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Hirata K, Araki T. Formation dynamics of branching structure in the slippery DLCA model. J Chem Phys 2024; 160:234901. [PMID: 38885038 DOI: 10.1063/5.0197122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 05/28/2024] [Indexed: 06/18/2024] Open
Abstract
We numerically investigated the aggregation dynamics and resulting network structures of colloidal gels using the slippery diffusion-limited cluster aggregation (DLCA) model. In this model, bonds are irreversibly formed upon the particle contacts, but the angles among them are not fixed, unlike the conventional DLCA. This allows clusters to be deformed in the process of aggregation. By characterizing the aggregation dynamics and using a reduced network scheme, our simulation revealed two distinct branching structure formation routes depending on the particle volume fraction ϕ. In lower volume fraction systems (ϕ ≤ 8%), the deformations of small-size clusters proceed prior to the percolation. When the Maxwell criterion is satisfied and the clusters become mechanically stable, the formation of the branching structure is nearly completed. After forming the branching structures, they aggregate and form a larger percolating network. Then, the aggregation proceeds through the elongation and straightening of the chain parts of the network. In higher volume fraction systems (ϕ > 8%), on the other hand, the clusters percolate, and a fine and homogeneous branching structure is formed at the early stage of the aggregation. In the aging stage, it collapses into a denser and more heterogeneous structure and becomes more stable. Our quantitative analyses of the branching structure will shed light on a new strategy for describing the network formation and elasticity of colloidal gels.
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Affiliation(s)
- Koichi Hirata
- Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502, Japan
| | - Takeaki Araki
- Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-8502, Japan
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2
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Attar ES, Chaudhari VH, Deokar CG, Dyawanapelly S, Devarajan PV. Nano Drug Delivery Strategies for an Oral Bioenhanced Quercetin Formulation. Eur J Drug Metab Pharmacokinet 2023; 48:495-514. [PMID: 37523008 DOI: 10.1007/s13318-023-00843-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2023] [Indexed: 08/01/2023]
Abstract
Quercetin, a naturally occurring flavonoid, has been credited with a wide spectrum of therapeutic properties. However, the oral use of quercetin is limited due to its poor water solubility, low bioavailability, rapid metabolism, and rapid plasma clearance. Quercetin has been studied extensively when used with various nanodelivery systems for enhancing quercetin bioavailability. To enhance its oral bioavailability and efficacy, various quercetin-loaded nanosystems such as nanosuspensions, polymer nanoparticles, metal nanoparticles, emulsions, liposomes or phytosomes, micelles, solid lipid nanoparticles, and other lipid-based nanoparticles have been investigated in in-vitro cells, in-vivo animal models, and humans. Among the aforementioned nanosystems, quercetin phytosomes are attracting more interest and are available on the market. The present review covers insights into the possibilities of harnessing quercetin for several therapeutic applications and a special focus on anticancer applications and the clinical benefits of nanoquercetin formulations.
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Affiliation(s)
- Esha S Attar
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra, 400019, India
| | - Vanashree H Chaudhari
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra, 400019, India
| | - Chaitanya G Deokar
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra, 400019, India
| | - Sathish Dyawanapelly
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra, 400019, India
| | - Padma V Devarajan
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N.P. Marg, Matunga, Mumbai, Maharashtra, 400019, India.
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3
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Xu Y, Mason TG. Jamming and depletion in extremely bidisperse mixtures of microscale emulsions and nanoemulsions. SCIENCE ADVANCES 2023; 9:eadh3715. [PMID: 37379378 DOI: 10.1126/sciadv.adh3715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/25/2023] [Indexed: 06/30/2023]
Abstract
While much attention has been given to jamming of granular and colloidal particles having monomodal size distributions, jamming of systems having more complex size distributions remains an interesting direction. We create concentrated, disordered binary mixtures of size-fractionated nanoscale and microscale oil-in-water emulsions, which are stabilized by the same common ionic surfactant, and measure the optical transport properties, microscale droplet dynamics, and mechanical shear rheological properties of these mixtures over a wide range of relative and total droplet volume fractions. Simple effective medium theories do not explain all of our observations. Instead, we show that our measurements are consistent with more complex collective behavior in extremely bidisperse systems, involving an effective continuous phase that governs nanodroplet jamming, as well as depletion attractions between microscale droplets induced by nanoscale droplets.
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Affiliation(s)
- Yixuan Xu
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Thomas G Mason
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095, USA
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4
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Yang Y, Zeng H, Wang D, Wu Y, Chen J, Huang Y, Wang P, Feng W. Fractal Growth of Quasi Two-Dimensional Copper Dendrites by Template-free Electrodeposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:3045-3051. [PMID: 36790122 DOI: 10.1021/acs.langmuir.2c03069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Fractal dendrites are extensively observed in industry, especially in the electrochemical deposition process. The fractal dendrite electrodeposition behavior of quasi-two-dimensional Cu (Q2D-Cu) metal based on the wire is examined via direct electrodeposition using a thin layer reactor. Here, to explain the fractal growth mechanism, the directional migration and random walking of ions are introduced in the traditional diffusion-limited aggregation model, and fractal patterns consistent with the experimental results are successfully simulated. In addition, the Cu fractal dendrite structure is finely adjusted by varying electrodeposition conditions, demonstrating its great potential for further optimization. The CuO/Q2D-Cu fractal dendrite photothermal device fabricated through in situ assembly of CuO nanowires on Cu fractal dendrite has good photothermal conversion ability. Therefore, metal fractal dendrites, which are considered harmful in the electroplating industry, have application prospects in the photothermal field.
