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Müller W, Sroka W, Schweins R, Nöcker B, Poon JF, Huber K. Impact of Additive Hydrophilicity on Mixed Dye-Nonionic Surfactant Micelles: Micelle Morphology and Dye Localization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8872-8885. [PMID: 38640353 DOI: 10.1021/acs.langmuir.4c00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
The nonionic surfactant pentaethylene glycol-monododecylether C12E5 forms micelles in aqueous solutions with a lower critical solution temperature. This characteristic solution behavior of C12E5 is independent of the pH. Such micelles are used to solubilize a large variety of active guest molecules like for instance dyestuffs. An example is an acidic azo dye termed Blue used as a hair colorant. Depending on the pH, Blue gradually changes its hydrophilicity from the protonated BlueH at pH = 2 to the bivalent anion Blue2- at pH = 13 while keeping the shape and size of Blue essentially unchanged. These features of C12E5 and Blue offer the unique chance to investigate the sole impact of a tunable hydrophilicity of a guest molecule on the solution behavior of mixed micelles of the guest and C12E5. Accordingly, the present work establishes a phase diagram of Blue-C12E5 micelles and analyzes their morphology including the spatial distribution of Blue in the micelles as a function of the hydrophilicity of Blue. Small angle neutron scattering reveals the size and shape of the micelles, and detailed contrast matching of the C12E5 supported by 1H NMR with NOESY provided insight into the localization of Blue within the micelles as its hydrophilicity changes.
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Affiliation(s)
- Wenke Müller
- Science Division/Large Scale Structures Group Institut Laue-Langevin 71 Avenue des Martyrs, Grenoble 38000, France
| | - Weronika Sroka
- Science Division/Large Scale Structures Group Institut Laue-Langevin 71 Avenue des Martyrs, Grenoble 38000, France
| | - Ralf Schweins
- Science Division/Large Scale Structures Group Institut Laue-Langevin 71 Avenue des Martyrs, Grenoble 38000, France
| | - Bernd Nöcker
- Basic Research & Technology Development KAO Germany GmbH Pfungstädter Straße 98-100, Darmstadt 64297, Germany
| | - Jia-Fei Poon
- European Spallation Source Box 176, Lund SE-221 00, Sweden
- Food Technology, Engineering and Nutrition Lund University Box 117, Lund SE-221 00, Sweden
| | - Klaus Huber
- Fakultät für Naturwissenschaften/Physical Chemistry Universität Paderborn Warburger Straße 100, Paderborn 33098, Germany
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2
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Hu X, Liao M, Shen K, Ding K, Campana M, van der Kamp S, McInnes EF, Padia F, Lu JR. Unraveling How Membrane Nanostructure Changes Impact the Eye Irritation of Nonionic Alkyl Ethoxylate Surfactants. ACS APPLIED MATERIALS & INTERFACES 2023; 15:59087-59098. [PMID: 38078441 PMCID: PMC10739585 DOI: 10.1021/acsami.3c14794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/22/2023]
Abstract
Nonionic surfactants used in agri-spraying processes may cause varying degrees of corneal irritation when they come in direct contact with farmers' eyes, and the exact irritations are thought to be determined by how surfactants interact with corneal cell membranes. However, how nonionic surfactants interact with cell membranes at the molecular and nano levels remains largely unexplored. In this study, the interactions between nonionic surfactants (alkyl ethoxylate, C12Em) and lipid membranes were examined by membrane permeability measurement, quartz crystal microbalance with dissipation, dual polarization interferometry, confocal laser scanning microscopy, and neutron reflection, aiming to reveal complementary structural features at the molecular and nano levels. Apart from the extremely hydrophobic surfactant C12E2, all nonionic surfactants studied could penetrate the model cell membrane composed of a phosphocholine lipid bilayer. Nonionic surfactants with intermediate amphiphilicity (C12E6) rapidly fused into the lipid membrane and stimulated the formation of pores across the lipid bilayer, consistent with the cytoplasm leakage and fast cell necrosis observed from the cytotoxicity study of corneal cells. In comparison, while hydrophobic and hydrophilic surfactants [those with long and short ethoxylates (C12E4,12,23)] could cause mild structural alteration to the outer lipid layer of the membrane, these structural changes were insufficient to elicit large cytoplasmic leakage rapidly and instead cell death occurred over longer periods of time due to changes in the membrane permeability. These results reveal the strong link of surfactant-lipid membrane interactions to surfactant cytotoxicity and the association with amphiphilicity of nonionic surfactants.
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Affiliation(s)
- Xuzhi Hu
- Biological
Physics Group, Department of Physics and Astronomy, School of Natural
Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Mingrui Liao
- Biological
Physics Group, Department of Physics and Astronomy, School of Natural
Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Kangcheng Shen
- Biological
Physics Group, Department of Physics and Astronomy, School of Natural
Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Ke Ding
- Biological
Physics Group, Department of Physics and Astronomy, School of Natural
Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Mario Campana
- Rutherford
Appleton Laboratory, STFC ISIS Facility, Didcot OX11 0QX, U.K.
| | - Sophie van der Kamp
- Jealott’s
Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42
6EY, U.K.
| | - Elizabeth F. McInnes
- Jealott’s
Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42
6EY, U.K.
| | - Faheem Padia
- Jealott’s
Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42
6EY, U.K.
| | - Jian R. Lu
- Biological
Physics Group, Department of Physics and Astronomy, School of Natural
Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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3
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Oggero J, Gasser FB, Zacarías SM, Burns P, Baravalle ME, Renna MS, Ortega HH, Vaillard SE, Vaillard VA. PEGylation of Chrysin Improves Its Water Solubility while Preserving the In Vitro Biological Activity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:19817-19831. [PMID: 38048427 DOI: 10.1021/acs.jafc.3c06357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Chrysin is a natural flavonoid that despite having numerous biological properties, its therapeutic value is limited due to its very low solubility in aqueous media. In this work, chrysin was conjugated with methoxypolyethylene glycols (mPEGs) of different molecular weights (350, 500, 750, and 2000 g/mol), affording PEGylated chrysins with high yields and excellent purities. In all cases, an increase in the water solubility of the conjugates was observed, which was highest when 500 g/mol of mPEG was used in the PEGylation reaction. Furthermore, in aqueous solution, PEGylated chrysins formed aggregates of ellipsoid shape. Electrochemical studies showed that the redox properties were conserved after PEGylation. While in vitro antibacterial and antifungal studies probed that the intrinsic activity was conserved, in vitro antitumor activities against HepG2 (liver carcinoma cells) and PC3 (prostate cancer cell) showed that PEGylated chrysins retained the cytotoxic activity and the ability of induction of apoptosis for the evaluated human cancer cells.
