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Chen, Y., Nishiyama, Y., Lu, A., Fang, Y., Shao, Z., Hu, T., . . . Chen, P. (2023). The thermodynamics of enhanced dope stability of cellulose solution in NaOH solution by urea. Carbohydrate Polymers, 311, 120744, Article ID 120744.
Open this publication in new window or tab >>The thermodynamics of enhanced dope stability of cellulose solution in NaOH solution by urea
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2023 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 311, p. 120744-, article id 120744Article in journal (Refereed) Published
Abstract [en]

The addition of urea in pre-cooled alkali aqueous solution is known to improve the dope stability of cellulose solution. However, its thermodynamic mechanism at a molecular level is not fully understood yet. By using molecular dynamics simulation of an aqueous NaOH/urea/cellulose system using an empirical force field, we found that urea was concentrated in the first solvation shell of the cellulose chain stabilized mainly by dispersion interaction. When adding a glucan chain into the solution, the total solvent entropy reduction is smaller if urea is present. Each urea molecule expelled an average of 2.3 water molecules away from the cellulose surface, releasing water entropy that over-compensates the entropy loss of urea and thus maximizing the total entropy. Scaling the Lennard-Jones parameter and atomistic partial charge of urea revealed that direct urea/cellulose interaction was also driven by dispersion energy. The mixing of urea solution and cellulose solution in the presence or absence of NaOH are both exothermic even after correcting for the contribution from dilution.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Urea, Dope stability of cellulose solution, Thermodynamics, Molecular dynamics simulation
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-325612 (URN)10.1016/j.carbpol.2023.120744 (DOI)000951583800001 ()37028854 (PubMedID)2-s2.0-85149982618 (Scopus ID)
Note

QC 20230406

Available from: 2023-04-06 Created: 2023-04-06 Last updated: 2023-06-08Bibliographically approved
Solhi, L., Guccini, V., Heise, K., Solala, I., Niinivaara, E., Xu, W., . . . Kontturi, E. (2023). Understanding Nanocellulose-Water Interactions: Turning a Detriment into an Asset. Chemical Reviews, 123(5), 1925-2015
Open this publication in new window or tab >>Understanding Nanocellulose-Water Interactions: Turning a Detriment into an Asset
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2023 (English)In: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 123, no 5, p. 1925-2015Article, review/survey (Refereed) Published
Abstract [en]

Modern technology has enabled the isolation of nanocellulose from plant -based fibers, and the current trend focuses on utilizing nanocellulose in a broad range of sustainable materials applications. Water is generally seen as a detrimental component when in contact with nanocellulose-based materials, just like it is harmful for traditional cellulosic materials such as paper or cardboard. However, water is an integral component in plants, and many applications of nanocellulose already accept the presence of water or make use of it. This review gives a comprehensive account of nanocellulose???water interactions and their repercussions in all key areas of contemporary research: fundamental physical chemistry, chemical modification of nanocellulose, materials applications, and analytical methods to map the water interactions and the effect of water on a nanocellulose matrix.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-327400 (URN)10.1021/acs.chemrev.2c00611 (DOI)000974438700001 ()36724185 (PubMedID)2-s2.0-85147442731 (Scopus ID)
Note

QC 20230526

Available from: 2023-05-26 Created: 2023-05-26 Last updated: 2023-05-26Bibliographically approved
Srikanth Sridhar, A., Berglund, L. & Wohlert, J. (2023). Wetting of native and acetylated cellulose by water and organic liquids from atomistic simulations. Cellulose, 30(13), 8089-8106
Open this publication in new window or tab >>Wetting of native and acetylated cellulose by water and organic liquids from atomistic simulations
2023 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 30, no 13, p. 8089-8106Article in journal (Refereed) Published
Abstract [en]

Wetting of cellulose by different liquids is interesting from the point of view of the processing of cellulose-based nanomaterials. Here, the contact angles formed by water and several organic liquids on both native and acetylated cellulose were calculated from molecular dynamics simulations. It was found that liquid surface tension was crucial for their wetting behavior. Acetylation decreases the work of adhesion to most liquids investigated, even non-polar ones, while others are not affected. Water has the highest affinity to cellulose, both native and acetylated. The results have implications for liquid infiltration of nanocellulose networks and the interaction of cellulose with different liquids in general.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Contact angle, Surface free energy, Surface modification
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-338524 (URN)10.1007/s10570-023-05352-z (DOI)001039335000005 ()2-s2.0-85166258169 (Scopus ID)
Note

