internal microstructure, a feature that is poorly controlled and characterized. We show that the hydroxyl concentration in the precursor solution has a drastic effect on the particles' microstructure. Moreover, discrepancies in the reported particle structure are shown to possibly arise from the carbonation of the strongly basic orthovanadate precursor. For this study, SAXS/WAXS is shown to be a powerful tool to characterize the multiscale structure of the particles. It could be shown that playing on the precursor composition, it may be varied between almost monocrystalline nanocrystals to particles exhibiting a hierarchical microstructure well described by a surface fractal model. This work provides a new methodology for the characterization of nanoparticles microstructure and opens new directions for its optimization in view of applications.
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http://dx.doi.org/10.1021/acs.langmuir.0c01266DOI Listing
August 2020

Combining surface chemistry modification and in situ small-angle scattering characterization to understand and optimize the biological behavior of nanomedicines.

J Mater Chem B 2020 08;8(30):6438-6450

Université Paris-Saclay, CEA, CNRS, NIMBE, 91191, Gif-sur-Yvette, France.

Nanomedicines are considered as promising therapeutics for cancer treatment. However, clinical translation is still scarce, partly because their biological behavior is not well understood. Extracting general guidelines from the great variety of nanoparticles and conditions studied is indeed difficult, and relevant techniques are lacking to obtain in situ information. Here, both issues are solved by combining versatile model nanoparticles with in situ tools based on small-angle scattering techniques (SAS). The strategy was to develop a library of nanoparticles and perform systematic study of their interactions with biological systems. Considering the promising properties of gold nanoparticles as cancer therapeutics, polymethacrylate-grafted gold nanoparticles were chosen as models. Modulation of polymer chemistry was shown to change the surface properties while keeping the same structure for all nanoparticles. This unity allowed reliable comparison to extract general principles, while the synthesis versatility enabled to fine-tune the nanoparticles surface properties, especially through copolymerization, and thus to optimize their biological behavior. Two specific aspects were particularly examined: colloidal stability and cell uptake. Positive charges and hydrophobicity were identified as key parameters influencing toxicity and internalization. In situ SAS gave valuable information about nanoparticles evolution in biologically relevant environments. Good colloidal stability was thereby shown in cell culture media, while intracellular transformation and quantity of nanoparticles were monitored, highlighting the potential of these techniques for nanomedicines studies.
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http://dx.doi.org/10.1039/d0tb01167cDOI Listing
August 2020

Self-Confined Nucleation of Iron Oxide Nanoparticles in a Nanostructured Amorphous Precursor.

Nano Lett 2020 Jul 24;20(7):5001-5007. Epub 2020 Jun 24.

Université Paris-Saclay, CNRS, CEA, NIMBE, LIONS, CEA Saclay, 91191 Cedex Gif sur Yvette, France.

Crystallization from solution is commonly described by classical nucleation theory, although this ignores that crystals often form via disordered nanostructures. As an alternative, the classical theory remains widely used in a "multistep" variant, where the intermediate nanostructures merely introduce additional thermodynamic parameters. However, this variant still requires validation by experiments addressing indeed proper time and spatial scales (millisecond, nanometer). Here, we used in situ X-ray scattering to determine the mechanism of magnetite crystallization and, in particular, how nucleation propagates at the nanometer scale within amorphous precursors. We find that the self-confinement by an amorphous precursor slows down crystal growth by 2 orders of magnitude once the crystal size reaches the amorphous particle size (∼3 nm). Thus, not only the thermodynamic properties of transient amorphous nanostructures but also their spatial distribution determine crystal nucleation.
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http://dx.doi.org/10.1021/acs.nanolett.0c01125DOI Listing
July 2020

Structure Factor of EuCl Aqueous Solutions via Coupled Molecular Dynamics Simulations and Integral Equations.

J Phys Chem B 2020 03 20;124(9):1787-1793. Epub 2020 Feb 20.

Université Paris-Saclay, CEA, CNRS, NIMBE, LIONS, 91191 Gif-sur-Yvette, France.

