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Publications (10 of 419) Show all publications
Erlandsson, J., Francon, H., Marais, A., Granberg, H. & Wågberg, L. (2019). Cross-Linked and Shapeable Porous 3D Substrates from Freeze-Linked Cellulose Nanofibrils. Paper presented at Symposium on Rational Design of Multifunctional Renewable-Resourced Materials held during the ACS National Meeting, AUG 19-23, 2018, Boston, MA. Biomacromolecules, 20(2), 728-737
Open this publication in new window or tab >>Cross-Linked and Shapeable Porous 3D Substrates from Freeze-Linked Cellulose Nanofibrils
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2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 2, p. 728-737Article in journal (Refereed) Published
Abstract [en]

Chemically cross-linked highly porous nano cellulose aerogels with complex shapes have been prepared using a freeze-linking procedure that avoids common post activation of cross-linking reactions and freeze-drying. The aerogel shapes ranged from simple geometrical three-dimensional bodies to swirls and solenoids. This was achieved by molding or extruding a periodate oxidized cellulose nanofibril (CNF) dispersion prior to chemical cross-linking in a regular freezer or by reshaping an already prepared aerogel by plasticizing the structure in water followed by reshaping and locking the aerogel into its new shape. The new shapes were most likely retained by new cross-links formed between CNFs brought into contact by the deformation during reshaping. This self-healing ability to form new bonds after plasticization and redrying also contributed to the mechanical resilience of the aerogels, allowing them to be cyclically deformed in the dry state, reswollen with water, and redried with good retention of mechanical integrity. Furthermore, by exploiting the shapeability and available inner structure of the aerogels, a solenoid-shaped aerogel with all surfaces coated with a thin film of conducting polypyrrole was able to produce a magnetic field inside the solenoid, demonstrating electromagnetic properties. Furthermore, by biomimicking the porous interior and stiff exterior of the beak of a toucan bird, a functionalized aerogel was created by applying a 300 mu m thick stiff wax coating on its molded external surfaces. This composite material displayed a 10-times higher elastic modulus compared to that of the plain aerogel without drastically increasing the density. These examples show that it is possible to combine advanced shaping with functionalization of both the inner structure and the surface of the aerogels, radically extending the possible use of CNF aerogels.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-245946 (URN)10.1021/acs.biomac.8b01412 (DOI)000458937200016 ()30394086 (PubMedID)2-s2.0-85057560598 (Scopus ID)
Conference
Symposium on Rational Design of Multifunctional Renewable-Resourced Materials held during the ACS National Meeting, AUG 19-23, 2018, Boston, MA
Note

QC 20190312

Available from: 2019-03-12 Created: 2019-03-12 Last updated: 2019-03-12Bibliographically approved
Farahani, S. K., Escalante, A., Toriz, G., Vilaplana, F., Gatenholm, P., Hansson, P. & Wågberg, L. (2019). Experimental and Theoretical Evaluation of the Solubility/Insolubility Spruce Xylan (Arabino Glucuronoxylan). Biomacromolecules, 20(3), 1263-1270
Open this publication in new window or tab >>Experimental and Theoretical Evaluation of the Solubility/Insolubility Spruce Xylan (Arabino Glucuronoxylan)
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2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 3, p. 1263-1270Article in journal (Refereed) Published
Abstract [en]

The molecular solubility of softwood arabinoglucuronoxylan (AGX) has been thoroughly investigated, and it has been shown that the chemical and physical structures of the extracted hemicellulose are not significantly influenced by different purification steps, but a transient molecular solubility of AGX was observed in aqueous media at low concentrations (1 g/L) when the dissolved macromolecules had a hydrodynamic diameter of up to 10 nm. A phase separation was detected when the concentration was increased to 15 g/L leading to an association of the smaller molecules into fractal structures with a considerably larger diameter, even though the dispersions were still transparent to ocular inspection. Dynamic Light Scattering and Cryo-Transmission Electron Microscopy showed dimensions in the range of 1000 nm. The phase separation of the sample was further characterized by estimating the χ-interaction parameter of AGX in water using the Flory-Huggins theory, and the results supported that water is a poor solvent for AGX. This behavior is crucial when films and hydrogels based on these biopolymers are made, since the association will dramatically affect barrier and mechanical properties of films made from these materials.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-248093 (URN)10.1021/acs.biomac.8b01686 (DOI)000461270500013 ()30689362 (PubMedID)2-s2.0-85061537168 (Scopus ID)
Note

