Bioinspired Mechanical Gradients in Cellulose Nanofibril/Polymer Nanopapers

Abstract

Mechanical gradients are important as tough joints, for strain field engineering in printable electronics,f or actuators,a nd for biological studies,y et they are difficult to prepare and quantitatively characterize.W ed emonstrate the additive fabrication of gradient bioinspired nanocomposites based on stiff,renewable cellulose nanofibrils that are bottomup toughened via at ailor-made copolymer.D irect filament writing of different nanocomposite hydrogels in patterns,a nd subsequent healing of the filaments into continuous films while drying leads to av ariety of linear,p arabolic and striped bulk gradients.I ns itu digital image correlation under tensile deformation reveals important differences in the strain fields regarding asymmetry and step heights of the patterns.W e envisage that merging top-down and bottom-up structuring of nanocellulose hybrids opens avenues for aperiodic and multiscale,b ioinspired nanocomposites with optimizedc ombinations of stiffness and toughness.

Three-Dimensional Printing of Wood-Derived Biopolymers: A Review Focused on Biomedical Applications

“… Image of 3D printed C-periodate nanocellulose on a nanocellulose film without cross-linking (a) reproduced from an open access article, 73 image of a 3D printed human ear with CNF/alginate Ink8020 (b) reproduced with copyright permission from the American Chemical Society, 45 image of a 3D bioprinted human ear with human nasal chondrocytes (hCN)-laden auricular constructs and open inner structure formed by Ca 2+ ionic cross-linking (c) reproduced with copyright permission from Elsevier, 93 formulation of microfibrillated cellulose (MFC)/lignosulfonate (LS) hydrogels followed by the manufacture of carbon objects by 3D printing and carbonization (d) adapted with copyright permission from the American Chemical Society, 88 and demonstration of high-molecular-weight polymer-enhanced CNF printing by bioinspired mechanical gradients in CNF/polymer nanopaper (e) adapted with copyright permission from Wiley-VCH. 90 …”

“…With manipulation of the compositional ratio of the nanocomposite hydrogel in adjacent filaments, a film prepared in this way featured mechanical gradients and gave an anisotropic response. 90 These gradients are relevant to fundamental studies of the interactions of cells with CNF materials.…”

Polymeric Complex Nanoparticles Enable the Fabrication of Mechanically Superstrong and Recyclable Poly(aryl ether sulfone)-based Polymer Composites

“…4,7,10,[11][12][13] Meanwhile, superstrong thermoplastic polymers are usually difficult to dissolve in proper solvents and to process. 3,5,14,15 A conventional and widely employed strategy for reinforcement of thermoplastic polymers is homogeneously dispersing stiff nanofillers, such as silica, 9,16 clays, 10,17,18 carbon nanotubes, [19][20][21] graphene oxides, 20,[22][23][24] cellulose nanocrystals, 25,26 metal nanoparticles, 27,28 and other nanofillers 3,[29][30][31] within them. Uniform nanofiller dispersion and strong interfacial interactions between nanofillers and polymer matrices are the most crucial factors that enhance the mechanical strength of the resulting polymer composites.…”

pH-Responsive Properties of Asymmetric Nanopapers of Nanofibrillated Cellulose

“…Gradient composite materials containing nanocelluloses enriched layers at different ratios show enhanced mechanical properties [ 16 , 17 ]. Hence, elastic properties and ductility of nanopapers composed of NFC and tailor-made synthetic copolymers can be modulated by the ratio of both components [ 18 ].…”