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Grisolia A, De Santo M, Curcio M, Cavallaro PA, Morelli C, Leggio A, Pasqua L. Engineered Mesoporous Silica-Based Nanoparticles: Characterization of Surface Properties. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3352. [PMID: 38998432 PMCID: PMC11243720 DOI: 10.3390/ma17133352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 06/25/2024] [Accepted: 06/27/2024] [Indexed: 07/14/2024]
Abstract
Mesoporous silica-based nanomaterials have emerged as multifunctional platforms with applications spanning catalysis, medicine, and nanotechnology. Since their synthesis in the early 1990s, these materials have attracted considerable interest due to their unique properties, including high surface area, tunable pore size, and customizable surface chemistry. This article explores the surface properties of a series of MSU-type mesoporous silica nanoparticles, elucidating the impact of different functionalization strategies on surface characteristics. Through an extensive characterization utilizing various techniques, such as FTIR, Z-potential, and nitrogen adsorption porosimetry, insights into the surface modifications of mesoporous silica nanoparticles are provided, contributing to a deeper understanding of their nanostructure and related interactions, and paving the way to possible unexpected actionability and potential applications.
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Affiliation(s)
- Antonio Grisolia
- Department of Environmental Engineering, University of Calabria, Via P. Bucci, 87036 Arcavacata di Rende, CS, Italy
| | - Marzia De Santo
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Manuela Curcio
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Palmira Alessia Cavallaro
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Catia Morelli
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Antonella Leggio
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Arcavacata di Rende, CS, Italy
| | - Luigi Pasqua
- Department of Environmental Engineering, University of Calabria, Via P. Bucci, 87036 Arcavacata di Rende, CS, Italy
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2
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Kim J, Wang Z, Lahlil K, Davidson P, Gacoin T, Kim J. Charge-driven liquid-crystalline behavior of ligand-functionalized nanorods in apolar solvent. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:86. [PMID: 37747573 DOI: 10.1140/epje/s10189-023-00345-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 09/05/2023] [Indexed: 09/26/2023]
Abstract
Concentrated colloidal suspensions of nanorods often exhibit liquid-crystalline (LC) behavior. The transition to a nematic LC phase, with long-range orientational order of the particles, is usually well-captured by Onsager's theory for hard rods, at least qualitatively. The theory shows how the volume fraction at the transition decreases with increasing aspect ratio of the rods. It also explains that the long-range electrostatic repulsive interaction occurring between rods stabilized by their surface charge can significantly increase their effective diameter, resulting in a decrease in the volume fraction at the transition, as compared to sterically stabilized rods. Here, we report on a system of ligand-stabilized LaPO4 nanorods, of aspect ratio ≈ 11, dispersed in apolar medium exhibiting the counter-intuitive observation that the onset of nematic self-assembly occurs at an extremely low volume fraction of ≈ 0.25%, which is lower than observed (≈ 3%) with the same particles when charged-stabilized in polar solvent. Furthermore, the nanorod volume fraction at the transition increases with increasing concentration of ligands, in a similar way as in polar media where increasing the ionic strength leads to surface charge screening. This peculiar system was investigated by dynamic light scattering, Fourier-transform infrared spectroscopy, zetametry, electron microscopy, polarized light microscopy, photoluminescence measurements, and X-ray scattering. Based on these experimental data, we formulate several tentative scenarios that might explain this unexpected phase behavior. However, at this stage, its full understanding remains a pending theoretical challenge. Nevertheless, this study shows that dispersing anisotropic nanoparticles in an apolar solvent may sometimes lead to spontaneous ordering events that defy our intuitive ideas about colloidal systems.
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Affiliation(s)
- Jeongmo Kim
- Laboratoire de Physique de la Matière Condensée, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Zijun Wang
- Laboratoire de Physique de la Matière Condensée, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Khalid Lahlil
- Laboratoire de Physique de la Matière Condensée, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Patrick Davidson
- Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, 91405, Orsay Cedex, France.
| | - Thierry Gacoin
- Laboratoire de Physique de la Matière Condensée, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France.
| | - Jongwook Kim
- Laboratoire de Physique de la Matière Condensée, CNRS, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France.
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3
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Peng C, Zhang R, Chen H, Liu Y, Zhang S, Fang T, Guo R, Zhang J, Shan Q, Jin Y, Wang L, Hou L, Zeng H. A Demulsification-Crystallization Model for High-Quality Perovskite Nanocrystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2206969. [PMID: 36303520 DOI: 10.1002/adma.202206969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/19/2022] [Indexed: 06/16/2023]
Abstract
A room-temperature technique with all-nonpolar-solvent, which circumvents the sensitivity of ionic perovskite to polar solvent, has become attractive for the synthesis of metal halide perovskite nanocrystals (PNCs). However, the lack of understanding of the inner mechanism, especially for the state of the precursor and the crystallization process of the PNCs, hinders further development of this technique. Here, through systematic study of the Pb precursor and in situ characterization of the PNCs, it is revealed that the reverse micelle nature of the Pb precursor exactly creates a novel demulsification-crystallization (D-C) model, namely, a two-stage nucleation is divided by a demulsification process for the PNCs. On this basis, a top efficiency for green light-emitting diodes based on PNCs is obtained with a maximum external quantum efficiency of 22.5% through tailoring the D-C model using a multiple-acid-anion synergistic assisted strategy to obtain high-quality PNCs. Beyond the high efficiency, the work paves the way for diverse ideas in PNC synthesis.
