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Guo D, Zhang P, Cao X, Liu Y, Cao H, Bian J. Effect of temperature on heavy hydrocarbon crystallization in natural gas. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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2
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Effect of Planar Interfaces on Nucleation in Melting and Crystallization. ENTROPY 2022; 24:e24081029. [PMID: 35893008 PMCID: PMC9394313 DOI: 10.3390/e24081029] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/18/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022]
Abstract
The effect of planar interfaces on nucleation (namely, on the work of critical cluster formation and their shape) is studied both for crystallization and melting. Advancing an approach formulated about 150 years ago by J. W. Gibbs for liquid phase formation at planar liquid−liquid interfaces, we show that nucleation of liquids in the crystal at crystal−vapor planar interfaces proceeds as a rule with a much higher rate compared to nucleation in the bulk of the crystal. Provided the surface tensions crystal−liquid (σcl), liquid−vapor (σlv), and crystal−vapor (σcv) obey the condition σcv=σcl+σlv, the work of critical cluster formation tends to zero; in the range σcv<σcl+σlv, it is less than one half of the work of critical cluster formation for bulk nucleation. The existence of a liquid−vapor planar interface modifies the work of critical cluster formation in crystal nucleation in liquids to a much less significant degree. The work of critical crystal cluster formation is larger than one half of the bulk value of the work of critical cluster formation, reaching this limit at σcv=σcl+σlv. The shape of the critical clusters can be described in both cases by spherical caps with a radius, R, and a width parameter, h. This parameter, h, is the distance from the cutting plane (coinciding with the crystal−vapor and liquid−vapor planar interface, respectively) to the top of the spherical cap. It varies for nucleation of a liquid in a crystal in the range (h/R)≤1 and for crystal nucleation in a liquid in the range 2≥(h/R)≥1. At σcv=σcl+σlv, the ratio (h/R) of the critical cluster for nucleation in melting tends to zero ((h/R)→0). At the same condition, the critical crystallite has the shape of a sphere located tangentially to the liquid−vapor interface inside the liquid ((h/R)≅2). We present experimental data which confirm the results of the theoretical analysis, and potential further developments of the theoretical approach developed here are anticipated.
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3
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Pontoni D, DiMichiel M, Deutsch M. Binary mixtures of homologous room-temperature ionic liquids: Nanoscale structure evolution with alkyl lengths’ difference. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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4
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Pontoni D, DiMichiel M, Deutsch M. Binary mixtures of homologous room-temperature ionic liquids: Temperature and composition evolution of the nanoscale structure. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Modak VP, Wyslouzil BE, Singer SJ. Mechanism of surface freezing of alkanes. J Chem Phys 2020; 153:224501. [PMID: 33317286 DOI: 10.1063/5.0031761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using molecular dynamics simulation of octane (C8) and nonadecane (C19), we probe the mechanism of n-alkane surface freezing, the appearance of a crystalline monolayer above the liquid at a temperature Tsf above the bulk freezing point Tf. Formation of a crystalline monolayer occurs robustly in these systems. When Tf > Tsf, the surface frozen phase is metastable with respect to the solid but persists for long periods for study in simulations. Surface freezing of both C8 and C19 is driven by significant energy-lowering when alkane chains become ordered along the surface normal, and we elucidate the origins of this phenomenon. The degree of configurational disorder in the surface frozen layer relative to the solid is much larger for C8 compared to C19. From the Gibbsian viewpoint, we extract the excess energy and entropy of the liquid and surface frozen phases. We also consider the surface frozen layer as an intervening third phase, the viewpoint taken in previous theoretical analyses. Here, we find significantly increased entropy of the surface frozen phase of C8 associated with configurational disorder, while the energy and entropy of the surface frozen phase of C19 are marginally different from the bulk solid. Finally, by combining our previously determined solid-vapor surface free energies of C8 and C19 with liquid-vapor surface tensions from this work, we eliminate wetting as a possible mechanism for C8 surface freezing, but it remains a possibility for C19. We analyze the molecular structure of the liquid, surface frozen, and solid surfaces and discuss its relevance to thermodynamic properties.
