Nanocellulose

Résumé

La nanocellulose est une nanostructure de cellulose. Elle existe sous trois formes :

nanofibre de cellulose ou nanofibrilles de cellulose ou cellulose nano-fibrillée (NFC / CNF) aussi appelée cellulose micro-fibrillée ou microfibrille de cellulose (CMF / MFC), obtenue par traitement mécanique ;
nanocellulose cristalline ou nanocristaux de cellulose (NCC) aussi appelée cellulose nanocristalline (CNC) et encore nanocellulose en ou nanoen de cellulose (CNW / NCW), produite par procédé chimique ;
nanocellulose bactérienne (BNC), synthétisée par des bactéries.

Histoire Grâce à l'évolution de la fabrication du papier, la cellulose a été découverte. Son étude a permis de découvrir ses structures de plus en plus finement : fibres (de la taille du millimètre), macrofibres, microfibres, et enfin microfibrilles (de la taille du nanomètre). Et à chaque étape on a pu fabriquer des matériaux nouveaux et plus performants, et envisager ce que pourrait apporter l'étape suivante. E

Source officielle

https://fr.wikipedia.org/wiki/Nanocellulose

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Photocured Nanocellulose Composites: Recent Advances

Julien Bras, Yves Leterrier, Mohammed Arif Poothanari, Aigoul Schreier

This perspective gives an overview of recent progress in thefield of photocured polymer composites based on variousforms of nanocelluloses, with a focus on cellulose nanofibrils. The manufacturing processes and performances of these nanocellulosecomposites are detailed, comprising solvent-assisted mixing processes, emulsification, coating and casting processes, preformimpregnation, and 3D printing. Attention is also paid to life-cycle engineered approaches to improve their sustainability. Thesematerialsfind applications in numerous domains, primarily as protective coatings but also as diffusion barrier composites andfilmsfor packaging and encapsulation of electronics, as composite hydrogels for biomedical applications, and as membranes for battery technologies.

AMER CHEMICAL SOC2022

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Cellulose Nanocrystals with Tethered Polymer Chains: Chemically Patchy versus Uniform Decoration

Alix Vaimiti Marie Dupire, Alke Fink, Harm-Anton Klok, Théo Gaston Gérard Lachat, Justin Orazio Zoppe

The site-specific surface modification of colloidal substrates, yielding "patchy" nanoparticles, is a rapidly expanding area of research as a result of the new complex structural hierarchies that are becoming accessible to chemists and materials scientists through colloidal self-assembly. The inherent directionality of cellulose chains, which feature a nonreducing and a reducing end, within individual cellulose nanocrystals (CNCs) renders them an interesting experimental platform for the synthesis of asymmetric nanorods with end-tethered polymer chains. Here, we present water-tolerant reaction pathways toward patchy and uniformly modified CNC hybrids based on atom transfer radical polymerization (ATRP) and initiators that were linked to the CNCs with carbodiimide-mediated coupling and Fischer esterification, respectively. Various monomers, including N-isopropylacrylamide (NIPAM), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC), and sodium 4-vinylbenzenesulfonate (4-SS), were polymerized from both types of initiator-modified CNCs, yielding chemically patchy and uniform CNC hybrids, via surface-initiated ATRP (SI-ATRP). Interestingly, the stereochemistry of tethered PNIPAM was affected by the precise location of ATRP initiating sites, as evidenced by H-1 NMR and circular dichroism (CD) spectroscopy. This effect may be related to the inherent right-handed chirality of CNCs. CNC/PMETAC hybrids were labeled with gold nanoparticles (AuNPs) in order to visualize the precise location of polymer tethers via cryo-electron microscopy. In some instances, the AuNPs were indeed concentrated at the end groups of the patchy CNC hybrids.

2017

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In this thesis several advances are made to the emerging field of 3D printed mechanical sensors. Techniques and processes were developed to enable the integration of highly conductive, and capacitive and piezoresistive sensing features embedded within 3D printed elastomeric materials. With these technologies we enabled the fabrication of fully 3D printed piezoresistive and capacitive sensors for normal force, shear forces and angular bending sensing.Integrating highly electrically conductive flexible silver films (

EPFL2022

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