Identifying the structure of an aqueous solution is essential to rationalize various phenomena such as crystallization in solution, chemical reactivity, extraction of rare earth elements, and so forth. Despite this, the efforts to describe the structure of an aqueous solution have been hindered by the difficulty to retrieve structural data both from experiments and simulations. To overcome this, first, undersaturated EuCl aqueous solutions of concentrations varying from 0.15 to 1.8 mol/kg were studied using X-ray scattering. Second, for the first time, the theoretical X-ray signal of 1.8 mol/kg EuCl aqueous solution was simulated, with precise details for the complete range of scattering vectors using coupled molecular dynamics and hypernetted chain integral equations, and satisfactorily compared with the 1.8 mol/kg experimental X-ray scattering signal. The theoretical calculations demonstrate that the experimental structure factor is dominated by Eu-Eu correlations.
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http://dx.doi.org/10.1021/acs.jpcb.9b11537DOI Listing
March 2020

Nanostructure Changes upon Polymerization of Aqueous and Organic Phases in Organized Mixtures.

Langmuir 2016 10 23;32(39):10104-10112. Epub 2016 Sep 23.

Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI), Université de Cergy-Pontoise, Institut des Matériaux , 5 mail Gay Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise Cedex, France.

The nanostructure of a microemulsion can be strongly affected by the liquid-to-solid transition during polymerization. Here, we examined the evolution of nanostructures of different ternary mixtures, including two microemulsions and a single lamellar phase that upon polymerization are quantitatively studied by SAXS/WAXS and DSC experiments systematically performed before and after the polymerization of both aqueous and organic phases. Samples are mixtures of the poly(2-acrylamido-2-methylpropanesulfonic acid) network as the aqueous phase and poly(hexyl methacrylate) as the organic phase stabilized by Brij35 surfactant. Upon polymerization, the surfactant is excluded from the water/oil interface and crystallizes, strongly changing the nanostructure of samples where it is the main component. In samples where the aqueous phase is the main component, only a few changes in structure are observed upon polymerization. This study demonstrates quantitatively the possibility to preserve nanostructures during polymerization, thus inducing a templating effect.
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http://dx.doi.org/10.1021/acs.langmuir.6b02626DOI Listing
October 2016

Molten fatty acid based microemulsions.

Phys Chem Chem Phys 2016 Jun 31;18(23):15911-8. Epub 2016 May 31.

LIONS, NIMBE, CEA, CNRS, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.

We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound.
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http://dx.doi.org/10.1039/c6cp00533kDOI Listing
June 2016

Quenched microemulsions: a new route to proton conductors.

Soft Matter 2014 Aug;10(32):5928-35

CEA, IRAMIS, NIMBE, CNRS, UMR3299 SIS2M CEA-CNRS, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire, F-91191 Gif-sur-Yvette, France.

Solid-state proton conductors operating under mild temperature conditions (T < 150 °C) would promote the use of electrochemical devices as fuel cells. Alternatives to the water-sensitive membranes made of perfluorinated sulfonated polymers require the use of protogenic moieties bearing phosphates/phosphonates or imidazole groups. Here, we formulate microemulsions using water, a cationic surfactant (cetyltrimethyl ammonium bromide, CTAB) and a fatty acid (myristic acid, MA). The fatty acid acts both as an oil phase above its melting point (52 °C) and as a protogenic moiety. We demonstrate that the mixed MA-CTA film presents significant proton conductivity. Furthermore, bicontinuous microemulsions are found in the water-CTAB-MA phase diagram above 52 °C, where molten MA plays both the role of the oil phase and the co-surfactant. This indicates that the hydrogen-bond rich MA-CTA film can be formulated in the molten phase. The microemulsion converts into a lamellar phase upon solidification at room temperature. Our results demonstrate the potential of such self-assembled materials for the design of bulk proton conductors, but also highlight the necessity to control the evolution of the nanostructure upon solidification of the oil phase.
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http://dx.doi.org/10.1039/c4sm00849aDOI Listing
August 2014

Amorphous to crystal conversion as a mechanism governing the structure of luminescent YVO4:Eu nanoparticles.

ACS Nano 2014 Mar 13;8(3):2602-8. Epub 2014 Feb 13.

Groupe de Chimie du Solide, Laboratoire de Physique de la Matière Condensée, UMR CNRS 7643, École Polytechnique , 91128 Palaiseau, France.

