The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
R Gallo - One of the best experts on this subject based on the ideXlab platform.
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Adsorption of Polyisobutenylsuccinimide Derivatives at a Solid−Hydrocarbon Interface †
Langmuir, 2001Co-Authors: Marie-claude Dubois-clochard, J.-p Durand, B Delfort, P Gateau, Loïc Barré, I Blanchard, Y Chevalier, R GalloAbstract:The Adsorption of Polymer dispersants of the polyisobutenylsuccinimide series has been studied at the solid/xylene interface. Carbon black was studied as a model solid. Adsorption isotherms were determined, the enthalpy of Adsorption was measured by calorimetry, and the thickness of the adsorbed layer was obtained from small-angle neutron scattering. The paper emphasizes the structure−properties relationships with the help of a series of polyisobutenylsuccinimides having different polyamine groups and different Polymer architectures, simple diblock (PIBSI) and comblike structure (polyPIBSI). The polyamine part ensured a strong Adsorption on the solid surface, which increased in strength with the number of amine groups. In the same way, changing the diblock structure for a comblike one led to an enhanced affinity of the Polymer for the solid surface. The Adsorption was enthalpic but the Gibbs free energy of Adsorption remained moderate because of a large entropy loss during Adsorption. There was an enthalpy−entropy compensation phenomenon. Below a concentration of 70 mmol/m3, the Polymers adsorbed as a 30 Å thick monolayer and the Adsorption phenomenon was irreversible, due to the Polymeric nature of the polar part. A drastic increase of adsorbed amount took place for higher concentrations. The formation of reverse hemimicelles was assumed as the origin of this phenomenon. The supplementary Adsorption was reversible, showing that the Polymer−Polymer interactions were weaker than the Polymer−surface interactions.
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Adsorption of Polyisobutenylsuccinimide Derivatives at a Solid-Hydrocarbon Interface †
Langmuir, 2001Co-Authors: Marie-claude Dubois-clochard, J.-p Durand, B Delfort, P Gateau, Loïc Barré, I Blanchard, Y Chevalier, R GalloAbstract:The Adsorption of Polymer dispersants of the polyisobutenylsuccinimide series has been studied at the solid/xylene interface. Carbon black was studied as a model solid. Adsorption isotherms were determined, the enthalpy of Adsorption was measured by calorimetry, and the thickness of the adsorbed layer was obtained from small-angle neutron scattering. The paper emphasizes the structure-properties relationships with the help of a series of polyisobutenylsuccinimides having different polyamine groups and different Polymer architectures, simple diblock (PIBSI) and comblike structure (polyPIBSI). The polyamine part ensured a strong Adsorption on the solid surface, which increased in strength with the number of amine groups. In the same way, changing the diblock structure for a comblike one led to an enhanced affinity of the Polymer for the solid surface. The Adsorption was enthalpic but the Gibbs free energy of Adsorption remained moderate because of a large entropy loss during Adsorption. There was an enthalpy-entropy compensation phenomenon. Below a concentration of 70 mmol/m 3 , the Polymers adsorbed as a 30 Å thick monolayer and the Adsorption phenomenon was irreversible, due to the Polymeric nature of the polar part. A drastic increase of adsorbed amount took place for higher concentrations. The formation of reverse hemimicelles was assumed as the origin of this phenomenon. The supplementary Adsorption was reversible, showing that the Polymer-Polymer interactions were weaker than the Polymer-surface interactions.
Oliver Baumchen - One of the best experts on this subject based on the ideXlab platform.
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Adsorption induced slip inhibition for Polymer melts on ideal substrates
Nature Communications, 2018Co-Authors: Mark Ilton, Thomas Salez, Paul Fowler, Marco Rivetti, Mohammed Aly, Michael Benzaquen, Joshua D Mcgraw, Elie Raphael, Kari Dalnokiveress, Oliver BaumchenAbstract:Hydrodynamic slip, the motion of a liquid along a solid surface, represents a fundamental phenomenon in fluid dynamics that governs liquid transport at small scales. For Polymeric liquids, de Gennes predicted that the Navier boundary condition together with Polymer reptation implies extraordinarily large interfacial slip for entangled Polymer melts on ideal surfaces; this Navier-de Gennes model was confirmed using dewetting experiments on ultrasmooth, low-energy substrates. Here, we use capillary leveling—surface tension driven flow of films with initially non-uniform thickness—of Polymeric films on these same substrates. Measurement of the slip length from a robust one parameter fit to a lubrication model is achieved. We show that at the low shear rates involved in leveling experiments as compared to dewetting ones, the employed substrates can no longer be considered ideal. The data is instead consistent with a model that includes physical Adsorption of Polymer chains at the solid/liquid interface.