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Affiliation(s)
- Yuxin Yang
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Haoyue Zeng
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Daiyi Wang
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Yujian Wu
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Jiaqi Chen
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Yanyan Huang
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Pan Wang
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
| | - Wei Feng
- School of Mechanical Engineering, Chengdu University, Chengdu610000, PR China
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5
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Xu Y, Mason TG. Complex optical transport, dynamics, and rheology of intermediately attractive emulsions. Sci Rep 2023; 13:1791. [PMID: 36720895 PMCID: PMC9889356 DOI: 10.1038/s41598-023-28308-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/17/2023] [Indexed: 02/02/2023] Open
Abstract
Introducing short-range attractions in Brownian systems of monodisperse colloidal spheres can substantially impact their structures and consequently their optical transport and rheological properties. Here, for size-fractionated colloidal emulsions, we show that imposing an intermediate strength of attraction, well above but not much larger than thermal energy ([Formula: see text] [Formula: see text], through micellar depletion leads to a striking notch in the measured inverse mean free path of optical transport, [Formula: see text], as a function of droplet volume fraction, [Formula: see text]. This notch, which appears between the hard-sphere glass transition, [Formula: see text], and maximal random jamming, [Formula: see text], implies the existence of a greater population of compact dense clusters of droplets, as compared to tenuous networks of droplets in strongly attractive emulsion gels. We extend a prior decorated core-shell network model for strongly attractive colloidal systems to include dense non-percolating clusters that do not contribute to shear rigidity. By constraining this extended model using the measured [Formula: see text], we improve and expand the microrheological interpretation of diffusing wave spectroscopy (DWS) experiments made on attractive colloidal systems. Our measurements and modeling demonstrate richness and complexity in optical transport and shear rheological properties of dense, disordered colloidal systems having short-range intermediate attractions between moderately attractive glasses and strongly attractive gels.
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Affiliation(s)
- Yixuan Xu
- grid.19006.3e0000 0000 9632 6718Department of Materials Science and Engineering, University of California- Los Angeles, Los Angeles, CA 90095 USA
| | - Thomas G. Mason
- grid.19006.3e0000 0000 9632 6718Department of Chemistry and Biochemistry, University of California- Los Angeles, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Physics and Astronomy, University of California- Los Angeles, Los Angeles, CA 90095 USA
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6
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Mahdieh Z, Cherne MD, Fredrikson JP, Sidar B, Sanchez HS, Chang CB, Bimczok D, Wilking JN. Granular Matrigel: restructuring a trusted extracellular matrix material for improved permeability. Biomed Mater 2022; 17. [PMID: 35609584 DOI: 10.1088/1748-605x/ac7306] [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: 02/01/2022] [Accepted: 05/24/2022] [Indexed: 11/11/2022]
Abstract
Matrigel is a polymeric extracellular matrix material produced by mouse cancer cells. Over the past four decades, Matrigel has been shown to support a wide variety of two- and three-dimensional cell and tissue culture applications including organoids. Despite widespread use, transport of molecules, cells, and colloidal particles through Matrigel can be limited. These limitations restrict cell growth, viability, and function and limit Matrigel applications. A strategy to improve transport through a hydrogel without modifying the chemistry or composition of the gel is to physically restructure the material into microscopic microgels and then pack them together to form a porous material. These 'granular' hydrogels have been created using a variety of synthetic hydrogels, but granular hydrogels composed of Matrigel have not yet been reported. Here we present a drop-based microfluidics approach for structuring Matrigel into a three-dimensional, mesoporous material composed of packed Matrigel microgels, which we call granular Matrigel. We show that restructuring Matrigel in this manner enhances the transport of colloidal particles and human dendritic cells (DCs) through the gel while providing sufficient mechanical support for culture of human gastric organoids (HGOs) and co-culture of human DCs with HGOs.