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Affiliation(s)
- Julia Oggero
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, Ruta Nacional 168, km 0, Paraje "El Pozo", Santa Fe 3000, Argentina
| | - Fátima B Gasser
- Instituto de Ciencias Veterinarias del Litoral (ICIVET), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, R. P. Kreder 2805, Esperanza 3080, Argentina
| | - Silvia M Zacarías
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, Ruta Nacional 168, km 0, Paraje "El Pozo", Santa Fe 3000, Argentina
| | - Patricia Burns
- Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ruta Nacional No. 168, km 472, Ciudad Universitaria UNL, Santa Fe 3000, Argentina
| | - María E Baravalle
- Instituto de Ciencias Veterinarias del Litoral (ICIVET), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, R. P. Kreder 2805, Esperanza 3080, Argentina
- Centro Universitario Gálvez, Universidad Nacional del Litoral, Florentino Ameghino 50 bis, Gálvez, Santa Fe S2252, Argentina
| | - Maria Sol Renna
- Instituto de Ciencias Veterinarias del Litoral (ICIVET), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, R. P. Kreder 2805, Esperanza 3080, Argentina
| | - Hugo H Ortega
- Instituto de Ciencias Veterinarias del Litoral (ICIVET), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, R. P. Kreder 2805, Esperanza 3080, Argentina
| | - Santiago E Vaillard
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, Ruta Nacional 168, km 0, Paraje "El Pozo", Santa Fe 3000, Argentina
| | - Victoria A Vaillard
- Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas, Ruta Nacional 168, km 0, Paraje "El Pozo", Santa Fe 3000, Argentina
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4
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Epelle EI, Cojuhari N, Mohamedsalih A, Macfarlane A, Cusack M, Burns A, McGinness C, Yaseen M. The synergistic antibacterial activity of ozone and surfactant mists. RSC Adv 2023; 13:22593-22605. [PMID: 37501772 PMCID: PMC10369041 DOI: 10.1039/d3ra03346e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/17/2023] [Indexed: 07/29/2023] Open
Abstract
The microbiological safety of medical equipment and general surfaces is paramount to both the well-being of patients and the public. The application of ozone (a potent oxidant) has been recognised and implemented for this purpose, globally. However, it has primarily been utilised in the gaseous and aqueous forms. In this study, we investigate the potency of fine ozone mists and evaluate the synergistic effect when combined with cationic, anionic and non-ionic surfactants (dodecyl trimethyl ammonium bromide - DTAB, sodium dodecyl sulfate - SDS, alkyl polyglycoside - APG) as well as polyethylene glycol (PEG). Ozone mist is generated via a nebuliser (equipped with a compressed gas stream) and the piezoelectric method; whereas fabric substrates contaminated with Escherichia coli and Staphylococcus aureus are utilised in this study. Contamination levels on the fabric swatches are evaluated using agar dipslides. Compared to gaseous ozonation and aqueous ozonation (via nanobubble generation), the produced ozone mists showed significantly inferior antimicrobial properties for the tested conditions (6 ppm, 5-15 min). However, the hybrid mist-based application of 'ozone + surfactants' and 'ozone + PEG' showed considerable improvements compared to their independent applications (ozone mist only and surfactant mist only). The 'ozone + DTAB' mist had the highest activity, with better results observed with the micron-mist nebuliser than the piezoelectric transducer. We propose a likely mechanism for this synergistic performance (micellar encapsulation) and demonstrate the necessity for continued developments of novel decontamination technologies.
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Affiliation(s)
- Emmanuel I Epelle
- School of Computing, Engineering & Physical Sciences, University of the West of Scotland Paisley PA1 2BE UK
- School of Engineering, Institute for Materials and Processes, The University of Edinburgh Sanderson Building, Robert Stevenson Road Edinburgh EH9 3FB UK
- ACS Clothing 6 Dovecote Road Central Point Logistics Park ML1 4GP UK
| | - Neli Cojuhari
- School of Computing, Engineering & Physical Sciences, University of the West of Scotland Paisley PA1 2BE UK
| | - Abdalla Mohamedsalih
- School of Computing, Engineering & Physical Sciences, University of the West of Scotland Paisley PA1 2BE UK
| | - Andrew Macfarlane
- ACS Clothing 6 Dovecote Road Central Point Logistics Park ML1 4GP UK
| | - Michael Cusack
- ACS Clothing 6 Dovecote Road Central Point Logistics Park ML1 4GP UK
| | - Anthony Burns
- ACS Clothing 6 Dovecote Road Central Point Logistics Park ML1 4GP UK
| | - Charles McGinness
- School of Computing, Engineering & Physical Sciences, University of the West of Scotland Paisley PA1 2BE UK
| | - Mohammed Yaseen
- School of Computing, Engineering & Physical Sciences, University of the West of Scotland Paisley PA1 2BE UK
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5
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Kroll P, Exner L, Brandenbusch C, Sadowski G. Influence of Hydrophobic and Hydrophilic Chain Length of C iE j Surfactants on the Solubilization of Active Pharmaceutical Ingredients. Mol Pharm 2023; 20:1296-1306. [PMID: 36565283 DOI: 10.1021/acs.molpharmaceut.2c00941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Up to 90% of all newly developed active pharmaceutical ingredients (APIs) are poorly water soluble, most likely also showing a low oral bioavailability. In order to increase the aqueous solubility of these APIs, surfactants are promising excipients to increase both solubility and consequently bioavailability (e.g., in lipid- and surfactant-based drug delivery systems). In this work, we investigated the influence of hydrophobic and hydrophilic chain lengths of CiEj surfactants (C8E6, C10E6, and C10E8) toward the solubilization of fenofibrate, naproxen, and lidocaine. Furthermore, we investigated the partitioning of these APIs between the surfactant aggregates and the surrounding aqueous bulk phase. For all APIs considered, we determined the locus of API solubilization as well as the individual aggregation numbers (Nagg) of surfactants and API molecules in an API/surfactant aggregate. We further determined the hydrodynamic radius (Rh) of the API/surfactant aggregates in the absence and presence of the APIs. The size of the API/surfactant aggregates (Nagg, Rh) passes through a minimum upon lidocaine solubilization; it gradually increases upon naproxen solubilization and is almost constant upon fenofibrate solubilization. The results give valuable insights into the solubilization mechanisms of APIs in the CiEj surfactant aggregates. Our results reveal that fenofibrate is solely solubilized in the hydrophobic core of the CiEj surfactant aggregates, as only the hydrophobic chain length of the surfactant influences its solubilization. Naproxen is solubilized in the palisade layer of the surfactant aggregates, as both the hydrophobic and hydrophilic chain lengths are decisive for its solubilization. Lidocaine is mainly solubilized in the rather hydrophilic corona region of the surfactant aggregates, as the hydrophilic chain length of the surfactant governs its solubilization. The results further reveal that the hydrophilic/lipophilic balance is not an appropriate measure to estimate the solubilization capacity of surfactant aggregates.
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Affiliation(s)
- Peter Kroll
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227Dortmund, Germany
| | - Lara Exner
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227Dortmund, Germany
| | - Christoph Brandenbusch
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227Dortmund, Germany
| | - Gabriele Sadowski
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227Dortmund, Germany
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6
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Shafiee O, Jenkins SG, Ito T, Higgins DA. Diffusion of hydrophilic to hydrophobic forms of Nile red in aqueous C 12EO 10 gels by variable area fluorescence correlation spectroscopy. Phys Chem Chem Phys 2023; 25:2853-2861. [PMID: 36625135 DOI: 10.1039/d2cp05578c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Solute diffusion within lyotropic liquid crystal gels prepared from a series of water and decaethylene glycol monododecyl ether (C12EO10) mixtures was explored by variable area fluorescence correlation spectroscopy. Aqueous C12EO10 gels were prepared in concentrations ranging from 55 : 45 to 70 : 30 wt% of surfactant and water. Small angle X-ray scattering revealed that these gels comprise hexagonal mesophases of cylindrical micelles. Micelle spacing was found to decrease with increasing C12EO10 concentration. Three different Nile red (NR) dyes were employed as model solutes and were separately doped into the gels at nanomolar levels. These include a hydrophilic form of NR incorporating an anionic sulfonate group (NRSO3-), a hydrophobic form incorporating a fourteen-carbon alkane tail (NRC14), and commercial NR as an intermediate case. FCS data acquired from the gels revealed that NRSO3- diffused primarily in 3D. Its diffusion coefficient exhibited a monotonic decrease with increasing gel concentration and micelle packing density, consistent with confinement of its motions by its exclusion from the micelle cores. NRC14 exhibited the smallest diffusion coefficient, most likely due to its larger size and enhanced interactions with the micelle cores. NR yielded an intermediate diffusion coefficient and the most anomalous behavior of the three dyes, attributable to its facile partitioning between core and corona regions, and greater participation by 1D diffusion. The results of these studies afford an improved understanding of molecular mass transport through soft-matter nanomaterials like those being developed for use in drug delivery and membrane based chemical separations.
