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Saoncella, S., Suo, S., Sundin, J., Parikh, A., Hultmark, M., van der Wijngaart, W., . . . Bagheri, S. (2024). Contact-angle hysteresis provides resistance to drainage of liquid-infused surfaces in turbulent flows. Physical Review Fluids, 9(5), Article ID 054002.
Open this publication in new window or tab >>Contact-angle hysteresis provides resistance to drainage of liquid-infused surfaces in turbulent flows
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2024 (English)In: Physical Review Fluids, E-ISSN 2469-990X, Vol. 9, no 5, article id 054002Article in journal (Refereed) Published
Abstract [en]

Lubricated textured surfaces immersed in liquid flows offer tremendous potential for reducing fluid drag, enhancing heat and mass transfer, and preventing fouling. According to current design rules, the lubricant must chemically match the surface to remain robustly trapped within the texture. However, achieving such chemical compatibility poses a significant challenge for large-scale flow systems, as it demands advanced surface treatments or severely limits the range of viable lubricants. In addition, chemically tuned surfaces often degrade over time in harsh environments. Here, we demonstrate that a lubricant-infused surface (LIS) can resist drainage in the presence of external shear flow without requiring chemical compatibility. Surfaces featuring longitudinal grooves can retain up to 50% of partially wetting lubricants in fully developed turbulent flows. The retention relies on contact-angle hysteresis, where triple-phase contact lines are pinned to substrate heterogeneities, creating capillary resistance that prevents lubricant depletion. We develop an analytical model to predict the maximum length of pinned lubricant droplets in microgrooves. This model, validated through a combination of experiments and numerical simulations, can be used to design chemistry-free LISs for applications where the external environment is continuously flowing. Our findings open up new possibilities for using functional surfaces to control transport processes in large systems.

Place, publisher, year, edition, pages
American Physical Society, 2024
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kth:diva-346796 (URN)10.1103/PhysRevFluids.9.054002 (DOI)2-s2.0-85193067831 (Scopus ID)
Note

QC 20240528

Available from: 2024-05-24 Created: 2024-05-24 Last updated: 2024-05-28Bibliographically approved
Amini, K., Mishra, A. A., Sivakumar, A. K., Arlov, D., Innings, F., Kádár, R., . . . Lundell, F. (2024). Scaling laws for near-wall flows of thixo-elasto-viscoplastic fluids in a millifluidic channel. Physics of fluids, 36(2), Article ID 023107.
Open this publication in new window or tab >>Scaling laws for near-wall flows of thixo-elasto-viscoplastic fluids in a millifluidic channel
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2024 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 36, no 2, article id 023107Article in journal (Refereed) Published
Abstract [en]

Thixo-elasto-viscoplastic (TEVP) fluids are very complex fluids. In addition to elasticity and viscoplasticity, they exhibit thixotropy, i.e., time-dependent rheology due to breakdown and recovery of internal structures at different length- and timescales. General and consistent methods for a priori flow prediction of TEVP fluids based on rheological characteristics are yet to be developed. We report a combined study of the rheology and flow of 18 samples of different TEVP fluids (three yogurts and three concentrations of Laponite and Carbopol, respectively, in water in both the unstirred and a stirred state). The rheology is determined both with standard protocols and with an ex situ protocol aiming at reproducing the shear history of the fluid in the flow. Micrometer resolution flow measurements in a millimeter scale rectangular duct are performed with Doppler Optical Coherence Tomography (D-OCT). As expected, the results show the existence of a plug flow region for samples with sufficiently high yield stress. At low flow rates, the plug extends almost all the way to the wall and the extent of the plug decreases not only with increased flow rate but also with increased thixotropy. The ex situ rheology protocol enables estimation of the shear rate and shear stress close to the wall, making it possible to identify two scaling laws that relates four different non-dimensional groups quantifying the key properties wall-shear stress and slip velocity. The scaling laws are suggested as an ansatz for a priori prediction of the near-wall flow of TEVP fluids based on shear flow-curves obtained with a rheometer.