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Affiliation(s)
- Zahra Mahdieh
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
| | - Michelle D Cherne
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States of America
| | - Jacob P Fredrikson
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
| | - Barkan Sidar
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
| | - Humberto S Sanchez
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
| | - Connie B Chang
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
| | - Diane Bimczok
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States of America
| | - James N Wilking
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT, United States of America.,Center for Biofilm Engineering, Montana State University, Bozeman, MT, United States of America
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7
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Hamed R, Seder BY, Bardaweel SK, Qawass H. Lipid-based formulations of microemulsion-loaded oleogels for the oral delivery of carvedilol. J DISPER SCI TECHNOL 2021. [DOI: 10.1080/01932691.2021.1964987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Rania Hamed
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
| | - Bayan Yaser Seder
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
| | - Sanaa K. Bardaweel
- Department of Pharmacy, School of Pharmacy, University of Jordan, Amman, Jordan
| | - Hala Qawass
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
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8
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Kim HS, Xu Y, Scheffold F, Mason TG. Self-motion and heterogeneous droplet dynamics in moderately attractive dense emulsions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:175101. [PMID: 33513598 DOI: 10.1088/1361-648x/abe157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
We show that diffusing wave spectroscopy (DWS) is sensitive to the presence of a moderate short-range attraction between droplets in uniform fractionated colloidal emulsions near and below the jamming point associated with monodisperse hard spheres. This moderate interdroplet attraction, induced by micellar depletion, has an energy of about ∼2.4kBT, only somewhat larger than thermal energy. Although changes in the mean free path of optical transport caused by this moderate depletion attraction are small, DWS clearly reveals an additional secondary decay-to-plateau in the intensity autocorrelation function at long times that is not present when droplet interactions are nearly hard. We hypothesize that this secondary decay-to-plateau does not reflect the average self-motion of individual droplets experiencing Brownian excitations, but instead results from heterogeneous dynamics involving a sub-population of droplets that still experience bound motion yet with significantly larger displacements than the average. By effectively removing the contribution of this secondary decay-to-plateau, which is linked to greater local heterogeneity in droplet structure caused by the moderate attraction, we obtain self-motion mean square displacements (MSDs) of droplets that reflect only the initial primary decay-to-plateau. Moreover, we show that droplet self-motion primary plateau MSDs can be interpreted using the generalized Stokes-Einstein relation of passive microrheology, yielding quantitative agreement with plateau elastic shear moduli measured mechanically.
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Affiliation(s)
- Ha Seong Kim
- Department of Chemistry and Biochemistry, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
| | - Yixuan Xu
- Department of Materials Science and Engineering, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
| | - Frank Scheffold
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Thomas G Mason
- Department of Chemistry and Biochemistry, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
- Department of Physics and Astronomy, University of California- Los Angeles, Los Angeles, CA 90095, United States of America
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9
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Abbasian Chaleshtari Z, Salimi-Kenari H, Foudazi R. Interdroplet Interactions and Rheology of Concentrated Nanoemulsions for Templating Porous Polymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:76-89. [PMID: 33337881 DOI: 10.1021/acs.langmuir.0c02366] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In the current study, we investigate the colloidal behavior of nanoemulsions over a wide range of oil volume fractions (φ) from dilute to concentrated regime. The dilute system contains 25% silicone oil dispersed in the aqueous phase consisting of poly(ethylene glycol)-diacrylate (PEGDA) and sodium dodecyl sulfate (SDS), which is concentrated through evaporation of water at two different rates at ambient temperature. The rheological studies show that the liquid-like nanoemulsions transform into viscoelastic gels at a volume fraction of ∼30%. The plateau storage modulus of the nanoemulsions increases in the semidilute systems (φ below 45%) and then decreases steadily with increasing φ up to 60%. Dependency of the modulus on the evaporation rate can be observed in the rheological results. According to the rheological results and the overall pairwise interactions estimated between droplets, we propose two regimes of colloidal interactions. In the semidilute regime, the attractive gelation occurs due to considerable short-range attractive depletion induced by the PEGDA oligomer and SDS micelles. In the concentrated regime, the gel weakens by increasing φ mainly due to the structural stabilization barrier from a high concentration of micelles. The PEGDA in the continuous phase of the nanoemulsions can be crosslinked through photopolymerization, resulting in nanoporous PEGDA hydrogels upon removal of oil droplets. We study the water uptake of the nanoporous hydrogels prepared from the nanoemulsion templates at φ = 60%. The hydrogel obtained from the nanoemulsion with fast evaporation rate shows higher water uptake than that obtained from the slowly concentrated nanoemulsion. The tunable viscoelastic behavior of concentrated nanoemulsions as well as the resulting nanoporous hydrogels offers a new platform to design the soft materials for a wide range of applications.
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Affiliation(s)
- Zahra Abbasian Chaleshtari
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Hamed Salimi-Kenari
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003, United States
- Faculty of Engineering & Technology, University of Mazandaran, Babolsar 47416-13534, Iran
| | - Reza Foudazi
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, New Mexico 88003, United States
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10
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Xu Y, Scheffold F, Mason TG. Diffusing wave microrheology of strongly attractive dense emulsions. Phys Rev E 2020; 102:062610. [PMID: 33466019 DOI: 10.1103/physreve.102.062610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/30/2020] [Indexed: 11/07/2022]
Abstract
We advance the microrheological interpretation of optical diffusing wave spectroscopy (DWS) measurements of strongly attractive emulsions at dense droplet volume fractions, ϕ. Beyond accounting for collective scattering, we show that measuring the mean free path of optical transport over a wide range of ϕ is necessary to quantify the effective size of the DWS probes, which we infer to be local dense clusters of droplets through a decorated core-shell network model. This approach yields microrheological elastic shear moduli that are in quantitative agreement with mechanical rheometry.
