kth.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Tailoring and Characterization of Polymer-linked Fibrillar Structures
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.ORCID iD: 0000-0002-2114-3014
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The development of sustainable and renewable materials is paramount in today’s society. As the most abundant biopolymer on Earth, cellulose from cellulose-rich fibres is an excellent alternative for advanced and innovative material solutions. Nonetheless, competing with the impressive material properties and the low manufacturing costs of fossil-based plastics imposes great challenges. To increase the potential of cellulose fibres in a broader set of applications, the material properties of cellulose need to be tuned depending on the application. An in-depth study of the fibre structure and the application of different tailoring techniques is required to induce tailoring of the physical and chemical properties of the cellulose fibre materials. 

This thesis focuses on the structure-property relationship of fibrillar hydrogel networks as model structures for the delignified wet-fibre wall. First, a mathematical framework was developed to describe the characteristics of the swelling and mechanical behaviour of anisotropic fibrillar structures, considering the fibril aspect ratio, surface chemistry of the fibrils, and electrolyte concentration in the system. A chemical functionalisation was then introduced to the fibrillar structure, which provided the CNFs with colloidal stability and the ability to participate in free radical polymerisation with monomers and telechelic oligomers. As a result, fibrillar networks were crosslinked with flexible polymer links that provided the network with different mechanical and chemical properties. Additionally, by tailoring the molecular weight of the crosslinks, the ionic strength of the solution, and even the aspect ratio of the fibrils, the mechanical properties of the network were tuned to be either stiffer or more ductile. 

Finally, an innovative and more sustainable approach was developed to introduce charge and alkene functionality to the fibres. Following the lessons learned from the CNF model investigations, a polymerisation approach was developed in the presence of functionalised fibres. The polymers were grown from the fibre wall, followed by radical crosslinking to create strong Fibre reinforced hydrogel structures. Depending on the application, the method can be easily applied to introduce other types of molecules and functionalities to the fibres and tailor the properties of the fibres to suit a wide range of applications.

Abstract [sv]

Utvecklingen av hållbara och förnyelsebara material är avgörande i dagens samhälle. Eftersom cellulosa ifrån växtfibrer är den mest förekommande biopolymeren på jorden är den ett utmärkt alternativ för användning i avancerade och innovativa materiallösningar. Det innebär dock en enorm utmaning att konkurrera med de imponerande materialegenskaperna och låga tillverkningskostnaderna hos fossilbaserade plaster. För att utnyttja den inneboende potentialen hos cellulosafibrerna och utveckla deras egenskapsrymd för användning i vidare tillämpningar är det helt nödvändigt att modifiera cellulosans materialegenskaper för att passa till specifika slutanvändningar. Det är därför nödvändigt att ingående studera hur olika modifieringstekniker kan användas för att skräddarsy fysikaliska och kemiska egenskaper hos cellulosan på olika strukturella nivåer i de delignifierade fibrerna.  

Arbetet i denna avhandling har fokuserats på att klarlägga struktur-egenskapsförhållandena för cellulosa-rika fibrilstrukturer. Initialt användes fibrillära hydrogelnätverk som modell för den delignifierade våtfibreväggen. Till att börja med utvecklades ett matematiskt ramverk för att beskriva det typiska svällningsbeteendet och de mekaniska egenskaperna hos de anisotropa fibrillstrukturerna med avseende på fibrillernas längs/tvärs förhållande, ytkemi och elektrolytkoncentration i systemet.  Efter detta modifierades fibrillerna på ett sådant sätt att de erhöll en god kolloidal stabilitet samtidigt som de försågs med en vinyl-funktionalitet som innebar att de kunde användas i friradikalpolymerisation med olika typer av monomerer och telecheliska oligomerer. Via denna typ av radikalpolymerisation var det möjligt att skapa fibrillnätverk med flexibla polymerkopplingar som resulterade i skräddarsydda mekaniska och kemiska egenskaper. Genom att kontrollera tvärbindningarnas molekylvikt, lösningens jonstyrka och fibrillernas längs/tvärs förhållande kunde nätverkets mekaniska egenskaper kontrolleras så att de antingen blev mer töjbara eller styva. 