QC 20231114

Available from: 2023-11-14 Created: 2023-11-14 Last updated: 2023-11-14Bibliographically approved
Wohlert, M., Benselfelt, T., Wågberg, L., Furo, I., Berglund, L. & Wohlert, J. (2022). Cellulose and the role of hydrogen bonds: not in charge of everything. Cellulose, 29(1), 1-23
Open this publication in new window or tab >>Cellulose and the role of hydrogen bonds: not in charge of everything
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2022 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 29, no 1, p. 1-23Article in journal (Refereed) Published
Abstract [en]

In the cellulose scientific community, hydrogen bonding is often used as the explanation for a large variety of phenomena and properties related to cellulose and cellulose based materials. Yet, hydrogen bonding is just one of several molecular interactions and furthermore is both relatively weak and sensitive to the environment. In this review we present a comprehensive examination of the scientific literature in the area, with focus on theory and molecular simulation, and conclude that the relative importance of hydrogen bonding has been, and still is, frequently exaggerated.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Cellulose, Computer modeling, Hydrogen bonding, Nanomaterials, Hydrogen bonds, Molecular structure, Cellulose based materials, Comprehensive examination, Computer models, Molecular simulations, Phenomena and properties, Scientific community, Scientific literature, Documents, Examination, Materials
National Category
Information Systems, Social aspects
Identifiers
urn:nbn:se:kth:diva-313261 (URN)10.1007/s10570-021-04325-4 (DOI)000720243800001 ()2-s2.0-85119261613 (Scopus ID)
Note

QC 20220608

Available from: 2022-06-08 Created: 2022-06-08 Last updated: 2022-06-25Bibliographically approved
Mianehrow, H., Berglund, L. & Wohlert, J. (2022). Interface effects from moisture in nanocomposites of 2D graphene oxide in cellulose nanofiber (CNF) matrix – A molecular dynamics study. Journal of Materials Chemistry A, 10(4), 2122-2132
Open this publication in new window or tab >>Interface effects from moisture in nanocomposites of 2D graphene oxide in cellulose nanofiber (CNF) matrix – A molecular dynamics study
2022 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 10, no 4, p. 2122-2132Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Royal Society of Chemistry (RSC), 2022
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-316572 (URN)10.1039/d1ta09286c (DOI)000741533700001 ()2-s2.0-85123719465 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation
Note

QC 20220823

Available from: 2022-08-23 Created: 2022-08-23 Last updated: 2022-08-31Bibliographically approved
Cederholm, L., Wohlert, J., Olsen, P., Hakkarainen, M. & Odelius, K. (2022). “Like Recycles Like”: Selective Ring-Closing Depolymerization of Poly(L-Lactic Acid) to L-Lactide. Angewandte Chemie International Edition, 61(33), Article ID e202204531.
Open this publication in new window or tab >>“Like Recycles Like”: Selective Ring-Closing Depolymerization of Poly(L-Lactic Acid) to L-Lactide
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2022 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 61, no 33, article id e202204531Article in journal (Refereed) Published
Abstract [en]

Chemical recycling of poly(L-lactic acid) to the cyclic monomer L-lactide is hampered by low selectivity and by epimerization and elimination reactions, impeding its use on a large scale. The high number of side reactions originates from the high ceiling temperature (Tc) of L-lactide, which necessitates high temperatures or multistep reactions to achieve recycling to L-lactide. To circumvent this issue, we utilized the impact of solvent interactions on the monomer–polymer equilibrium to decrease the Tc of L-lactide. Analyzing the observed Tc in different solvents in relation to their Hildebrand solubility parameter revealed a “like recycles like” relationship. The decreased Tc, obtained by selecting solvents that interact strongly with the monomer (dimethyl formamide or the green solvent γ-valerolactone), allowed chemical recycling of high-molecular-weight poly(L-lactic acid) directly to L-lactide, within 1–4 h at 140 °C, with >95 % conversion and 98–99 % selectivity. Recycled L-lactide was isolated and repolymerized with high control over molecular weight and dispersity, closing the polymer loop. 

Place, publisher, year, edition, pages
Wiley, 2022
Keywords
Chemical Recycling, L-Lactide, Ring-Opening Polymerization, Solvent Effects, Thermodynamics, Amides, Lactic acid, Molecular weight, Monomers, Recycling, Ring opening polymerization, Solvents, Cyclic monomers, Elimination reaction, Epimerization, Large-scales, Poly-l-lactic acids, Ring-closing depolymerization, Side reactions, dilactide, dioxane derivative, polyester, polylactide, polymer, solvent, Dioxanes, Polyesters, Polymers
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-324568 (URN)10.1002/anie.202204531 (DOI)000808244100001 ()35582840 (PubMedID)2-s2.0-85131510064 (Scopus ID)
Note