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Affiliation(s)
- Viraj P Modak
- William G. Lowrie Department of Chemical and Biomolecular Engineering, Columbus, Ohio 43210, USA
| | - Barbara E Wyslouzil
- William G. Lowrie Department of Chemical and Biomolecular Engineering, Columbus, Ohio 43210, USA
| | - Sherwin J Singer
- Department of Chemistry and Biochemistry, Columbus, Ohio 43210, USA
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6
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Mishra K, Bergfreund J, Bertsch P, Fischer P, Windhab EJ. Crystallization-Induced Network Formation of Tri- and Monopalmitin at the Middle-Chain Triglyceride Oil/Air Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7566-7572. [PMID: 32520568 DOI: 10.1021/acs.langmuir.0c01195] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Crystalline glycerides play an important role in the formation of multiphase systems such as emulsions and foams. The stabilization of oil/water interfaces by glyceride crystals has been extensively studied compared to only few studies which have been dedicated to oil/air interfaces. This study investigates the crystallization and network formation of tripalmitin (TP) and monopalmitin (MP) at the middle-chain triglyceride (MCT) oil/air interface. TP crystals were found to crystallize in the bulk before aggregating as large rectangular crystal conglomerates at the MCT oil/air interface. This leads to the slow formation of a plastic deformable, macroscopic crystal layer with high interfacial rheological moduli. MP crystals form directly at the MCT oil/air interface resulting in a comparatively fast formation of an elastic deformable network. Crystals with tentacle-like morphology were found to be responsible for the network elasticity. In this work, we show how interfacial crystallization dynamics and mechanical strength can be linked to the molecular structure and crystallization behavior of glyceride crystals.
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Affiliation(s)
- Kim Mishra
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Jotam Bergfreund
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Pascal Bertsch
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Peter Fischer
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Erich J Windhab
- Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
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7
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Kovacik F, Okur HI, Smolentsev N, Scheu R, Roke S. Hydration mediated interfacial transitions on mixed hydrophobic/hydrophilic nanodroplet interfaces. J Chem Phys 2018; 149:234704. [PMID: 30579299 DOI: 10.1063/1.5035161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Interfacial phase transitions are of fundamental importance for climate, industry, and biological processes. In this work, we observe a hydration mediated surface transition in supercooled oil nanodroplets in aqueous solutions using second harmonic and sum frequency scattering techniques. Hexadecane nanodroplets dispersed in water freeze at a temperature of ∼15 °C below the melting point of the bulk alkane liquid. Addition of a trimethylammonium bromide (CXTA+) type surfactant with chain length equal to or longer than that of the alkane causes the bulk oil droplet freezing transition to be preceded by a structural interfacial transition that involves water, oil, and the surfactant. Upon cooling, the water loses some of its orientational order with respect to the surface normal, presumably by reorienting more parallel to the oil interface. This is followed by the surface oil and surfactant alkyl chains losing some of their flexibility, and this chain stretching induces alkyl chain ordering in the bulk of the alkane phase, which is then followed by the bulk transition occurring at a 3 °C lower temperature. This behavior is reminiscent of surface freezing observed in planar tertiary alkane/surfactant/water systems but differs distinctively in that it appears to be induced by the interfacial water and requires only a very small amount of surfactant.
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Affiliation(s)
- Filip Kovacik
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Halil I Okur
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Nikolay Smolentsev
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Rüdiger Scheu
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sylvie Roke
- Laboratory for fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), and Institute of Materials Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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8
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Tsuura M, Shuto A, Hiraki S, Imai Y, Sakamoto H, Matsubara H, Aratono M, Tanida H, Nitta K, Uruga T, Takiue T. Surface freezing and molecular miscibility of binary fluoroalkanol-alkanol liquid mixture. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.04.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Gao X, Fu D, Xie B, Su Y, Wang D. Confined Phase Diagram of Binary n-Alkane Mixtures within Three-Dimensional Microcapsules. J Phys Chem B 2014; 118:12549-55. [DOI: 10.1021/jp5069818] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xia Gao
- Beijing
National Laboratory
for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dongsheng Fu
- Beijing
National Laboratory
for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Baoquan Xie
- Beijing
National Laboratory
for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunlan Su
- Beijing
National Laboratory
for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dujin Wang
- Beijing
National Laboratory
for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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10
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Yefet S, Sloutskin E, Tamam L, Sapir Z, Cohen A, Deutsch M, Ocko BM. Surfactant-induced phases in water-supported alkane monolayers: I. Thermodynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:8000-8009. [PMID: 24918482 DOI: 10.1021/la501567s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Alkanes longer than n = 6 carbons do not spread on the water surface, but condense in a macroscopic lens. However, adding trimethylammonium-based surfactants, C(m)TAB, in submillimolar concentrations causes the alkanes to spread and form a single Langmuir-Gibbs (LG) monolayer of mixed alkanes and surfactant tails, which coexists with the alkane lenses. Upon cooling, this LG film surface-freezes at a temperature T(s) above the bulk freezing temperature T(b). The thermodynamics of surface freezing (SF) of these LG films is studied by surface tension measurements for a range of alkanes (n = 12-21) and surfactant alkyl lengths (m = 14, 16, 18), at several concentrations c. The surface freezing range T(s)-T(b) observed is up to 25 °C, an order of magnitude larger than the temperature range of SF monolayers on the surface of pure alkane melts. The measured (n,T) surface phase diagram is accounted for well by a model based on mixtures' theory, which includes an interchange energy term ω. ω is found to be negative, implying attraction between unlike species, rather than the repulsion found for SF of binary alkane mixtures. Thus, the surfactant/alkane mixing is a necessary condition for the occurrence of SF in these LG films. The X-ray derived structure of the films is presented in an accompanying paper.
