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Zhou W, Liu X, Long Y, Xie G, Chen Y. Monitoring effects of hydrodynamic cavitation pretreatment of sodium oleate on the aggregation of fine diaspore particles through small-angle laser scattering. ULTRASONICS SONOCHEMISTRY 2023; 100:106574. [PMID: 37734167 PMCID: PMC10514452 DOI: 10.1016/j.ultsonch.2023.106574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/23/2023]
Abstract
Hydrodynamic cavitation (HC) enhanced fine particle aggregation could be largely due to the generation of tiny bubbles and their role in bridging particles. However, the lack of adequate characterizations of aggregates severally limits our further understanding of the associated aggregation behaviors. In this study, the aggregation of fine diaspore particles was comparatively investigated in sodium oleate (NaOl) solutions with and without HC pretreatment through the small-angle laser scattering (SALS) technique in a shear-induced aggregation (SIA) system. Results showed that HC pretreatment caused the formation of bulk nanobubbles (BNBs), which significantly modified the particle interactions and thereby modified the size and mass fractal dimension (Df) of aggregates under different SIA conditions. Although HC pretreatment did not noticeably alter the gradual change trend of aggregate size and structure characteristics under specific variables, BNBs bridging facilitated the aggregation process towards the diffusion-limited cluster aggregation model, resulting in the formation of larger but looser aggregates. This effect was more pronounced under relatively high NaOl concentrations. Apart from BNBs, the aggregation was also affected by cavitation bubbles formed during shear cavitation, which was more significant under high stirring intensity conditions (i.e., 1800 rpm) than the low stirring intensity conditions (i.e., 600 rpm).
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Affiliation(s)
- Weiguang Zhou
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China; Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Metal Mineral Resources, Kunming University of Science and Technology, Kunming 650093, PR China
| | - Xinran Liu
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China
| | - Yufeng Long
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China
| | - Guangyuan Xie
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, PR China.
| | - Yanfei Chen
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China.
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2
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Ninham B, Reines B, Battye M, Thomas P. Pulmonary surfactant and COVID-19: A new synthesis. QRB DISCOVERY 2022; 3:e6. [PMID: 37564950 PMCID: PMC10411325 DOI: 10.1017/qrd.2022.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/24/2022] [Accepted: 04/05/2022] [Indexed: 11/06/2022] Open
Abstract
Chapter 1 COVID-19 pathogenesis poses paradoxes difficult to explain with traditional physiology. For instance, since type II pneumocytes are considered the primary cellular target of SARS-CoV-2; as these produce pulmonary surfactant (PS), the possibility that insufficient PS plays a role in COVID-19 pathogenesis has been raised. However, the opposite of predicted high alveolar surface tension is found in many early COVID-19 patients: paradoxically normal lung volumes and high compliance occur, with profound hypoxemia. That 'COVID anomaly' was quickly rationalised by invoking traditional vascular mechanisms-mainly because of surprisingly preserved alveolar surface in early hypoxemic cases. However, that quick rejection of alveolar damage only occurred because the actual mechanism of gas exchange has long been presumed to be non-problematic, due to diffusion through the alveolar surface. On the contrary, we provide physical chemical evidence that gas exchange occurs by an process of expansion and contraction of the three-dimensional structures of PS and its associated proteins. This view explains anomalous observations from the level of cryo-TEM to whole individuals. It encompasses results from premature infants to the deepest diving seals. Once understood, the COVID anomaly dissolves and is straightforwardly explained as covert viral damage to the 3D structure of PS, with direct treatment implications. As a natural experiment, the SARS-CoV-2 virus itself has helped us to simplify and clarify not only the nature of dyspnea and its relationship to pulmonary compliance, but also the fine detail of the PS including such features as water channels which had heretofore been entirely unexpected. Chapter 2 For a long time, physical, colloid and surface chemistry have not intersected with physiology and cell biology as much as we might have hoped. The reasons are starting to become clear. The discipline of physical chemistry suffered from serious unrecognised omissions that rendered it ineffective. These foundational defects included omission of specific ion molecular forces and hydration effects. The discipline lacked a predictive theory of self-assembly of lipids and proteins. Worse, theory omitted any role for dissolved gases, O2, N2, CO2, and their existence as stable nanobubbles above physiological salt concentration. Recent developments have gone some way to explaining the foam-like lung surfactant structures and function. It delivers O2/N2 as nanobubbles, and efflux of CO2, and H2O nanobubbles at the alveolar surface. Knowledge of pulmonary surfactant structure allows an explanation of the mechanism of corona virus entry, and differences in infectivity of different variants. CO2 nanobubbles, resulting from metabolism passing through the molecular frit provided by the glycocalyx of venous tissue, forms the previously unexplained foam which is the endothelial surface layer. CO2 nanobubbles turn out to be lethal to viruses, providing a plausible explanation for the origin of 'Long COVID'. Circulating nanobubbles, stable above physiological 0.17 M salt drive various enzyme-like activities and chemical reactions. Awareness of the microstructure of Pulmonary Surfactant and that nanobubbles of (O2/N2) and CO2 are integral to respiratory and circulatory physiology provides new insights to the COVID-19 and other pathogen activity.
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Affiliation(s)
- Barry Ninham
- Materials Physics (formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT2600, Australia
- School of Science, University of New South Wales, Northcott Drive, Campbell, Canberra, ACT2612, Australia
| | - Brandon Reines
- Materials Physics (formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT2600, Australia
- Department of Biomedical Informatics, University of Pittsburgh School of Medicine, 5607 Baum Blvd, Pittsburgh, PA15206, USA
| | | | - Paul Thomas
- Materials Physics (formerly Department of Applied Mathematics), Research School of Physics, Australian National University, Canberra, ACT2600, Australia
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3
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Geng Z, Zhou L, Fang Z, Wang J, Yuan K, Zhang L, Hu J. Influence of the Dissolved Gas on the Interfacial Properties of Decane Surface Nanodroplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:2213-2219. [PMID: 35133844 DOI: 10.1021/acs.langmuir.1c02626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface nanodroplets have received extensive attention recently due to their potential in the fabrication of functional materials with nanostructures and chemical reactions at micro- and nanoscales. Although the effect of dissolved gas in water has been realized in some important processes such as spontaneous emulsification of oil droplets in water, its roles in the wetting behavior of surface nanodroplets at the hydrophobic interface have been largely neglected. Here, we focused on the influence of dissolved gas on the interfacial properties of surface nanodroplets and characterized their morphological evolution when exposed to different air-saturated water samples. Results indicated that the morphology of surface nanodroplets barely changed in air-oversaturated cold water. However, their contact angle first decreases gradually in deionized water, increases immediately after replacement with degassed water, and eventually decreases gradually with time. Furthermore, the surface tension of nanodroplets would change similarly after the injection of degassed water. We considered these changes to be caused by the removal or reduction of the enriched gas at the substrate interface, in which the surface hydrophobicity was changed. Our findings could shed some light on the wetting behavior of nanodroplets at the hydrophobic surface in different air-saturated water samples and inspire the microscale manipulation and reaction of surface nanodroplets.
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Affiliation(s)
- Zhanli Geng
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Limin Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Zhou Fang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Wang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaiwei Yuan
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lijuan Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Ji Y, Zheng J, Geng Z, Tan T, Hu J, Zhang L, Zhang Y. Controllable formation of bulk perfluorohexane nanodroplets by solvent exchange. SOFT MATTER 2022; 18:425-433. [PMID: 34905593 DOI: 10.1039/d1sm01457a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Perfluorocarbon (PFC) nanodroplets have rapidly developed into useful ultrasound imaging agents in modern medicine due to their non-toxic and stable chemical properties that facilitate disease diagnosis and targeted therapy. In addition, with the good capacity for carrying breathing gases and the anti-infection ability, they are employed as blood substitutes and are the most ideal liquid respirators. However, it is still a challenge to prepare stable PFC nanodroplets of uniform size and high concentration for their efficient use. Herein, we developed a simple and highly reproducible method, i.e., propanol-water exchange, to prepare highly homogeneous and stable perfluorohexane (PFH) bulk nanodroplets. Interestingly, the size distribution and concentration of formed nanodroplets could be regulated by controlling the volume fraction of PFH and percentage of propanol in the propanol-water mixture. We demonstrated good reproducibility in the formation of bulk nanodroplets with PFH volume fractions of 1/2000-1/200 and propanol percentage of 5-40%, with uniform particle size distribution and high droplet concentration. Also, the prepared nanodroplets were very stable and could survive for several hours. We constructed a ternary phase diagram to describe the relationship between the PFH volume ratio, propanol concentration, and the size distribution and concentration of the formed PFH nanodroplets. This study provides a very useful method to prepare uniform size, high concentration and stable PFC nanodroplets for their medical applications.