The development of functional materials by taking advantage of the physical properties of nanoparticles needs an optimal control over their size and crystal quality. In this context, the synthesis of crystalline oxide nanoparticles in water at room temperature is a versatile and industrially appealing process but lacks control especially for "large" nanoparticles (>30 nm), which commonly consist of agglomerates of smaller crystalline primary grains. Improvement of these syntheses is hampered by the lack of knowledge on possible intermediate, noncrystalline stages, although their critical importance has already been outlined in crystallization processes. Here, we show that during the synthesis of luminescent Eu-doped YVO4 nanoparticles a transient amorphous network forms with a two-level structuration. These two prestructuration scales constrain topologically the nucleation of the nanometer-sized crystalline primary grains and their aggregation in nanoparticles, respectively. This template effect not only clarifies why the crystal size is found independent of the nucleation rate, in contradiction with the classical nucleation models, but also supports the possibility to control the final nanostructure with the amorphous phase.
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http://dx.doi.org/10.1021/nn4062534DOI Listing
March 2014

Formation of single-crystalline CuS at the organic-aqueous interface.

J Phys Condens Matter 2013 Oct 3;25(39):395401. Epub 2013 Sep 3.

Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064, India.

We report here the results of a study to understand the formation mechanism of single crystals of the transition metal chalcogenide, CuS, at the water-toluene interface through an interfacial reaction. Systematic measurements carried out using synchrotron x-ray scattering, electron microscopy, atomic force microscopy and calorimetric techniques clearly show that nano-crystallites of CuS form within a few minutes at the interface as the reagents are brought from the organic (upper) and aqueous (lower) layers to the interface, then crystallization of CuS proceeds over a few hours only by reorganization, despite the large excess available in both upper and lower liquid phases. The interface confinement and passivation by organics is critical here in the formation of single crystals having sizes of 6 and 200 nm along the normal and in-plane directions of the liquid-liquid interface.
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http://dx.doi.org/10.1088/0953-8984/25/39/395401DOI Listing
October 2013

Adsorption, organization, and rheology of catanionic layers at the air/water interface.

Langmuir 2013 Mar 1;29(10):3214-22. Epub 2013 Mar 1.

Laboratoire de Physique des Solides, UMR 8502, Université Paris Sud, Orsay, France.

We have investigated the adsorption and organization at the air/water interface of catanionic molecules released from a dispersion of solid-like catanionic vesicles composed of myristic acid and cetyl trimethylammonium chloride at the 2:1 ratio. These vesicles were shown recently to be promising foam stabilizers. Using Brewster angle microscopy, we observed the formation of a catanionic monolayer at the air/water interface composed of liquid-condensed domains in a liquid-expanded matrix. Further adsorption of catanionic molecules forced them to pack, thereby forming a very dense monolayer that prevented further vesicle rupture by avoiding contact of the vesicles with air. Moreover, confocal fluorescence microscopy revealed the presence of layers of intact vesicles that were progressively creaming toward this catanionic monolayer; the surface tension of the vesicle dispersion remained constant upon creaming. The catanionic monolayer behaved as a soft glassy material, an amorphous solid with time- and temperature-dependent properties. Using interfacial oscillatory rheology, we found that the monolayer relaxed mechanical stresses in seconds and melted at a temperature very close to the melting transition temperature of the vesicle bilayers. These results have potential application in the design of smart foams that have temperature-tunable stability.
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http://dx.doi.org/10.1021/la304868nDOI Listing
March 2013

Interfacial behavior of catanionic surfactants.

Langmuir 2010 Jul;26(13):10663-9

Laboratoire de Physique des Solides, Université Paris-Sud, UMR CNRS 8502, 91405 Orsay Cedex, France.

We report a dramatic increase in foam stability for catanionic mixtures (myristic acid and cetyl trimethylammonium bromide, CTABr) with respect to that of CTABr solutions. This increase was related to the low surface tension, high surface concentration, and high viscoelastic compression moduli, as measured with rising bubble experiments and ellipsometry. Dialysis of the catanionic mixtures has been used to decrease the concentration of free surfactant ions (CTA(+)). The equilibrium surface tension is reached faster for nondialyzed samples because of the presence of these free ions. As a consequence, the foamability of the dialyzed solutions is lower. Foam coarsening has been studied using multiple light scattering: it is similar for dialyzed and nondialyzed samples and much slower than for pure CTABr foams.
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http://dx.doi.org/10.1021/la100954vDOI Listing
July 2010

Absence of lateral phase segregation in fatty acid-based catanionic mixtures.

J Phys Chem B 2010 Feb;114(5):1932-8

CEA, IRAMIS, SIS2M, LIONS (Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire), F-91191 Gif-sur-Yvette cedex, France.