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Affiliation(s)
- Shai Yefet
- Physics Department and Institute of Nanotechnology, Bar-Ilan University , Ramat-Gan 52900, Israel
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11
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12
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Takiue T, Shimasaki M, Tsuura M, Sakamoto H, Matsubara H, Aratono M. Surface Freezing and Molecular Miscibility of Binary Alkane–Alkane and Fluoroalkane–Alkane Liquid Mixtures. J Phys Chem B 2014; 118:1519-26. [DOI: 10.1021/jp406431m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takanori Takiue
- Department
of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki
6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
| | - Mayuko Shimasaki
- Department
of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki
6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
| | - Miyako Tsuura
- Department
of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki
6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
| | - Hiroyasu Sakamoto
- Department
of Visual Communication Design, Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan
| | - Hiroki Matsubara
- Department
of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki
6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
| | - Makoto Aratono
- Department
of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki
6-10-1, Higashi-ku, Fukuoka 812-8581, Japan
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13
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Su Y, Liu G, Xie B, Fu D, Wang D. Crystallization features of normal alkanes in confined geometry. Acc Chem Res 2014; 47:192-201. [PMID: 23947401 DOI: 10.1021/ar400116c] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
How polymers crystallize can greatly affect their thermal and mechanical properties, which influence the practical applications of these materials. Polymeric materials, such as block copolymers, graft polymers, and polymer blends, have complex molecular structures. Due to the multiple hierarchical structures and different size domains in polymer systems, confined hard environments for polymer crystallization exist widely in these materials. The confined geometry is closely related to both the phase metastability and lifetime of polymer. This affects the phase miscibility, microphase separation, and crystallization behaviors and determines both the performance of polymer materials and how easily these materials can be processed. Furthermore, the size effect of metastable states needs to be clarified in polymers. However, scientists find it difficult to propose a quantitative formula to describe the transition dynamics of metastable states in these complex systems. Normal alkanes [CnH2n+2, n-alkanes], especially linear saturated hydrocarbons, can provide a well-defined model system for studying the complex crystallization behaviors of polymer materials, surfactants, and lipids. Therefore, a deeper investigation of normal alkane phase behavior in confinement will help scientists to understand the crystalline phase transition and ultimate properties of many polymeric materials, especially polyolefins. In this Account, we provide an in-depth look at the research concerning the confined crystallization behavior of n-alkanes and binary mixtures in microcapsules by our laboratory and others. Since 2006, our group has developed a technique for synthesizing nearly monodispersed n-alkane containing microcapsules with controllable size and surface porous morphology. We applied an in situ polymerization method, using melamine-formaldehyde resin as shell material and nonionic surfactants as emulsifiers. The solid shell of microcapsules can provide a stable three-dimensional (3-D) confining environment. We have studied multiple parameters of these microencapsulated n-alkanes, including surface freezing, metastability of the rotator phase, and the phase separation behaviors of n-alkane mixtures using differential scanning calorimetry (DSC), temperature-dependent X-ray diffraction (XRD), and variable-temperature solid-state nuclear magnetic resonance (NMR). Our investigations revealed new direct evidence for the existence of surface freezing in microencapsulated n-alkanes. By examining the differences among chain packing and nucleation kinetics between bulk alkane solid solutions and their microencapsulated counterparts, we also discovered a mechanism responsible for the formation of a new metastable bulk phase. In addition, we found that confinement suppresses lamellar ordering and longitudinal diffusion, which play an important role in stabilizing the binary n-alkane solid solution in microcapsules. Our work also provided new insights into the phase separation of other mixed system, such as waxes, lipids, and polymer blends in confined geometry. These works provide a profound understanding of the relationship between molecular structure and material properties in the context of crystallization and therefore advance our ability to improve applications incorporating polymeric and molecular materials.