QC 20190429

Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2019-05-22Bibliographically approved
Chen, C., Pettersson, T., Illergård, J., Ek, M. & Wågberg, L. (2019). Influence of Cellulose Charge on Bacteria Adhesion and Viability to PVAm/CNF/PVAm-Modified Cellulose Model Surfaces. Biomacromolecules
Open this publication in new window or tab >>Influence of Cellulose Charge on Bacteria Adhesion and Viability to PVAm/CNF/PVAm-Modified Cellulose Model Surfaces
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2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602Article in journal (Refereed) Published
Abstract [en]

A contact-active antibacterial approach based on the physical adsorption of a cationic polyelectrolyte onto the surface of a cellulose material is today regarded as an environment-friendly way of creating antibacterial surfaces and materials. In this approach, the electrostatic charge of the treated surfaces is considered to be an important factor for the level of bacteria adsorption and deactivation/killing of the bacteria. In order to clarify the influence of surface charge density of the cellulose on bacteria adsorption as well as on their viability, bacteria were adsorbed onto cellulose model surfaces, which were modified by physically adsorbed cationic polyelectrolytes to create surfaces with different positive charge densities. The surface charge was altered by the layer-by-layer (LbL) assembly of cationic polyvinylamine (PVAm)/anionic cellulose nanofibril/PVAm onto the initially differently charged cellulose model surfaces. After exposing the LbL-treated surfaces to Escherichia coli in aqueous media, a positive correlation was found between the adsorption of bacteria as well as the ratio of nonviable/viable bacteria and the surface charge of the LbL-modified cellulose. By careful colloidal probe atomic force microscopy measurements, it was estimated, due to the difference in surface charges, that interaction forces at least 50 nN between the treated surfaces and a bacterium could be achieved for the surfaces with the highest surface charge, and it is suggested that these considerable interaction forces are sufficient to disrupt the bacterial cell wall and hence kill the bacteria.

National Category
Biochemistry and Molecular Biology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-249635 (URN)10.1021/acs.biomac.9b00297 (DOI)000468120800025 ()2-s2.0-85065660991 (Scopus ID)
Note

QC 20190611

Available from: 2019-04-15 Created: 2019-04-15 Last updated: 2019-06-11Bibliographically approved
Benselfelt, T., Nordenström, M., Hamedi, M. & Wågberg, L. (2019). Ion-induced assemblies of highly anisotropic nanoparticles are governed by ion-ion correlation and specific ion effects. Nanoscale, 11(8), 3514-3520
Open this publication in new window or tab >>Ion-induced assemblies of highly anisotropic nanoparticles are governed by ion-ion correlation and specific ion effects
2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 8, p. 3514-3520Article in journal (Refereed) Published
Abstract [en]

Ion-induced assemblies of highly anisotropic nanoparticles can be explained by a model consisting of ion-ion correlation and specific ion effects: dispersion interactions, metal-ligand complexes, and local acidic environments. Films of cellulose nanofibrils and montmorillonite clay were treated with different ions, and their subsequent equilibrium swelling in water was related to important parameters of the model in order to investigate the relative importance of the mechanisms. Ion-ion correlation was shown to be the fundamental attraction, supplemented by dispersion interaction for polarizable ions such as Ca2+ and Ba2+, or metal-ligand complexes for ions such as Cu2+, Al3+ and Fe3+. Ions that form strong complexes induce local acidic environments that also contribute to the assembly. These findings are summarized in a comprehensive semi-quantitative model and are important for the design of nanomaterials and for understanding biological systems where specific ions are involved.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-245906 (URN)10.1039/c8nr10175b (DOI)000459504400008 ()30742178 (PubMedID)2-s2.0-85061966436 (Scopus ID)
Note

QC 20190308

Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-04-08Bibliographically approved
Träger, A., Klein, G., Carrick, C., Pettersson, T., Johansson, M., Wågberg, L., . . . Carlmark, A. (2019). Macroscopic cellulose probes for the measurement of polymer grafted surfaces. Cellulose (London), 26(3), 1467-1477
Open this publication in new window or tab >>Macroscopic cellulose probes for the measurement of polymer grafted surfaces
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2019 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 3, p. 1467-1477Article in journal (Refereed) Published
Abstract [en]

A synthesis protocol was identified to produce covalent grafting of poly(dimethyl siloxane) from cellulose, based on prior studies of analogous ring opening polymerizations. Following this polymer modification of cellulose, the contact adhesion was anticipated to be modified and varied as a function of the polymer molecular mass. The synthetic details were optimized for a filter paper surface before grafting the polymer from bulk cellulose spheres. The adhesion of the unmodified and grafted, bulk cellulose spheres were evaluated using the Johnson-Kendall-Roberts (JKR) theory with a custom build contact adhesion testing setup. We report the first example of grafting poly(dimethyl siloxane) directly from bulk cellulose using ring opening polymerization. For short grafting lengths, both the JKR work of adhesion and the adhesion energy at the critical energy release rate (G(c)) were comparable to unmodified cellulose beads. When polymer grafting lengths were extended sufficiently where chain entanglements occur, both the JKR work of adhesion and G(c) were increased by as much as 190%. Given the multitude of options available to graft polymers from cellulose, this study shows the potential to use this type of cellulose spheres to study the interaction between different polymer surfaces in a controlled manner. [GRAPHICS] .