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Affiliation(s)
- Yuwen Ji
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Zheng
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanli Geng
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
| | - Tingyuan Tan
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Hu
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
| | - Lijuan Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
| | - Yi Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Zhangjiang Lab, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
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5
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Zhou S, Zhou W, Dong L, Peng Y, Xie G. Micellization Transformations of Sodium Oleate Induced by Gas Nucleation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9701-9710. [PMID: 34339198 DOI: 10.1021/acs.langmuir.1c01008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The interfacial properties of surfactant solutions are closely related to the micellization of surfactants. Temperature, salt type and concentration, pH, and other parameters affecting the micellization of surfactants have all been extensively investigated previously. However, the effect of dissolved gas on surfactant micellization and associated interfacial properties' transformations is not completely understood yet. In this study, sodium oleate (NaOl) was chosen as the research object, and the role of gas/gas nucleation in NaOl micellization was systematically investigated. The results indicated that the solution changed to be more turbid and the dissolved oxygen content increased after NaOl solutions were subjected to compression-decompression treatments. Meanwhile, the surface tension of the NaOl solution was altered, which was more pronounced when the concentration of NaOl was close to the critical micelle concentration. Given that the surface tension was a good indicator of the assembly and distribution state of the soluble monomers and insoluble micelles of NaOl, interactions between nucleated bubbles originating from the gas nucleation and NaOl molecules were unveiled through the analysis of the size distribution and zeta potential of sub-micro- and nanoscale particles in bulk solutions. Finally, possible micellization models of NaOl molecules, fully considering the role of gas/gas nucleation, were proposed under varying NaOl concentration conditions.
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Affiliation(s)
- Shaoqi Zhou
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
| | - Weiguang Zhou
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
| | - Lisha Dong
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Yaoli Peng
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
| | - Guangyuan Xie
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
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6
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Karakashev SI, Firouzi M, Wang J, Alexandrova L, Nguyen AV. On the stability of thin films of pure water. Adv Colloid Interface Sci 2019; 268:82-90. [PMID: 30954719 DOI: 10.1016/j.cis.2019.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 03/08/2019] [Indexed: 11/30/2022]
Abstract
The stability of water films has been the focus of many researchers in the recent decades. Unfortunately, there is no consensus on the stability of these foam films or on the mechanisms responsible for stabilizing water films. This paper examines the reported results on this matter and scrutinizes them based on speciation analysis of the dissolved species and the recent achievements in the adsorption of inorganic ions on the air/water interface. Our results confirm the key role of surface contamination, interface approach velocity and evaporation in the drainage and lifetime of these water films. It confirms the stabilizing effect of contamination and the destabilizing effect of air-water interface approach velocity. Moreover, the negative sign of the surface/zeta potential of the air/water interface and its dependence on the pH value were explained.
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7
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The effect of dissolved gas on coalescence of oil drops studied with microfluidics. J Colloid Interface Sci 2018; 528:166-173. [DOI: 10.1016/j.jcis.2018.05.083] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/22/2018] [Accepted: 05/22/2018] [Indexed: 11/18/2022]
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8
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Haidar I, Harding IH, Bowater IC, Eldridge DS, Charman WN. The role of lecithin degradation on the pH dependent stability of halofantrine encapsulated fat nano-emulsions. Int J Pharm 2017; 528:524-535. [DOI: 10.1016/j.ijpharm.2017.06.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 06/06/2017] [Accepted: 06/12/2017] [Indexed: 11/24/2022]
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9
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Surface forces: Changing concepts and complexity with dissolved gas, bubbles, salt and heat. Curr Opin Colloid Interface Sci 2017. [DOI: 10.1016/j.cocis.2016.09.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Zhou W, Chen H, Ou L, Shi Q. Aggregation of ultra-fine scheelite particles induced by hydrodynamic cavitation. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.minpro.2016.11.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Lo Nostro P, Ninham BW. Editorial: Electrolytes and specific ion effects. New and old horizons. Curr Opin Colloid Interface Sci 2016. [DOI: 10.1016/j.cocis.2016.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Salis A, Ninham BW. Models and mechanisms of Hofmeister effects in electrolyte solutions, and colloid and protein systems revisited. Chem Soc Rev 2014; 43:7358-77. [PMID: 25099516 DOI: 10.1039/c4cs00144c] [Citation(s) in RCA: 382] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Specific effects of electrolytes have posed a challenge since the 1880's. The pioneering work was that of Franz Hofmeister who studied specific salt induced protein precipitation. These effects are the rule rather the exception and are ubiquitous in chemistry and biology. Conventional electrostatic theories (Debye-Hückel, DLVO, etc.) cannot explain such effects. Over the past decades it has been recognised that additional quantum mechanical dispersion forces with associated hydration effects acting on ions are missing from theory. In parallel Collins has proposed a phenomenological set of rules (the law of matching water affinities, LMWA) which explain and bring to order the order of ion-ion and ion-surface site interactions at a qualitative level. The two approaches appear to conflict. Although the need for inclusion of quantum dispersion forces in one form or another is not questioned, the modelling has often been misleading and inappropriate. It does not properly describe the chemical nature (kosmotropic/chaotropic or hard/soft) of the interacting species. The success of the LMWA rules lies in the fact that they do. Here we point to the way that the two apparently opposing approaches might be reconciled. Notwithstanding, there are more challenges, which deal with the effect of dissolved gas and its connection to 'hydrophobic' interactions, the problem of water at different temperatures and 'water structure' in the presence of solutes. They take us to another dimension that requires the rebuilding of theoretical foundations.
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Affiliation(s)
- Andrea Salis
- Department of Chemical and Geological Science, University of Cagliari, Italy and CSGI.
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13
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Nanoemulsion stability: experimental evaluation of the flocculation rate from turbidity measurements. Adv Colloid Interface Sci 2012; 178:1-20. [PMID: 22657245 DOI: 10.1016/j.cis.2012.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/14/2012] [Accepted: 05/01/2012] [Indexed: 11/20/2022]
Abstract
The coalescence of liquid drops induces a higher level of complexity compared to the classical studies about the aggregation of solid spheres. Yet, it is commonly believed that most findings on solid dispersions are directly applicable to liquid mixtures. Here, the state of the art in the evaluation of the flocculation rate of these two systems is reviewed. Special emphasis is made on the differences between suspensions and emulsions. In the case of suspensions, the stability ratio is commonly evaluated from the initial slope of the absorbance as a function of time under diffusive and reactive conditions. Puertas and de las Nieves (1997) developed a theoretical approach that allows the determination of the flocculation rate from the variation of the turbidity of a sample as a function of time. Here, suitable modifications of the experimental procedure and the referred theoretical approach are implemented in order to calculate the values of the stability ratio and the flocculation rate corresponding to a dodecane-in-water nanoemulsion stabilized with sodium dodecyl sulfate. Four analytical expressions of the turbidity are tested, basically differing in the optical cross section of the aggregates formed. The first two models consider the processes of: a) aggregation (as described by Smoluchowski) and b) the instantaneous coalescence upon flocculation. The other two models account for the simultaneous occurrence of flocculation and coalescence. The latter reproduce the temporal variation of the turbidity in all cases studied (380≤[NaCl]≤600 mM), providing a method of appraisal of the flocculation rate in nanoemulsions.
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14
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Preparation of O/W Pickering emulsion with oxygen plasma treated carbon nanotubes as surfactants. J IND ENG CHEM 2011. [DOI: 10.1016/j.jiec.2010.10.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Layfield JP, Troya D. Molecular Simulations of the Structure and Dynamics of Water Confined between Alkanethiol Self-Assembled Monolayer Plates. J Phys Chem B 2011; 115:4662-70. [DOI: 10.1021/jp1120178] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Joshua P. Layfield
- Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, Virginia 24061-0212, United States
| | - Diego Troya
- Department of Chemistry, Virginia Tech, 107 Davidson Hall, Blacksburg, Virginia 24061-0212, United States
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16
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Bunkin NF, Ninham BW, Babenko VA, Suyazov NV, Sychev AA. Role of dissolved gas in optical breakdown of water: differences between effects due to helium and other gases. J Phys Chem B 2010; 114:7743-52. [PMID: 20496876 DOI: 10.1021/jp101657f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is shown that water contains defects in the form of heterogeneous optical breakdown centers. Long-living complexes composed of gas and liquid molecules may serve as nuclei for such centers. A new technique for removing dissolved gas from water is developed. It is based on a "helium washing" routine. The structure of helium-washed water is very different from that of water containing dissolved atmospheric gas. It is able to withstand higher optical intensities and temperatures of superheating compared with the nonprocessed ones. The characteristics of plasma spark and values of the breakdown thresholds for processed and nonprocessed samples are given.
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Affiliation(s)
- N F Bunkin
- A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, ul. Vavilova, 38, 119991, Moscow, Russia.