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Affiliation(s)
- Chencheng Peng
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Rui Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Hongting Chen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
| | - Yang Liu
- Centre for Chemistry of High-Performance & Novel Materials, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Shuai Zhang
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
| | - Tao Fang
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
| | - Runda Guo
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Jibin Zhang
- Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China
| | - Qingsong Shan
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
| | - Yizheng Jin
- Centre for Chemistry of High-Performance & Novel Materials, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027, P. R. China
| | - Lei Wang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Lintao Hou
- Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials, Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632, P. R. China
| | - Haibo Zeng
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
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Sergeevich Popovetskiy P, Victorovich Kasyanov A, Anatolievich Maximovskiy E, Eugenievich Plyusnin P. Electrophoretic mobility of silver nanoparticles stabilized with nonionic surfactant Ecosurf SA4: origin of charged particles, concentration by electrophoresis and production of conductive coatings. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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5
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Kim J, Jeong J, Hyun Y, Chung SK, Lee J. Electrostatic Stabilization of Nano Liquid Metals in Doped Nonpolar Liquids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2104143. [PMID: 34623028 DOI: 10.1002/smll.202104143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Liquid metals and alloys are attracting renewed attention owing to their potential for application in various advanced technologies. Eutectic gallium-indium (EGaIn) has been focused on in particular because of its integrated advantages of high conductivity, low melting point, and low toxicity. In this study, the colloidal behavior of nano-dispersed EGaIn in nonpolar oils is investigated. Although the nonpolar oil continuous phase is commonly considered to be free of electric charges, electrostatic repulsion appears to be crucial in the colloidal stabilization of the nano-dispersed EGaIn phases, the modulation of which is possible by doping the oil phases with different types of oil-soluble surfactants. The qualitative correlation between the observed colloidal stabilities and the "zero field" particle mobilities inferred from the field-dependent electrophoretic mobilities indicates that the electric charging of EGaIn particles in surfactant-doped nonpolar oils is a static phenomenon that is maintained in equilibrium, rather than a solely field-induced process. A systematic investigation of the charging properties of these unique biphasic particles, consisting of the liquid Ga-In bulk and the solid Ga2 O3 surface that formed spontaneously, reveals the complicated system-dependent nature of the charging mechanisms mediated by ionic and nonionic surfactants in nonpolar media.
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Affiliation(s)
- Jieun Kim
- Department of Chemical Engineering, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, 17058, Korea
| | - Jinwon Jeong
- Department of Mechanical Engineering, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, 17058, Korea
| | - Youngbin Hyun
- Department of Mechanical Engineering, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, 17058, Korea
| | - Sang Kug Chung
- Department of Mechanical Engineering, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, 17058, Korea
| | - Joohyung Lee
- Department of Chemical Engineering, Myongji University, 116 Myongji-ro, Cheoin-gu, Yongin, Gyeonggi-do, 17058, Korea
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6
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Popovetskiy PS, Kolodin AN, Maximovskiy EA, Plyusnin PE, Korolkov IV, Gerasimov EY. Electrophoretic concentration and production of conductive coatings from silver nanoparticles stabilized with non-ionic surfactant Span 80. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126961] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Shaparenko NO, Demidova MG, Bulavchenko AI. Electrophoretic mobility and stability of SiO 2 nanoparticles in the solutions of AOT in n-hexadecane-chloroform mixtures. Electrophoresis 2021; 42:1648-1654. [PMID: 34213016 DOI: 10.1002/elps.202100060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 05/24/2021] [Accepted: 06/10/2021] [Indexed: 11/11/2022]
Abstract
Electrophoretic mobility of SiO2 nanoparticles in a n-hexadecane-chloroform mixture depending on AOT concentration and chloroform content was determined. It was shown that an increase in chloroform content and a decrease in AOT concentration cause a growth in electrophoretic mobility. The use of the values of Debye lengths (characteristic thickness) of the diffuse part of the electric double layer (EDL) that were determined previously allowed us to calculate the electrokinetic potential and to evaluate the stability of organosols. The obtained data were in good correlation with the dynamics of temporal changes of hydrodynamic radius and the intensity of light scattering. Organosols may be used for heteroaggregation (sorption) of Au and Ag nanoparticles on SiO2 .
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Affiliation(s)
| | - Marina G Demidova
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russia
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8
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Prieve DC, Yezer BA, Xu K, Khair AS, Schneider JW, Sides PJ. Determination of the zeta potential of planar solids in nonpolar liquids. J Colloid Interface Sci 2021; 592:271-278. [PMID: 33662831 DOI: 10.1016/j.jcis.2021.02.044] [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: 12/30/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 10/22/2022]
Abstract
ZetaSpin determines zeta potential by measuring the streaming potential generated by rotating a disk-shaped sample about its axis while submerged in the liquid. The apparatus and procedure developed for ZetaSpin in aqueous solutions was adapted for use in highly nonpolar fluids like surfactant-doped alkanes. Perhaps most unexpected is the need for up to 10 min (instead of a fraction of one second for aqueous solutions) for the electrometer to display changes in streaming potential in response to changes in rotation speed. Four tests (suggested by theory) confirm that the potential finally reported by the electrometer was indeed the streaming potential. Compared to electrophoresis, ZetaSpin does not require a value for the Debye length, avoids the complication caused by the electric-field-dependence of electrophoretic mobility and can be used with planar samples as well as colloidal particles.