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Affiliation(s)
- Yunlan Su
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Guoming Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Baoquan Xie
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dongsheng Fu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dujin Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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14
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Modak VP, Pathak H, Thayer M, Singer SJ, Wyslouzil BE. Experimental evidence for surface freezing in supercooled n-alkane nanodroplets. Phys Chem Chem Phys 2013; 15:6783-95. [DOI: 10.1039/c3cp44490b] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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15
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Fu D, Liu Y, Gao X, Su Y, Liu G, Wang D. Binary n-Alkane Mixtures from Total Miscibility to Phase Separation in Microcapsules: Enrichment of Shorter Component in Surface Freezing and Enhanced Stability of Rotator Phases. J Phys Chem B 2012; 116:3099-105. [DOI: 10.1021/jp2125119] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dongsheng Fu
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yufeng Liu
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xia Gao
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunlan Su
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Guoming Liu
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dujin Wang
- Beijing National Laboratory for Molecular
Sciences, Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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16
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Tamam L, Pontoni D, Sapir Z, Yefet S, Sloutskin E, Ocko BM, Reichert H, Deutsch M. Modification of deeply buried hydrophobic interfaces by ionic surfactants. Proc Natl Acad Sci U S A 2011; 108:5522-5. [PMID: 21422287 PMCID: PMC3078380 DOI: 10.1073/pnas.1014100108] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrophobicity, the spontaneous segregation of oil and water, can be modified by surfactants. The way this modification occurs is studied at the oil-water interface for a range of alkanes and two ionic surfactants. A liquid interfacial monolayer, consisting of a mixture of alkane molecules and surfactant tails, is found. Upon cooling, it freezes at T(s), well above the alkane's bulk freezing temperature, T(b). The monolayer's phase diagram, derived by surface tensiometry, is accounted for by a mixtures-based theory. The monolayer's structure is measured by high-energy X-ray reflectivity above and below T(s). A solid-solid transition in the frozen monolayer, occurring approximately 3 °C below T(s), is discovered and tentatively suggested to be a rotator-to-crystal transition.
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Affiliation(s)
- Lilach Tamam
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-llan University, Ramat-Gan 52900, Israel
| | - Diego Pontoni
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble, France
| | - Zvi Sapir
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-llan University, Ramat-Gan 52900, Israel
| | - Shai Yefet
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-llan University, Ramat-Gan 52900, Israel
| | - Eli Sloutskin
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-llan University, Ramat-Gan 52900, Israel
| | - Benjamin M. Ocko
- Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973; and
| | - Harald Reichert
- European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble, France
- Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Moshe Deutsch
- Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-llan University, Ramat-Gan 52900, Israel
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17
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de Aguiar HB, Strader ML, de Beer AGF, Roke S. Surface Structure of Sodium Dodecyl Sulfate Surfactant and Oil at the Oil-in-Water Droplet Liquid/Liquid Interface: A Manifestation of a Nonequilibrium Surface State. J Phys Chem B 2011; 115:2970-8. [DOI: 10.1021/jp200536k] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Hilton B. de Aguiar
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Matthew L. Strader
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Alex G. F. de Beer
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
| | - Sylvie Roke
- Max-Planck-Institut fuer Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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18
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Fu D, Liu Y, Liu G, Su Y, Wang D. Confined crystallization of binary n-alkane mixtures: stabilization of a new rotator phase by enhanced surface freezing and weakened intermolecular interactions. Phys Chem Chem Phys 2011; 13:15031-6. [DOI: 10.1039/c1cp21281h] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Sloutskin E, Sapir Z, Bain CD, Lei Q, Wilkinson KM, Tamam L, Deutsch M, Ocko BM. Wetting, mixing, and phase transitions in Langmuir-Gibbs films. PHYSICAL REVIEW LETTERS 2007; 99:136102. [PMID: 17930612 DOI: 10.1103/physrevlett.99.136102] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Indexed: 05/25/2023]
Abstract
Millimolar bulk concentrations of the surfactant cetyltrimethylammonium bromide (CTAB) induce spreading of alkanes, H(CH(2))(n)H (denoted C(n)) 12< or =n< or =21, on the water surface, which is not otherwise wet by these alkanes. The novel Langmuir-Gibbs film (LGF) formed is a liquidlike monolayer comprising both alkanes and CTAB tails. Upon cooling, an ordering transition occurs, yielding a hexagonally packed, quasi-2D crystal. For 11< or =n< or =17 this surface-frozen LGF is a crystalline monolayer. For 18< or =n< or =21 the LGF is a bilayer with a crystalline, pure-alkane, upper monolayer, and a liquidlike lower monolayer. The phase diagram and film structure were determined by x-ray, ellipsometry, and surface tension measurements. A thermodynamic theory accounts quantitatively for the observations.