Place, publisher, year, edition, pages
AIP Publishing, 2024
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-343664 (URN)10.1063/5.0186668 (DOI)001159051800005 ()2-s2.0-85184810292 (Scopus ID)
Note

QC 20240222

Available from: 2024-02-22 Created: 2024-02-22 Last updated: 2024-04-05Bibliographically approved
Lendel, C., Hedenqvist, M. S., Langton, M. & Lundell, F. (2023). Design of hierarchical protein materials for a sustainable society. European Biophysics Journal, 52(SUPPL 1), S48-S48
Open this publication in new window or tab >>Design of hierarchical protein materials for a sustainable society
2023 (English)In: European Biophysics Journal, ISSN 0175-7571, E-ISSN 1432-1017, Vol. 52, no SUPPL 1, p. S48-S48Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
SPRINGER, 2023
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-335875 (URN)001029235400103 ()
Note

QC 20230911

Available from: 2023-09-11 Created: 2023-09-11 Last updated: 2023-09-11Bibliographically approved
Motezakker, A. R., Córdoba, A., Rosén, T., Lundell, F. & Söderberg, D. (2023). Effect of Stiffness on the Dynamics of Entangled Nanofiber Networks at Low Concentrations. Macromolecules, 56(23), 9595-9603
Open this publication in new window or tab >>Effect of Stiffness on the Dynamics of Entangled Nanofiber Networks at Low Concentrations
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2023 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 56, no 23, p. 9595-9603Article in journal, Editorial material (Refereed) Published
Abstract [en]

Biopolymer network dynamics play a significant role in both biological and materials science. This study focuses on the dynamics of cellulose nanofibers as a model system given their relevance to biology and nanotechnology applications. Using large-scale coarse-grained simulations with a lattice Boltzmann fluid coupling, we investigated the reptation behavior of individual nanofibers within entangled networks. Our analysis yields essential insights, proposing a scaling law for rotational diffusion, quantifying effective tube diameter, and revealing release mechanisms during reptation, spanning from rigid to semiflexible nanofibers. Additionally, we examine the onset of entanglement in relation to the nanofiber flexibility within the network. Microrheology analysis is conducted to assess macroscopic viscoelastic behavior. Importantly, our results align closely with previous experiments, validating the proposed scaling laws, effective tube diameters, and onset of entanglement. The findings provide an improved fundamental understanding of biopolymer network dynamics and guide the design of processes for advanced biobased materials. 

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Biophysics Bioinformatics (Computational Biology)
Identifiers
urn:nbn:se:kth:diva-343525 (URN)10.1021/acs.macromol.3c01526 (DOI)001141570800001 ()2-s2.0-85178555657 (Scopus ID)
Funder
Swedish Research Council, 2018-06469Knut and Alice Wallenberg Foundation
Note

QC 20240216

Available from: 2024-02-15 Created: 2024-02-15 Last updated: 2024-05-31Bibliographically approved
Kulkarni, R. A., Apazidis, N., Larsson, P. T., Lundell, F. & Söderberg, D. (2023). Experimental studies of dynamic compression of cellulose pulp fibers. Sustainable Materials and Technologies, 38, Article ID e00774.
Open this publication in new window or tab >>Experimental studies of dynamic compression of cellulose pulp fibers
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2023 (English)In: Sustainable Materials and Technologies, ISSN 2214-9937, Vol. 38, article id e00774Article in journal (Refereed) Published
Abstract [en]

