| 1. |
- Falciani, Gabriele, et al.
(författare)
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A multi-scale perspective of gas transport through soap-film membranes
- 2020
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Ingår i: Molecular Systems Design & Engineering. - : ROYAL SOC CHEMISTRY. - 2058-9689. ; 5:5, s. 911-921
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Tidskriftsartikel (refereegranskat)abstract
- Soap films represent unique aqueous systems, whose physical properties can be tuned by acting on their nanoscale structure. Here, we specifically focus on transport properties through membranes realized in the form of soap films. While diffusion phenomena in the water core and surfactant monolayers are described using a continuum model, molecular dynamics is used to compute the static and dynamical properties of water, gases and the surfactant in the monolayers which is hexaethylene glycol monododecyl ether (C12E6). The obtained atomistic details are then incorporated into a drift-diffusion model for consistently extracting a boundary condition for the above continuum model describing transport phenomena at a larger scale. Numerical predictions are validated against experimental data from both properly designed experiments and the literature. Finally, the developed model is used to estimate the characteristic time for disparate gas mixing when initially separated by soap film membranes.
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| 2. |
- Falciani, Gabriele, et al.
(författare)
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A novel concept of photosynthetic soft membranes : a numerical study
- 2023
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Ingår i: DISCOVER NANO. - : Springer Nature. - 2731-9229. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- We focus on a novel concept of photosynthetic soft membranes, possibly able to allow the conversion of solar energy and carbon dioxide (CO2) into green fuels. The considered membranes rely on self-assembled functional molecules in the form of soap films. We elaborate a multi-scale and multi-physics model to describe the relevant phenomena, investigating the expected performance of a single soft photosynthetic membrane. First, we present a macroscale continuum model, which accounts for the transport of gaseous and ionic species within the soap film, the chemical equilibria and the two involved photocatalytic half reactions of the CO2 reduction and water oxidation at the two gas-surfactant-water interfaces of the soap film. Second, we introduce a mesoscale discrete Monte Carlo model, to deepen the investigation of the structure of the functional monolayers. Finally, the morphological information obtained at the mesoscale is integrated into the continuum model in a multi-scale framework. The developed tools are then used to perform sensitivity studies in a wide range of possible experimental conditions, to provide scenarios on fuel production by such a novel approach.
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| 3. |
- Falciani, Gabriele, et al.
(författare)
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Design and testing of a device for the characterization of gas transfer through soap films and measurement protocol based on color matching
- 2023
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Ingår i: International Communications in Heat and Mass Transfer. - : Elsevier. - 0735-1933 .- 1879-0178. ; 149
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Tidskriftsartikel (refereegranskat)abstract
- Soap films are interesting for their potential utilization as soft, self-assembled, self-healing and possibly recyclable membranes. The intrinsic possibility of tuning their properties, such as e.g. surface and bulk elasticity or permeability, via tailored chemistry makes them flexible enough for a wide range of physical-chemical applications. Here we introduce a novel device that can serve as a research platform for the detailed experimental characterization of the soap film permeability to gases. The design and manufacturing of the novel platform are discussed, along with a sample characterization protocol based on a color-matching procedure for dioxygen diffusion through typical soap films. The experimental data is compared with the results obtained from a numerical model, specifically developed for the problem, and good agreement is found. In perspective, the proposed platform can serve for the precise characterization of gas transfer properties of soap films made from different surfactant mixtures and in the presence of different gases.
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| 4. |
- Gera, Rahul, et al.
(författare)
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Emergence of Electric Fields at the Water-C12E6 Surfactant Interface
- 2021
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 143:37, s. 15103-15112
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Tidskriftsartikel (refereegranskat)abstract
- We study the properties of the interface of water and the surfactant hexaethylene glycol monododecyl ether (C12E6) with a combination of heterodyne-detected vibrational sum frequency generation (HD-VSFG), Kelvin-probe measurements, and molecular dynamics (MD) simulations. We observe that the addition of the hydrogen-bonding surfactant C12E6, close to the critical micelle concentration (CMC), induces a drastic enhancement in the hydrogen bond strength of the water molecules close to the interface, as well as a flip in their net orientation. The mutual orientation of the water and C12E6 molecules leads to the emergence of a broad (similar to 3 nm) interface with a large electric field of similar to 1 V/nm, as evidenced by the Kelvin-probe measurements and MD simulations. Our findings may open the door for the design of novel electric-field-tuned catalytic and light-harvesting systems anchored at the water-surfactant-air interface.
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| 5. |
- Kaul, Nidhi, et al.
(författare)
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Realizing Symmetry-Breaking Architectures in Soap Films
- 2024
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:2
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Tidskriftsartikel (refereegranskat)abstract
- We show here that soap films-typically expected to host symmetric molecular arrangements-can be constructed with differing opposite surfaces, breaking their symmetry, and making them reminiscent of functional biological motifs found in nature. Using fluorescent molecular probes as dopants on different sides of the film, resonance energy transfer could be employed to confirm the lack of symmetry, which was found to persist on timescales of several minutes. Further, a theoretical analysis of the main transport phenomena involved yielded good agreement with the experimental observations.
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