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17
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Francis M, Boyson T, Pashley R. Oil droplet size manipulation applied to surfactant-free emulsion polymerization. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2008.06.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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The hydrophobicity of non-aqueous liquids and their dispersion in water under degassed conditions. Curr Opin Colloid Interface Sci 2008. [DOI: 10.1016/j.cocis.2007.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Trompette J, Vergnes H, Coufort C. Enhanced electrocoagulation efficiency of lyophobic colloids in the presence of ammonium electrolytes. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Lo Nostro P, Giustini L, Fratini E, Ninham BW, Ridi F, Baglioni P. Threading, Growth, and Aggregation of Pseudopolyrotaxanes. J Phys Chem B 2008; 112:1071-81. [DOI: 10.1021/jp075380q] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pierandrea Lo Nostro
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Luca Giustini
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Emiliano Fratini
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Barry W. Ninham
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Francesca Ridi
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
| | - Piero Baglioni
- Department of Chemistry and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy, and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australia 0200
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21
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Eastoe J, Ellis C. De-gassed water and surfactant-free emulsions: history, controversy, and possible applications. Adv Colloid Interface Sci 2007; 134-135:89-95. [PMID: 17531182 DOI: 10.1016/j.cis.2007.04.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recent reports claiming stabilisation of surfactant-free oil-in-water emulsions (o/w SFEM's) have intrigued the colloid science community, and been reported in both the scientific literature and popular press. Key to the formation of SFEM's is a sequence of solidification by freeze quenching, degassing by action of vacuum, then thawing, known as freeze-pump-thaw (F-P-T). It is believed that the "emulsification" is caused by a reduction of hydrophobic interactions owing removal of dissolved gas after these F-P-T cycles. This review summarises literature on SFEM's, covering experiments, proposed mechanisms, and some potentially exciting applications.
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Affiliation(s)
- Julian Eastoe
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
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Murgia S, Portesani F, Ninham BW, Monduzzi M. Interaction of Sodium Ions with Cationic Surfactant Interfaces. Chemistry 2006; 12:7889-98. [PMID: 16847988 DOI: 10.1002/chem.200600080] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The thermodynamically stable microemulsion and lamellar phases in the didodecyldimethylammonium bromide/water/n-decane ternary system were explored in the presence of NaBr to gain information on sodium ion-interface interactions. Experimental results, obtained by different NMR techniques, strongly suggest accumulation of sodium ions at the cationic interface. This apparently counterintuitive result is explained by invoking the dispersion potential experienced by the ions near the interface. A mechanism is proposed that can account for the dramatic shrinkage of the microemulsion phase region when an electrolyte is added.
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Affiliation(s)
- Sergio Murgia
- Dipartimento di Scienze Chimiche, Università di Cagliari - CSGI Cittadella Monserrato, S.S. 554 Bivio Sestu, 09042 Monserrato, Italy
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24
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Meyer EE, Rosenberg KJ, Israelachvili J. Recent progress in understanding hydrophobic interactions. Proc Natl Acad Sci U S A 2006; 103:15739-46. [PMID: 17023540 PMCID: PMC1635073 DOI: 10.1073/pnas.0606422103] [Citation(s) in RCA: 572] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present here a brief review of direct force measurements between hydrophobic surfaces in aqueous solutions. For almost 70 years, researchers have attempted to understand the hydrophobic effect (the low solubility of hydrophobic solutes in water) and the hydrophobic interaction or force (the unusually strong attraction of hydrophobic surfaces and groups in water). After many years of research into how hydrophobic interactions affect the thermodynamic properties of processes such as micelle formation (self-assembly) and protein folding, the results of direct force measurements between macroscopic surfaces began to appear in the 1980s. Reported ranges of the attraction between variously prepared hydrophobic surfaces in water grew from the initially reported value of 80-100 Angstrom to values as large as 3,000 Angstrom. Recent improved surface preparation techniques and the combination of surface force apparatus measurements with atomic force microscopy imaging have made it possible to explain the long-range part of this interaction (at separations >200 Angstrom) that is observed between certain surfaces. We tentatively conclude that only the short-range part of the attraction (<100 Angstrom) represents the true hydrophobic interaction, although a quantitative explanation for this interaction will require additional research. Although our force-measuring technique did not allow collection of reliable data at separations <10 Angstrom, it is clear that some stronger force must act in this regime if the measured interaction energy curve is to extrapolate to the measured adhesion energy as the surface separation approaches zero (i.e., as the surfaces come into molecular contact).