The ability to control the structure of the wood-pulp fiber cell wall is an attractive means to obtain increased accessibility to the fiber interior, providing routes for functionalization of the fibers that support further processing and novel material concepts, e.g. improved degree of polymerization, nanofiltration as demonstrated in previous studies. It has been proposed that dynamic compression and decompression of the cellulose pulp fibers in the wet state make it possible to modify the cell wall significantly. We hypothesize that hydrostatic pressure exerted on fibers fully submerged in water will increase the accessibility of the fiber wall by penetrating the fiber through weak spots in the cell wall. To pursue this, we have developed an experimental facility that can subject wet cellulose pulp samples to a pressure pulse -10 ms long and with a peak pressure of -300 MPa. The experiment is thus specifically designed to elucidate the effect of a rapid high-pressure pulse passing through the cellulose sample and enables studies of changes in structural properties over different size ranges. Different characterization techniques, including Scanning electron microscopy, X-ray diffraction, and wide- and small-angle X-ray scattering, have been used to evaluate the material exposed to pulsed pressure. The mechanism of pressure build-up is estimated computationally to complement the results. Key findings from the experiments consider a decrease in crystallinity and changes in the surface morphology of the cellulose sample.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Cellulose fiber modification, Dynamic compression, Accessibility, Cell wall, High-pressure, X-ray scattering, Computations
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-341813 (URN)10.1016/j.susmat.2023.e00774 (DOI)001122972200001 ()2-s2.0-85179623066 (Scopus ID)
Note

QC 20240103

Available from: 2024-01-03 Created: 2024-01-03 Last updated: 2024-01-03Bibliographically approved
Yada, S., Lacis, U., van der Wijngaart, W., Lundell, F., Amberg, G. & Bagheri, S. (2022). Droplet Impact on Asymmetric Hydrophobic Microstructures. Langmuir, 38(26), 7956-7964
Open this publication in new window or tab >>Droplet Impact on Asymmetric Hydrophobic Microstructures
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2022 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 38, no 26, p. 7956-7964Article in journal (Refereed) Published
Abstract [en]

Textured hydrophobic surfaces that repel liquid droplets unidirectionally are found in nature such as butterfly wings and ryegrass leaves and are also essential in technological processes such as self-cleaning and anti-icing. In many occasions, surface textures are oriented to direct rebounding droplets. Surface macrostructures (>100 μm) have often been explored to induce directional rebound. However, the influence of impact speed and detailed surface geometry on rebound is vaguely understood, particularly for small microstructures. Here, we study, using a high-speed camera, droplet impact on surfaces with inclined micropillars. We observed directional rebound at high impact speeds on surfaces with dense arrays of pillars. We attribute this asymmetry to the difference in wetting behavior of the structure sidewalls, causing slower retraction of the contact line in the direction against the inclination compared to with the inclination. The experimental observations are complemented with numerical simulations to elucidate the detailed movement of the drops over the pillars. These insights improve our understanding of droplet impact on hydrophobic microstructures and may be useful for designing structured surfaces for controlling droplet mobility. 

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
High speed cameras, Hydrophobicity, Textures, Wetting, Anti-icing, Butterfly wings, Droplets impact, Hydrophobic surfaces, Hydrophobics, Impact speed, Liquid droplets, Self cleaning, Surface textures, Technological process, Drops, animal, food, movement (physiology), plant leaf, wettability, Animals, Movement, Plant Leaves
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:kth:diva-325697 (URN)10.1021/acs.langmuir.2c00561 (DOI)000818745800001 ()35737474 (PubMedID)2-s2.0-85134083336 (Scopus ID)
Note

QC 20230412

Available from: 2023-04-12 Created: 2023-04-12 Last updated: 2023-04-12Bibliographically approved
Wang, G., Kudo, M., Daicho, K., Harish, S., Xu, B., Shao, C., . . . Shiomi, J. (2022). Enhanced High Thermal Conductivity Cellulose Filaments via Hydrodynamic Focusing. Nano Letters, 22(21), 8406-8412
Open this publication in new window or tab >>Enhanced High Thermal Conductivity Cellulose Filaments via Hydrodynamic Focusing
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2022 (English)In: Nano Letters, ISSN 1530-6984, E-ISSN 1530-6992, Vol. 22, no 21, p. 8406-8412Article in journal (Refereed) Published
Abstract [en]

Nanocellulose is regarded as a green and renewable nanomaterial that has attracted increased attention. In this study, we demonstrate that nanocellulose materials can exhibit high thermal conductivity when their nanofibrils are highly aligned and bonded in the form of filaments. The thermal conductivity of individual filaments, consisting of highly aligned cellulose nanofibrils, fabricated by the flow-focusing method is measured in dried condition using a T-type measurement technique. The maximum thermal conductivity of the nanocellulose filaments obtained is 14.5 W/m-K, which is approximately five times higher than those of cellulose nanopaper and cellulose nanocrystals. Structural investigations suggest that the crystallinity of the filament remarkably influence their thermal conductivity. Smaller diameter filaments with higher crystallinity, that is, more internanofibril hydrogen bonds and less intrananofibril disorder, tend to have higher thermal conductivity. Temperature-dependence measurements also reveal that the filaments exhibit phonon transport at effective dimension between 2D and 3D. 