QC 20230612

Available from: 2023-03-08 Created: 2023-03-08 Last updated: 2023-06-12Bibliographically approved
Tavares da Costa, M. V., Wohlert, J. & Berglund, L. (2022). Mechanical modelling to assess stiffness, strength and toughness of nacre-inspired nano composites. In: : . Paper presented at 18th European Mechanics of Materials Conference (EMMC18), April 4 - 6, 2022, Oxford, UK. Oxford, UK
Open this publication in new window or tab >>Mechanical modelling to assess stiffness, strength and toughness of nacre-inspired nano composites
2022 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Nacre-like materials have been extensively studied in the literature for different material system due its capability of balancing strength and toughness [1]. In this material system, weak interfaces between inclusions and matrices are key to allow the crack deflection, and thus, higher toughness is achieved. Over a decade our research group have been able to reproduce nacre-like nanostructure on cellulosic papers as matrix, and montmorillonite clay as nano platelets inclusions [2, 3]. Apart of good functionally in our material system, such as transparency, fire retardance and gas barrier functions, we have also finetuned its recyclability in recent findings. Our objective now is to understand better what is failure mechanism that control our nanostructure and how we can predict the mechanical performance in terms of stiffness, strength and toughness in the macroscopic level.In this presentation, we are going to show micromechanical modelling to estimate the composite modulus of this novel biocomposite, and compare the results to numerical predictions and experimental measurements. Furthermore, we will present our efforts in an atomistic-continuum modelling framework to predict strength and toughness for our nano composite. First, molecular dynamics simulations are performed on our cellulose nanofibrils (CNF) to obtain the stress-strain curve in order to calibration the continuum model. Then, the continuum model containing the calibrated phase field model for fracture in the CNF matrix, and calibrated cohesive zone model at the interfaces will be explored to predict the failure. The advantages and disadvantages of our framework will be addressed, as well as the accuracy of the assumptions in their underlying models.

REFERENCES

1. Barthelat, F., Architectured materials in engineering and biology: fabrication, structure, mechanics and performance. International Materials Reviews, 2015. 60(8): p. 413-430.

2. Liu, A., et al., Clay Nanopaper with Tough Cellulose Nanofiber Matrix for Fire Retardancy and Gas Barrier Functions. Biomacromolecules, 2011. 12(3): p. 633-641.

3. Medina, L., et al., Nanostructure and Properties of Nacre-Inspired Clay/Cellulose Nanocomposites—Synchrotron X-ray Scattering Analysis. Macromolecules, 2019. 52(8): p. 3131-3140.

Place, publisher, year, edition, pages
Oxford, UK: , 2022
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-334221 (URN)
Conference
18th European Mechanics of Materials Conference (EMMC18), April 4 - 6, 2022, Oxford, UK
Note

QC 20230825

Available from: 2023-08-17 Created: 2023-08-17 Last updated: 2023-08-25Bibliographically approved
Mianehrow, H., Berglund, L. & Wohlert, J. (2022). MOISTURE EFFECTS IN NANOCOMPOSITES OF 2D GRAPHENE OXIDE IN CELLULOSE NANOFIBER (CNF) MATRIX: A MOLECULAR DYNAMICS STUDY. In: ECCM 2022: Proceedings of the 20th European Conference on Composite Materials: Composites Meet Sustainability. Paper presented at 20th European Conference on Composite Materials: Composites Meet Sustainability, ECCM 2022, Lausanne, Switzerland, Jun 26 2022 - Jun 30 2022 (pp. 718-725). Composite Construction Laboratory (CCLab), Ecole Polytechnique Federale de Lausanne (EPFL)
Open this publication in new window or tab >>MOISTURE EFFECTS IN NANOCOMPOSITES OF 2D GRAPHENE OXIDE IN CELLULOSE NANOFIBER (CNF) MATRIX: A MOLECULAR DYNAMICS STUDY
2022 (English)In: ECCM 2022: Proceedings of the 20th European Conference on Composite Materials: Composites Meet Sustainability, Composite Construction Laboratory (CCLab), Ecole Polytechnique Federale de Lausanne (EPFL) , 2022, p. 718-725Conference paper, Published paper (Refereed)
Abstract [en]

Moisture largely affects properties in nanocellulose-based nanocomposites. Despite this fact, in-depth studies on moisture effects at the interface in such nanocomposites is missing. In this work, molecular dynamics (MD) simulation is used to study effects from moisture at cellulose nanofibril (CNF)-graphene oxide (GO) interfaces on atomistic level. Two nanocellulose models with different surface chemistry are used as models for native cellulose nanofibrils (NCNF) and TEMPO-oxidized cellulose nanofibrils (TCNF). Work of adhesion and interfacial shear strength at CNF-GO interface is calculated and compared with CNF-graphene interface to study interaction mechanisms. Simulations are done in the presence and absence of water to study the effect of moisture. Interfacial adhesion mechanism between CNF and GO is also investigated.