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Affiliation(s)
- Yixuan Xu
- Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA
| | - Frank Scheffold
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Thomas G Mason
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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11
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Lee JY, Sung M, Seo H, Park YJ, Lee JB, Shin SS, Lee Y, Shin K, Kim JW. Temperature-responsive interdrop association of condensed attractive nanoemulsions. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.02.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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12
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Cheng LC, Kuei Vehusheia SL, Doyle PS. Tuning Material Properties of Nanoemulsion Gels by Sequentially Screening Electrostatic Repulsions and Then Thermally Inducing Droplet Bridging. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3346-3355. [PMID: 32216359 PMCID: PMC7311086 DOI: 10.1021/acs.langmuir.0c00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/17/2020] [Indexed: 06/10/2023]
Abstract
Nanoemulsions are widely used in applications such as food products, cosmetics, pharmaceuticals, and enhanced oil recovery for which the ability to engineer material properties is desirable. Moreover, nanoemulsions are emergent model colloidal systems because of the ease in synthesizing monodisperse samples, flexibility in formulations, and tunable material properties. In this work, we study a nanoemulsion system previously developed by our group in which gelation occurs through thermally induced polymer bridging of droplets. We show here that the same system can undergo a sol-gel transition at room temperature through the addition of salt, which screens the electrostatic interaction and allows the system to assemble via depletion attraction. We systematically study how the addition of salt followed by a temperature jump can influence the resulting microstructures and rheological properties of the nanoemulsion system. We show that the salt-induced gel at room temperature can dramatically restructure when the temperature is suddenly increased and achieves a different gelled state. Our results offer a route to control the material properties of an attractive colloidal system by carefully tuning the interparticle potentials and sequentially triggering the colloidal self-assembly. The control and understanding of the material properties can be used for designing hierarchically structured hydrogels and complex colloid-based materials for advanced applications.
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Affiliation(s)
- Li-Chiun Cheng
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Patrick S. Doyle
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
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13
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Nouri V, Pontes De Siqueira Moura M, Payre B, De Almeida O, Déjugnat C, Franceschi S, Perez E. How an organogelator can gelate water: gelation transfer from oil to water induced by a nanoemulsion. SOFT MATTER 2020; 16:2371-2378. [PMID: 32064481 DOI: 10.1039/d0sm00128g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A hydrogel can be formed by an organogelator in the presence of a nanoemulsion. It is expected that this is due to a gelation transfer from oil to water. The system started with an oil-in-water nanoemulsion prepared according to a phase inversion temperature (PIT) process. Into this nanoemulsion consisting of Kolliphor® RH40 and Brij® L4 as surfactants, and Miglyol® 812 as oil and water, we introduced the organogelator 12-hydroxyoctadecanoic acid (12-HOA) in the oil phase. After cooling at room temperature, a slow reversible gelation of the water phase occurred with persistence of the nanoemulsion. This thermally reversible system was investigated using various techniques (rheology, turbidimetry, optical and electron microscopies, scattering techniques). Successive stages appeared during the cooling process after the nanoemulsion formation, corresponding to the migration and self-assembly of the organogelator from the oil nanodroplets to the water phase. According to our measurements and the known self-assembly of 12-HOA, a mechanism explaining the formation of the gelled nanoemulsion is proposed.
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Affiliation(s)
- Vivien Nouri
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France.
| | | | - Bruno Payre
- Centre de Microscopie Electronique Appliquée à la Biologie (CMEAB) Faculté de Médecine Rangueil, 133, Route de Narbonne, 31062 Toulouse, France
| | - Olivier De Almeida
- Institut Clément Ader (ICA), Université de Toulouse, CNRS, IMT Mines Albi, UPS, INSA, ISAE-SUPAERO, Campus Jarlard, CT Cedex 09 81013, Albi, France
| | - Christophe Déjugnat
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France.
| | - Sophie Franceschi
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France.
| | - Emile Perez
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Toulouse III - Paul Sabatier, France.