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Adsorption-induced slip inhibition for Polymer melts on ideal substrates
Nature Communications, 2018Co-Authors: Mark Ilton, Thomas Salez, Marco Rivetti, Michael Benzaquen, Joshua D Mcgraw, Elie Raphael, Paul D. Fowler, Kari Dalnoki-veress, Oliver BaumchenAbstract:Hydrodynamic slip, the motion of a liquid along a solid surface, represents a fundamental phenomenon in fluid dynamics that governs liquid transport at small scales. For Polymeric liquids, de Gennes predicted that the Navier boundary condition together with Polymer reptation implies extraordinarily large interfacial slip for entangled Polymer melts on ideal surfaces; this Navier-de Gennes model was confirmed using dewetting experiments on ultra-smooth, low-energy substrates. Here, we use capillary leveling—surface tension driven flow of films with initially non-uniform thickness—of Polymeric films on these same substrates. Measurement of the slip length from a robust one parameter fit to a lubrication model is achieved. We show that at the low shear rates involved in leveling experiments as compared to dewetting ones, the employed substrates can no longer be considered ideal. The data is instead consistent with a model that includes physical Adsorption of Polymer chains at the solid/liquid interface. When modeling fluid flow over a solid surface, one must determine the slip velocity at the boundary. Here Ilton et al. perform experiments to quantify the slip length of Polymer melts at a nearly ideal solid surface and capture them in a model involving the density of physically adsorbed Polymer chains.
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Adsorption induced slip inhibition for Polymer melts on ideal substrates
arXiv: Soft Condensed Matter, 2017Co-Authors: Mark Ilton, Thomas Salez, Paul Fowler, Marco Rivetti, Mohammed Aly, Michael Benzaquen, Joshua D Mcgraw, Elie Raphael, Kari Dalnokiveress, Oliver BaumchenAbstract:Hydrodynamic slip of a liquid at a solid surface represents a fundamental phenomenon in fluid dynamics that governs liquid transport at small scales. For Polymeric liquids, de Gennes predicted that the Navier boundary condition together with the theory of Polymer dynamics imply extraordinarily large interfacial slip for entangled Polymer melts on ideal surfaces; this Navier-de Gennes model was confirmed using dewetting experiments on ultra-smooth, low-energy substrates. Here, we use capillary leveling - surface tension driven flow of films with initially non-uniform thickness - of Polymeric films on these same substrates. Measurement of the slip length from a robust one-parameter fit to a lubrication model is achieved. We show that at the lower shear rates involved in leveling experiments as compared to dewetting ones, the employed substrates can no longer be considered ideal. The data is instead consistent with physical Adsorption of Polymer chains at the solid/liquid interface. We extend the Navier-de Gennes description using one additional parameter, namely the density of physically adsorbed chains per unit surface. The resulting formulation is found to be in excellent agreement with the experimental observations.
Yu.s Lipatov - One of the best experts on this subject based on the ideXlab platform.
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Effect of flexibility of Polymer chains on the kinetics of Adsorption of Polymer mixtures from solutions
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2007Co-Authors: V.n. Chornaya, Yu.s Lipatov, Galina Menzheres, T. T. Todosiichuk, Yu. V. MaslakAbstract:Abstract The study of the kinetics of Adsorption of Polymers from solutions of mixtures of Polymers with different thermodynamic flexibility ( σ ) of Polymer chains, such as cellulose triacetate (CTA) ( σ = 6.0) and poly(butylmethacrylate) (PBMA) ( σ = 2.0) has been done. Aerosil was used as an adsorbent. Adsorption parameters, such as an Adsorption value ( Г ), Adsorption interaction energy ( Q ) and degree of the adsorbent surface coverage ( θ ) were determined by infrared spectroscopy. The Adsorption rate ( V = ∂ Γ /∂ t ) at different parts of the kinetic characteristics, and diffusion coefficients ( D ) in the Adsorption process also were calculated. The values of the diffusion coefficients ( D = 5.0 × 10 −12 to 7.0 × 10 −14 ) determined for binary and ternary Polymer solutions indicate high restraint of Polymer macromolecules in the solutions. In such conditions, the Adsorption rate is limited by the integration of the new adsorbing macromolecules to the already formed Adsorption layer for establishing the equilibrium conformation. The data on the Adsorption interaction energy and the degree of the adsorbent surface coverage for both Polymers by Adsorption from binary and ternary solutions are discussed. The obtained results provide a possibility to determine the relationship between the kinetic and thermodynamic parameters that affect the structure of the Adsorption layer in the process of establishing the Adsorption equilibrium.