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Affiliation(s)
- Dennis C Prieve
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States.
| | - Benjamin A Yezer
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States
| | - Keyi Xu
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States
| | - Aditya S Khair
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States
| | - James W Schneider
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States
| | - Paul J Sides
- Center for Complex Fluids Engineering and Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213, United States
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9
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The Effects of Ethanol Concentration and of Ionic Strength on the Zeta Potential of Titania in the Presence of Sodium Octadecyl Sulfate. COLLOIDS AND INTERFACES 2020. [DOI: 10.3390/colloids4040049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Sodium octadecyl sulfate (C18H37SO4Na) induces a negative zeta potential of metal oxides at very low surfactant concentrations as compared with shorter-chained sodium alkyl sulfates. The problem of low solubility of sodium octadecyl sulfate in water was solved by the addition of the surfactant to dispersions as ethanolic stock solution, but then the presence of ethanol in dispersions was inevitable. We demonstrate that the concentration of ethanol (up to 5% by mass) in a dispersion containing titania (TiO2) and sodium octadecyl sulfate has an insignificant effect on the zeta potential of particles. We further demonstrate that the shifts in the IEP of titania induced by the presence of sodium octadecyl sulfate are independent of the NaCl concentration. The results obtained in this study can be generalized for 1-1 salts other than NaCl, for metal oxides other than titania, for organic co-solvents other than ethanol, and for sparingly soluble ionic surfactants other than sodium octadecyl sulfate.
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10
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Is the combination of two particles with different degrees of hydrophobicity an alternative method for tuning the average particle hydrophobicity? J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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11
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Khademi M, Cheng SSY, Barz DPJ. Charge and Electrical Double Layer Formation in a Nonpolar Solvent Using a Nonionic Surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5156-5164. [PMID: 32326706 DOI: 10.1021/acs.langmuir.0c00311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, we study the charge formation and the characteristics of the electrical double layer in a nonpolar medium using electrical impedance spectroscopy. To stabilize the free ionic species, a nonionic surfactant is added to the system. The conductivity and permittivity of the medium are obtained from high- to medium-frequency impedance data. Based on the correlation between (viscosity-adjusted) conductivity and surfactant concentration, we conclude that charge formation occurs due to a disproportionation mechanism. We accordingly estimate the concentration of the charge carriers in the sample and the Debye length of the diffuse double layer. The capacitance of the electrical double layer can be extracted from the low-frequency impedance data. We use this data to calculate the electrode distance of an equivalent parallel-plate capacitor. It is found that this distance is on the order of magnitude of Angstroms, indicating that the measured electrical double-layer capacitance is in fact the Stern layer capacitance.
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Affiliation(s)
- Mahmoud Khademi
- Department of Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Sammi Sham Yin Cheng
- Department of Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Dominik P J Barz
- Department of Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
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12
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Sengupta R, Khair AS, Walker LM. Dynamic interfacial tension measurement under electric fields allows detection of charge carriers in nonpolar liquids. J Colloid Interface Sci 2020; 567:18-27. [DOI: 10.1016/j.jcis.2020.01.081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 11/28/2022]
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13
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Ponto BS, Berg JC. Nanoparticle charging with mixed reverse micelles in apolar media. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2019.124275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Li S, Jin C, Feng N, Deng F, Xiao L, Fan J. Regulation of acidic properties of WO3-ZrO2 for Friedel–Crafts reaction with surfactant. CATAL COMMUN 2019. [DOI: 10.1016/j.catcom.2019.01.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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15
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Farrokhbin M, Stojimirović B, Galli M, Khajeh Aminian M, Hallez Y, Trefalt G. Surfactant mediated particle aggregation in nonpolar solvents. Phys Chem Chem Phys 2019; 21:18866-18876. [DOI: 10.1039/c9cp01985e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aggregation behavior of particles in nonpolar media is studied with time-resolved light scattering.
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Affiliation(s)
- Mojtaba Farrokhbin
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | - Biljana Stojimirović
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | - Marco Galli
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
| | | | - Yannick Hallez
- Laboratoire de Génie Chimique
- Université de Toulouse
- CNRS
- INPT
- UPS
| | - Gregor Trefalt
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- Sciences II
- 1205 Geneva
- Switzerland
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16
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Dukhin A, Parlia S. Adsorption of surfactant from non-polar liquid into porous material characterized using conductivity measurement. J Colloid Interface Sci 2018; 531:523-532. [DOI: 10.1016/j.jcis.2018.07.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 11/16/2022]
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17
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Lee J. Charge carriers created by interaction of a nonionic surfactant with water in a nonpolar medium. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.06.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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18
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Abstract
Highly hydrophobic, water-insoluble nonionic surfactants are often considered irrelevant to the ionization of interfaces at which they adsorb, despite observations that suggest otherwise. In the present study, we provide unambiguous evidence for the participation of a water-insoluble surfactant in interfacial ionization by conducting electrophoresis experiments for surfactant-stabilized nonpolar oil droplets in aqueous continuous phase. It was found that the surfactant with amine headgroup positively charged the surface of oil suspended in aqueous continuous phase (oil/water interface), which is consistent with its basic nature. In nonpolar oil continuous phase, the same surfactant positively charged the surface of solid silica (solid/oil interface) which is often considered acidic. The latter observation is exactly opposite to what the traditional acid-base mechanism of surface charging would predict, most clearly suggesting the possibility for another charging mechanism.
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Affiliation(s)
- Joohyung Lee
- Department of Chemical Engineering , Myongji University , Yongin , Gyeonggi 17058 , Korea
| | - Zhang-Lin Zhou
- Hewlett-Packard Company , 16399 W Bernardo Drive , San Diego , California 92127 , United States
| | - Sven Holger Behrens
- School of Chemical & Biomolecular Engineering , Georgia Institute of Technology , 311 Ferst Drive NW , Atlanta , Georgia 30332 , United States
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Strubbe F, Neyts K. Charge transport by inverse micelles in non-polar media. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:453003. [PMID: 28895874 DOI: 10.1088/1361-648x/aa8bf6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Charged inverse micelles play an important role in the electrical charging and the electrodynamics of nonpolar colloidal dispersions relevant for applications such as electronic ink displays and liquid toner printing. This review examines the properties and the behavior of charged inverse micelles in microscale devices in the absence of colloidal particles. It is discussed how charge in nonpolar liquids is stabilized in inverse micelles and how conductivity depends on the inverse micelle size, water content and ionic impurities. Frequently used nonpolar surfactant systems are investigated with emphasis on aerosol-OT (AOT) and poly-isobutylene succinimide (PIBS) in dodecane. Charge generation in the bulk by disproportionation is studied from measurements of conductivity as a function of surfactant concentration and from generation currents in quasi steady-state. When a potential difference is applied, the steady-state situation can show electric field screening or complete charge separation. Different regimes of charge transport are identified when a voltage step is applied. It is shown how the transient and steady-state currents depend on the rate of bulk generation, on insulating layers and on the sticking or non-sticking behavior of charged inverse micelles at interfaces. For the cases of AOT and PIBS in dodecane, the magnitude of the generation rate and the type of interaction at the interface are very different.
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Affiliation(s)
- Filip Strubbe
- Electronics and Information Systems Department and Center for Nano and Biophotonics, Ghent University, Technologiepark Zwijnaarde 15, 9052 Zwijnaarde, Belgium
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20
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Prasad M, Strubbe F, Beunis F, Neyts K. Electrokinetics and behavior near the interface of colloidal particles in non-polar dispersions. SOFT MATTER 2017; 13:5604-5612. [PMID: 28737178 DOI: 10.1039/c7sm00559h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electrokinetics and charging of nonpolar colloidal dispersions subjected to a voltage are investigated by electric current and optical measurements. From electric current measurements in response to an alternating triangular voltage with a peak value of a few hundred volts, we find that polystyrene toner particles are compacted near the electrodes and their charge increases by more than a factor of 20. The important increase of charge is interpreted by a mechanism in which counter charges, which are originally at the particle surface, are desorbed. Optical measurements performed under a dc voltage of the order of a few hundred volts demonstrate that the charge of the particles can again decrease or even be inverted. These phenomena are attributed to the movement of counter charged species from the interface layers onto the surface of the particles. The findings of this study are relevant for electrophoretic displays and liquid toner printing.
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Affiliation(s)
- Manoj Prasad
- Electronics and Information Systems, Ghent University, Technologiepark Zwijnaarde 15, 9052 Gent, Belgium.
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21
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Bleier BJ, Yezer BA, Freireich BJ, Anna SL, Walker LM. Droplet-based characterization of surfactant efficacy in colloidal stabilization of carbon black in nonpolar solvents. J Colloid Interface Sci 2017; 493:265-274. [DOI: 10.1016/j.jcis.2017.01.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 10/20/2022]
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Gourdin-Bertin S, Chassagne C. Application of classical thermodynamics to the conductivity in non-polar media. J Chem Phys 2016; 144:244501. [DOI: 10.1063/1.4954046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. Gourdin-Bertin
- Environmental Fluid Mechanics, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - C. Chassagne
- Environmental Fluid Mechanics, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2600 GA Delft, The Netherlands
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Prasad M, Strubbe F, Beunis F, Neyts K. Different Types of Charged-Inverse Micelles in Nonpolar Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5796-5801. [PMID: 27231768 DOI: 10.1021/acs.langmuir.6b00468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Over the last few years, the electrodynamics of charged inverse micelles (CIMs) in nonpolar liquids and the generation mechanism and properties of newly generated CIMs have been studied extensively for the model system of polyisobutylene succinimide in dodecane. However, the newly generated CIMs, which accumulate at the electrodes when a continuous voltage is applied, behave differently compared to the regular CIMs present in equilibrium in the absence of a field. In this work, we use transient current measurements to investigate the behavior of the newly generated CIMs when the field is reduced to zero or reversed. We demonstrate that the newly generated CIMs do not participate in the diffuse double layer near the electrode formed by the regular CIMs but form an interface layer at the electrode surface. A fraction of the newly generated negative CIMs can be released from this interface layer when the field there becomes zero. The findings of this study provide a better understanding of fundamental processes in nonpolar liquids and are relevant for applications such as electronic ink displays and liquid toner printing.
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Affiliation(s)
- Manoj Prasad
- Electronics and Information Systems and Center for Nano and Biophotonics (NB-Photonics), Ghent University , Technologiepark Zwijnaarde 15, 9052 Gent, Belgium
| | - Filip Strubbe
- Electronics and Information Systems and Center for Nano and Biophotonics (NB-Photonics), Ghent University , Technologiepark Zwijnaarde 15, 9052 Gent, Belgium
| | - Filip Beunis
- Electronics and Information Systems and Center for Nano and Biophotonics (NB-Photonics), Ghent University , Technologiepark Zwijnaarde 15, 9052 Gent, Belgium
| | - Kristiaan Neyts
- Electronics and Information Systems and Center for Nano and Biophotonics (NB-Photonics), Ghent University , Technologiepark Zwijnaarde 15, 9052 Gent, Belgium
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24
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Lee J, Zhou ZL, Behrens SH. Charging Mechanism for Polymer Particles in Nonpolar Surfactant Solutions: Influence of Polymer Type and Surface Functionality. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4827-4836. [PMID: 27135950 DOI: 10.1021/acs.langmuir.6b00583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Surface charging phenomena in nonpolar dispersions are exploited in a wide range of industrial applications, but their mechanistic understanding lags far behind. We investigate the surface charging of a variety of polymer particles with different surface functionality in alkane solutions of a custom-synthesized and purified polyisobutylene succinimide (PIBS) polyamine surfactant and a related commercial surfactant mixture commonly used to control particle charge. We find that the observed electrophoretic particle mobility cannot be explained exclusively by donor-acceptor interactions between surface functional groups and surfactant polar moieties. Our results instead suggest an interplay of multiple charging pathways, which likely include the competitive adsorption of ions generated among inverse micelles in the solution bulk. We discuss possible factors affecting the competitive adsorption of micellar ions, such as the chemical nature of the particle bulk material and the size asymmetry between inverse micelles of opposite charge.
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Affiliation(s)
- Joohyung Lee
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive Northwest, Atlanta, Georgia 30332, United States
| | - Zhang-Lin Zhou
- HP Incorporated, 16399 West Bernardo Drive, San Diego, California 92127, United States
| | - Sven Holger Behrens
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive Northwest, Atlanta, Georgia 30332, United States
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25
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Determination of charge carrier concentration in doped nonpolar liquids by impedance spectroscopy in the presence of charge adsorption. J Colloid Interface Sci 2016; 469:325-337. [DOI: 10.1016/j.jcis.2016.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/23/2015] [Accepted: 02/03/2016] [Indexed: 11/22/2022]
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26
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Lee J, Zhou ZL, Alas G, Behrens SH. Mechanisms of Particle Charging by Surfactants in Nonpolar Dispersions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11989-11999. [PMID: 26484617 DOI: 10.1021/acs.langmuir.5b02875] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electric charging of colloidal particles in nonpolar solvents plays a crucial role for many industrial applications and products, including rubbers, engine oils, toners, or electronic displays. Although disfavored by the low solvent permittivity, particle charging can be induced by added surfactants, even nonionic ones, but the underlying mechanism is poorly understood, and neither the magnitude nor the sign of charge can generally be predicted from the particle and surfactant properties. The conclusiveness of scientific studies has been limited partly by a traditional focus on few surfactant types with many differences in their chemical structure and often poorly defined composition. Here we investigate the surface charging of poly(methyl methacrylate) particles dispersed in hexane-based solutions of three purified polyisobutylene succinimide polyamine surfactants with "subtle" structural variations. We precisely vary the surfactant chemistry by replacing only a single electronegative atom located at a fixed position within the polar headgroup. Electrophoresis reveals that these small differences between the surfactants lead to qualitatively different particle charging. In the respective particle-free surfactant solutions we also find potentially telling differences in the size of the surfactant aggregates (inverse micelles), the residual water content, and the electric solution conductivity as well as indications for a significant size difference between oppositely charged inverse micelles of the most hygroscopic surfactant. An analysis that accounts for the acid/base properties of all constituents suggests that the observed particle charging is better described by asymmetric adsorption of charged inverse micelles from the liquid bulk than by charge creation at the particle surface. Intramicellar acid-base interaction and intermicellar surfactant exchange help rationalize the formation of micellar ions pairs with size asymmetry.