Place, publisher, year, edition, pages
SPRINGER, 2019
Keywords
Grafted polymer, Cellulose, Contact mechanics, Adhesion, Johnson-Kendall-Roberts theory
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-247840 (URN)10.1007/s10570-018-2196-2 (DOI)000460617900004 ()
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-05-20Bibliographically approved
Kaldéus, T., Nordenström, M., Erlandsson, J., Wågberg, L. & Malmström, E. (2019). Redispersibility properties of dried cellulose nanofibrils - influence on structure and mechanical properties.
Open this publication in new window or tab >>Redispersibility properties of dried cellulose nanofibrils - influence on structure and mechanical properties
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2019 (English)In: Article in journal (Other academic) Epub ahead of print
National Category
Polymer Technologies Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-244055 (URN)
Note

QC 20190218

Available from: 2019-02-15 Created: 2019-02-15 Last updated: 2019-02-18Bibliographically approved
Qin, S., Ghanadpour, M., Lazar, S., Köklükaya, O., Gerringer, J., Song, Y., . . . Grunlan, J. C. (2019). Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films. Advanced Materials Interfaces, 6(2), Article ID 1801424.
Open this publication in new window or tab >>Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films
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2019 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 6, no 2, article id 1801424Article in journal (Refereed) Published
Abstract [en]

Cellulose nanofibrils (CNF) are abundant in the fiber cell walls of many plants and are considered a nearly inexhaustible resource. With the goal of improving the flame resistance and gas barrier properties of cellulose-based films, cationic CNF are assembled with anionic vermiculite (VMT) clay using the layer-by-layer deposition process. The highly aligned VMT nanoplatelets, together with cellulose nanofibrils, form a nanobrick wall structure that exhibits high optical transparency, flame resistance, super oxygen barrier, and high modulus. A 20 CNF/VMT bilayer (BL) nanocoating, with a thickness of only 136 nm, exhibits an oxygen transmission rate of 0.013 cc (m(2) day atm)(-1). With only 2 BL of CNF/VMT, the melting of flexible polyurethane foam exposed to a butane torch is prevented. These nanocoatings also exhibit a high elastic modulus (20 GPa) and hardness (1 GPa). This study demonstrates a unique, renewable, cellulose-based nanocoating that could be used in a variety of packaging and protection applications.

Place, publisher, year, edition, pages
WILEY, 2019
Keywords
cellulose nanofibril, flame resistance, layer-by-layer assembly, mechanical properties, oxygen barrier
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-243958 (URN)10.1002/admi.201801424 (DOI)000456673900011 ()2-s2.0-85056621866 (Scopus ID)
Note

QC 20190301

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2019-03-01Bibliographically approved
Engström, J., Benselfelt, T., Wågberg, L., D'Agosto, F., Lansalot, M., Carlmark, A. & Malmström, E. (2019). Tailoring adhesion of anionic surfaces using cationic PISA-latexes – towards tough nanocellulose materials in the wet state. Nanoscale, 11, 4287-4302
Open this publication in new window or tab >>Tailoring adhesion of anionic surfaces using cationic PISA-latexes – towards tough nanocellulose materials in the wet state
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2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, p. 4287-4302Article in journal (Refereed) Published
Abstract [en]

Cationic latexes with Tgs ranging between −40 °C and 120 °C were synthesised using n-butyl acrylate (BA) and/or methyl methacrylate (MMA) as the core polymers. Reversible addition–fragmentation chain transfer (RAFT) combined with polymerisation-induced self-assembly (PISA) allowed for in situ chain-extension of a cationic macromolecular RAFT agent (macroRAFT) of poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMA), used as stabiliser in so-called surfactant-free emulsion polymerisation. The resulting narrowly distributed nanosized latexes adsorbed readily onto silica surfaces and to model surfaces of cellulose nanofibrils, as demonstrated by quartz crystal microbalance with dissipation monitoring (QCM-D) measurements. Adsorption to anionic surfaces increased when increasing ionic strength to 10 mM, indicating the influence of the polyelectrolyte effect exerted by the corona. The polyelectrolyte corona affected the interactions in the wet state, the stability of the latex and re-dispersibility after drying. The QCM-D measurements showed that a lower Tg of the core results in a more strongly interacting adsorbed layer at the solid–liquid interface, despite a comparable adsorbed mass, indicating structural differences of the investigated latexes in the wet state. The two latexes with Tg below room temperature (i.e. PBATg-40 and P(BA-co-MMA)Tg3) exhibited film formation in the wet state, as shown by AFM colloidal probe measurements. It was observed that P(BA-co-MMA)Tg3 latex resulted in the largest pull-off force, above 200 m Nm−1 after 120 s in contact. The strongest wet adhesion was achieved with PDMAPMA-stabilized latexes soft enough to allow for interparticle diffusion of polymer chains, and stiff enough to create a strong adhesive joint. Fundamental understanding of interfacial properties of latexes and cellulose enables controlled and predictive strategies to produce strong and tough materials with high nanocellulose content, both in the wet and dry state.