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Affiliation(s)
- E Sloutskin
- Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
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20
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Nash DG, Tolocka MP, Baer T. The uptake of O3 by myristic acid-oleic acid mixed particles: evidence for solid surface layers. Phys Chem Chem Phys 2006; 8:4468-75. [PMID: 17001415 DOI: 10.1039/b609855j] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The oleic acid ozonolysis in mixed oleic and myristic acid particles was studied in a flow tube reactor using single particle mass spectrometry. The change in reactivity was investigated as a function of the myristic acid concentration in these 2 micron particles. For pure oleic acid aerosol, the reactive ozone uptake coefficient, gamma, was found to be 3.4 (+/-0.3) x 10(-4) after taking secondary reactions into account. At the myristic acid crystallization point, where only 2.5% of the particle is in the solid phase, the uptake coefficient was reduced to 9.7 (+/-1.0) x 10(-5). This dramatic drop in the uptake coefficient is explained by the presence of a crystalline monolayer of myristic acid, through which ozone diffusion is reduced by several orders of magnitude, relative to liquid oleic acid. Scanning electron microscope images of the mixed particles confirm that the particle surface is crystalline when the myristic acid mole fraction exceeds 0.125. The findings of these experiments illustrate that particle morphology is important to understanding the reactivity of species in a mixed particle. The decay of myristic acid during the course of ozonolysis is explained in terms of a reaction with stabilized Criegee intermediates, which attack the acidic groups of the oleic and myristic acids with equal rate constants.
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Affiliation(s)
- David G Nash
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
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Ofer E, Sloutskin E, Tamam L, Ocko BM, Deutsch M. Surface freezing in binary alkane-alcohol mixtures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:021602. [PMID: 17025441 DOI: 10.1103/physreve.74.021602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Indexed: 05/12/2023]
Abstract
Surface freezing was detected and studied in mixtures of alcohol and alkane molecules, using surface tensiometry and surface-specific x-ray scattering methods. Considering that surface freezing in pure alkanes forms an ordered monolayer and in alcohols it forms an ordered bilayer, the length mismatch repulsion was minimized by varying the carbon number of the alkane component around 2n, where n is the carbon number of the alcohol molecule. A solutionlike behavior was found for all mixtures, where the ideal liquid mixture phase-separates upon freezing both in the bulk and the surface. The solid exhibits a herringbone crystalline phase below an alkane mole fraction phi(t) approximately 0.8 and a rotator phase above it. The surface frozen film below phi(t) is an alkane monolayer exhibiting a next-nearest neighbor molecular tilt of a composition-dependent magnitude. Above phi(t), no diffraction peaks were observed. This could be explained by the intrinsically shorter-range order of the rotator phase and a possible proliferation of defects.
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Affiliation(s)
- E Ofer
- Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
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Sloutskin E, Solutskin E, Ocko BM, Tamam L, Taman L, Kuzmenko I, Gog T, Deutsch M. Surface Layering in Ionic Liquids: An X-ray Reflectivity Study. J Am Chem Soc 2005; 127:7796-804. [PMID: 15913369 DOI: 10.1021/ja0509679] [Citation(s) in RCA: 241] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations, were studied by X-ray reflectivity and surface tensiometry. A molecular layer of a density approximately 18% higher than that of the bulk is found to form at the free surface of these liquids. In common with surface layering in liquid metals and surface freezing in melts of organic chain molecules, this effect is induced by the lower dimensionality of the surface. The concentrations of the oppositely charged ions within the surface layer are determined by chemical substitution of the anion. The temperature-dependent surface tension measurements reveal a normal, negative-slope temperature dependence. The different possible molecular arrangements within the enhanced-density surface layer are discussed.
