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El Khaoui S, Talha L, Khatouri M, Ahfir R, Naji M, Filali M. Relaxation modes in a smart system: weakly charged microemulsion and polyelectrolyte. SEP SCI TECHNOL 2022. [DOI: 10.1080/01496395.2022.2075755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- S. El Khaoui
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
| | - L. Talha
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
| | - M. Khatouri
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
| | - R. Ahfir
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
| | - M. Naji
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
| | - M. Filali
- LPAIS Laboratory, University of Sidi Mohamed Ben Abdellah, Fès-Atlas, Morocco
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Ahfir R, Elkhaoui S, Khatouri M, Lemaalem M, Talha L, Filali M. Probing the balance of Telechelic Polymers Bridging and Screened-Coulomb Interactions in Microemulsion System. IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING 2021; 1160:012002. [DOI: 10.1088/1757-899x/1160/1/012002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
The structural properties of neutral oil-in-water (O/W) microemulsions nanodroplets in the presence of telechelic polymers PEO modified with two hydrophobic end functions (PEO- 2m) were studied by Small-Angle Neutron Scattering (SANS). We show that the unknown attractive interaction introduced by the addition of PEO-2m, can could be balanced by a known repulsion interaction due to the addition of a cationic surfactant Cp +, which causes a progressive transformation of the bridges connecting the nanodroplets into loops. For this, we compute the structure factor S(q) with an effective pair potential, using the Ornstein Zernicke (OZ) integral equation approach with the Hypernetted Chain (HNC) closure relation. Generally, the agreement between the neutron scattering spectra and the numerical study is reasonable and allows a detailed description for each sample.
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Hagita K. Particle-mesh two-dimensional pattern reverse Monte Carlo analysis on filled-gels during uniaxial expansion. SOFT MATTER 2019; 15:7237-7249. [PMID: 31478543 DOI: 10.1039/c9sm01060b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A particle-mesh-based two-dimensional pattern reverse Monte Carlo (RMC) analysis method (PM-2DpRMC) is proposed for analyzing two-dimensional small-angle-scattering (2D-SAS) patterns. The results of analyzing such patterns in expanded gel networks filled with spherical nano-particles during uniaxial elongation are provided. Previously, characteristic 2D-SAS patterns, such as the two-point bar plate and figure-8 patterns, were observed to possess high stretching ratios in a coarse-grained molecular dynamics (CGMD) simulation, and the patterns were found to depend on the properties of the networks, such as whether they were topologically percolated or not. To establish real-space visualizations of the changes in the particle-configurations corresponding to the 2D-SAS patterns, the on-the-fly PM-2DpRMC method was employed to model the morphology changes of the filler particles during stretching in a series of 2D-SAS patterns. The use of quasi-dynamics to express deformation was validated by evaluating the accuracy of the elongation speed and the number of RMC trials predicted from the behavior of the converged χ2. The results confirm that the obtained sequences of 3D configurations were similar to the original configurations obtained in the CGMD simulations. Further, a demonstrative test using actual experimental data was conducted to verify the completeness of the confirmation.
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Affiliation(s)
- Katsumi Hagita
- Department of Applied Physics, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan.
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Hagita K, Tominaga T, Sone T. Large-scale reverse Monte Carlo analysis for the morphologies of silica nanoparticles in end-modified rubbers based on ultra-small-angle X-ray scattering data. POLYMER 2018. [DOI: 10.1016/j.polymer.2017.12.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Oberdisse J, Hellweg T. Structure, interfacial film properties, and thermal fluctuations of microemulsions as seen by scattering experiments. Adv Colloid Interface Sci 2017; 247:354-362. [PMID: 28751064 DOI: 10.1016/j.cis.2017.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022]
Abstract
The physics of microemulsions and in particular Dominique Langevin's contributions to the understanding of microemulsion structure and bending properties using scattering techniques are reviewed. Among the many methods used by her and her co-workers, we particularly emphasize optical techniques and small angle neutron scattering (SANS), but also neutron spin echo spectroscopy (NSE). The review is then extended to more recent studies of properties of microemulsions close to surfaces, using reflectometry and grazing-incidence small angle neutron scattering (GISANS).