Place, publisher, year, edition, pages
Composite Construction Laboratory (CCLab), Ecole Polytechnique Federale de Lausanne (EPFL), 2022
Keywords
Cellulose nanofibrils, Graphene Oxide, Interfacial adhesion, Moisture
National Category
Composite Science and Engineering
Identifiers
urn:nbn:se:kth:diva-333392 (URN)2-s2.0-85149409598 (Scopus ID)
Conference
20th European Conference on Composite Materials: Composites Meet Sustainability, ECCM 2022, Lausanne, Switzerland, Jun 26 2022 - Jun 30 2022
Note

Part of ISBN 9782970161400

QC 20230801

Available from: 2023-08-01 Created: 2023-08-01 Last updated: 2023-08-01Bibliographically approved
Chen, P., Zhao, C., Wang, H., Li, Y., Tan, G., Shao, Z., . . . Wohlert, J. (2022). Quantifying the Contribution of the Dispersion Interaction and Hydrogen Bonding to the Anisotropic Elastic Properties of Chitin and Chitosan. Biomacromolecules, 23(4), 1633-1642
Open this publication in new window or tab >>Quantifying the Contribution of the Dispersion Interaction and Hydrogen Bonding to the Anisotropic Elastic Properties of Chitin and Chitosan
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2022 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 4, p. 1633-1642Article in journal (Refereed) Published
Abstract [en]

The elastic tensors of chitin and chitosan allomorphs were calculated using density functional theory (DFT) with and without the dispersion correction and compared with experimental values. The longitudinal Young's moduli were 114.9 or 126.9 GPa for alpha-chitin depending on the hydrogen bond pattern: 129.0 GPa for beta-chitin and 191.5 GPa for chitosan. Furthermore, the moduli were found to vary between 17.0 and 52.8 GPa in the transverse directions and between 2.2 and 15.2 GPa in shear. Switching off the dispersion correction led to a decrease in modulus by up to 63%, depending on the direction. The transverse Young's moduli of a-chitin strongly depended on the hydroxylmethyl group conformation coupled with the dispersion correction, suggesting a synergy between hydrogen bonding and dispersion interactions. The calculated longitudinal Young's moduli were, in general, higher than experimental values obtained in static conditions, and the Poisson's ratios were lower than experimental values obtained in static conditions.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
National Category
Condensed Matter Physics Composite Science and Engineering Bio Materials
Identifiers
urn:nbn:se:kth:diva-312211 (URN)10.1021/acs.biomac.1c01488 (DOI)000787824500013 ()35352926 (PubMedID)2-s2.0-85127834136 (Scopus ID)
Note

QC 20220516

Available from: 2022-05-16 Created: 2022-05-16 Last updated: 2022-06-25Bibliographically approved
Ramamohan, P., Furo, I. & Wohlert, J. (2022). Timescales for convergence in all-atom molecular dynamics simulations of hydrated amorphous xylan. Carbohydrate Polymers, 286, 119263-119263, Article ID 119263.
Open this publication in new window or tab >>Timescales for convergence in all-atom molecular dynamics simulations of hydrated amorphous xylan
2022 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 286, p. 119263-119263, article id 119263Article in journal (Refereed) Published
Abstract [en]

Atomistic molecular dynamics simulation is an important complement to experimental techniques for investi­gating properties of hydrated carbohydrate polymers at the molecular scale. A critical problem is to determinewhether or not a simulation has converged to thermal equilibrium before data collection can begin. In this work,simulations of xylan oligomers starting from random configurations at different levels of hydration are per­formed. The simulations show clear evidence of phase separation into water-rich and polymer-rich phases athigher hydration, in spite of standard indicators of equilibrium, such as density and energy, remaining constant.Using instead a set of parameters that are coupled to the structural and dynamical heterogeneity of the system, itis shown that simulation times on the order of one microsecond are needed to reach an equilibrated state.Moreover, qualitative similarities in the temporal evolution of these parameters suggest significant interplaybetween the structure and both polymer and water dynamics.

Place, publisher, year, edition, pages
Elsevier BV, 2022
Keywords
Biomaterials Polysaccharide structure-dynamics Aggregation Phase separation
National Category
Engineering and Technology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-327115 (URN)10.1016/j.carbpol.2022.119263 (DOI)000791295400008 ()35337496 (PubMedID)2-s2.0-85125459491 (Scopus ID)
Funder
Swedish Research Council, CGIA63646Knut and Alice Wallenberg Foundation
Note

QC 20230522

Available from: 2023-05-19 Created: 2023-05-19 Last updated: 2023-06-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6732-2571

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