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Affiliation(s)
- Joohyung Lee
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive NW, Atlanta, Georgia 30332, United States
| | - Zhang-Lin Zhou
- Hewlett-Packard Company, 16399 W Bernardo Drive, San Diego, California 92127, United States
| | - Guillermo Alas
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States
| | - Sven Holger Behrens
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , 311 Ferst Drive NW, Atlanta, Georgia 30332, United States
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27
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28
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Stabilization of highly concentrated emulsions with oversaturated dispersed phase: Effect of surfactant/particle ratio. Chem Eng Res Des 2015. [DOI: 10.1016/j.cherd.2015.06.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Gacek MM, Berg JC. Effect of surfactant hydrophile-lipophile balance (HLB) value on mineral oxide charging in apolar media. J Colloid Interface Sci 2015; 449:192-7. [DOI: 10.1016/j.jcis.2014.11.075] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 11/20/2014] [Accepted: 11/20/2014] [Indexed: 11/24/2022]
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30
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Gacek MM, Berg JC. The role of acid-base effects on particle charging in apolar media. Adv Colloid Interface Sci 2015; 220:108-23. [PMID: 25891860 DOI: 10.1016/j.cis.2015.03.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 03/24/2015] [Accepted: 03/25/2015] [Indexed: 11/30/2022]
Abstract
The creation and stabilization of electric charge in apolar environments (dielectric constant≈2) have been an area of interest dating back to when an explanation was sought for the occurrence of what are now known as electrokinetic explosions during the pumping of fuels. More recently attention has focused on the charging of suspended particles in such media, underlying such applications as electrophoretic displays (e.g., the Amazon Kindle® reader) and new printing devices (e.g., the HP Indigo® Digital Press). The endeavor has been challenging owing to the complexity of the systems involved and the large number of factors that appear to be important. A number of different, and sometimes conflicting, theories for particle surface charging have been advanced, but most observations obtained in the authors' laboratory, as well as others, appear to be explainable in terms of an acid-base mechanism. Adducts formed between chemical functional groups on the particle surface and monomers of reverse micelle-forming surfactants dissociate, leaving charged groups on the surface, while the counter-charges formed are sequestered in the reverse micelles. For a series of mineral oxides in a given medium with a given surfactant, surface charging (as quantified by the maximum electrophoretic mobility or zeta potential obtained as surfactant concentration is varied) was found to scale linearly with the aqueous PZC (or IEP) values of the oxides. Different surfactants, with the same oxide series, yielded similar behavior, but with different PZC crossover points between negative and positive particle charging, and different slopes of charge vs. PZC. Thus the oxide series could be used as a yardstick to characterize the acid-base properties of the surfactants. This has led directly to the study of other materials, including surface-modified oxides, carbon blacks, pigments (charge transfer complexes), and polymer latices. This review focuses on the acid-base mechanism of particle charging in the context of the many other factors that are important to the phenomenon, including the presence of water, of other components (e.g., synergists and contaminants), and of electric field effects. The goal is the construction of a road map describing the anticipated particle charging behavior in a wide variety of systems, assisting in the choice or development of materials for specific applications.
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Affiliation(s)
| | - John C Berg
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA.
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31
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Lee J, Zhou ZL, Behrens SH. Characterizing the Acid/Base Behavior of Oil-Soluble Surfactants at the Interface of Nonpolar Solvents with a Polar Phase. J Phys Chem B 2015; 119:6628-37. [DOI: 10.1021/jp510748q] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joohyung Lee
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive Northwest, Atlanta, Georgia 30332, United States
| | - Zhang-Lin Zhou
- Hewlett-Packard Company, 16399 West Bernardo
Drive, San Diego, California 92127, United States
| | - Sven Holger Behrens
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive Northwest, Atlanta, Georgia 30332, United States
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32
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Karvar M, Strubbe F, Beunis F, Kemp R, Smith N, Goulding M, Neyts K. Investigation of various types of inverse micelles in nonpolar liquids using transient current measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12138-12143. [PMID: 25255418 DOI: 10.1021/la502287m] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Transient current measurements are used to characterize a wide variety of charge carriers in nonpolar liquids. The transient current method allows us to obtain both the concentration and mobility of charge carriers and therefore also the hydrodynamic radius using Stokes' law. In this article, five different surfactants in dodecane are investigated: OLOA11K, Solsperse13940, Span80, Span85, and AOT. We show that different types of currents are observed depending on the size of the inverse micelles. For large inverse micelles such as for OLOA11K, Solsperse13940, and Span80, the measurement of the transient current is straightforward because of the low steady-state current level. However, for small inverse micelles such as AOT and Span85, the current from the generation of charges is much larger such that high voltages, a small distance between the electrodes, and dielectric coatings on the electrodes are required to measure the signal related to the initially present charged inverse micelles. The estimated hydrodynamic radii of AOT and Span85, the two smallest inverse micelles, are in good agreement with the values reported in the literature. The comparison of the transient currents with simulations indicates that the dynamics of the charge transport are well-understood.
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Affiliation(s)
- Masoumeh Karvar
- Department of Electronics and Information Systems and ‡Center for Nano- and Biophotonics, Ghent University , B-9000 Ghent, Belgium
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33
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Yezer BA, Khair AS, Sides PJ, Prieve DC. Use of electrochemical impedance spectroscopy to determine double-layer capacitance in doped nonpolar liquids. J Colloid Interface Sci 2014; 449:2-12. [PMID: 25315405 DOI: 10.1016/j.jcis.2014.08.052] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 08/13/2014] [Accepted: 08/23/2014] [Indexed: 11/30/2022]
Abstract
Electrochemical impedance spectroscopy in a thin cell (10 μm) was used to infer conductivity, permittivity and the differential double-layer capacitance of solutions of dodecane doped with OLOA 11000 [poly(isobutylene) succinimide] for concentrations of dopant between 0.1% and 10% by weight. All spectra (frequencies between 1 Hz and 100 kHz) were well fit by an equivalent circuit having four elements including a constant-phase element representing the double-layer capacitance. Using Gouy-Chapman theory for small zeta potentials and assuming univalent charge carriers, the double-layer capacitances were converted into charge carrier concentration which was found to be directly proportional to the weight percent of dopant with a 1 wt% solution having 87 carriers/μm(3) (the concentration of either positive or negative charges). This is only 17 ppm of the total monomer concentration calculated from the average molecule weight of the dopant. Dividing the measured conductivities by the charge carrier concentration, we inferred the mobility and hydrodynamic diameters for the charged micelles. The hydrodynamic diameters of carriers were significantly larger than the average diameter of all micelles measured independently by dynamic light scattering. This suggests that only large micelles become charged.
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Affiliation(s)
- Benjamin A Yezer
- Center for Complex Fluids Engineering and Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Aditya S Khair
- Center for Complex Fluids Engineering and Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Paul J Sides
- Center for Complex Fluids Engineering and Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Dennis C Prieve
- Center for Complex Fluids Engineering and Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United States.
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34
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Magnetically-responsive electrophoretic silica organosols. J Colloid Interface Sci 2014; 426:252-5. [DOI: 10.1016/j.jcis.2014.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/31/2014] [Accepted: 04/01/2014] [Indexed: 11/24/2022]
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35
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Bombard AJF, Dukhin A. Ionization of a nonpolar liquid with an alcohol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4517-4521. [PMID: 24694066 DOI: 10.1021/la500221n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Nonpolar liquids whose dielectric permittivities are close to 2 have very low conductivities, usually below 10 × 10(-10) S/m. Their ionization is suppressed by the lack of solvation resulting from the negligible dipole moment of such liquids' molecules. Ionization could be enhanced by the addition of other substances that could serve as solvating agents, creating inverse micelles around ions and preventing them from reassociating into ion pairs and neutral molecules. Surfactants are normally used for this purpose, but we show here that alcohols could perform a similar function. However, the mechanism of ionization by alcohols turns out to be quite different compared to the mechanism of ionization by surfactant. For instance, the conductivity of poly-α-olefin oil (PAO) depends on the concentration of added octanol (alcohol) as an exponential function above 10% of the octanol content. At concentrations below approximately 10%, octanol does not affect the conductivity at all. This phenomenon has never been observed for surfactant solutions. Apparently, octanol is completely dissolved at concentrations below 10% and forms micelles only above this concentration, which is the cmc for octanol-PAO mixtures. Below the cmc, octanol molecules do not dissociate, despite being able to dissociate in pure octanol, which has a conductivity of about 10 × 10(-7) S/m. This again stresses the importance of the solvating factor in the ionization of liquids. Above 10% concentration, octanol molecules form micelles, which become charged by the disproportionation mechanism when they collide. To explain the exponential dependence of conductivity on octanol content, we assume that charged micelles grow in volume with increasing octanol content faster than neutral ones. Ion-dipole interactions are responsible for the preferential adsorption of octanol molecules onto charged micelles. Additional ionization occurs in such larger micelles, which then break down into smaller ones carrying individual electric charges.
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Affiliation(s)
- Antonio J F Bombard
- Universidade Federal de Itajubá/IFQ , Av. BPS 1303, Itajubá - MG, 37500-903, Brazil
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36
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Dukhin A. Critical concentration of ion-pairs formation in nonpolar media. Electrophoresis 2014; 35:1773-81. [DOI: 10.1002/elps.201300611] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/15/2014] [Accepted: 01/26/2014] [Indexed: 11/11/2022]
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37
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Effect of synergists on organic pigment particle charging in apolar media. Electrophoresis 2014; 35:1766-72. [DOI: 10.1002/elps.201300593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/21/2014] [Accepted: 01/26/2014] [Indexed: 11/07/2022]
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38
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Electric charging of inverse micelles in a nonpolar liquid with surfactant. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Hussain G, Robinson A, Bartlett P. Charge generation in low-polarity solvents: poly(ionic liquid)-functionalized particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4204-4213. [PMID: 23402544 DOI: 10.1021/la3049086] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a straightforward strategy for the synthesis of highly charged poly(ionic liquid)-functionalized particles in low-polarity solvents. A series of cationic liquid monomers consisting of a tetraalkyl ammonium cation and a fluorinated tetrakis[phenyl] borate anion linked, via a C3-alkyl chain, to a methacrylate unit were synthesized. The addition of this ionic monomer to a conventional dispersion polymerization of methyl methacrylate and methacrylic acid at 80 °C in a mixed dodecane/hexane solvent yielded spherical, highly monodisperse particles with mean diameters of between ~50 and 2500 nm with high electrophoretic mobility and stability in nonpolar solvents such as dodecane. The surface potential in dodecane could be adjusted in the range from 0 to 180 ± 9 mV by altering the ratio of ionic monomer to methacrylate monomers. The particles open up new opportunities for the electrostatic assembly of nanoparticles and organized structures in nonpolar environments.