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Affiliation(s)
- Eli Sloutskin
- Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
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Sloutskin E, Bain CD, Ocko BM, Deutsch M. Surface freezing of chain molecules at the liquid–liquid and liquid–air interfaces. Faraday Discuss 2005; 129:339-52; discussion 353-66. [PMID: 15715317 DOI: 10.1039/b405969g] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Surface freezing (SF) is the formation of a crystalline monolayer at the free surface of a melt at a temperature Ts, a few degrees above the bulk freezing temperature, Tb. This effect, i.e. Ts > Tb, common to many chain molecules, is in a marked contrast with the surface melting effect, i.e. Ts < or = Tb, shown by almost all other materials. Depending on chain length, n, the SF layer shows a variety of phases, in some cases tuneable by bulk additives. The SF behaviour of binary mixtures of different-length alkanes and alcohols is governed by the relative chain length mismatch, /delta n/n/2, yielding a quasi-"universal" behaviour for the freezing of both bulk and surface. While SF at the liquid air interface was studied rather extensively, Lei and Bain (Phys. Rev. Lett., 2004, 94, 176103) have shown only very recently that interfacial freezing (IF) can be induced also at the water: tetradecane interface by adding the ionic surfactant CTAB to the water phase. We present measurements of the interfacial tension of the water: hexadecane interface, as a function of temperature and the ionic surfactant STAB, revealing IF at a STAB-concentration-dependent temperature Ti > Tb. The measurements indicate that a single frozen monolayer is formed, with a temperature-existence range of up to 10 degrees C, much larger than the 1.2 degrees C found for SF at the free surface of the melt. We also find a new effect, where the IF allows tuning of the interfacial tension between the two bulk phases to zero for a range of temperatures, deltaT = Tmix - Tb < or = Ti - Tb by cooling the system below Ti. We discuss qualitatively the factors stabilizing the frozen layer and their variation from the liquid-air to the liquid-liquid interfaces. The surfactant concentration dependence of Ti is also discussed and a tentative theoretical explanation is suggested.
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Affiliation(s)
- Eli Sloutskin
- Physics Department, Bar-Ilan University, Ramat-Gan 52900, Israel
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Sloutskin E, Sirota EB, Gang O, Wu XZ, Ocko BM, Deutsch M. Surface and bulk interchange energy in binary mixtures of chain molecules. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2004; 13:109-112. [PMID: 15052420 DOI: 10.1140/epje/e2004-00047-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interchange (interaction) parameter, controlling the phase behaviour of a binary mixture, is determined for the bulk and the surface of binary mixtures of different types of chain molecules, using surface tensiometry and a mean-field theory. For all mixtures and concentrations studied an identical behaviour is observed at the surface, depending only on the square of the reduced chain length mismatch delta n/n, where delta n and dealta n are the difference in and average of the number of carbons of the two components.
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Affiliation(s)
- E Sloutskin
- Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel
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Sloutskin E, Gang O, Kraack H, Doerr A, Sirota EB, Ocko BM, Deutsch M. Surface freezing in binary mixtures of chain molecules. II. Dry and hydrated alcohol mixtures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 68:031606. [PMID: 14524780 DOI: 10.1103/physreve.68.031606] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2002] [Revised: 05/05/2003] [Indexed: 05/24/2023]
Abstract
Surface freezing is studied in dry and hydrated alcohol mixtures by surface x-ray scattering and surface tension measurements. A crystalline bilayer is formed at the surface a few degrees above the bulk freezing temperature. The packing is hexagonal, with molecules aligned along the surface normal in all cases. The in-plane lattice constant reveals a qualitatively different behavior with composition for hydrated and dry mixtures. The simple theoretical approach used successfully for alkane and deuterated alkane mixtures accounts well also for the alcohol mixtures. The repulsive length-mismatch term opposing the mixing entropy term in the free energy of the mixtures is shown to have a universal behavior for all mixtures studied: protonated alkanes, deuterated alkanes, and dry and wet alcohols. This universality is somewhat counterintuitive in view of the different interactions (e.g., hydrogen bonding in alcohols) in the different mixtures.
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Affiliation(s)
- E Sloutskin
- Physics Department, Bar Ilan University, Ramat Gan 52900, Israel
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