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Affiliation(s)
| | | | - Jacob Israelachvili
- Chemical Engineering, University of California, Santa Barbara, CA 93106
- To whom correspondence should be addressed. E-mail:
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25
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26
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Hartmann J, Urbani C, Whittaker MR, Monteiro MJ. Effect of Degassing on Surfactant-Free Emulsion Polymerizations of Styrene Mediated with RAFT. Macromolecules 2006. [DOI: 10.1021/ma052295c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julia Hartmann
- Australian Institute of Bioengineering and Nanotechnology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Carl Urbani
- Australian Institute of Bioengineering and Nanotechnology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Michael R. Whittaker
- Australian Institute of Bioengineering and Nanotechnology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia
| | - Michael J. Monteiro
- Australian Institute of Bioengineering and Nanotechnology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia
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27
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Vallée P, Lafait J, Mentré P, Monod MO, Thomas Y. Effects of pulsed low frequency electromagnetic fields on water using photoluminescence spectroscopy: Role of bubble/water interface. J Chem Phys 2005; 122:114513. [PMID: 15836235 DOI: 10.1063/1.1860553] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effects of a pulsed low frequency electromagnetic field were investigated on photoluminescence of well characterized water and prepared under controlled conditions (container, atmospheric, electromagnetic, and acoustic environments). When reference water samples were excited at 260 nm, two wide emission bands centered at 345 nm (3.6 eV) and 425 nm (2.9 eV) were observed. By contrast under 310 nm excitation, only one band appeared at 425 nm. Interestingly, electromagnetic treatment (EMT) induced, at both excitation wavelengths, a decrease (around 70%) in the 425 nm band relative photoluminescence intensity. However, no difference between reference and treated sample was observed in the 345 nm band. Other experiments, performed on outgassed samples (reference and treated), show that the emission bands (position, shape, intensity) under excitation at 260 nm and 310 nm were similar and close to the corresponding bands of the treated nonoutgassed samples. Similar effects were observed on photoluminescence excitation of water samples. Two excitation bands monitored at 425 nm were observed at 272 nm and 330 nm. After EMT and/or outgassing, a decrease (>60%) was observed in the intensity of these two bands. Altogether, these results indicate that electromagnetic treatment and/or outgassing decrease in a similar fashion the photoluminescence intensity in water samples. They also suggest that this effect is most likely indirectly attributed to the presence of gas bubbles in water. The possible role of hydrated ionic shell around the bubbles in the observed extraluminescence is discussed.
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Affiliation(s)
- Philippe Vallée
- Laboratoire d'Optique des Solides (UMR CNRS 7601), Université Pierre et Marie Curie, Paris, France.
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28
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Kozempel S, Tauer K, Rother G. Aqueous heterophase polymerization of styrene—a study by means of multi-angle laser light scattering. POLYMER 2005. [DOI: 10.1016/j.polymer.2004.11.060] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Meyer EE, Lin Q, Israelachvili JN. Effects of dissolved gas on the hydrophobic attraction between surfactant-coated surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:256-259. [PMID: 15620311 DOI: 10.1021/la048318i] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effect of dissolved gas on the hydrophobic attraction between double-chained surfactant monolayers physisorbed on mica has been studied using a surface forces apparatus (SFA). Distance vs time data were obtained over the full distance regime from D approximately 1000 A down to contact using the dynamic SFA method. Removal of dissolved gas was seen to reduce the range of the attraction while the short-range attraction (under approximately 250 A) remained unchanged. The implications for the possibility of two distinct force regimes in the interactions between hydrophobic surfaces are discussed.
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Affiliation(s)
- Emily E Meyer
- Departments of Physics and Chemical Engineering, University of California at Santa Barbara, CA 93106, USA
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30
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Lin Q, Meyer EE, Tadmor M, Israelachvili JN, Kuhl TL. Measurement of the long- and short-range hydrophobic attraction between surfactant-coated surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:251-255. [PMID: 15620310 DOI: 10.1021/la048317q] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have measured the attractive long-range 'hydrophobic' forces in water between double-chained surfactant monolayers physisorbed on mica. We used both normal and high-speed video cameras to follow the dynamics and possible rate-dependence of force-distance profiles in the distance regime from 1000 A to adhesive contact, including the short-distance regime below 100 A-the regime of greatest biological interest. We find that the hydrophobic interaction follows a double-exponential function down to separations of approximately 50 A, after which point the attractive force appears to become considerably stronger.