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Elghazrani K, Azougarh A, Oberdisse J, Filali M. Interactions between microemulsion droplets decorated with hydrophobically modified polymers: a small-angle neutron scattering study. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2014; 37:128. [PMID: 25537095 DOI: 10.1140/epje/i2014-14128-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 06/04/2023]
Abstract
The shape and interactions between microemulsion droplets (R = 8.2 nm, polydispersity 20%) either decorated with PEO modified with a single hydrophobic end function (PEO-m: C12H25 - (EO)n, M(PEO) = 5.2 kg/mol), or with telechelic polymers of twice the mass (PEO-2m: C12H25 - (EO)2n - C12H25, M(PEO) = 10.4 kg/mol) have been studied by small-angle neutron scattering (SANS). The results as a function of droplet and polymer concentration have been compared to the reference case of the bare microemulsion which was shown to be unchanged using Porod representations. The interactions between bare and decorated droplets have been analyzed using the structure factor S(q), at first in a model-free way based on its low-q limit S(q → 0). This analysis provides clear evidence on the concentration-dependent repulsive or attractive nature of the contributions to the pair droplet-droplet pair potential of the polymers. Model pair potentials describing the steric repulsions and attractions by copolymer bridging are used to describe the low-q behavior of the structure factor based on an integral equation approach, giving an estimate of the range and amplitude of the potentials. Moreover, they provide an explanation for the observed transient clustering in terms of a shallow minimum of the total potential, as they establish the respective repulsive and attractive contributions of the polymer molecules.
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Affiliation(s)
- Karim Elghazrani
- Laboratoire de Physique théorique et appliquée (LPTA), Université Sidi Mohamed Ben Abdellah, Faculté des Sciences Dhar El Mahraz, BP 1796 Fes, Atlas, Maroc
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Malo de Molina P, Appavou MS, Gradzielski M. Oil-in-water microemulsion droplets of TDMAO/decane interconnected by the telechelic C18-EO150-C18: clustering and network formation. SOFT MATTER 2014; 10:5072-5084. [PMID: 24901947 DOI: 10.1039/c4sm00501e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The effect of a doubly hydrophobically end-capped water soluble polymer (C18-PEO150-C18) on the properties of an oil-in-water (O/W) droplet microemulsion (R ∼ 2.85 nm) has been studied as a function of the amount of added telechelic polymer. Macroscopically one observes a substantial increase of viscosity once a concentration of ∼5 hydrophobic stickers per droplet is surpassed and effective cross-linking of the droplets takes place. SANS measurements show that the size of the individual droplets is not affected by the polymer addition but it induces attractive interactions at low concentration and repulsive ones at high polymer content. Measurements of the diffusion coefficient by DLS and FCS show increasing sizes at low polymer addition that can be attributed to the formation of clusters of microemulsion droplets interconnected by the polymer. At higher polymer content the network formation leads to an additional slow relaxation mode in DLS that can be related to the rheological behaviour, while the self-diffusion observed in FCS attains a lower plateau value, i.e., the microemulsion droplets remain effectively fixed within the network. The combination of SANS, DLS, and FCS allows us to derive a self-consistent picture of the evolution of structure and dynamics of the mixed system microemulsion/telechelic polymer as a function of the polymer content, which is not only relevant for controlling the macroscopic rheological properties but also with respect to the internal dynamics as it is, for instance, relevant for the release and transport of active agents.
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Affiliation(s)
- Paula Malo de Molina
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Straße des 17. Juni 124, Sekr. TC7, Technische Universität Berlin, D-10623 Berlin, Germany
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de Molina PM, Herfurth C, Laschewsky A, Gradzielski M. Structure and dynamics of networks in mixtures of hydrophobically modified telechelic multiarm polymers and oil in water microemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15994-16006. [PMID: 23075139 DOI: 10.1021/la303673a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The structural and dynamical properties of oil-in-water (O/W) microemulsions (MEs) modified with telechelic polymers of different functionality (e.g., number of hydrophobically modified arms, f) were studied by means of dynamic light scattering (DLS), small-angle neutron scattering (SANS), and high frequency rheology measurements as a function of the polymer architecture and the amount of added polymer. For this purpose, we employed tailor-made hydrophobically end-capped poly(N,N-dimethylacrylamide) star polymers of a variable number of endcaps, f, of different alkyl chain lengths, synthesized by the reversible addition-fragmentation chain transfer method. The addition of the different end-capped polymers to an uncharged ME of O/W droplets leads to a large enhancement of the viscosity of the systems. SANS experiments show that the O/W ME droplets are not changed upon the addition of the polymer, and its presence only changes the interdroplet interactions. The viscosity increases largely upon addition of a polymer, and this enhancement depends pronouncedly on the alkyl length of the hydrophobic sticker as it controls the residence time in a ME droplet. Similarly, the high frequency modulus G(0) depends on the amount of added polymer but not on the sticker length. G(0) was found to be directly proportional to f - 1. The onset of network formation is shifted to a lower number of stickers per ME droplet with increasing f, and the network formation becomes more effective. Thus, the dynamics of network formation are controlled by the polymer architecture. The effect on the dynamics seen by DLS is even more pronounced. Upon increasing the polymer concentration, slower relaxation modes appear that become especially pronounced with increasing number of arms. The relaxation dynamics are correlated to the rheological relaxation, and both are controlled by the polymer architecture.
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Affiliation(s)
- Paula Malo de Molina
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin, Germany.
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Rufier C, Collet A, Viguier M, Oberdisse J, Mora S. Influence of Surfactants on Hydrophobically End-Capped Poly(ethylene oxide) Self-Assembled Aggregates Studied by SANS. Macromolecules 2011. [DOI: 10.1021/ma201150g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Julian Oberdisse
- Laboratoire Leon Brillouin, CEA Saclay, F-91191 Gif Sur Yvette, France
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Ashcraft E, Ji H, Mays J, Dadmun M. Grafting Polymer Loops onto Functionalized Nanotubes: Monitoring Grafting and Loop Formation. MACROMOL CHEM PHYS 2011. [DOI: 10.1002/macp.201000557] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Causse J, Oberdisse J, Jestin J, Lagerge S. Small-angle neutron scattering study of solubilization of tributyl phosphate in aqueous solutions of L64 Pluronic triblock copolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:15745-15753. [PMID: 20873831 DOI: 10.1021/la1021164] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have studied the solubilization behavior of tributylphosphate (TBP) in aqueous solutions of L64-Pluronics, using light and small angle neutron scattering (SANS). Varying the temperature and the oil content, the system presents a nontrivial phase behavior. In particular, at 308 K, a first solubilization followed by an emulsification failure and a resolubilization is found. We have measured the microstructure by SANS and characterized the microemulsion droplet core size, corona thickness, polydispersity, and interactions. It is shown that at low oil content, the system is made of small swollen micelles. After the phase separation, the resolubilization is carried by larger oil droplets decorated by copolymer. From specific surface measurements at large angles, a surprising change in surfactant conformation is found to accompany this morphological evolution which is also supported by previous results obtained from ¹H NMR experiments. In independent measurements, our structural modeling is confirmed using contrast-variation SANS.
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Affiliation(s)
- J Causse
- Institut Charles Gerhardt CNRS UMR-5253 équipe Agrégats Interfaces Matériaux pour l'Energie, Université Montpellier II, Case 015, Place E. Bataillon, 34095 Montpellier Cedex 05, France
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Chen X, Dong W, Zhang X. Self-assembly of amphiphilic molecules: A review on the recent computer simulation results. Sci China Chem 2010. [DOI: 10.1007/s11426-010-4064-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Binks B, Fletcher P, Tian L. Influence of nanoparticle addition to Winsor surfactant microemulsion systems. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.03.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Testard V, Oberdisse J, Ligoure C. Monte Carlo Simulations of Colloidal Pair Potential Induced by Telechelic Polymers: Statistics of Loops and Bridges. Macromolecules 2008. [DOI: 10.1021/ma8005813] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vincent Testard
- Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR 5587 CNRS/UM2, Université Montpellier II, F-34095 Montpellier Cedex 5, France
| | - Julian Oberdisse
- Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR 5587 CNRS/UM2, Université Montpellier II, F-34095 Montpellier Cedex 5, France
| | - Christian Ligoure
- Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR 5587 CNRS/UM2, Université Montpellier II, F-34095 Montpellier Cedex 5, France
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