| 1. |
- Kumar, Sonal, et al.
(författare)
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A Bi-based artificial interphase to achieve ultra-long cycling life of Al-metal anode in non-aqueous electrolyte
- 2024
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Ingår i: Energy Storage Materials. - 2405-8297. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- Rechargeable aluminum-ion batteries (RAB) with Al-metal anode are regarded as cost-effective and environmentally sustainable energy storage systems. However, tapping the high volumetric capacity of the Al-anode has been a challenge because of the spontaneous and irreversible formation of the oxide layer on its surface that renders it electrochemically inactive. Though recently reported AlCl3-based electrolytes overcome this problem by breaking down this oxide layer, their highly corrosive nature hampers commercialization. Here, we investigate a novel approach to protect the Al-anode from severe oxidation by engineering an artificial protective interphase. A unique and less corrosive combination of Al(CF3SO3)3 salt and BiCl3 additive reacts with the Al-anode intrinsically to form an inorganic-rich protective bilayer. This layer is electronically insulating and significantly reduces the charge transfer resistance and surface activation energy at the anode, enabling plating/stripping at extremely low overpotential of <0.1 V that can be sustained for record-long cycling times of >4000 h.
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| 2. |
- Lohcharoenkal, Warangkana, et al.
(författare)
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Advances in Nanotechnology-Based Biosensing of Immunoregulatory Cytokines
- 2021
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Ingår i: Biosensors. - : MDPI AG. - 0956-5663 .- 2079-6374. ; 11:10
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Forskningsöversikt (refereegranskat)abstract
- Cytokines are a large group of small proteins secreted by immune and non-immune cells in response to external stimuli. Much attention has been given to the application of cytokines’ detection in early disease diagnosis/monitoring and therapeutic response assessment. To date, a wide range of assays are available for cytokines detection. However, in specific applications, multiplexed or continuous measurements of cytokines with wearable biosensing devices are highly desirable. For such efforts, various nanomaterials have been extensively investigated due to their extraordinary properties, such as high surface area and controllable particle size and shape, which leads to their tunable optical emission, electrical, and magnetic properties. Different types of nanomaterials such as noble metal, metal oxide, and carbon nanoparticles have been explored for various biosensing applications. Advances in nanomaterial synthesis and device development have led to significant progress in pushing the limit of cytokine detection. This article reviews currently used methods for cytokines detection and new nanotechnology-based biosensors for ultrasensitive cytokine detection
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| 3. |
- Quiñones, A. O., et al.
(författare)
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Influence of concentration and temperature dependent dielectric constants on the thermodynamics of electrolytes
- 2023
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 371
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Tidskriftsartikel (refereegranskat)abstract
- The symmetric Poisson–Boltzmann theory, the modified Poisson–Boltzmann theory, and the mean spherical approximation are utilized to calculate the osmotic coefficient, and the individual and mean activity coefficients of model KCl, LiCl, NaCl, and NaClO4 electrolytes all dissociated in water where the dielectric constant depends on concentration. The theories are also employed to compute the same thermodynamic quantities for HCl and NaCl solutions where the dielectric constant is now temperature dependent. In each situation the theoretical predictions are compared with the corresponding exact benchmark Monte Carlo simulation results. The mean spherical approximation and the modified Poisson–Boltzmann theory reproduce the simulation data for osmotic coefficient quantitatively and that for the mean activity almost quantitatively. The individual activities are accurately represented by the modified Poisson–Boltzmann theory but only qualitatively by the symmetric Poisson–Boltzmann and the mean spherical approximation. In general, the symmetric Poisson–Boltzmann theory shows good agreement with the simulations at low concentrations but deviates at higher concentrations.
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| 4. |
- Rama, Prasad, et al.