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
crystallinity, filament, flow focusing, Nanocellulose, thermal conductivity, Cellulose, Diameter, Dimensions, Filaments, Hydrogen Bonds, Transport, Hydrodynamics, Nanoparticles, Nanostructures, Focusing, Nanofibers, Temperature distribution, nanomaterial, nanoparticle, Cellulose nanofibrils, Condition, Cristallinity, High thermal conductivity, Hydrodynamic focusing, Measurement techniques, Nano-cellulose, Nano-fibrils, chemistry
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-328881 (URN)10.1021/acs.nanolett.2c02057 (DOI)000877600400001 ()36283691 (PubMedID)2-s2.0-85140957245 (Scopus ID)
Note

QC 20230613

Available from: 2023-06-13 Created: 2023-06-13 Last updated: 2023-06-13Bibliographically approved
Redlinger-Pohn, J. D., Brouzet, C., Aulin, C., Engström, Å., Riazanova, A., Holmqvist, C., . . . Söderberg, D. (2022). Mechanisms of Cellulose Fiber Comminution to Nanocellulose by Hyper Inertia Flows. ACS Sustainable Chemistry and Engineering, 10(2), 703-719
Open this publication in new window or tab >>Mechanisms of Cellulose Fiber Comminution to Nanocellulose by Hyper Inertia Flows
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2022 (English)In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 10, no 2, p. 703-719Article in journal (Refereed) Published
Abstract [en]

Nanocelluloses are seen as the basis of high-performance materials from renewable sources, enabling a bio-based sustainable future. Unsurprisingly, research has initially been focused on the design of new material concepts and less on new and adapted fabrication processes that would allow large-scale industrial production and widespread societal impact. In fact, even the processing routes for making nanocelluloses and the understanding on how the mechanical action fibrillates plant raw materials, albeit chemically or enzymatically pre-treated, are only rudimentary and have not evolved significantly during the past three decades. To address the challenge of designing cellulose comminution processes for a reliable and predictable production of nanocelluloses, we engineered a study setup, referred to as Hyper Inertia Microfluidizer, to observe and quantify phenomena at high speeds and acceleration into microchannels, which is the underlying flow in homogenization. We study two different channel geometries, one with acceleration into a straight channel and one with acceleration into a 90 degrees bend, which resembles the commercial equipment for microfluidization. With the purpose of intensification of the nanocellulose production process, we focused on an efficient first pass fragmentation. Fibers are strained by the extensional flow upon acceleration into the microchannels, leading to buckling deformation and, at a higher velocity, fragmentation. The treatment induces sites of structural damage along and at the end of the fiber, which become a source for nanocellulose. Irrespectively on the treatment channel, these nanocelluloses are fibril-agglomerates, which are further reduced to smaller sizes. In a theoretical analysis, we identify fibril delamination as failure mode from bending by turbulent fluctuations in the flow as a comminution mechanism at the nanocellulose scale. Thus, we argue that intensification of the fibrillation can be achieved by an initial efficient fragmentation of the cellulose in smaller fragments, leading to a larger number of damaged sites for the nanocellulose production. Refinement of these nanocelluloses to fibrils is then achieved by an increase in critical bending events, i.e., decreasing the turbulent length scale and increasing the residence time of fibrils in the turbulent flow.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
homogenization, microfluidization, fibrillation, delamination, nanocellulose quality, nature-based materials, process description, process design
National Category
Bio Materials
Identifiers
urn:nbn:se:kth:diva-310581 (URN)10.1021/acssuschemeng.1c03474 (DOI)000741130000001 ()2-s2.0-85122750336 (Scopus ID)
Note