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14
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Cheng LC, Hashemnejad SM, Zarket B, Muthukrishnan S, Doyle PS. Thermally and pH-responsive gelation of nanoemulsions stabilized by weak acid surfactants. J Colloid Interface Sci 2020; 563:229-240. [DOI: 10.1016/j.jcis.2019.12.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/12/2019] [Accepted: 12/13/2019] [Indexed: 02/07/2023]
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15
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Modeling the influence of effective oil volume fraction and droplet repulsive interaction on nanoemulsion gelation. J FOOD ENG 2019. [DOI: 10.1016/j.jfoodeng.2018.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Enhancing Curcumin Oral Bioavailability Through Nanoformulations. Eur J Drug Metab Pharmacokinet 2019; 44:459-480. [DOI: 10.1007/s13318-019-00545-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Wei Y, Sun C, Dai L, Mao L, Yuan F, Gao Y. Novel Bilayer Emulsions Costabilized by Zein Colloidal Particles and Propylene Glycol Alginate. 2. Influence of Environmental Stresses on Stability and Rheological Properties. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:1209-1221. [PMID: 30571105 DOI: 10.1021/acs.jafc.8b04994] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Novel bilayer emulsions co-stabilized by zein colloidal particles (ZCPs) and propylene glycol alginate (PGA) were designed to overcome some limitations of conventional emulsions or Pickering emulsions. The bilayer emulsions of various concentrations of PGA (0.01-1.50%, w/v) and different incorporation sequences of ZCPs and PGA (ZCPs/PGA and PGA/ZCPs) were fabricated using the layer by layer (LBL) electrostatic deposition technique. Influence of environmental stresses (pH 2.5-8.5; temperature 60-80 °C ; ionic strength 0-100 mM NaCl) was focused on the stability and rheological properties of the novel bilayer emulsions. In comparison to the Pickering emulsion stabilized by ZCPs alone, bilayer emulsions exhibited improved stability and unique rheological characteristics under environmental stresses. The microstructure of well-defined spheres existing a branchlike network was observed in bilayer emulsions by TEM. A comprehensive evaluation was made of the physical characteristics and stimuli-responsive behavior of bilayer emulsions. The result provided meaningful information for understanding the changing mechanism of rheology of bilayer emulsions under environmental stresses.
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Affiliation(s)
- Yang Wei
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
| | - Cuixia Sun
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
| | - Lei Dai
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
| | - Like Mao
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
| | - Fang Yuan
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
| | - Yanxiang Gao
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering , China Agricultural University , Box 112, No. 17 Qinghua East Road , Beijing 100083 , People's Republic of China
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Zhao K, Mason TG. Assembly of colloidal particles in solution. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:126601. [PMID: 29978830 DOI: 10.1088/1361-6633/aad1a7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Advances in both top-down and bottom-up syntheses of a wide variety of complex colloidal building blocks and also in methods of controlling their assembly in solution have led to new and interesting forms of highly controlled soft matter. In particular, top-down lithographic methods of producing monodisperse colloids now provide precise human-designed control over their sub-particle features, opening up a wide range of new possibilities for assembly structures that had been previously limited by the range of shapes available through bottom-up methods. Moreover, an increasing level of control over anisotropic interactions between these colloidal building blocks, which can be tailored through local geometries of sub-particle features as well as site-specific surface modifications, is giving rise to new demonstrations of massively parallel off-chip self-assembly of specific target structures with low defect rates. In particular, new experimental realizations of hierarchical self-assembly and control over the chiral purity of resulting assembly structures have been achieved. Increasingly, shape-dependent, shape-complementary, and roughness-controlled depletion attractions between non-spherical colloids are being used in novel ways to create assemblies that go far beyond early examples, such as fractal clusters formed by diffusion-limited and reaction-limited aggregation of spheres. As self-assembly methods have progressed, a wide variety of advanced directed assembly methods have also been developed; approaches based on microfluidic control and applying structured electromagnetic fields are particularly promising.
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Affiliation(s)
- Kun Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
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19
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Koroleva M, Nagovitsina T, Yurtov E. Nanoemulsions stabilized by non-ionic surfactants: stability and degradation mechanisms. Phys Chem Chem Phys 2018; 20:10369-10377. [PMID: 29611566 DOI: 10.1039/c7cp07626f] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The prevailing opinion in the literature is that the main mechanism of O/W nanoemulsion degradation is Ostwald ripening. Nevertheless, the experimental rates of Ostwald ripening are usually several orders of magnitude higher than the theoretical values. This suggests that other mechanisms, such as coalescence, flocculation and subsequent creaming, significantly influence nanoemulsion breakdown. We investigated O/W nanoemulsions stabilized by Brij 30 or by a mixture of Tween 80 and Span 80 and with liquid paraffin as a dispersed phase. The results indicate that Ostwald ripening is the main process leading to nanoemulsion coarsening only in nanoemulsions with low oil phase fractions of up to 0.05. For quasi-steady state conditions the rates of Ostwald ripening are equal to (1.5 ± 0.3) × 10-29 and (1.1 ± 0.3) × 10-29 m3 s-1 in nanoemulsions with Brij 30 and Tween 80 & Span 80, respectively. In nanoemulsions with oil phase fractions of 0.15-0.45, different mechanisms are identified. Flocculation prevails over other processes during the first days in nanoemulsions stabilized by Brij 30. Coalescence is the main mechanism of nanoemulsion degradation for long times. An increase in droplet size 5-10 days after nanoemulsion preparation due to Ostwald ripening takes place in the case of nanoemulsion stabilization by Tween 80 and Span 80. The stability behavior of these nanoemulsions at later stages is distinctly affected by coalescence and flocculation.