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Polymer blends and interpenetrating Polymer networks at the interface with solids
Progress in Polymer Science, 2002Co-Authors: Yu.s LipatovAbstract:Abstract This review deals with a variety of the processes proceeding in Polymer blends at the interface with solids. By the contact of a Polymer blend with a solid surface, the thermodynamic state of the blends changes due to physical interaction of the blend component with the surface. In processes of Adsorption of Polymer mixtures at the interface with solid from solutions and processes of surface segregation from one-phase blends there takes place the formation of near-surface layers with compositions different from the composition of the initial Polymer blends. Such a differences change the conditions of phase separation in thin films of a Polymer blend. The effects under consideration depend on three thermodynamic interaction parameters: Polymer A–solid, Polymer B–solid, Polymers A–B. Theoretical concepts and experimental data on the Adsorption of Polymer blends from solution, surface segregation and phase separation at the interface with solid are presented and discussed. Special attention is paid to the analysis of the phase state of the Polymer blends in thin layers at the interface and to the mechanisms of the changing conditions of phase separation in the presence of a solid. The peculiarities of the behavior of the formation of interpenetrating Polymer networks (IPNs) in the presence of a solid are considered and the characteristic features of phase separation and surface segregation of IPNs in the course of the chemical reactions are discussed.
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Dependence of the Adsorption of Polymer mixtures from solution on the amount of an adsorbent
Journal of colloid and interface science, 2002Co-Authors: Yu.s Lipatov, Tamara Todosijchuk, V.n. Chornaya, Galina MenzheresAbstract:Simultaneous competitive Adsorption from solutions of mixtures of poly(butyl methacrylate) and polystyrene and Adsorption of each component from binary solutions have been studied for three ratios of the adsorbent mass to the solution volume, A/V. It was found that Adsorption from both binary and ternary solutions strongly depends on the amount of an adsorbent, Adsorption of poly(butyl methacrylate) being preferential. The characteristic Adsorption isotherms of both Polymers were constructed under conditions of equal equilibrium concentration of each component to estimate the parameters of preferential Adsorption and their dependence on the A/V ratio. It was found that the A/V effect plays an important role in Adsorption from Polymer mixtures and determines the peculiarities of Adsorption from Polymer mixtures as well as from solution of single Polymers. Changing the A/V ratio may be one way to regulate the composition of an Adsorption layer consisting of two chemically different Polymers. The reasons for the A/V effect are considered in the framework of the concept of the plurality of Adsorption equilibria between two chemically different components and between fractions of different molecular mass of each component having various absorbability.
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Polydispersity effect on the Adsorption of Polymer mixtures
Journal of colloid and interface science, 2000Co-Authors: Yu.s Lipatov, Aron Feinerman, Tamara Todosijchuk, V.n. Chornaya, G. V. DudarenkoAbstract:The changes in molecular mass distribution (MMD) after Adsorption from solution in concentration regions below and above the critical concentration of overlapping have been studied for various Polymers and their mixtures. It was found that the formation of entanglements in both binary and ternary solutions affects the changes in MMD. For binary and ternary solutions above the critical concentration of overlapping, C*, the entanglements lead to diminishing selectivity of Adsorption of high-molecular-weight fractions. Simultaneously, transition through C* diminishes Adsorption of the fractions of higher surface activity. It may be assumed that the entanglements play the role of an additional energetic barrier which macromolecules must overcome to be adsorbed. The transition through the critical concentration of overlapping for the case of binary solutions diminishes the selectivity of Adsorption of high molecular fractions. Adsorption of polar Polymers from the ternary solutions both below and above C* leads to the appearance of the bimodality of MMD due to Adsorption of surface-active fractions. Copyright 2000 Academic Press.
Marie-claude Dubois-clochard - One of the best experts on this subject based on the ideXlab platform.
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Adsorption of Polyisobutenylsuccinimide Derivatives at a Solid−Hydrocarbon Interface †
Langmuir, 2001Co-Authors: Marie-claude Dubois-clochard, J.-p Durand, B Delfort, P Gateau, Loïc Barré, I Blanchard, Y Chevalier, R GalloAbstract:The Adsorption of Polymer dispersants of the polyisobutenylsuccinimide series has been studied at the solid/xylene interface. Carbon black was studied as a model solid. Adsorption isotherms were determined, the enthalpy of Adsorption was measured by calorimetry, and the thickness of the adsorbed layer was obtained from small-angle neutron scattering. The paper emphasizes the structure−properties relationships with the help of a series of polyisobutenylsuccinimides having different polyamine groups and different Polymer architectures, simple diblock (PIBSI) and comblike structure (polyPIBSI). The polyamine part ensured a strong Adsorption on the solid surface, which increased in strength with the number of amine groups. In the same way, changing the diblock structure for a comblike one led to an enhanced affinity of the Polymer for the solid surface. The Adsorption was enthalpic but the Gibbs free energy of Adsorption remained moderate because of a large entropy loss during Adsorption. There was an enthalpy−entropy compensation phenomenon. Below a concentration of 70 mmol/m3, the Polymers adsorbed as a 30 Å thick monolayer and the Adsorption phenomenon was irreversible, due to the Polymeric nature of the polar part. A drastic increase of adsorbed amount took place for higher concentrations. The formation of reverse hemimicelles was assumed as the origin of this phenomenon. The supplementary Adsorption was reversible, showing that the Polymer−Polymer interactions were weaker than the Polymer−surface interactions.
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Adsorption of Polyisobutenylsuccinimide Derivatives at a Solid-Hydrocarbon Interface †
Langmuir, 2001Co-Authors: Marie-claude Dubois-clochard, J.-p Durand, B Delfort, P Gateau, Loïc Barré, I Blanchard, Y Chevalier, R GalloAbstract:The Adsorption of Polymer dispersants of the polyisobutenylsuccinimide series has been studied at the solid/xylene interface. Carbon black was studied as a model solid. Adsorption isotherms were determined, the enthalpy of Adsorption was measured by calorimetry, and the thickness of the adsorbed layer was obtained from small-angle neutron scattering. The paper emphasizes the structure-properties relationships with the help of a series of polyisobutenylsuccinimides having different polyamine groups and different Polymer architectures, simple diblock (PIBSI) and comblike structure (polyPIBSI). The polyamine part ensured a strong Adsorption on the solid surface, which increased in strength with the number of amine groups. In the same way, changing the diblock structure for a comblike one led to an enhanced affinity of the Polymer for the solid surface. The Adsorption was enthalpic but the Gibbs free energy of Adsorption remained moderate because of a large entropy loss during Adsorption. There was an enthalpy-entropy compensation phenomenon. Below a concentration of 70 mmol/m 3 , the Polymers adsorbed as a 30 Å thick monolayer and the Adsorption phenomenon was irreversible, due to the Polymeric nature of the polar part. A drastic increase of adsorbed amount took place for higher concentrations. The formation of reverse hemimicelles was assumed as the origin of this phenomenon. The supplementary Adsorption was reversible, showing that the Polymer-Polymer interactions were weaker than the Polymer-surface interactions.
Xiangming Kong - One of the best experts on this subject based on the ideXlab platform.
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Effect of highly carboxylated colloidal Polymers on cement hydration and interactions with calcium ions
Cement and Concrete Research, 2018Co-Authors: Xiangming Kong, Chaoyang Zhang, Yi CaiAbstract:Abstract Polymer latexes are often found to retard cement hydration. Interaction of Polymer particles with Ca2+ in pore solution and Adsorption of Polymer on cement were proposed as possible mechanisms for the retardation effect. This paper aims at disclosing the retardation mechanism of colloidal Polymers using a highly carboxylated polystyrene latex. Interaction between colloidal particles and Ca2+ was studied by post-treatment of the latex with Ca(NO3)2. Techniques including calorimetry, Adsorption test, ICP-OES, SEM, are involved to investigate effects of the post-treated latexes on hydrations of cement and C3S. It is found that enrichment of Ca2+ on surface of colloidal particles doesn't contribute to the retardation effect of Polymer on cement hydration. Furthermore, the acceleration effect of the two-step treated latex using Ca(NO3)2 and Na2SiO3 suggests that nucleation inhibition of the adsorbed Polymer layer on cement surface is the more conceivable mechanism responsible for the retardation effect of the highly carboxylated latex.
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influences of styrene acrylate latexes on cement hydration in oil well cement system at different temperatures
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016Co-Authors: Xiangming Kong, Biqin Dong, Ziming Wang, Yanrong Zhang, Yi Cai, Qing Zhang, Feng XingAbstract:Abstract Influences of styrene-acrylate (SA) latexes on cement hydration were investigated by isothermal calorimetry and the mechanism wasdiscussed. Super-retardation phenomenon caused by addition of SA latexes on oil well cement hydration was found at 80 °C by setting time measurement. Quantitative analysis of hydrolysis of SA latexes in cementitious systems and their effect on cement hydration were investigated by FTIR, zeta potential and surface charge density measurements. Results show that the hydrolysis of ester groups in acrylate units is significantly accelerated by elevated temperature in alkaline condition. The continuous production of carboxyl groups promotes the Adsorption of Polymer particles on the surface of cement grains and/or leads to continuous Ca 2+ sequestration from pore solution. These two aspects are the causes of the super-retardation effect. It is concluded that unless special chemistry is involved in the preparation of SA latexes, such as construction of core-shell structure of the colloidal particles, SA latexes with high content of acrylate units, due to the severe hydrolysis of the ester groups in the Polymer chains, are not recommended to be used in oil well cement system.
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Interaction of silylated superplasticizers with cementitious materials
Journal of Applied Polymer Science, 2016Co-Authors: Zichen Lu, Xiangming Kong, Biqin Dong, Ziming Wang, Yanrong Zhang, Feng XingAbstract:Incorporation of silane groups into polycarboxylate superplasticizer (PCE) opens a new technical approach to improve properties of PCE, such as to enhance the Adsorption of PCE on cement and hence the dispersing performance, to minimize the retardation effect, and potentially to increase mechanical strength of cement mortars. Silylated PCEs were synthesized using silane monomer via radical coPolymerization. Dispersing effect, Adsorption behaviors, and influences on mortar strength of these Polymers were systematically investigated. Results show that increasing the incorporation of sliane groups in PCE promotes the Adsorption of Polymer on cement surface and hence leads to good fluidity retention capability. Furthermore, sulfate resistance ability of silylated PCE is superior due to stronger chemical Adsorption of Polymer on cement surface. The retardation effect of PCE is minimized by the introduction of silane groups. The addition of silylated PCE significantly increases 3 days compressive strength without notably affecting the long-term strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44161.
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Retardation effect of styrene-acrylate coPolymer latexes on cement hydration
Cement and Concrete Research, 2015Co-Authors: Xiangming Kong, Sebastian Emmerling, Joachim Pakusch, Markus Rueckel, Jörg NieberleAbstract:Interactions between styrene-acrylate latexes and cement are investigated with emphasis of the charge properties of the Polymer particles by means of calorimetry, Adsorption measurement, and confocal laser scanning microscope. Three latexes with varied surface charges of Polymer particles were prepared by respectively using methacrylic acid (MAA), sodium styrene sulfonate (SSS) and methyl poly(ethylene glycol) methacrylate (MPEGMA) as water soluble monomers during synthesis. It is found that the Polymer latexes retard cement hydration in two manners, namely the delaying effect represented by a delayed hydration peak and the slowing down effect characterized by a reduced main hydration peak during the acceleration period. The delaying effect is closely related to the concentration of carboxylic groups existing in the latex, while the depression effect of hydration rate is majorly caused by the Adsorption of Polymer particles on surface of cement grains and proportional to the total charge density of Polymer particles.