QC 20220406

Available from: 2022-04-06 Created: 2022-04-06 Last updated: 2022-10-18Bibliographically approved
Gowda, V. K., Rosén, T., Roth, S. V., Söderberg, D. & Lundell, F. (2022). Nanofibril Alignment during Assembly Revealed by an X-ray Scattering-Based Digital Twin. ACS Nano, 16(2), 2120-2132
Open this publication in new window or tab >>Nanofibril Alignment during Assembly Revealed by an X-ray Scattering-Based Digital Twin
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2022 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 16, no 2, p. 2120-2132Article in journal (Refereed) Published
Abstract [en]

The nanostructure, primarily particle orientation, controls mechanical and functional (e.g., mouthfeel, cell compatibility, optical, morphing) properties when macroscopic materials are assembled from nanofibrils. Understanding and controlling the nanostructure is therefore an important key for the continued development of nanotechnology. We merge recent developments in the assembly of biological nanofibrils, X-ray diffraction orientation measurements, and computational fluid dynamics of complex flows. The result is a digital twin, which reveals the complete particle orientation in complex and transient flow situations, in particular the local alignment and spatial variation of the orientation distributions of different length fractions, both along the process and over a specific cross section. The methodology forms a necessary foundation for analysis and optimization of assembly involving anisotropic particles. Furthermore, it provides a bridge between advanced in operandi measurements of nanostructures and phenomena such as transitions between liquid crystal states and in silico studies of particle interactions and agglomeration.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
alignment, cellulose nanofibrils, flow-focusing, X-ray scattering, rotary diffusion, assembly
National Category
Physical Chemistry Fluid Mechanics and Acoustics Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-311622 (URN)10.1021/acsnano.1c07769 (DOI)000776691400036 ()35104107 (PubMedID)2-s2.0-85124313849 (Scopus ID)
Note

QC 20220502

Available from: 2022-05-02 Created: 2022-05-02 Last updated: 2023-09-19Bibliographically approved
Ananthaseshan, S., Bojakowski, K., Sacharczuk, M., Poznanski, P., Skiba, D. S., Prahl Wittberg, L., . . . Religa, P. (2022). Red blood cell distribution width is associated with increased interactions of blood cells with vascular wall. Scientific Reports, 12(1), Article ID 13676.
Open this publication in new window or tab >>Red blood cell distribution width is associated with increased interactions of blood cells with vascular wall
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2022 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 13676Article in journal (Refereed) Published
Abstract [en]

The mechanism underlying the association between elevated red cell distribution width (RDW) and poor prognosis in variety of diseases is unknown although many researchers consider RDW a marker of inflammation. We hypothesized that RDW directly affects intravascular hemodynamics, interactions between circulating cells and vessel wall, inducing local changes predisposing to atherothrombosis. We applied different human and animal models to verify our hypothesis. Carotid plaques harvested from patients with high RDW had increased expression of genes and proteins associated with accelerated atherosclerosis as compared to subjects with low RDW. In microfluidic channels samples of blood from high RDW subjects showed flow pattern facilitating direct interaction with vessel wall. Flow pattern was also dependent on RDW value in mouse carotid arteries analyzed with Magnetic Resonance Imaging. In different mouse models of elevated RDW accelerated development of atherosclerotic lesions in aortas was observed. Therefore, comprehensive biological, fluid physics and optics studies showed that variation of red blood cells size measured by RDW results in increased interactions between vascular wall and circulating morphotic elements which contribute to vascular pathology.

Place, publisher, year, edition, pages
Springer Nature, 2022
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:kth:diva-316835 (URN)10.1038/s41598-022-17847-z (DOI)000840073200056 ()35953533 (PubMedID)2-s2.0-85135781831 (Scopus ID)
Note

QC 20220912

Available from: 2022-09-01 Created: 2022-09-01 Last updated: 2022-09-15Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-2504-3969

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