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Affiliation(s)
- Omid Shafiee
- Department of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506-0401, USA.
| | - Samantha G Jenkins
- Department of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506-0401, USA.
| | - Takashi Ito
- Department of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506-0401, USA.
| | - Daniel A Higgins
- Department of Chemistry, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506-0401, USA.
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7
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Kroll P, Sadowski G, Brandenbusch C. Solubilization of Aldehydes and Amines in Aqueous C iE j Surfactant Aggregates: Solubilization Capacity and Aggregate Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10022-10031. [PMID: 35926216 DOI: 10.1021/acs.langmuir.2c01463] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Hydroformylation of olefins to aldehydes and subsequent reductive amination of aldehydes to amines takes place in an aqueous system using a water-soluble catalyst. It is limited to short-chain molecules due to an insufficient solubility of long-chain molecules in water. A promising approach to increase the solubility of long-chain aldehydes and amines is the addition of surfactants to the aqueous phase. In this work, we thus determined the solubilization capacity (SC) of different nonionic CiEj surfactants (C8E6, C10E6, and C10E8) toward long-chain aldehydes and amines. We used static and dynamic light scattering techniques to investigate the influence of both the surfactant and solute molecular structures on the SC as well as on the aggregation number (Nagg) and hydrodynamic radius (Rh) of mixed aggregates. Our data reveals that an optimum ratio of hydrophobic to hydrophilic chain length of CiEj surfactants exists where the SC toward long-chain aldehydes and amines possesses a maximum. Further, the size of the aggregates (Nagg, Rh) passes through a minimum upon amine solubilization, while upon aldehyde solubilization, the aggregate size increases gradually. The results shown in this work give valuable insights to the solubilization of aldehydes and n-amines into nonionic CiEj surfactants and facilitate the search of suitable surfactants for hydroformylation and reductive amination as "green" solvents based on the detailed knowledge about the aggregate structure.
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Affiliation(s)
- Peter Kroll
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Straße 70, 44227 Dortmund, Germany
| | - Gabriele Sadowski
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Straße 70, 44227 Dortmund, Germany
| | - Christoph Brandenbusch
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Straße 70, 44227 Dortmund, Germany
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8
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Hu X, Carter J, Ge T, Liao M, Margaret Stephens A, Mclnnes EF, Padia F, Lu JR. Impacts of chain and head lengths of nonionic alkyl ethoxylate surfactants on cytotoxicity to human corneal and skin cells in agri-spraying processes*. J Colloid Interface Sci 2022; 628:162-173. [DOI: 10.1016/j.jcis.2022.08.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/19/2022] [Accepted: 08/03/2022] [Indexed: 10/15/2022]
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9
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Hu X, Gong H, Liu H, Wang X, Wang W, Liao M, Li Z, Ma K, Li P, Rogers S, Schweins R, Liu X, Padia F, Bell G, Lu JR. Contrasting impacts of mixed nonionic surfactant micelles on plant growth in the delivery of fungicide and herbicide. J Colloid Interface Sci 2022; 618:78-87. [PMID: 35334364 DOI: 10.1016/j.jcis.2022.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/13/2022] [Accepted: 03/01/2022] [Indexed: 10/18/2022]
Abstract
HYPOTHESIS Nonionic alkyl ethoxylate surfactants are widely used in agrochemicals to facilitate the permeation of systemic herbicides and fungicides across the plant waxy film. Industrial grade surfactants are often highly mixed and how the mixing affects their interactions with pesticides and wax films remains largely unexplored. A better understanding could enable design of mixed nonionic surfactants for herbicides and fungicides to maximize their efficiency and reduce wastage whilst controlling their impact on plant wax films. EXPERIMENT In this study, nonionic surfactants with general structure n-oxyethylene glycol monododecyl ether (C12En) were used to form surfactant mixtures with the same average ethoxylate numbers but different hydrophilic-lipophilic balance (HLB) values. Their mixed micellar systems were then used to solubilize a herbicide diuron (DN) and a fungicide cyprodinil (CP), followed by plant wax solubilization upon contact with wax films. These processes were monitored by 1H NMR and SANS. FINDING Pesticide solubilization made surfactant micelles effectively more hydrophobic but subsequent wax dissolution caused pesticide release and the restoration of the micellar amphiphilicity. Nonionic surfactants with lower HLBs form larger nanoaggregates, show enhanced wettability, and have better ability to solubilize and permeate pesticides across the wax film, but may cause significant damage to plant growth. These observations help explain why herbicides applied on weeds would benefit from surfactants with lower HLB values while fungicides require surfactants with HLBs to balance between delivery efficiency and potential phytotoxicity risks.
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Affiliation(s)
- Xuzhi Hu
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Haoning Gong
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Huayang Liu
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Xi Wang
- Department of Materials, School of Natural Sciences, the University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Weimiao Wang
- Department of Materials, School of Natural Sciences, the University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Mingrui Liao
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Zongyi Li
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Kun Ma
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Peixun Li
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Sarah Rogers
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Ralf Schweins
- Large Scale Structures Group, Institut Laue-Langevin, CS 20 156, 38042 Grenoble CEDEX 9, France
| | - Xuqing Liu
- Department of Materials, School of Natural Sciences, the University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Faheem Padia
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Gordon Bell
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jian R Lu
- Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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10
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Kroll P, Benke J, Enders S, Brandenbusch C, Sadowski G. Influence of Temperature and Concentration on the Self-Assembly of Nonionic C iE j Surfactants: A Light Scattering Study. ACS OMEGA 2022; 7:7057-7065. [PMID: 35252696 PMCID: PMC8892478 DOI: 10.1021/acsomega.1c06766] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/02/2022] [Indexed: 06/07/2023]
Abstract
Nonionic poly(ethylene oxide) alkyl ether (CiEj) surfactants self-assemble into aggregates of various sizes and shapes above their critical micelle concentration (CMC). Knowledge on solution attributes such as CMC as well as aggregate characteristics is crucial to choose the appropriate surfactant for a given application, e.g., as a micellar solvent system. In this work, we used static and dynamic light scattering to measure the CMC, aggregation number (N agg), and hydrodynamic radius (R h) of four different CiEj surfactants (C8E5, C8E6, C10E6, and C10E8). We examined the influence of temperature, concentration, and molecular structure on the self-assembly in the vicinity of the CMC. A minimum in the CMC vs temperature curve was identified for all surfactants investigated. Further, extending the hydrophilic and hydrophobic chain lengths leads to an increase and decrease of the CMC, respectively. The size of the aggregates strongly depends on temperature. N agg and R h increase with increasing temperature for all surfactants investigated. Additionally, N agg and R h both increase with increasing surfactant concentration. The data obtained in this work further improve the understanding of the influence of temperature and molecular structure on the self-assembly of CiEj surfactants and will further foster their use in micellar solvent systems.
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Affiliation(s)
- Peter Kroll
- Laboratory
of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Julius Benke
- Laboratory
of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Sabine Enders
- Institute
for Technical Thermodynamics and Refrigeration, Karlsruhe Institute of Technology, Engler-Bunte-Ring 21, 76131 Karlsruhe, Germany
| | - Christoph Brandenbusch
- Laboratory
of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
| | - Gabriele Sadowski
- Laboratory
of Thermodynamics, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 70, 44227 Dortmund, Germany
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11
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Liu H, Fa K, Hu X, Li Z, Ma K, Liao M, Zhang L, Schweins R, Maestro A, Li P, Webster JRP, Petkov J, Thomas RK, Lu JR. How do chain lengths of acyl-l-carnitines affect their surface adsorption and solution aggregation? J Colloid Interface Sci 2021; 609:491-502. [PMID: 34863541 DOI: 10.1016/j.jcis.2021.11.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS l-carnitines in our body systems can be readily converted into acyl-l-carnitines which have a prominent place in cellular energy generation by supporting the transport of long-chain fatty acids into mitochondria. As biocompatible surfactants, acyl-l-carnitines have potential to be useful in technical, personal care and healthcare applications. However, the lack of understanding of the effects of their molecular structures on their physical properties has constrained their potential use. EXPERIMENTS This work reports the study of the influence of the acyl chain lengths of acyl-l-carnitines (CnLC) on solubility, surface adsorption and aggregation. Critical micellar concentrations (CMCs) of CnLC were determined by surface tension measurements. Neutron reflection (NR) was used to further examine the structure and composition of the adsorbed CnLC layer. The structural changes of the micellar aggregates under different concentrations of CnLC, pH and ionic strength were determined by dynamic light scattering (DLS) and small angle neutron scattering (SANS). FINDINGS C12LC is fully soluble over a wide temperature and concentration range. There is however a strong decline of solubility with increasing acyl chain length. The adsorption and aggregation behavior of C14LC was therefore studied at 30 °C and C16LC at 45 °C. The solubility boundaries displayed distinct hysteresis with respect to heating and cooling. The CMCs of C12LC, C14LC and C16LC at pH 7 were 1.1 ± 0.1, 0.10 ± 0.02 and 0.010 ± 0.005 mM, respectively, with the limiting values of the area per molecule at the CMC being 45.4 ± 2, 47.5 ± 2 and 48.8 ± 2 Å2 and the thicknesses of the adsorbed CnLC layers at the air/water interface increasing from 21.5 ± 2 to 22.6 ± 2 to 24.2 ± 2 Å, respectively. All three surfactants formed core-shell spherical micelles with comparable dimensional parameters apart from an increase in core radius with acyl chain length. This study outlines the effects of acyl chain length on the physicochemical properties of CnLCs under different environmental conditions, serving as a useful basis for developing their potential applications.
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Affiliation(s)
- Huayang Liu
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Ke Fa
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Xuzhi Hu
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Zongyi Li
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Kun Ma
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - Mingrui Liao
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Lin Zhang
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Ralf Schweins
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS20156, 38042 Grenoble Cedex 9, France
| | - Armando Maestro
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS20156, 38042 Grenoble Cedex 9, France
| | - Peixun Li
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - John R P Webster
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - Jordan Petkov
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK; Arxada, Hexagon Tower, Delaunays Road, Blackley, Manchester M9 8ZS, UK.
| | - Robert K Thomas
- Physical and Theoretical Chemistry, University of Oxford, South Parks, Oxford OX1 3QZ, UK
| | - Jian Ren Lu
- Biological Physics Laboratory, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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Helden L, Knippenberg T, Tian L, Archambault A, Ginot F, Bechinger C. Critical Casimir interactions of colloids in micellar critical solutions. SOFT MATTER 2021; 17:2737-2741. [PMID: 33533371 DOI: 10.1039/d0sm02021d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We study the temperature-dependence of critical Casimir interactions in a critical micellar solution of the nonionic surfactant C12E5 dissolved in water. Experimentally, this is achieved with total internal reflection microscopy (TIRM) which measures the interaction between a single particle and a flat wall. For comparison, we also studied the pair interactions of a two dimensional layer of colloidal particles in the identical micellar system which yields good agreement with the TIRM results. Although, at the surfactant concentration considered here, the fluid forms a dynamical network of wormlike micelles whose structure is considerably more complex than that of simple critical molecular fluids, the temperature-dependence of the measured interactions is - for surface-to-surface distances above 160 nm - in excellent quantitative agreement with theory. Below 160 nm, deviations arise which we attribute to the adsorption of micelles to the interacting surfaces.
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Affiliation(s)
- Laurent Helden
- 2. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, Stuttgart, D-70550, Germany.
| | - Timo Knippenberg
- Fachbereich Physik, Universität Konstanz, Konstanz, D-78464, Germany
| | - Li Tian
- Fachbereich Physik, Universität Konstanz, Konstanz, D-78464, Germany
| | - Aubin Archambault
- Fachbereich Physik, Universität Konstanz, Konstanz, D-78464, Germany
| | - Felix Ginot
- Fachbereich Physik, Universität Konstanz, Konstanz, D-78464, Germany
| | - Clemens Bechinger
- Fachbereich Physik, Universität Konstanz, Konstanz, D-78464, Germany
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Hu X, Gong H, Hollowell P, Liao M, Li Z, Ruane S, Liu H, Pambou E, Mahmoudi N, Dalgliesh RM, Padia F, Bell G, Lu JR. What happens when pesticides are solubilised in binary ionic/zwitterionic-nonionic mixed micelles? J Colloid Interface Sci 2021; 586:190-199. [PMID: 33162043 DOI: 10.1016/j.jcis.2020.10.083] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 10/23/2022]
Abstract
HYPOTHESIS Surfactants have been widely used as adjuvants in agri-sprays to enhance the solubility of pesticides in foliar spray deposits and their mobility through leaf cuticles. Previously, we have characterised pesticide solubilisation in nonionic surfactant micelles, but what happens when pesticides become solubilised in anionic, cationic and zwitterionic and their mixtures with nonionic surfactants remain poorly characterised. EXPERIMENTS To facilitate characterisations by SANS and NMR, we used nonionic surfactant hexaethylene glycol monododecyl ether (C12E6), anionic sodium dodecylsulphate (SDS), cationic dodecyltrimethylammonium bromide (DTAB) and zwitterionic dodecylphosphocholine (C12PC) as model adjuvant systems to solubilise 3 pesticides, Cyprodinil (CP), Azoxystrobin (AZ) and Difenoconazole (DF), representing different structural features. The investigation focused on the influence of solubilisates in driving changes to the micellar nanostructures in the absence or presence of electrolytes. NMR and NOESY were applied to investigate the solubility and location of each pesticide in the micelles. SANS was used to reveal subtle changes to the micellar structures due to pesticide solubilisation with and without electrolytes. FINDINGS Unlike nonionic surfactants, the ionic and zwitterionic surfactant micellar structures remain unchanged upon pesticide solubilisation. Electrolytes slightly elongate the ionic surfactant micelles but have no effect on nonionic and zwitterionic surfactants. Pesticide solubilisation could alter the structures of the binary mixtures of ionic/zwitterionic and ionic/nonionic micelles by causing elongation, shell shrinkage and dehydration, with the exact alteration being determined by the molar ratio in the mixture.
