On the mechanism behind freezing-induced chemical crosslinking in ice-templated cellulose nanofibril aerogels

Erlandsson, Johan; Pettersson, Torbjörn; Ingverud, Tobias; Granberg, Hjalmar; Larsson, Per Tomas; Malkoch, Michael; Wågberg, Lars

doi:10.1039/c8ta06319b

Cited by 74 publications

(67 citation statements)

References 45 publications

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“…Consequently, these samples could resist the structural stress caused by the destructive capillary forces during evaporation; whereas the ones prepared without any salt addition largely collapsed. It is worth noting that ice crystals have been shown to push CNFs close enough toward each other to establish chemical contact in a previous study …”

Section: Aerogels From Cellulose Nanofibers and Sodium Alginatementioning

confidence: 90%

“…This is commonly achieved by crosslinking the fibrillar structure, either in the dry or the wet state, with covalent inter‐fibrillar bonds such as ether, urethane, ester, or hemiacetal linkages . Recent studies demonstrated the preparation of wet‐stable aerogels from dialdehyde CNFs by using a simple freezing, thawing, and solvent exchange procedure . Thanks to the absence of critical point drying and freeze‐drying, this process could presumably be fairly easily made continuous and meet industrial requirements both in terms of energy consumption and production rate.…”

Section: Introductionmentioning

confidence: 99%

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Ambient‐Dried, 3D‐Printable and Electrically Conducting Cellulose Nanofiber Aerogels by Inclusion of Functional Polymers

Françon

Wang

Marais

et al. 2020

Adv Funct Materials

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114

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This study presents a novel, green, and efficient way of preparing crosslinked aerogels from cellulose nanofibers (CNFs) and alginate using non‐covalent chemistry. This new process can ultimately facilitate the fast, continuous, and large‐scale production of porous, light‐weight materials as it does not require freeze‐drying, supercritical CO2 drying, or any environmentally harmful crosslinking chemistries. The reported preparation procedure relies solely on the successive freezing, solvent‐exchange, and ambient drying of composite CNF‐alginate gels. The presented findings suggest that a highly‐porous structure can be preserved throughout the process by simply controlling the ionic strength of the gel. Aerogels with tunable densities (23–38 kg m−3) and compressive moduli (97–275 kPa) can be prepared by using different CNF concentrations. These low‐density networks have a unique combination of formability (using molding or 3D‐printing) and wet‐stability (when ion exchanged to calcium ions). To demonstrate their use in advanced wet applications, the printed aerogels are functionalized with very high loadings of conducting poly(3,4‐ethylenedioxythiophene):tosylate (PEDOT:TOS) polymer by using a novel in situ polymerization approach. In‐depth material characterization reveals that these aerogels have the potential to be used in not only energy storage applications (specific capacitance of 78 F g−1), but also as mechanical‐strain and humidity sensors.

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Section: Aerogels From Cellulose Nanofibers and Sodium Alginatementioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Ambient‐Dried, 3D‐Printable and Electrically Conducting Cellulose Nanofiber Aerogels by Inclusion of Functional Polymers

Françon

Wang

Marais

et al. 2020

Adv Funct Materials

Self Cite

114

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“… 303 This freeze-linking process applies to cross-linker-free systems, as in the ice driven packing of sodium periodate-oxidized CNFs that were made wet-stable (then suitable for application or functionalization in liquid media, e.g., layer-by-layer assembly of multilayers) 950 via hemiacetal cross-links between the introduced aldehyde groups and their native hydroxyls. 951 , 952 …”

Section: Formation Of Multiscale Architecturesmentioning

confidence: 99%

Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials

et al. 2021

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This review considers the most recent developments in supramolecular and supraparticle structures obtained from natural, renewable biopolymers as well as their disassembly and reassembly into engineered materials. We introduce the main interactions that control bottom-up synthesis and top-down design at different length scales, highlighting the promise of natural biopolymers and associated building blocks. The latter have become main actors in the recent surge of the scientific and patent literature related to the subject. Such developments make prominent use of multicomponent and hierarchical polymeric assemblies and structures that contain polysaccharides (cellulose, chitin, and others), polyphenols (lignins, tannins), and proteins (soy, whey, silk, and other proteins). We offer a comprehensive discussion about the interactions that exist in their native architectures (including multicomponent and composite forms), the chemical modification of polysaccharides and their deconstruction into high axial aspect nanofibers and nanorods. We reflect on the availability and suitability of the latter types of building blocks to enable superstructures and colloidal associations. As far as processing, we describe the most relevant transitions, from the solution to the gel state and the routes that can be used to arrive to consolidated materials with prescribed properties. We highlight the implementation of supramolecular and superstructures in different technological fields that exploit the synergies exhibited by renewable polymers and biocolloids integrated in structured materials.

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“…The capillary forces between the particles of a porous material affect its density. A decrease in capillary forces decreases the density of the material, resulting in lighter materials [93]. Freeze-drying avoids capillary forces; for example, freezing at −18 • C and subsequent freeze-drying produced the lightest cellulose material (density 0.0002 g/cm 3 ) from a 0.1% cellulose nanofibril hydrogel [94].…”

Section: Capillary Forcesmentioning

confidence: 99%

Cellulose Cryogels as Promising Materials for Biomedical Applications

Tyshkunova

Poshina

Skorik

2022

IJMS

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The availability, biocompatibility, non-toxicity, and ease of chemical modification make cellulose a promising natural polymer for the production of biomedical materials. Cryogelation is a relatively new and straightforward technique for producing porous light and super-macroporous cellulose materials. The production stages include dissolution of cellulose in an appropriate solvent, regeneration (coagulation) from the solution, removal of the excessive solvent, and then freezing. Subsequent freeze-drying preserves the micro- and nanostructures of the material formed during the regeneration and freezing steps. Various factors can affect the structure and properties of cellulose cryogels, including the cellulose origin, the dissolution parameters, the solvent type, and the temperature and rate of freezing, as well as the inclusion of different fillers. Adjustment of these parameters can change the morphology and properties of cellulose cryogels to impart the desired characteristics. This review discusses the structure of cellulose and its properties as a biomaterial, the strategies for cellulose dissolution, and the factors affecting the structure and properties of the formed cryogels. We focus on the advantages of the freeze-drying process, highlighting recent studies on the production and application of cellulose cryogels in biomedicine and the main cryogel quality characteristics. Finally, conclusions and prospects are presented regarding the application of cellulose cryogels in wound healing, in the regeneration of various tissues (e.g., damaged cartilage, bone tissue, and nerves), and in controlled-release drug delivery.

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On the mechanism behind freezing-induced chemical crosslinking in ice-templated cellulose nanofibril aerogels

Abstract: The underlying mechanism related to freeze-induced crosslinking of aldehyde-containing cellulose nanofibrils (CNFs) has been investigated, and the critical parameters behind this process have been identified.

Cited by 74 publications

References 45 publications

Ambient‐Dried, 3D‐Printable and Electrically Conducting Cellulose Nanofiber Aerogels by Inclusion of Functional Polymers

Ambient‐Dried, 3D‐Printable and Electrically Conducting Cellulose Nanofiber Aerogels by Inclusion of Functional Polymers

Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials

Cellulose Cryogels as Promising Materials for Biomedical Applications

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