(författare)
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Interfacial interactions of humic acids with polystyrene nano-plastics in aqueous/ionic environments: a molecular dynamics exploration
- 2023
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Ingår i: Environmental Science-Nano. - : Royal Society of Chemistry (RSC). - 2051-8153 .- 2051-8161. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Plastics pose a serious threat to both marine and freshwater life after being discarded and broken down into smaller particles such as micro and nano-plastic particles. The nano-sized plastic particles are small enough in size and similar to surfaces of biological molecules, thereby potentially altering the intra-cellular interactions and their biological fate. In order to increase our understanding of the interactions among the molecules of natural organic matter and carboxylate functionalized polystyrene nano-plastics, we have performed a modelling study of the aquatic environment at different pH conditions using molecular dynamics (MD) simulations at an atomistic scale. Humic acids (HAs) are the most common constituents of natural organic matter, usually found in soil, water, and its sediments. As a proxy for humic acids, we have used Temple-Northeastern-Birmingham (TNB), an equivalent molecule to HA in its composition. We show that TNB molecules exhibit strong interactions with polystyrene (PS) nano-plastic particles at pH-4 but weak interaction at pH-7, whereas moderate interaction at pH-9 both in fresh and saltwater. The interaction between carboxylated polystyrene particles and TNB molecules is found to be counter-ion mediated and is enhanced in the presence of saltwater, i.e., at 0.5 M NaCl electrolyte. An enhanced condensation of Na+ counter-ions onto the surface of nano-plastics brings more water molecules to its interface, hence, enriching the hydrophilicity of nano-plastics. An ordered network structure of water molecules has also been observed at the interface of the PS-slab with an increase in pH of the aquatic environment, leading to a preferential alignment of water molecules, resulting in a strong hydration layer. This strong hydration layer also keeps the TNB molecules away from the vicinity of the PS-slab interface. The surface potential trends obtained from the MD simulations are in agreement with the measured zeta potential values showing that the surface charge density of PS nano-plastics increases with an increase in the pH of aquatic solutions. Hence, our simulations provide molecular-level insights into the phenomenon associated with the adsorption/accumulation of molecules of natural organic matter towards the nano-plastics and are helpful in understanding the formation of eco-corona on plastic nanoparticles.
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| 5. |
- Rama, Prasad, et al.
(författare)
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The influence of silica nanoparticle geometry on the interfacial interactions of organic molecules: a molecular dynamics study
- 2022
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 24, s. 3713-3721
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Tidskriftsartikel (refereegranskat)abstract
- The role of nanoparticle shape in the interaction and adsorption of organic molecules on the particle surface is an unexplored area. On the other hand, such knowledge is not only vital for a basic understanding of organic molecule interaction with nanoparticle surfaces but also essential for evaluating the cellular uptake of nanoparticles for living organisms. The current study investigates the role of silica nanoparticle shape in the interactions of phthalic acid organic molecules by using molecular dynamics simulations. Silica nanoparticles of two different geometries namely spheroid and cuboid with varying charge densities along with protonated and deprotonated phthalic acid molecules are studied. The adsorption characteristics of phthalic acid molecules on these nanoparticles have been analysed under different aquatic environments. The interactions of phthalic acid molecules, water molecules and ions were found to be different for spheroid and cubic shaped particles at pH values of 2-3, 7 and 9-10. The interaction of phthalic acid molecules with cubical silica nanoparticles is enhanced compared to the spherical shape particles. Such an enhanced interaction was seen when the silica surface is neutral, pH 2-3 and when the silica surface is charged at pH 7 and pH 9-10 in the presence of 0.5 M NaCl electrolyte. The cuboid-shaped silica also exhibited more hydrophilicity and less negative surface potential compared to spheroid shaped particles at pH 9-10. This is due to the enhanced condensation of Na+ counter-ions at the cuboid nanoparticle solution interface as to the interface of spheroid particles, which is well in agreement with Manning's theory of counter-ion condensation. Simulation results presented in this study indicate that the shape of the silica nanoparticle has significant influence on the interaction of water molecules, counter-ions and organic molecules which consequently determine the adsorption behaviour of organic molecules on the nanoparticle surface.
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| 6. |
- Simonsson, Isabelle, 1990, et al.
(författare)
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Experimental investigations into the irregular synthesis of iron(iii) terephthalate metal-organic frameworks MOF-235 and MIL-101 dagger
- 2021
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 50, s. 4976-4985
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Tidskriftsartikel (refereegranskat)abstract
- MOF-235(Fe) and MIL-101(Fe) are two well-studied metal-organic frameworks (MOFs) with dissimilar crystal structures and topologies. Previously reported syntheses of the former show that it has greatly varying surface areas, indicating a lack of phase purity of the products, i.e. the possible presence of both MOFs in the same sample. To find the reason for this, we have tested and modified the commonly used synthesis protocol of MOF-235(Fe), where a 3 : 5 molar ratio of iron(iii) ions and a terephthalic acid linker is heated in a 1 : 1 DMF : ethanol solvent at 80 degrees C for 24 h. Using XRD and BET surface area (SA(BET)) measurements, we found that it is difficult to obtain a pure phase of MOF-235, as MIL-101 also appears to form during the solvothermal treatment. Comparison of the XRD peak height ratios of the synthesis products revealed a direct correlation between the MOF-235/MIL-101 content and surface area; more MOF-235 yields a lower surface area and vice versa. In general, using a larger (3 : 1) DMF : ethanol ratio than that reported in the literature and a stoichiometric (4 : 3) Fe(iii) : TPA ratio yields a nearly pure MOF-235 product (SA(BET) = 295 m(2) g(-1), 67% yield). An optimized synthesis procedure was developed to obtain high-surface area MIL-101(Fe) (SA(BET) > 2400 m(2) g(-1)) in a large yield and at a previously unreported temperature (80 degrees C vs. previously used 110-150 degrees C). In situ X-ray scattering was utilized to investigate the crystallization of MOF-235 and MIL-101. At 80 degrees C, only MOF-235 formed and at 85 and 90 degrees C, only MIL-101 formed.
