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Marais, Andrew
Publications (5 of 5) 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: 2019-09-13Bibliographically approved
Wang, Z., Ouyang, L., Tian, W., Erlandsson, J., Marais, A., Tybrandt, K., . . . Hamedi, M. (2019). Layer-by-Layer Assembly of High-Performance Electroactive Composites Using a Multiple Charged Small Molecule. Langmuir, 35(32), 10367-10373
Open this publication in new window or tab >>Layer-by-Layer Assembly of High-Performance Electroactive Composites Using a Multiple Charged Small Molecule
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2019 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, no 32, p. 10367-10373Article in journal (Refereed) Published
Abstract [en]

Layer-by-layer (LbL) assembly is a versatile tool for fabricating multilayers with tailorable nanostructures. LbL, however, generally relies on polyelectrolytes, which are mostly insulating and induce large interlayer distances. We demonstrate a method in which we replace polyelectrolytes with the smallest unit capable of LbL self-assembly: a molecule with multiple positive charges, tris(3-aminopropyl)amine (TAPA), to fabricate LbL films with negatively charged single-walled carbon nanotubes (CNTs). TAPA introduces less defects during the LbL build-up and results in more efficient assembly of films with denser micromorphology. Twenty bilayers of TAPA/CNT showed a low sheet resistance of 11 k Omega, a high transparency of 91% at 500 nm, and a high electronic conductivity of 1100 S/m on planar substrates. We also fabricated LbL films on porous foams with a conductivity of 69 mS/m and used them as electrodes for supercapacitors with a high specific capacitance of 43 F/g at a discharging current density of 1 A/g.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-257441 (URN)10.1021/acs.langmuir.9b01587 (DOI)000480827000013 ()31322359 (PubMedID)2-s2.0-85071226711 (Scopus ID)
Note

QC 20190903

Available from: 2019-09-03 Created: 2019-09-03 Last updated: 2019-09-03Bibliographically approved
Wågberg, L., Hamedi, M., Marais, A., Nyström, G., Francon, H., Granberg, H. & Erlandsson, J. (2018). The use of the layer-by-layer technology and low density networks of cellulose nanofibrils for preparing new materials for energy storage. Paper presented at 255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA. Abstract of Papers of the American Chemical Society, 255
Open this publication in new window or tab >>The use of the layer-by-layer technology and low density networks of cellulose nanofibrils for preparing new materials for energy storage
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2018 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240172 (URN)000435537702661 ()
Conference
255th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nexus of Food, Energy, and Water, MAR 18-22, 2018, New Orleans, LA
Note

QC 20181214

Available from: 2018-12-14 Created: 2018-12-14 Last updated: 2018-12-14Bibliographically approved
Pettersson, T., Pendergraph, S. A., Utsel, S., Marais, A., Gustafsson, E. & Wågberg, L. (2015). Robust and tailored wet adhesion in biopolymer thin film with wet adhesion and toughness superior to wet adhesion in bone. Abstracts of Papers of the American Chemical Society, 249
Open this publication in new window or tab >>Robust and tailored wet adhesion in biopolymer thin film with wet adhesion and toughness superior to wet adhesion in bone
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2015 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2015
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-243698 (URN)000411183303677 ()
Note

QC 20190227

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-08-21Bibliographically approved
Hamedi, M., Wågberg, L., Nyström, G., Marais, A., Karabulut, E. & Cui, Y. (2015). Soft, compressible and fully Interdigitated 3D energy storage devices built by layer-by-layer assembly inside aerogels. Abstract of Papers of the American Chemical Society, 249
Open this publication in new window or tab >>Soft, compressible and fully Interdigitated 3D energy storage devices built by layer-by-layer assembly inside aerogels
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2015 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2015
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-243685 (URN)000411186504791 ()
Note

QC 20190305

Available from: 2019-03-05 Created: 2019-03-05 Last updated: 2019-03-05Bibliographically approved
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