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Affiliation(s)
- Qi Lin
- Department of Chemical Engineering, University of California at Santa Barbara, CA 93106, USA
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31
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Pashley RM, Rzechowicz M, Pashley LR, Francis MJ. De-Gassed Water Is a Better Cleaning Agent. J Phys Chem B 2004; 109:1231-8. [PMID: 16851085 DOI: 10.1021/jp045975a] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is demonstrated that de-gassed water is more effective at dispersing hydrophobic "dirt", such as liquid hydrocarbons or oils. This effect appears to be due to the reduction of natural cavitation, which would otherwise oppose the dispersion of hydrophobic liquid droplets into water. De-gassing of the oil enhances this effect still further, and this has led to a proposal for a novel cleaning process, based on using a combination of a de-gassed (hydrophobic) solvent followed by rinsing in de-gassed water. This method might be useful as an effective, detergent-free cleaning process. Also reported are some initial studies which suggest that the effect of "inert" dissolved gases on the electrical conductivity of water may need to be reconsidered.
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Affiliation(s)
- R M Pashley
- Department of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
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Maeda N, Rosenberg KJ, Israelachvili JN, Pashley RM. Further studies on the effect of degassing on the dispersion and stability of surfactant-free emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:3129-37. [PMID: 15875839 DOI: 10.1021/la036028g] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Recently reported results indicate that the formation of surfactant-free, oil-in-water emulsions can be significantly enhanced by the almost complete removal of dissolved gases and that the reintroduction of dissolved gases does not immediately destabilize the already-formed emulsions. These initial experiments have been repeated and extended to include a wider range of organic liquids and the application of light scattering to determine droplet size and distribution. The earlier observations have been confirmed. In addition, a systematic trend was found between the solubility of the oil in water and the stability (lifetime) of the degassed oil droplets in water. The lower the solubility, the more stable the emulsion, and for oils that are sparingly soluble in water such as squalane, the small droplets remain stable for several weeks, with buoyancy separation being the main cause of instability of the large droplets with time. The addition of electrolytes, up to molar concentrations, substantially reduces the enhancement of the dispersions on degassing but appears to have little effect on the stability of the already-formed emulsions. The reduction of pH to about 2 significantly reduces both the enhancement of the dispersions on degassing and the stability of the already-formed emulsions. In contrast, the increase of pH to about 11 hardly affects the enhancement of the dispersions on degassing or the stability of the already-formed emulsions. We have confirmed the importance of dissolved gas and its association with the electrostatic effects, but we still cannot provide a complete explanation for the effect of degassing on the hydrophobic dispersions.
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Affiliation(s)
- Nobuo Maeda
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
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34
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Wennerström H. Influence of Dissolved Gas on the Interaction between Hydrophobic Surfaces in Water. J Phys Chem B 2003. [DOI: 10.1021/jp030927w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Håkan Wennerström
- Division of Physical Chemistry 1, The Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
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35
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Maeda N, Israelachvili JN, Kohonen MM. Evaporation and instabilities of microscopic capillary bridges. Proc Natl Acad Sci U S A 2003; 100:803-8. [PMID: 12538868 PMCID: PMC298682 DOI: 10.1073/pnas.0234283100] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The formation and disappearance of liquid bridges between two surfaces can occur either through equilibrium or nonequilibrium processes. In the first instance, the bridge molecules are in thermodynamic equilibrium with the surrounding vapor medium. In the second, chemical potential gradients result in material transfer; mechanical instabilities, because of van der Waals force jumps on approach or a Rayleigh instability on rapid separation, may trigger irreversible film coalescence or bridge snapping. We have studied the growth and disappearance mechanisms of laterally microscopic liquid bridges of three hydrocarbon liquids in slit-like pores. At rapid slit-opening rates, the bridges rupture by means of a mechanical instability described by the Young-Laplace equation. Noncontinuum but apparently reversible behavior is observed when a bridge is held at nanoscopic surface separations H close to the thermodynamic equilibrium Kelvin length, 2r(K)costheta, where r(K) is the Kelvin radius and theta is the contact angle. During the course of slow evaporation (at H > 2r(K)costheta) and subsequent regrowth by capillary condensation (at H < 2r(K)costheta), the refractive index of the bridge may vary continuously and reversibly between that of the bulk liquid and vapor. The evaporation process becomes irreversible only at the very final stage of evaporation, when the refractive index of the fluid attains virtually that of the vapor. Measured refractive index profiles and the time-dependence of evaporating neck diameters also seem to differ from predictions based on a continuum picture of bridge evaporation far from the critical point. We discuss these findings in terms of the probable density profiles in evolving liquid bridges.
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Affiliation(s)
- Nobuo Maeda
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA.