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Affiliation(s)
- Xuzhi Hu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Haoning Gong
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Peter Hollowell
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Mingrui Liao
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Zongyi Li
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Sean Ruane
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Huayang Liu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Elias Pambou
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Najet Mahmoudi
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | | | - Faheem Padia
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Gordon Bell
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jian R Lu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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14
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Chen Q, Yang Z, Tai X, Bai Y, Wang G. Study on influencing factors of Pickering emulsion stabilized by modified montmorillonite and fatty alcohol polyoxyethylene ether. J DISPER SCI TECHNOL 2021. [DOI: 10.1080/01932691.2021.1884088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Qian Chen
- China Research Institute of Daily Chemistry Co., Ltd, Taiyuan, P. R. China
| | - Zeyu Yang
- China Research Institute of Daily Chemistry Co., Ltd, Taiyuan, P. R. China
| | - Xiumei Tai
- China Research Institute of Daily Chemistry Co., Ltd, Taiyuan, P. R. China
| | - Yanyun Bai
- China Research Institute of Daily Chemistry Co., Ltd, Taiyuan, P. R. China
| | - Guoyong Wang
- China Research Institute of Daily Chemistry Co., Ltd, Taiyuan, P. R. China
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15
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Liu H, Hu X, Li Z, Fa K, Gong H, Ma K, Liao M, Li P, Webster JRP, Petkov JT, Thomas RK, Ren Lu J. Surface adsorption and solution aggregation of a novel lauroyl-l-carnitine surfactant. J Colloid Interface Sci 2021; 591:106-114. [PMID: 33592522 DOI: 10.1016/j.jcis.2021.01.106] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/18/2021] [Accepted: 01/31/2021] [Indexed: 11/19/2022]
Abstract
HYPOTHESIS l-carnitine plays a crucial role in the cellular production of energy by transporting fatty acids into mitochondria. Acylated l-carnitines are amphiphilic and if appropriate physical properties were demonstrated, they could replace many currently used surfactants with improved biocompatibility and health benefits. EXPERIMENTS This work evaluated the surface adsorption of lauroyl-l-carnitine (C12LC) and its aggregation behavior. The size and shape of the aggregates of C12LC surfactant were studied at different temperatures, concentrations, pH and ionic strength by dynamic light scattering (DLS) and small-angle neutron scattering (SANS). Surface tension measurements were carried out to determine the critical micellar concentration (CMC) of C12LC. Combining with the Gibbs equation, the surface excess at different concentrations could be determined. Neutron reflection (NR) was used to determine the structure of the adsorbed layer at the air/water interface with the help of isotopic contrast variations. FINDINGS At pH 7, the limiting area per molecule (ACMC) of the zwitterionic C12LC adsorbed layer at the air/water interface was found to be 46 Å2 from surface tension and neutron reflection, smaller than the values of C12PC, C12E5, DTAB, C12C4betaine and C12C8betaine but close to that of SDS. A pronounced surface tension minimum at pH 2 at the low ionic strength was linked to a minimum value of area per molecule of about 30 Å2, indicating the competitive adsorption from traces of lauric acid produced by hydrolysis of C12LC. As the concentration increased, area per molecule reached a plateau of 37-39 Å2, indicating the dissolution of the more surface-active lauric acid into the micelles of C12LC. DLS and SANS showed that the size and shape of micelles had little response to temperature, concentration, ionic strength or pH. The SANS profiles measured under 3 isotopic contrasts could be well fitted by the core-shell model, giving a spherical core radius of 15.7 Å and a shell thickness of 10.5 Å. The decrease of pH led to more protonated carboxyl groups and more positively charged micelles, but the micellar structures remained unchanged, in spite of their stronger interaction. These features make C12LC potentially attractive as a solubilizing agent.
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Affiliation(s)
- Huayang Liu
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Xuzhi Hu
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Zongyi Li
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Ke Fa
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Haoning Gong
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Kun Ma
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - Mingrui Liao
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Peixun Li
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - John R P Webster
- ISIS Neutron Facility, Rutherford Appleton Laboratory, STFC, Chilton, Didcot, Oxon OX11 0QX, UK
| | - Jordan T Petkov
- Arch UK Biocides Ltd, Lonza, Hexagon Tower, Delaunays Road, Blackley, Manchester M9 8ZS, UK
| | - Robert K Thomas
- Physical and Theoretical Chemistry, University of Oxford, South Parks, Oxford OX1 3QZ, UK
| | - Jian Ren Lu
- Biological Physics Laboratory, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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16
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Hu X, Pambou E, Gong H, Liao M, Hollowell P, Liu H, Wang W, Bawn C, Cooper J, Campana M, Ma K, Li P, Webster JRP, Padia F, Bell G, Lu JR. How does substrate hydrophobicity affect the morphological features of reconstituted wax films and their interactions with nonionic surfactant and pesticide? J Colloid Interface Sci 2020; 575:245-253. [PMID: 32361410 DOI: 10.1016/j.jcis.2020.04.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 01/19/2023]
Abstract
HYPOTHESIS Surfactants are widely used in agri-sprays to improve pesticide efficiency, but the mechanism underlying their interactions with the surface wax film on plants remains poorly understood. To facilitate physical characterisations, we have reconstituted wheat cuticular wax films onto an optically flat silicon substrate with and without octadecyltrimethoxysilane modification to control surface hydrophobicity. EXPERIMENTS Imaging techniques including scanning electron microscopy (SEM) unravelled morphological features of the reconstituted wax films similar to those on leaves, showing little impact from the different substrates used. Neutron reflection (NR) established that reconstituted wax films were comprised of an underlying wax film decorated with top surface wax protrusions, a common feature irrespective of substrate hydrophobicity and highly consistent with what was observed from natural wax films. NR measurements, with the help of isotopic H/D substitutions to modify the scattering contributions of the wax and solvent, revealed different wax regimes within the wax films, illustrating the impact of surface hydrophilicity on the nanostructures within the wax films. FINDINGS It was observed from both spectroscopic ellipsometry and NR measurements that wax films formed on the hydrophobic substrate were more robust and durable against attack by nonionic surfactant C12E6 solubilised with pesticide Cyprodinil (CP) than films coated on the bare hydrophilic silica. Thus, the former could be a more feasible model for studying the wax-surfactant-pesticide interactions.
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Affiliation(s)
- Xuzhi Hu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Elias Pambou
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Haoning Gong
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Mingrui Liao
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Peter Hollowell
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Huayang Liu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Weimiao Wang
- Department of Materials and National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Carlo Bawn
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Jos Cooper
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Mario Campana
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Kun Ma
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Peixun Li
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - John R P Webster
- STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Faheem Padia
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Gordon Bell
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK
| | - Jian R Lu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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17
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Hu X, Gong H, Li Z, Ruane S, Liu H, Hollowell P, Pambou E, Bawn C, King S, Rogers S, Ma K, Li P, Padia F, Bell G, Ren Lu J. How does solubilisation of plant waxes into nonionic surfactant micelles affect pesticide release? J Colloid Interface Sci 2019; 556:650-657. [DOI: 10.1016/j.jcis.2019.08.098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 08/24/2019] [Accepted: 08/26/2019] [Indexed: 12/24/2022]
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18
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Talley Edwards A, Javidialesaadi A, Weigandt KM, Stan G, Eads CD. Structure and Dynamics of Spherical and Rodlike Alkyl Ethoxylate Surfactant Micelles Investigated Using NMR Relaxation and Atomistic Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13880-13892. [PMID: 31573205 PMCID: PMC10552554 DOI: 10.1021/acs.langmuir.9b01345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Predicting and controlling the properties of amphiphile aggregate mixtures require understanding the arrangements and dynamics of the constituent molecules. To explore these topics, we study molecular arrangements and dynamics in alkyl ethoxylate nonionic surfactant micelles by combining NMR relaxation measurements with large-scale atomistic molecular dynamics simulations. We calculate parameters that determine relaxation rates directly from simulated trajectories, without introducing specific functional forms to describe the dynamics. NMR relaxation rates, which depend on relative motions of interacting atom pairs, are influenced by wide distributions of dynamic time scales. We find that relative motions of neighboring atom pairs are rapid and liquidlike but are subject to structural constraints imposed by micelle morphology. Relative motions of distant atom pairs are slower than nearby atom pairs because changes in distances and angles are smaller when the moving atoms are further apart. Large numbers of atom pairs undergoing these slow relative motions contribute to predominantly negative cross-relaxation rates. For spherical micelles, but not for cylindrical micelles, cross-relaxation rates are positive only for surfactant tail atoms connected to the hydrophilic headgroup. This effect is related to the lower packing density of these atoms at the hydrophilic-hydrophobic boundary in spherical vs cylindrical arrangements, with correspondingly rapid and less constrained motion of atoms at the boundary.
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Affiliation(s)
- Allison Talley Edwards
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
- Corporate Research & Development, The Procter & Gamble Company, Mason, Ohio 45040, United States
| | | | - Katie M. Weigandt
- National Institute of Standards and Technology, 100 Bureau Drive, MS 6102, Gaithersburg, Maryland 20899, United States
| | - George Stan
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Charles D. Eads
- Corporate Research & Development, The Procter & Gamble Company, Mason, Ohio 45040, United States
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19
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Wu X, Chen L, Fan Y, Fu F, Li J, Zhang J. Water Solubility and Surface Property of Alkyl Di-/Tri-/Tetraoxyethyl β-d-Xylopyranosides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:10361-10372. [PMID: 31487173 DOI: 10.1021/acs.jafc.9b03435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides as derivatives of alkyl xylosides are a class of non-ionic sugar-based surfactants. They were stereoselectively synthesized by the Helferich method. Their properties including hydrophilic-lipophilic balance number, water solubility, surface property, foam property, emulsifying property, and thermotropic liquid crystal property were mainly investigated. The results showed that their water solubility decreased with increasing the alkyl chain length and increasing the number of the oligooxyethyl fragment. The critical micelle concentration had a monotonous decreasing trend with increasing the alkyl chain length. Nonyl di-/tri-/tetraoxyethyl β-d-xylopyranosides [-(OCH2CH2)m-, where m = 2, 3, and 4] exhibited the most excellent foaming ability and foam stability. In the n-octane/water system, dodecyl tetraoxyethyl β-d-xylopyranosides and tetradecyl tetraoxyethyl β-d-xylopyranosides had the strongest emulsion ability. In addition, some alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides had thermotropic liquid crystal properties. Such sugar-based surfactants, alkyl di-/tri-/tetraoxyethyl β-d-xylopyranosides, will be expected to develop for a variety of practical application.
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Affiliation(s)
- Xiubing Wu
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
| | - Langqiu Chen
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
| | - Yulin Fan
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
| | - Fang Fu
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
| | - Jiping Li
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
| | - Jing Zhang
- Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry , Xiangtan University , Xiangtan , Hunan 411105 , People's Republic of China
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20
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Băran A, Stîngă G, Anghel DF, Brânzoi F. Micellar size changing in the systems of octaethylene glycol mono(n-dodecyl) ether without and with poly(acrylic acid). J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.04.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Hu X, Gong H, Li Z, Ruane S, Liu H, Pambou E, Bawn C, King S, Ma K, Li P, Padia F, Bell G, Lu JR. What happens when pesticides are solubilized in nonionic surfactant micelles. J Colloid Interface Sci 2019; 541:175-182. [DOI: 10.1016/j.jcis.2019.01.056] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/12/2019] [Accepted: 01/14/2019] [Indexed: 11/26/2022]
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22
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Pambou E, Hu X, Li Z, Campana M, Hughes A, Li P, Webster JRP, Bell G, Lu JR. Structural Features of Reconstituted Cuticular Wax Films upon Interaction with Nonionic Surfactant C 12E 6. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3395-3404. [PMID: 29444568 DOI: 10.1021/acs.langmuir.8b00143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The interaction of nonionic surfactant hexaethylene glycol monododecyl ether (C12E6) with a reconstituted cuticular wheat wax film has been investigated by spectroscopic ellipsometry and neutron reflection (NR) to help understand the role of the leaf wax barrier during pesticide uptake, focusing on the mimicry of the actions adjuvants impose on the physical integrity and transport of the cuticular wax films against surfactant concentration. As the C12E6 concentration was increased up to the critical micelle concentration (CMC = 0.067 mM), an increasing amount of surfactant mass was deposited onto the wax film. Alongside surface adsorption, C12E6 was also observed to penetrate the wax film, which is evident from the NR measurements using fully protonated and chain-deuterated surfactants. Furthermore, surfactant action upon the model wax film was found to be physically reversible below the CMC, as water rinsing could readily remove the adsorbed surfactant, leaving the wax film in its original state. Above the CMC, the detergency action of the surfactant became dominant, and a significant proportion of the wax film was removed, causing structural damage. The results thus reveal that both water and C12E6 could easily penetrate the wax film throughout the concentration range measured, indicating a clear pathway for the transport of active ingredients while the removal of the wax components above the CMC must have enhanced the transport process. As the partial removal of the wax film could also expose the underlying cutaneous substrate to the environment and undermine the plant's health, this study has a broad implication to the roles of surfactants in crop care.
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Affiliation(s)
- Elias Pambou
- Biological Physics Group, School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Xuzhi Hu
- Biological Physics Group, School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Zongyi Li
- Biological Physics Group, School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Mario Campana
- STFC ISIS Facility, Rutherford Appleton Laboratory , Didcot OX11 0QX , U.K
| | - Arwel Hughes
- STFC ISIS Facility, Rutherford Appleton Laboratory , Didcot OX11 0QX , U.K
| | - Peixun Li
- STFC ISIS Facility, Rutherford Appleton Laboratory , Didcot OX11 0QX , U.K
| | - John R P Webster
- STFC ISIS Facility, Rutherford Appleton Laboratory , Didcot OX11 0QX , U.K
| | - Gordon Bell
- Syngenta, Jealott's Hill International Research Centre , Bracknell , Berkshire RG42 6EY , U.K
| | - Jian R Lu
- Biological Physics Group, School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
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23
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Vierros S, Sammalkorpi M. Effects of 1-hexanol on C 12E 10 micelles: a molecular simulations and light scattering study. Phys Chem Chem Phys 2018; 20:6287-6298. [PMID: 29431748 DOI: 10.1039/c7cp07511a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The micelles of the non-ionic C12E10 surfactant and 1-hexanol as an aqueous solution additives are studied toward the purpose of understanding the role of alcohol additives in tuning the characteristics of alkyl-ethoxylate micellar systems. Our dynamic light scattering and cloud point experiments show that the addition of hexanol induces a response similar to an increase of temperature. We associate the change with increased attraction between the micelles at low to moderate hexanol loadings and a potential increase of the aggregate size at a high hexanol-to-surfactant ratio. Detailed molecular dynamic simulation characterization shows that hexanol solubilizes to a micelle palisade layer when the hexanol-to-C12E10 ratio is less than or equal to 0.5 while swollen micelles, in which a part of hexanol forms an oil core, are present when the ratio increases above approximately 1.5. The simulations indicate that the surface of the micelles is rough. Formation of reverse hexanol structures akin to those found in bulk octanol is observed in the oil core. Molecular simulations associate the increase in attraction between micelles observed via the experiments with decreased chain density in the headgroup region. This density decrease is caused by hexanol molecules solubilized between neighbouring surfactants. Altogether, these findings provide detailed physical characterization of the effect of an archetypal solution additive, hexanol, on an alkyl ethoxylate micelle system. These findings could bear a significance in designing micellar and emulsion based systems with desired solution characteristics or properties for e.g. drug delivery, catalysis, or platforms for green chemistry reactions.
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Affiliation(s)
- Sampsa Vierros
- Department of Chemistry and Materials Science, School of Chemical Engineering, Aalto University, P. O. Box 16100, FI-00076 Aalto, Finland.
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24
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Dar AA, Romsted LS, Nazir N, Zhang Y, Gao X, Gu Q, Liu C. A novel combined chemical kinetic and trapping method for probing the relationships between chemical reactivity and interfacial H 2O, Br - and H + ion molarities in CTAB/C 12E 6 mixed micelles. Phys Chem Chem Phys 2018. [PMID: 28627562 DOI: 10.1039/c7cp03413j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A delicate balance-of-forces governs the interactions responsible for surfactant self-assembly and chemical reactivity within them. Chemical reactions in micellar media generally occur in the interfacial region of micelles that is a complex mixture of: water, headgroups, counterions, co-ions, acids or bases, organic solvents, and the reactants themselves. We have carried out a detailed study of a complex chemical reaction in mixed CTAB/C12E6 micelles by using the chemical kinetic (CK) and chemical trapping (CT) methods. The results provide a detailed quantitative treatment of the reaction of the anion of the antioxidant t-butylhydroquinone, TBHQ-, with 4-hexadecylbenzenediazonium, 16-ArN2+, within the interfacial region of the mixed micelles in the C12E6 mole fraction range of 0 to 1 at three different total surfactant concentrations. CK experiments showed that this reaction is monophasic in C12E6 micelles, but biphasic in mixed micelles. The results were fully consistent with a complex mechanism in which TBHQ- reacts with 16-ArN2+ to give a transient diazoether intermediate that competitively breaks down into products and or reverts to starting materials. The kinetics are the same in mixed micelles of CTAB/C12E6 (grow) and CTAB/C12E8 (don't grow) showing that the rates only depend on micelle composition, not shape. CT results provided estimates of interfacial molarities of H2O are approximately constant at ca. 39 and Br- decreases from ca. 2.75 to 0.05 moles per liter of interfacial volume as C12E6 mole fraction increases from 0 to 1. Combined CK/CT results provided values for interfacial pH, ranging from ca. 4.25 in cationic micelles to 1.5 in nonionic micelles despite a constant bulk pH of 1.5 and the TBHQ interfacial pKa = 3.8 at all C12E6 molar fractions. In totality, these results yielded an extraordinary amount of quantitative information about the relationships between the chemical reactivity and interfacial compositions of the mixed micelles.
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Affiliation(s)
- Aijaz Ahmad Dar
- Physical Chemistry Division, Department of Chemistry, University of Kashmir, Hazratbal, Srinagar-190006, J&K, India.
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25
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Nakahara H, Nishizaka H, Iwasaki K, Otsuji Y, Sato M, Matsuoka K, Shibata O. Role of the spacer of Gemini surfactants in solubilization into their micelles. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Singh AK, Thota BNS, Schade B, Achazi K, Khan A, Böttcher C, Sharma SK, Haag R. Aggregation Behavior of Non-ionic Twinned Amphiphiles and Their Application as Biomedical Nanocarriers. Chem Asian J 2017; 12:1796-1806. [DOI: 10.1002/asia.201700450] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 04/24/2017] [Indexed: 01/10/2023]
Affiliation(s)
| | - Bala N. S. Thota
- Institut für Chemie und Biochemie; Freie Universität Berlin; Takustraße 3 14195 Berlin Germany
| | - Boris Schade
- Forschungszentrum für Elektronenmikroskopie; Institut für Chemie und Biochemie; Freie Universität Berlin; Fabeckstraße 36 a 14195 Berlin Germany
| | - Katharina Achazi
- Institut für Chemie und Biochemie; Freie Universität Berlin; Takustraße 3 14195 Berlin Germany
| | - Abdullah Khan
- Department of Chemistry; University of Delhi; Delhi India
| | - Christoph Böttcher
- Forschungszentrum für Elektronenmikroskopie; Institut für Chemie und Biochemie; Freie Universität Berlin; Fabeckstraße 36 a 14195 Berlin Germany
| | | | - Rainer Haag
- Institut für Chemie und Biochemie; Freie Universität Berlin; Takustraße 3 14195 Berlin Germany
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27
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Zhang L, Kang W, Xu D, Jiang J, Feng H, Yang M, Zhou Q, Wu H. Study on thermally-induced aggregates transformation and its mechanism in cetyltrimethyl ammonium bromide/sodium dodecyl sulfate surfactants mixtures. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.03.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Zhang L, Kang W, Xu D, Feng H, Zhang P, Li Z, Lu Y, Wu H. The rheological characteristics for the mixtures of cationic surfactant and anionic–nonionic surfactants: the role of ethylene oxide moieties. RSC Adv 2017. [DOI: 10.1039/c6ra28071d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Ethylene oxide moieties in various numbers regulate the rheological characteristics of anionic–nonionic/cationic surfactants solutions by affecting the molecular self-assembly.
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Affiliation(s)
- Liming Zhang
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Wanli Kang
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
- School of Petroleum Engineering
| | - Derong Xu
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Haishun Feng
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Pengyi Zhang
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Zhe Li
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Yao Lu
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
| | - Hairong Wu
- Institute of Enhanced Oil Recovery
- China University of Petroleum (Beijing)
- Beijing
- P.R. China
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29
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Zhang WF, Yang Y, Su X, Xu DY, Yan YL, Gao Q, Duan MH. Deoxyschizandrin suppresses dss-induced ulcerative colitis in mice. Saudi J Gastroenterol 2016; 22:448-455. [PMID: 27976641 PMCID: PMC5184746 DOI: 10.4103/1319-3767.195552] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND/AIMS Deoxyschizandrin as one of the most important component of Schisandra chinensis (Turcz.) Baill plays an immunomodulatory role in a variety of diseases, yet its role in ulcerative colitis remains to be elucidated. We aimed to investigate the role of deoxyschizandrin in DSS-induced ulcerative colitis in mice. PATIENTS AND METHODS In the present study, an inflammation model of cells was constructed to confirm the anti-inflammatory effect of deoxyschizandrin. Then a mouse model with Dextran sulfate sodium sulfate (DSS)-induced ulcerative colitis was constructed, and the effects of deoxyschizandrin on mouse colon inflammation, apoptosis, and CD4 T lymphocyte infiltration in ulcerative colitis were examined. RESULT Deoxyschizandrin could improve the symptoms of ulcerative colitis, determined by hematoxylin-eosin (HE) staining and histopathological scores. Moreover, deoxyschizandrin reduced the levels of inflammatory cytokines, suppressed CD4 T cell infiltration, and effectively inhibited apoptosis in the colon of DSS-induced ulcerative colitis mice. CONCLUSION In summary, deoxyschizandrin can effectively rescue the symptoms of DSS-induced ulcerative colitis in mice by inhibiting inflammation. T cell infiltration and apoptosis in the colon, suggesting that deoxyschizandrin could be a potential drug in treating ulcerative colitis.