National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-241447 (URN)10.1039/C8NR08057G (DOI)000465410200012 ()2-s2.0-85062644682 (Scopus ID)
Note

QC 20190123

Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-05-29Bibliographically approved
Karlsson, R.-M. P., Larsson, P. T., Hansson, P. & Wågberg, L. (2019). Thermodynamics of the Water-Retaining Properties of Cellulose-Based Networks. Biomacromolecules, 20(4), 1603-1612
Open this publication in new window or tab >>Thermodynamics of the Water-Retaining Properties of Cellulose-Based Networks
2019 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, no 4, p. 1603-1612Article in journal (Refereed) Published
Abstract [en]

Noncrystalline cellulose-based gel beads were used as a model material to investigate the effect of osmotic stress on a cellulosic network. The gel beads were exposed to osmotic stress by immersion in solutions with different concentrations of high molecular mass dextran and the equilibrium dimensional change of the gel beads was studied using optical microscopy. The volume fraction of cellulose was calculated from the volume of the gel beads in dextran solutions and their dry content and the relation between the cellulose volume fraction and the total osmotic pressure was thus obtained. The results show that the contribution to the osmotic pressure from counterions increases the water-retaining capacity of the beads at high osmotic pressures but also that the main factor controlling the gel bead collapse at high osmotic strains is the resistance to the deformation of the polymer chain network within the beads. Furthermore, the osmotic pressure associated with the deformation of the polymer network, which counteracts the deswelling of the beads, could be fitted to the Wall model indicating that the response of the cellulose polymer networks was independent of the charge of the cellulose. The best fit to the Wall model was obtained when the Flory-Huggins interaction parameter () of the cellulose-water system was set to 0.55-0.60, in agreement with the well-established insolubility of high molecular mass β-(1,4)-d-glucan polymers in water.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Polymer Chemistry
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-250012 (URN)10.1021/acs.biomac.8b01791 (DOI)000464248300013 ()2-s2.0-85063128803 (Scopus ID)
Note

QC 20190509

Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-05-22Bibliographically approved
Larsson, P. A., Riazanova, A., Ciftci, G. C., Rojas, R., Ovrebo, H. H., Wågberg, L. & Berglund, L. (2019). Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach. Cellulose (London), 26(3), 1565-1575
Open this publication in new window or tab >>Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach
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2019 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 3, p. 1565-1575Article in journal (Refereed) Published
Abstract [en]

For the successful commercialisation of microfibrillated cellulose (MFC) it is of utmost importance to carefully characterise the constituent cellulose particles. This could for instance lead to the development of MFC grades with size distributions tailored for specific applications. Characterization of MFC is challenging due to the heterogeneous chemical and structural nature of MFC. This study describes a fractionation approach that combines two steps of physical sieving of larger particles and a final centrifugation step to separate out the smallest, colloidally stable particles, resulting in four distinctly different size fractions. The properties, such as size and charge, of each fraction were studied, as well as MFC filtration time, film formation, and film properties (mechanical and optical). It was found that virtually all surface charges, determined by polyelectrolyte adsorption, are located in the colloidally stable fraction of the MFC. In addition, the amount of available surface charges can be used as an estimate of the degree of fibrillation of the MFC. The partly fibrillated particles frequently displayed a branching, fringed morphology. Mechanical testing of films from the different fractions revealed that the removal of large particles may be more important for strength than achieving full fibrillation. Overall, this study demonstrates that by controlling the size distribution in MFC grades, property profiles including dewatering time to make films by filtration, rheology, film strength and optical transmittance could be optimised. [GRAPHICS] .

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Cellulose nanofibrils, Cellulose films, Fractionation, Microfibrillated cellulose, Nanocellulose, Nanopaper
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-247842 (URN)10.1007/s10570-018-2214-4 (DOI)000460617900011 ()2-s2.0-85059322104 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-05-21Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-8622-0386

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