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36
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Pashley RM. Effect of Degassing on the Formation and Stability of Surfactant-Free Emulsions and Fine Teflon Dispersions. J Phys Chem B 2003. [DOI: 10.1021/jp026744b] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. M. Pashley
- Department of Chemical Engineering, University of California, Santa Barbara, California, California 93106
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Li M, Rharbi Y, Winnik MA, Hahn KG. Aggregation Behavior of Nonionic Surfactants Synperonic A7 and A50 in Aqueous Solution. J Colloid Interface Sci 2001; 240:284-293. [PMID: 11446812 DOI: 10.1006/jcis.2001.7625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aggregation behavior of Synperonic A7 and A50, fatty alcohol ethoxylate nonionic surfactants (C(m)E(n)) with mean polyoxyethylene chain lengths of 7 and 50, respectively, was investigated in aqueous solution by means of surface tension, laser light scattering, steady-state fluorescence, and fluorescence quenching experiments. Surface tension measurements at room temperature indicate that the critical micelle concentration of A7 is 0.1 g/L (0.22 mM) and that of A50 is 0.17 g/L (0.07 mM). Static light scattering measurements reveal that the averaged aggregation number of A7 in water is 417 and that of A50 is 23. When solutions of A7 were allowed to age over a period of months at room temperature, the micelle M(w) and hydrodynamic radius increased. The aggregation numbers found from fluorescence quenching measurements, using excimer formation from 1-ethylpyrene as a probe, were about 300 for freshly prepared solutions of A7 and about 40 for A50. We also found that the presence of air has a strong effect on the data obtained from the fluorescence quenching measurements. Copyright 2001 Academic Press.
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Affiliation(s)
- Mei Li
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
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38
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Karaman M, Antelmi D, Pashley R. The production of stable hydrophobic surfaces by the adsorption of hydrocarbon and fluorocarbon carboxylic acids onto alumina substrates. Colloids Surf A Physicochem Eng Asp 2001. [DOI: 10.1016/s0927-7757(00)00821-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Miller J, Hu Y, Veeramasuneni S, Lu Y. In-situ detection of butane gas at a hydrophobic silicon surface. Colloids Surf A Physicochem Eng Asp 1999. [DOI: 10.1016/s0927-7757(98)00891-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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40
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Sierra ML, Zana R. Study of the Effect of Solubilized Gases on the Properties of Microemulsion Droplets. J Colloid Interface Sci 1999; 212:162-166. [PMID: 10072286 DOI: 10.1006/jcis.1998.6028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of dissolved gas (nitrogen, argon) on the properties of the droplets in water-in-oil and oil-in-water microemulsions (surfactant aggregation number, microviscosity, and micropolarity) has been investigated by means of time-resolved fluorescence quenching and spectrofluorometry. This study extends a similar one on aqueous micellar solutions (R. G. Alargova et al., Langmuir 14, 1575, 1998). The selected microemulsions were characterized by droplets of fairly large size and high volume fraction, in order to minimize the effect of the curvature of the surfactant layer and maximize the amount of gas that can be solubilized in the system. Within the experimental error, the investigated properties (surfactant aggregation number, intradroplet quenching rate constant which is related to the droplet microviscosity, and fluorescent probe lifetime and micropolarity) were found to be independent on whether the system was degassed, nitrogen-saturated, or argon-saturated, in the temperature range between 10 and 35 degrees C. The results confirm the conclusion reached in the above study; i.e., the effect of solubilized gases on the hydrophobic interaction which controls the formation of surfactant assemblies is extremely small and well below the sensitivity of the fluorescence probing techniques used in this investigation. Copyright 1999 Academic Press.
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Affiliation(s)
- ML Sierra
- Institut Charles Sadron, 6 Rue Boussingault, Strasbourg, 67000, France
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41
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Deschenes LA, Barrett J, Muller LJ, Fourkas JT, Mohanty U. Inhibition of Bubble Coalescence in Aqueous Solutions. 1. Electrolytes. J Phys Chem B 1998. [DOI: 10.1021/jp980828w] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laura A. Deschenes
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167
| | - Justin Barrett
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167
| | - Laura J. Muller
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167
| | - John T. Fourkas
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167
| | - Udayan Mohanty
- Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167
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42
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Effects of Amplitude of the Radiofrequency Electromagnetic Radiation on Aqueous Suspensions and Solutions. J Colloid Interface Sci 1998. [DOI: 10.1006/jcis.1997.5367] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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43
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Ninham B, Kurihara K, Vinogradova O. Hydrophobicity, specific ion adsorption and reactivity. Colloids Surf A Physicochem Eng Asp 1997. [DOI: 10.1016/s0927-7757(96)03794-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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