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Affiliation(s)
- Wen-feng Zhang
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Yan Yang
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Xin Su
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Da-yan Xu
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Yu-li Yan
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Qiao Gao
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China
| | - Ming-hua Duan
- Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road 1035, Changchun, Jilin, China,Address for correspondence: Dr. Ming-hua Duan, Changchun University of Chinese Medicine, Changchun Jingyue Street, Boshuo Road, China. E-mail:
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30
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Pambou E, Crewe J, Yaseen M, Padia FN, Rogers S, Wang D, Xu H, Lu JR. Structural Features of Micelles of Zwitterionic Dodecyl-phosphocholine (C₁₂PC) Surfactants Studied by Small-Angle Neutron Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9781-9789. [PMID: 26301341 DOI: 10.1021/acs.langmuir.5b02077] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Small-angle neutron scattering (SANS) was used to investigate the size and shape of zwitterionic dodecyl phosphocholine (C12PC) micelles formed at various concentrations above its critical micelle concentration (CMC = 0.91 mM). The predominant spherical shape of micelles is revealed by SANS while the average micellar size was found to be broadly consistent with the hydrodynamic diameters determined by dynamic light scattering (DLS). Cryogenic tunneling electron microscopy (cryo-TEM) shows a uniform distribution of structures, proposing micelle monodispersity ( Supporting Information ). H/D substitution was utilized to selectively label the chain, head, or entire surfactant so that structural distributions within the micellar assembly could be investigated using fully protonated, head-deuterated, and tail-deuterated PC surfactants in D2O and fully deuterated surfactants in H2O. Using the analysis software we have developed, the four C12PC contrasts at a given concentration were simultaneously analyzed using various core-shell models consisting of a hydrophobic core and a shell representing hydrated polar headgroups. Results show that at 10 mM, C12PC micelles can be well represented by a spherical core-shell model with a core radius and shell thicknesses of 16.9 ± 0.5 and 10.2 ± 2.0 Å (total radius 27.1 ± 2.0 Å), respectively, with a surfactant aggregation number of 57 ± 5. As the concentration was increased, the SANS data revealed an increase in core-shell mixing, characterized by the emergence of an intermediate mixing region at the spherical core-shell interface. C12PC micelles at 100 mM were found to have a core radius and shell thicknesses of 19.6 ± 0.5 and 7.8 ± 2.0 Å, with an intermediate mixing region of 3.0 ± 0.5 Å. Further reduction in the shell thickness with concentration was also observed, coupled with an increased mixing of the core and shell regions and a reduction in miceller hydration, suggesting that concentration has a significant influence on surfactant packing and aggregation within micelles.
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Affiliation(s)
- Elias Pambou
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - John Crewe
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Mohammed Yaseen
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Faheem N Padia
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
| | - Sarah Rogers
- STFC ISIS Facility, Rutherford Appleton Laboratory , Didcot OX11 0QX, United Kingdom
| | - Dong Wang
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266555, China
| | - Hai Xu
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266555, China
| | - Jian R Lu
- Biological Physics Group, School of Physics and Astronomy, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom
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31
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Size characterization of commercial micelles and microemulsions by Taylor dispersion analysis. Int J Pharm 2015; 492:46-54. [DOI: 10.1016/j.ijpharm.2015.06.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/19/2015] [Accepted: 06/20/2015] [Indexed: 01/09/2023]
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32
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Song J, Salas C, Rojas OJ. Role of textile substrate hydrophobicity on the adsorption of hydrosoluble nonionic block copolymers. J Colloid Interface Sci 2015; 454:89-96. [PMID: 26004573 DOI: 10.1016/j.jcis.2015.04.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/28/2015] [Indexed: 10/23/2022]
Abstract
The adsorption of polyalkylene glycols and co-polymers of ethylene oxide and propylene oxide on substrates relevant to textiles with varying surface energies (cellulose, polypropylene, nylon and polyester) was studied by using quartz crystal microgravimetry. Langmuirian-type isotherms were observed for the adsorption profiles of nonionic block polymers of different architectures. The affinity with the surfaces is discussed based on experimental observations, which highlights the role of hydrophobic effects. For a given type of block polymer, micellar and monomeric adsorption is governed by the balance of polymer structure (mainly, chain length of hydrophobic segments) and substrate's surface energy.
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Affiliation(s)
- Junlong Song
- Jiangsu Provincial Key Laboratory of Pulp and Paper Science & Technology, Nanjing Forestry University, Nanjing, Jiangsu 210037, PR China; Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, NC 27695-8005, USA.
| | - Carlos Salas
- Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, NC 27695-8005, USA
| | - Orlando J Rojas
- Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, NC 27695-8005, USA; Bio-based Colloids and Materials, School of Chemical Technology, Aalto University, P.O. Box 16300, Aalto FIN-00076, Finland.
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Nakahara H, Kojima Y, Moroi Y, Shibata O. Solubilization of n-alkylbenzenes into gemini surfactant micelles in aqueous medium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5771-5779. [PMID: 24802668 DOI: 10.1021/la501519a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Solubilization of benzene, toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, and n-pentylbenzene into micelles of decanediyl-1-10-bis(dimethyltetradecylammonium bromide) (14-10-14,2Br(-)) has been investigated in the temperature range from 288.2 to 308.2 K. The equilibrium concentrations of all the solubilizates are determined spectrophotometrically. The concentration of the solubilizates remains constant below the critical micelle concentration (cmc) and increases linearly with an increase in 14-10-14,2Br(-) concentration above the cmc. Compared to the mother micelle, the solubilized micelles indicate much larger hydrodynamic diameters, which are determined by dynamic light scattering. Therefore, the Gibbs energy change for the solubilization of n-alkylbenzenes has been evaluated by the partitioning of the solubilizates between the aqueous and micellar phases. Furthermore, the enthalpy and entropy changes for the solubilization could be calculated from temperature dependence of the Gibbs energy change. From the thermodynamic parameters, it is found that the solubilization for the present system is entropy-driven and that the location of the solubilizates moves into the inner core of the micelle with an elongation of their alkyl chains. The movement on the location is also supported by the results of absorption spectra, Fourier transform infrared (FTIR) spectra, and two-dimensional nuclear Overhauser effect spectroscopy (2-D NOESY).
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Affiliation(s)
- Hiromichi Nakahara
- Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University ; 2825-7 Huis Ten Bosch, Sasebo, Nagasaki 859-3298, Japan
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