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Affiliation(s)
- M Koroleva
- Mendeleev University of Chemical Technology, Miusskaya pl. 9, Moscow, 125047, Russia.
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20
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Kim HS, Mason TG. Advances and challenges in the rheology of concentrated emulsions and nanoemulsions. Adv Colloid Interface Sci 2017; 247:397-412. [PMID: 28821349 DOI: 10.1016/j.cis.2017.07.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/02/2017] [Indexed: 11/26/2022]
Abstract
We review advances that have been made in the rheology of concentrated emulsions and nanoemulsions, which can serve as model soft materials that have highly tunable viscoelastic properties at droplet volume fractions near and above the glass transition and jamming point. As revealed by experiments, simulations, and theoretical models, interfacial and positional structures of droplets can depend on the applied flow history and osmotic pressure that an emulsion has experienced, thereby influencing its key rheological properties such as viscoelastic moduli, yield stress and strain, and flow behavior. We emphasize studies of monodisperse droplets, since these have led to breakthroughs in the fundamental understanding of dispersed soft matter. This review also covers the rheological properties of attractive emulsions, which can exhibit a dominant elasticity even at droplet volume fractions far below maximal random jamming of hard spheres.
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21
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Abbas S, Yadav I, Kumar S, Aswal VK, Kohlbrecher J. Structure and interaction in pathway of charged nanoparticles aggregation in saline water as probed by scattering techniques. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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22
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Erramreddy VV, Tu S, Ghosh S. Rheological reversibility and long-term stability of repulsive and attractive nanoemulsion gels. RSC Adv 2017. [DOI: 10.1039/c7ra09605d] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The storage modulus (G′) of a canola oil nanoemulsion gel depends on the storage time and SDS emulsifier concentration.
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Affiliation(s)
| | - Sylvana Tu
- Department of Food and Bioproduct Sciences
- University of Saskatchewan
- Saskatoon
- Canada
| | - Supratim Ghosh
- Department of Food and Bioproduct Sciences
- University of Saskatchewan
- Saskatoon
- Canada
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23
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Helgeson ME. Colloidal behavior of nanoemulsions: Interactions, structure, and rheology. Curr Opin Colloid Interface Sci 2016. [DOI: 10.1016/j.cocis.2016.06.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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24
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Erramreddy VV, Ghosh S. Influence of emulsifier concentration on nanoemulsion gelation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11062-74. [PMID: 25137632 DOI: 10.1021/la502733v] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nanoemulsion gels are a new class of soft materials that manifest stronger elasticity even at lower dispersed phase volume fraction. In this work, gelation in 40 wt % canola oil-in-water nanoemulsions was investigated as a function of emulsifier type (anionic sodium dodecyl sulfate (SDS) or nonionic Tween 20) and concentration. It was observed that the liquid nanoemulsions transformed into viscoelastic gels at a specific concentration range of SDS, whereas no gelation was observed for Tween 20. The apparent viscosity, yield stress, and storage modulus of the nanogels increased with SDS concentration until 15 times critical micelle concentration (CMC), thereafter decreased steadily as the gelation weakened beginning 20 CMC. Three regimes of colloidal interactions in the presence of emulsifier were proposed. (1) Repulsive gelation: at low SDS concentration (0.5-2 times CMC) the repulsive charge cloud around the nanodroplets acted as interfacial shell layer that significantly increased the effective volume fraction of the dispersed phase (ϕ(eff)). When ϕ(eff) became comparable to the volume fraction required for maximal random jamming, nanoemulsions formed elastic gels. (2) Attractive gelation: as the SDS concentration increased to 5-15 times CMC, ϕ(eff) dropped due to charge screening by more counterions from SDS, but depletion attractions generated by micelles in the continuous phase led to extensive droplet aggregation which immobilized the continuous phase leading to stronger gel formation. (3) Decline in gelation due to oscillatory structural forces (OSF): at very high SDS concentration (20-30 time CMC), structural forces were manifested due to the layered-structuring of excess micelles in the interdroplet regions resulting in loss of droplet aggregation. Tween 20 nanoemulsions, on the other hand, did not show repulsive gelation due to lack of charge cloud, while weak depletion attraction and early commencement of OSF regime leading to liquid-like behavior at all concentrations. The nanogels possess great potential for use in low-fat foods, pharmaceuticals and cosmetic products.
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Affiliation(s)
- Vivek Vardhan Erramreddy
- Department of Food and Bioproduct Sciences, University of Saskatchewan , Saskatoon, Saskatchewan S7N 5A8, Canada
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25
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Wang T, LaMontagne D, Lynch J, Zhuang J, Cao YC. Colloidal superparticles from nanoparticle assembly. Chem Soc Rev 2013; 42:2804-23. [DOI: 10.1039/c2cs35318k] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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26
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27
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Affiliation(s)
| | - Thomas G. Mason
- Department of Chemistry and Biochemistry,
- Department of Physics and Astronomy, and
- California NanoSystems Institute, University of California, Los Angeles, California 90095;
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28
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Zhu X, Fryd MM, Huang JR, Mason TG. Optically probing nanoemulsion compositions. Phys Chem Chem Phys 2012; 14:2455-61. [DOI: 10.1039/c2cp23007k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Campi G, Mari A, Pifferi A, Amenitsch H, Fratini M, Suber L. Control of silver-polymer aggregation mechanism by primary particle spatial correlations in dynamic fractal-like geometry. NANOSCALE 2011; 3:3774-3779. [PMID: 21826362 DOI: 10.1039/c1nr10474h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Silver nanocrystals have been prepared by reacting silver nitrate with ascorbic acid in aqueous solution containing a low concentration of a commercial polynaphthalene sulfonate polymer (Daxad 19). Various crystalline morphologies have been obtained simply by tuning the reaction temperature. We have investigated the nanoparticle formation mechanism at three different temperatures by in situ and time resolved small angle X-ray scattering measurements. By modeling the scattering intensity with interacting spherical particles in a fractal-like polymer-Ag matrix, we found signatures of nucleation, growth and assembly of primary particles of about 15-20 nm. We observed how the time evolution of both spatial correlations between primary particles and the dynamic fractal geometry of the polymer-Ag matrix could influence and determine both the aggregation mechanism and the morphology of forming nanostructures in solution.
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Affiliation(s)
- Gaetano Campi
- CNR- Istituto di Cristallografia, Via Salaria, Km 29.300, Monterotondo Stazione, RM I-00015, Italy
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30
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Pippa N, Demetzos C, Danezis E. The formalism of fractal aggregation phenomena of colloidal drug delivery systems. J Liposome Res 2011; 22:55-61. [DOI: 10.3109/08982104.2011.590142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Gimel JC, Nicolai T. Self-diffusion of non-interacting hard spheres in particle gels. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:234115. [PMID: 21613689 DOI: 10.1088/0953-8984/23/23/234115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Different kinds of particle gels were simulated using a process of random aggregation of hard spheres. The mean square displacement of Brownian spherical tracer particles through these rigid gels was monitored and the average diffusion coefficient, normalized with the free diffusion coefficient (D), was obtained. For each gel structure the effect of the gel volume fraction (φ) and size ratio of the tracer (d) on the relative diffusion coefficient was investigated systematically. The volume fraction that is accessible to the tracers (φ(a)) was determined in each case. D was found to be approximately the same if φ(a) was the same, independent of φ, d and the gel structure. However a different behaviour is found if the tracers can penetrate the strands of the gel. A state diagram of d versus φ is given that shows the critical values (d(c), φ(c)) at which all tracers become trapped. Different values are found for different gel structures. The dependence of D on φ/φ(c) is independent of d, while the dependence of D on d/d(c) is independent of φ.
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Affiliation(s)
- Jean-Christophe Gimel
- L'UNAM Université, Laboratoire Polymères, Colloides et Interfaces, UMR CNRS 6120-Université du Maine, av. O. Messioen, 72085 Le Mans cedex 9, France.
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32
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Wilking JN, Chang CB, Fryd MM, Porcar L, Mason TG. Shear-induced disruption of dense nanoemulsion gels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:5204-5210. [PMID: 21469673 DOI: 10.1021/la200021r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The structural evolution and rheology of dense nanoemulsion gels, which have been formed by creating strong attractions between slippery nanodroplets, are explored as a function of steady shear rate using rheological small-angle neutron scattering (rheo-SANS). For applied stresses above the yield stress of the gel, the network yields, fracturing into aggregates that break and reform as they tumble and interact in the shear flow. The average aggregate size decreases with increasing shear rate; meanwhile, droplet rearrangements within the clusters, allowed by the slippery nature of the attractive interaction, increase the local density within the aggregates. At the highest shear rates, all clusters disaggregate completely into individual droplets.
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Affiliation(s)
- James N Wilking
- Department of Chemistry and Biochemistry, University of California-Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095, United States
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33
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Gong XJ, Xing XC, Wei XL, Ngai T. Direct measurement of weak depletion force between two surfaces. CHINESE JOURNAL OF POLYMER SCIENCE 2010. [DOI: 10.1007/s10118-010-1012-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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Malins A, Williams SR, Eggers J, Tanaka H, Royall CP. Geometric frustration in small colloidal clusters. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:425103. [PMID: 21715858 DOI: 10.1088/0953-8984/21/42/425103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We study the structure of clusters in a model colloidal system with competing interactions using Brownian dynamics simulations. A short-ranged attraction drives clustering, while a weak, long-ranged repulsion is used to model electrostatic charging in experimental systems. The former is treated with a short-ranged Morse attractive interaction, the latter with a repulsive Yukawa interaction. We consider the yield of clusters of specific structure as a function of the strength of the interactions, for clusters with m = 3,4,5,6,7,10 and 13 colloids. At sufficient strengths of the attractive interaction (around 10k(B)T), the average bond lifetime approaches the simulation timescale and the system becomes nonergodic. For small clusters, m≤5, where geometric frustration is not relevant, despite nonergodicity, for sufficient strengths of the attractive interaction the yield of clusters which maximize the number of bonds approaches 100%. However for m = 7 and higher, in the nonergodic regime we find a lower yield of these structures where we argue geometric frustration plays a significant role. m = 6 is a special case, where two structures, of octahedral and C(2v) symmetry, compete, with the latter being favoured by entropic contributions in the ergodic regime and by kinetic trapping in the nonergodic regime. We believe that our results should be valid as long as the one-component description of the interaction potential is valid. A system with competing electrostatic repulsions and van der Waals attractions may be such an example. However, in some cases, the one-component description of the interaction potential may not be appropriate.
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Affiliation(s)
- Alex Malins
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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35
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Xing X, Li Z, Ngai T. pH-Controllable Depletion Attraction Induced by Microgel Particles. Macromolecules 2009. [DOI: 10.1021/ma901130x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xiaochen Xing
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Zifu Li
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - To Ngai
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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36
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Alves SG, Vilesov AF, Ferreira SC. Effects of the mean free path and relaxation in a model for the aggregation of particles in superfluid media. J Chem Phys 2009; 130:244506. [DOI: 10.1063/1.3158359] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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37
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Zhao K, Mason TG. Suppressing and enhancing depletion attractions between surfaces roughened by asperities. PHYSICAL REVIEW LETTERS 2008; 101:148301. [PMID: 18851582 DOI: 10.1103/physrevlett.101.148301] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 04/06/2008] [Indexed: 05/26/2023]
Abstract
By decorating the surfaces of smooth, flat platelets with hemispheroidal asperities and calculating the overlapping excluded volume of spherical depletion agents as two platelets approach face to face, we determine the depletion interaction potential for both ordered and disordered surface asperities. Depending on the surface morphologies, the depletion attraction between rough surfaces can be either dramatically reduced or amplified. A phase diagram of roughened Janus platelets is calculated and agrees well with prior experiments. This model explains the observed self-assembly of rough platelets and provides quantitative predictions of roughness-controlled depletion attractions for conditions that have not yet been explored experimentally.
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Affiliation(s)
- Kun Zhao
- Department of Physics, University of California-Los Angeles, Los Angeles, California 90095, USA
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38
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Ruzicka B, Zulian L, Angelini R, Sztucki M, Moussaïd A, Ruocco G. Arrested state of clay-water suspensions: gel or glass? PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:020402. [PMID: 18351973 DOI: 10.1103/physreve.77.020402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 01/09/2008] [Indexed: 05/26/2023]
Abstract
The aging of a charged colloidal system has been studied by small-angle x-ray scattering, in the exchanged momentum range Q=0.03-5 nm(-1) , and by dynamic light scattering, at different clay concentrations (C(w)=0.6-2.8%) . The static structure factor S(Q) has been determined as a function of both aging time and concentration. This is the direct experimental evidence of the existence and evolution with aging time of two different arrested states in a single system simply obtained only by changing its volume fraction: an inhomogeneous state is reached at low concentrations, while a homogeneous one is found at high concentrations.
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Affiliation(s)
- B Ruzicka
- SOFT INFM-CNR and Dipartimento di Fisica, Università di Roma La Sapienza, Rome, Italy
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39
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Zhao K, Mason TG. Directing colloidal self-assembly through roughness-controlled depletion attractions. PHYSICAL REVIEW LETTERS 2007; 99:268301. [PMID: 18233607 DOI: 10.1103/physrevlett.99.268301] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Indexed: 05/25/2023]
Abstract
The surfaces of colloidal particles resulting from many new fabrication methods are not molecularly smooth, so understanding how surface roughness can affect the depletion attraction between the particles and their assembly is very important. We show that the depletion attraction between custom-shaped microscale platelets can be suppressed when the nanoscale surface asperity heights become larger than the depletion agent. In the opposite limit, the attraction reappears and columnar stacks of platelets are formed. Exploiting this, we selectively increase the site-specific roughness on only one side of the platelets to direct the mass production of a single desired assembly: a pure dimer phase.
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Affiliation(s)
- Kun Zhao
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
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40
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Seager CR, Mason TG. Slippery diffusion-limited aggregation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:011406. [PMID: 17358149 DOI: 10.1103/physreve.75.011406] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Indexed: 05/14/2023]
Abstract
Colloidal particles that interact through strong, short-range, secondary attractions in liquids form irreversible "slippery" bonds that are not shear-rigid. Through event-driven simulations of slippery attractive spheres, we show that space-filling fractal clusters still emerge from the process of "slippery" diffusion-limited aggregation (DLA). Although slippery and classic DLA clusters have the same fractal dimension, d_{f}=2.5 , their average coordination numbers are quite different: z_{S}=6 whereas z_{C}=2 . Local tetrahedral attractive jamming of the particles leads to a structure factor, S(q) , that exhibits dense cluster peaks at higher wave numbers, q , and a fractal power-law rise toward lower q .
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Affiliation(s)
- Clair R Seager
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
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