Mixtures of ionic surfactants of opposite charge ("catanionic" mixtures) show strongly nonideal behaviors, for example, in terms of evolution of surface tension, critical micelle concentration, or morphology with respect to composition in each surfactant. In several catanionic systems, it has been proposed that the interaction between both surfactants is so strong that lateral phase segregation occurs within bilayers, with crystallites of preferential composition demixing from the excess of the other surfactant. Here, we investigate the temperature-composition phase diagram of the myristic acid/cetyltrimethylammonium mixtures. Combining microcalorimetry, X-ray diffusion, and solid-state deuterium NMR, we demonstrate that no separation is observed in the gel (L(beta)) state. The catanionic mixtures therefore behave like two-dimensional solid solutions with a negative azeotrope: the existence of a composition at which a maximum in melting temperature is observed does not imply the existence of a preferential crystal of this composition, but results from the preferential attraction between unlike amphiphilic molecules. Additionally, this study reveals the presence of a so-called intermediate phase, that is, a phase that shows dynamic properties intermediate between that of the L(beta) and the L(alpha) phases.
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http://dx.doi.org/10.1021/jp910267vDOI Listing
February 2010

Ripening of catanionic aggregates upon dialysis.

Langmuir 2009 Jan;25(2):698-706

CEA, IRAMIS, SCM, LIONS (Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire), F-91191 Gif-sur-Yvette, France

We have studied the dialysis of surfactant mixtures of two oppositely charged surfactants (catanionic mixture) by combining HPLC, neutron activation, confocal microscopy, and NMR. In mixtures of n-alkyl trimethylammonium halides and n-fatty acids, we have demonstrated the existence of a specific ratio between both surfactant contents (anionic/cationic almost equal to 2:1) that determines the morphology, the elimination of ions, and the elimination of the soluble cationic surfactant upon dialysis. In mixtures prepared with lower anionic surfactant contents, ill-defined aggregates are formed, and dialysis quickly eliminates the ion pairs (H+X-) formed upon surfactant association and also the cationic surfactant until a limiting 2:1 ratio is reached. By contrast, mixtures prepared above the anionic/cationic 2:1 ratio form micrometer-sized vesicles resistant to dialysis. These closed aggregates retain a significant number of ions (30%) over 1000 hours, and dialysis is unable to eliminate the soluble surfactant. The interactions between surfactants have been estimated by measuring the partitioning of the CTA molecules between the catanionic bilayer, the bulk solution, and mixed micelles when they exist. The mean extraction free energy per CTA in the membrane has been found to increase by 1 kBT to 2 kBT as the soluble surfactant is depleted from the bilayer, which is enough to stop the dialysis. The vesicles produced above the anionic/cationic 2:1 ratio are formed by frozen bilayers and are resistant to extensive dialysis and therefore show an interesting potential for encapsulation as far as durability is concerned.
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http://dx.doi.org/10.1021/la8018293DOI Listing
January 2009

Ion exchange in catanionic mixtures: from ion pair amphiphiles to surfactant mixtures.

Langmuir 2007 Jun 11;23(12):6554-60. Epub 2007 May 11.

Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire, CEA, Saclay, Gif-sur-Yvette Cedex, France.

We have studied concentrated equimolar mixtures of tetradecanoic acid (myristic acid, C13COOH) and hexadecyltrimethylammonium hydroxide (CTAOH) in which the OH- counterions are gradually exchanged by other anions (Cl-, Br-, CH3COO-, CH3-(C6H4)-SO3-). We demonstrate that the stability of a Lbeta phase can be achieved at equimolarity between both surfactants, provided that the phase contains also a sufficient number of anions exchanged with OH-. In the absence of exchange (equimolar mixture of C13COOH and CTAOH), a three-dimensional crystalline Lc phase is produced. As the OH- ions are replaced by other ions, a swollen Lbeta lamellar phase appears, first in coexistence with the Lc (D* = 400 A) and then in coexistence with a dilute phase only (D* = 215 A). In the latter regime, the repeating distance depends very little on the exchange ratio, but rather on the nature of the counterion. If too many OH- ions are exchanged, the Lbeta phase becomes unstable again. A Poisson-Boltzmann model with charge regulation computed for a closed system predicts qualitatively the existence of this narrow domain of stability for the Lbeta phase.
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http://dx.doi.org/10.1021/la070184wDOI Listing
June 2007

Counter-ion activity and microstructure in polyelectrolyte complexes as determined by osmotic pressure measurements.