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40
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Dukhin A, Parlia S. Ions, ion pairs and inverse micelles in non-polar media. Curr Opin Colloid Interface Sci 2013. [DOI: 10.1016/j.cocis.2013.02.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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41
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Beunis F, Strubbe F, Karvar M, Drobchak O, Brans T, Neyts K. Inverse micelles as charge carriers in nonpolar liquids: Characterization with current measurements. Curr Opin Colloid Interface Sci 2013. [DOI: 10.1016/j.cocis.2013.02.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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42
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43
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Surfactant mediated charging of polymer particles in a nonpolar liquid. J Colloid Interface Sci 2013; 392:83-89. [DOI: 10.1016/j.jcis.2012.09.070] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 09/26/2012] [Indexed: 11/22/2022]
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44
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Cao H, Lu N, Ding B, Qi M. Regulation of charged reverse micelles on particle charging in nonpolar media. Phys Chem Chem Phys 2013; 15:12227-34. [DOI: 10.1039/c3cp51212f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Smith GN, Eastoe J. Controlling colloid charge in nonpolar liquids with surfactants. Phys Chem Chem Phys 2013. [DOI: 10.1039/c2cp42625k] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Gacek MM, Berg JC. Investigation of surfactant mediated acid-base charging of mineral oxide particles dispersed in apolar systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:17841-17845. [PMID: 23157688 DOI: 10.1021/la303943k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The current work examines the role of acid-base properties on particle charging in apolar media. Manipulating the polarity and magnitude of charge in such systems is of growing interest to a number of applications. A major hurdle to the implementation of this technology is that the mechanism(s) of particle charging remain a subject of debate. The authors previously conducted a study of the charging of a series of mineral oxide particles dispersed in apolar systems that contained the surfactant AOT. It was observed that there was a correlation between the particle electrophoretic mobility and the acid-base nature of the particle, as characterized by aqueous point of zero charge (PZC) or the isoelectric point (IEP). The current study investigates whether or not a similar correlation is observed with other surfactants, namely, the acidic Span 80 and the basic OLOA 11000. This is accomplished by measuring the electrophoretic mobility of a series of mineral oxides that are dispersed in Isopar-L containing various concentrations of either Span 80 or OLOA 11000. The mineral oxides used have PZC values that cover a wide range of pH, providing a systematic study of how particle and surfactant acid-base properties impact particle charge. It was found that the magnitude and polarity of particle surface charge varied linearly with the particle PZC for both surfactants used. In addition, the point at which the polarity of charge reversed for the basic surfactant OLOA 11000 was shifted to a pH of approximately 8.5, compared to the previous result of about 5 for AOT. This proves that both surfactant and particle acid-base properties are important, and provides support for the theory of acid-base charging in apolar media.
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Affiliation(s)
- Matthew M Gacek
- Department of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195-1750, USA
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47
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Yin PP, Wu G, Dai RY, Qin WL, Wang M, Chen HZ. Fine encapsulation of dual-particle electronic ink by incorporating block copolymer for electrophoretic display application. J Colloid Interface Sci 2012; 388:67-73. [DOI: 10.1016/j.jcis.2012.08.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 08/02/2012] [Accepted: 08/18/2012] [Indexed: 10/27/2022]
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48
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Li L, Zhang J, Sun H, Xu J, Sun D. Dispersion stability of organoclay in octane improved by adding nonionic surfactants. Colloids Surf A Physicochem Eng Asp 2012. [DOI: 10.1016/j.colsurfa.2012.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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49
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Michor EL, Berg JC. Extension to the charge fluctuation model for the prediction of the conductivity of apolar, reverse micellar systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:15751-15755. [PMID: 23098157 DOI: 10.1021/la303455n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper presents an extension to current theory regarding charging behavior in apolar, micellar systems. Electrical conductivity in such systems accompanying the formation of neutral reverse micelles is commonly explained by the possibility of intermicellar collisions resulting in a pair of oppositely charged micelles. The sequestration of the resulting charges within the micelles prevents their immediate recombination. The current theory underlying the charging process has thus far been applied in only approximate form, and is only used to validate experimental trends and to abstract values for the fraction of charged micelles. The extended theory proposed here uses knowledge of the solvent and surfactant characteristics, together with water content, to predict solution conductivity in absolute terms. It is verified in experiments with the solvent Isopar-L and surfactants Aerosol OT, OLOA 11000, and Span 80, in which significant differences from the approximate theory are observed.
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Affiliation(s)
- Edward L Michor
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-1750, United States
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50
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Design, optimization and in vitro evaluation of reverse micelle-loaded lipid nanocarriers containing erlotinib hydrochloride. Int J Pharm 2012; 436:194-200. [DOI: 10.1016/j.ijpharm.2012.06.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 11/17/2022]
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