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| 7. |
- Sögaard, Christian, 1990, et al.
(författare)
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Hofmeister effects in the gelling of silica nanoparticles in mixed salt solutions
- 2021
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 611
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the nature of specific interaction of ions with the charged silica nanoparticles is vital not only to produce gels for applications such as grouting but also for determining their long term stability. Interaction of silica nanoparticles in single salt solutions has been thoroughly investigated but in mixed salt solutions is rarely investigated. In this work we have investigated the gelling of silica nanoparticles in the mixtures of monovalent ions as well as in the mixtures of divalent and monovalent ions. To gain an understanding of the interaction of ions with the charged silica surface at molecular level we have performed molecular dynamics (MD) simulations. Our overall goal was to find out if in salt mixtures ions silica interactions follow the Hofmeister series or not and how ion specific interactions may change when chaotropic ions are successively replaced by kosmotropic or vice versa. The gelling results show that generally monvalent ions in salt mixtures follow the Hofmeister series, e.g., the gel times in the mixtures of lithium and sodium chlorides are much longer than in the mixtures of lithium and potassium chlorides. On the other hand, gel times in the salt mixtures containing divalent ions do not follow the expected Hofmeister series e.g. mixtures of magnesium and sodium chlorides show shorter gel times than that of calcium and sodium chlorides. However, pH dependent gelling revealed that at pH values less than 9 gelling in these mixtures follow the normal Hofmeister series i.e., longer gelling time in magnesium and sodium chlorides than in calcium and sodium chlorides. This reversal of Hofmeister series for divalent and monovalent salt mixtures at pH > 9 and normal Hofmeister series at pH < 9 is reported for the first time in literature. Such a revesal at pH> 9 is explained due to enhanced surface charge, ordring of surface water layer which leads to enhanced ion specificity of strongly hydrated ions such as Mg2+. Moreover, in mixtures having the same divalent salt but different monovalent salts such as magnesium chlorides mixtures with lithium, sodium and potassium chlorides a normal Hofmeister series prevails. MD simulations results revealed that Mg2+ ions retain their strong hydration shell while interacting with the oppositely charged silica surface which means that the shorter gelling times obtained in magnesium salts mixtures are not due to inner sphere complexation of magnesium with the silica surface. Instead magnesium interacts with the silica surface through its hydrating water molecules.
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| 8. |
- Sögaard, Christian, 1990, et al.
(författare)
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Temperature and Particle-size Effects on the Formation of Silica Gels from Silica Sols
- 2022
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Ingår i: Silicon. - : Springer Science and Business Media LLC. - 1876-990X .- 1876-9918. ; 15:8, s. 3441-51
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Tidskriftsartikel (refereegranskat)abstract
- Silica nanoparticles (silica sols) based gels have increasingly been used as alternative grouting material for sealing the small fractures in the tunnel walls. Gelling of silica nanoparticles at room temperature has been investigated thoroughly but gelling at different temperatures scarcely investigated. At the same time temperature is one of major factor which can affect the long-term stability of grouted silica. In this work we have investigated the gelling of three different types of silica sols (Levasil CS40-213, Levasil CS40-222, and Levasil CS30-236) having different particle sizes, in 0.28 M NaCl at 10, 20 and 30 ?. Aggregation process, starting from the addition of salt to the gelling point, was monitored by measuring the time dependent particle size distribution. Electrospray scanning mobility particle sizer (ES-SMPS) was used to measure the aggregating. These measurements were complemented by rheological measurements in order to get a relationship between changes in aggregate structure and in the viscosity of silica suspension. Data from the temperature dependent gel time measurements were used to calculate the activation energy. At room temperature, silica sols with smallest average particle size showed the shortest gel times whereas the sols with the largest particle size showed the longest gel time. However, at increasing temperature shorter gel times were seen for all the sols. Temperature dependent rheological measurements showed similar trends in viscosity changes as seen for gel times i.e., increased temperature leads to quicker increase in the viscosity and a sharp increase in viscosity near the gelling point. Our calculations of fractal dimensions showed that in the gel network there are still many free particles which continuously incorporated into the gel network. Apparent activation energies calculated for CS40-213, CS40-222, CS30-236 were 13.40, 23.36 and 41.45 kJ/mol, respectively. These values are lower than values reported for silica in the literature. Moreover, temperature dependent zeta potential measurements show that zeta potential get less negative as temperature increase. The above mentioned measurements are at odd what has been reported in literature but we have provided plausible explanation of these results.
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