Phys Chem Chem Phys 2006 Jul 1;8(26):3141-6. Epub 2006 Jun 1.

Laboratoire sur l'Organisation Nanométrique et Supramoléculaire, CEA de Saclay, DRECAM/SCM, 91191, Gif-sur-Yvette Cedex, France.

We have investigated the activity of counter-ions at 60 degrees C through the osmotic coefficient K in solutions of anionic and cationic polyelectrolyte complexes of variable compositions. For excess of polyanion in the complexes (molar fraction of polycation f < 0.5), K increases as the polyanion is neutralized by the polycation (f getting closer to 0.5). By contrast, for an excess of polycation (f > 0.5), K stays constant or even slightly decreases as the polycation is getting neutralized by the polyanion. This asymmetric behavior depending on the charge of the complexes indicates that the globally negatively charged complexes are homogeneous and can be treated as a single polyelectrolyte of reduced linear charge density. On the other hand, the positively charged complexes show a micro-phase separation between neutral fully compensated microdomains and domains where the excess polycation is locally segregated. These two different microstructures are reminiscent of the coacervation and segregation regimes observed at higher concentrations and salinities, and also of polyelectrolyte complexes with oppositely charged surfactants. This interpretation is supported by two simple predictive models.
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http://dx.doi.org/10.1039/b602583hDOI Listing
July 2006

Modification of the surface properties of porous nanometric zirconia particles by covalent grafting.

Langmuir 2004 Apr;20(8):3449-55

Laboratoire de Physique de la Matière Condensée, CNRS UMR 7643C, Ecole Polytechnique, 91128 Palaiseau Cedex, France.

We here report on the covalent grafting of various phosphated species (phosphoric acid, phenylphosphonic acid, and octyl phosphate) onto the surface of monoclinic zirconia nanoparticles obtained by hydrothermal treatment of zirconium acetate. The initial particles are 60 nm aggregates of nanometric primary grains and present an inner porosity. Small-angle X-ray scattering shows that the high specific area of the colloidal particles (450 m2 x g(-1)) decreases to 150 m2 x g(-1) upon drying. Therefore, phosphated reactants can access the whole internal surface of the aggregates only before drying. The surface of the particles can be covered with functional groups bound through a variable number of Zr-O-P bonds. Several factors probably enhance the reaction between the particles and the phosphates or phosphonates: the large specific area of the particles, a fully accessible porous network, and a large concentration of surface terminal groups. At the same time, the morphology of the particles is well preserved upon grafting. This is due to the good crystallinity of the primary grains that constitute the particles. In addition, the grafting drastically modifies the surface properties of the colloids. For example, the polarizability of the particles decreases in the sequence -POH > as-prepared ZrO2 > -PC6H5 > -POC8H17. Furthermore, the grafting of octyl phosphate allows exclusion of water from pores of 2 nm radius, up to hydrostatic pressures of 20 MPa.
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http://dx.doi.org/10.1021/la036249mDOI Listing
April 2004

Oscillations in solvent fraction of polyelectrolyte multilayers driven by the charge of the terminating layer.

Langmuir 2004 Dec;20(26):11465-72

Max-Planck Institute for Colloids and Interfaces, D-14424 Potsdam, Germany.

We have investigated polyelectrolyte multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) in contact with D2O by neutron reflectometry. The study particularly focuses on the changes in the solvent fraction of the system upon addition of a layer. When the layers are deposited at a low salt concentration (0.25 M NaCl), no significant changes in the solvent fraction are detected. In contrast, at a larger salt concentration (1 M NaCl), oscillations in the solvent fraction are detected when a new layer is deposited. In this case, addition of PSS systematically increases the solvent volume fraction, and addition of PAH decreases the solvent fraction. The results suggest that one of the parameters driving the oscillations in solvent fraction is the uncompensated charges present in the layers. This study opens new perspectives on results previously published by other authors: in addition to polymer desorption, water uptake or release might contribute to the different regimes of multilayer growth reported in the literature (linear, asymmetric, or exponential growth). In addition, comparison to NMR results previously reported allows for conclusions about the mobility of the solvent in the multilayers: the average rotational correlation time of the water molecules in the polyelectrolyte layers decreases upon addition of PSS and increases upon addition of PAH.
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http://dx.doi.org/10.1021/la0486436DOI Listing
December 2004