Med hjälp av en innovativ och mer hållbar modifieringsteknik visade det sig vidare möjligt att samtidigt skapa hög laddning och att introducera en vinylfunktionalitet hos cellulosa-rika fibrer. Genom att använda de tidigare erfarenheterna ifrån de modifierade fibrillnätverken visade det sig möjligt att utveckla en polymerisationsmetod i närvaro av de funktionaliserade fibrer där polymerisation initierades både inuti och omkring de modifierade fibrerna. Polymererna ympades ifrån den modifierade fibreväggen både inuti och omkring fibrerna, följt av radikaltvärbindning för att skapa helt nya typer av starka, fibrebaserade hydrogelstrukturer. Beroende på den slutliga tillämpningen, av denna nya typ av fiberförstärkta hydrogeler, är det enkelt att använda metoden för att inkludera andra molekyler och funktionaliteter till fibrerna för att skräddarsy gelegenskaperna.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2024. , p. 58
Series
TRITA-CBH-FOU ; 2024:4
Keywords [en]
Cellulose nanofibrils, hydrogels, cellulose fibres, functionalisation, structure-property relationships.
National Category
Paper, Pulp and Fiber Technology
Research subject
Fibre and Polymer Science
Identifiers
URN: urn:nbn:se:kth:diva-342125ISBN: 978-91-8040-819-6 (print)OAI: oai:DiVA.org:kth-342125DiVA, id: diva2:1828230
Public defence
2024-02-09, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
Knut and Alice Wallenberg Foundation
Note

QC 20240118

Embargo godkänt av skolchef Amelie Eriksson Karlström via e-post 2024-01-16

Available from: 2024-01-18 Created: 2024-01-16 Last updated: 2024-01-22Bibliographically approved
List of papers
1. Elastoplastic behavior of anisotropic, physically crosslinked hydrogel networks comprising stiff, charged fibrils in an electrolyte
Open this publication in new window or tab >>Elastoplastic behavior of anisotropic, physically crosslinked hydrogel networks comprising stiff, charged fibrils in an electrolyte
Show others...
2023 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 19, no 15, p. 2792-2800Article in journal (Refereed) Published
Abstract [en]

Fibrillar hydrogels are remarkably stiff, low-density networks that can hold vast amounts of water. These hydrogels can easily be made anisotropic by orienting the fibrils using different methods. Unlike the detailed and established descriptions of polymer gels, there is no coherent theoretical framework describing the elastoplastic behavior of fibrillar gels, especially concerning anisotropy. In this work, the swelling pressures of anisotropic fibrillar hydrogels made from cellulose nanofibrils were measured in the direction perpendicular to the fibril alignment. This experimental data was used to develop a model comprising three mechanical elements representing the network and the osmotic pressure due to non-ionic and ionic surface groups on the fibrils. At low solidity, the stiffness of the hydrogels was dominated by the ionic swelling pressure governed by the osmotic ingress of water. Fibrils with different functionality show the influence of aspect ratio, chemical functionality, and the remaining amount of hemicelluloses. This general model describes physically crosslinked hydrogels comprising fibrils with high flexural rigidity - that is, with a persistence length larger than the mesh size. The experimental technique is a framework to study and understand the importance of fibrillar networks for the evolution of multicellular organisms, like plants, and the influence of different components in plant cell walls.

Place, publisher, year, edition, pages
Royal Society of Chemistry (RSC), 2023
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-330921 (URN)10.1039/d2sm01571d (DOI)000960684700001 ()36992628 (PubMedID)2-s2.0-85152114916 (Scopus ID)
Note

QC 20230704

Available from: 2023-07-04 Created: 2023-07-04 Last updated: 2024-04-29Bibliographically approved
2. Shape-recovering nanocellulose networks: Preparation, characterization and modeling
Open this publication in new window or tab >>Shape-recovering nanocellulose networks: Preparation, characterization and modeling
Show others...
2023 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 315, p. 120950-, article id 120950Article in journal (Refereed) Published
Abstract [en]

Development of strong cellulose nanofibril (CNF) networks for advanced applications, such as in the biomedical field, is of high importance owing to the biocompatible nature and plant-based origin of cellulose nanofibrils. Nevertheless, lack of mechanical strength and complex synthesis methods hinder the application of these ma-terials in areas where both toughness and manufacturing simplicity are required. In this work, we introduce a facile method for the synthesis of a low solid content (< 2 wt%), covalently crosslinked CNF hydrogel where Poly (N-isopropylacrylamide) (NIPAM) chains are utilized as crosslinks between the nanofibrils. The resulting net-works have the capability to fully recover the shape in which they were formed after various drying and rewetting cycles. Characterization of the hydrogel and its constitutive components was performed using X-ray scattering, rheological investigations and uniaxial testing in compression. Influence of covalent crosslinks was compared with networks crosslinked by the addition of CaCl2. Among other things the results show that the mechanical properties of the hydrogels can be tuned by controlling the ionic strength of the surrounding me-dium. Finally, a mathematical model was developed based on the experimental results, which describes and predicts to a decent degree the large-deformation, elastoplastic behavior, and fracture of these networks.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Nanocellulose, Networks, Hydrogel, Modeling, Nanofibrils
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-329948 (URN)10.1016/j.carbpol.2023.120950 (DOI)001001403200001 ()37230608 (PubMedID)2-s2.0-85158836395 (Scopus ID)
Note

QC 20230626

Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2024-01-16Bibliographically approved
3. Photocross-Linkable and Shape-Memory Biomaterial Hydrogel Based on Methacrylated Cellulose Nanofibres
Open this publication in new window or tab >>Photocross-Linkable and Shape-Memory Biomaterial Hydrogel Based on Methacrylated Cellulose Nanofibres
Show others...
2023 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 24, no 8, p. 3835-3845Article in journal (Refereed) Published
Abstract [en]

In the context of three-dimensional (3D) cell culture and tissue engineering, 3D printing is a powerful tool for customizing in vitro 3D cell culture models that are critical for understanding the cell-matrix and cell-cell interactions. Cellulose nanofibril (CNF) hydrogels are emerging in constructing scaffolds able to imitate tissue in a microenvironment. A direct modification of the methacryloyl (MA) group onto CNF is an appealing approach to synthesize photocross-linkable building blocks in formulating CNF-based bioinks for light-assisted 3D printing; however, it faces the challenge of the low efficiency of heterogenous surface modification. Here, a multistep approach yields CNF methacrylate (CNF-MA) with a decent degree of substitution while maintaining a highly dispersible CNF hydrogel, and CNF-MA is further formulated and copolymerized with monomeric acrylamide (AA) to form a super transparent hydrogel with tuneable mechanical strength (compression modulus, approximately 5-15 kPa). The resulting photocurable hydrogel shows good printability in direct ink writing and good cytocompatibility with HeLa and human dermal fibroblast cell lines. Moreover, the hydrogel reswells in water and expands to all directions to restore its original dimension after being air-dried, with further enhanced mechanical properties, for example, Young’s modulus of a 1.1% CNF-MA/1% PAA hydrogel after reswelling in water increases to 10.3 kPa from 5.5 kPa.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Biomaterials Science Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-338508 (URN)10.1021/acs.biomac.3c00476 (DOI)001041093700001 ()37527286 (PubMedID)2-s2.0-85167801418 (Scopus ID)
Note

QC 20231115

Available from: 2023-11-15 Created: 2023-11-15 Last updated: 2024-02-29Bibliographically approved
4. Structure-Properties Relationships of Defined CNF Single-Networks Crosslinked by Telechelic PEGs
Open this publication in new window or tab >>Structure-Properties Relationships of Defined CNF Single-Networks Crosslinked by Telechelic PEGs
Show others...
(English)Manuscript (preprint) (Other academic)
Keywords
Hydrogel, Cellulose Nanofibrils, Network, Nanostructure, Polymerization
National Category
Paper, Pulp and Fiber Technology
Research subject
Materials Science and Engineering
Identifiers
urn:nbn:se:kth:diva-342359 (URN)
Note

QC 20240117

Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-01-17Bibliographically approved
5. Dual-functionalized Cellulosic Pulp Fibres for Sustainable Fibre Reinforced Hydrogel Composites
Open this publication in new window or tab >>Dual-functionalized Cellulosic Pulp Fibres for Sustainable Fibre Reinforced Hydrogel Composites
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-342360 (URN)
Note

QC 20240117

Available from: 2024-01-16 Created: 2024-01-16 Last updated: 2024-01-17Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records

Cortes Ruiz, Maria F.

Search in DiVA

By author/editor
Cortes Ruiz, Maria F.
By organisation
Fibre Technology
Paper, Pulp and Fiber Technology

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 824 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf