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openaire: EC/H2020/788489/EU//BioELCell Funding Information: This work was supported by the National Natural Science Foundation of China (Grant Nos. 31730106, 31770623, 31670555), the Canada Excellence Research Chair initiative (CERC-2018-00006), and Canada Foundation for Innovation (Project number 38623), as well as the European Research Council (ERC), under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 788489). T.G. would like to acknowledge the financial support from China Scholarship Council (CSC). The authors thank Dr. Zhifeng Wang of the Test Center at Yangzhou University for technical assistance. Publisher Copyright: © 2021 American Chemical Society. All rights reserved. We investigate the mechanism of binding of dopamine-conjugated carboxymethyl cellulose (DA-CMC) with carbon nanotubes (CNTs) and the strain-induced interfacial strengthening that takes place upon wet drawing and stretching filaments produced by wet-spinning. The filaments are known for their tensile strength (as high as 972 MPa and Young modulus of 84 GPa) and electrical conductivity (241 S cm-1). The role of axial orientation in the development of interfacial interactions and structural changes, enabling shear load bearing, is studied by molecular dynamics simulation, which further reveals the elasto-plasticity of the system. We propose that the reversible torsion of vicinal molecules and DA-CMC wrapping around CNTs are the main contributions to the interfacial strengthening of the filaments. Such effects play important roles in impacting the properties of filaments, including those related to electrothermal heating and sensing. Our findings contribute to a better understanding of high aspect nanoparticle assembly and alignment to achieve high-performance filaments.

openaire: EC/H2020/788489/EU//BioELCell Funding Information: This work was a part of the Academy of Finland's Flagship Programme under Projects No. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES. J.V. acknowledges the Academy of Finland project “SUBSTAINABLE” (Decision number 334818) for generous funding. T.A. acknowledges funding from Formas for the “SUBSTAINABLE” project granted through the Tandem Forest Values program (Formas grant number 2019–02508). O.J.R. and J.J.K. acknowledge funding support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 788489, “BioElCell”). Publisher Copyright: © 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH This review addresses the reconstruction of structural plant components (cellulose, lignin, and hemicelluloses) into materials displaying advanced optical properties. The strategies to isolate the main building blocks are discussed, and the effects of fibrillation, fibril alignment, densification, self-assembly, surface-patterning, and compositing are presented considering their role in engineering optical performance. Then, key elements that enable lignocellulosic to be translated into materials that present optical functionality, such as transparency, haze, reflectance, UV-blocking, luminescence, and structural colors, are described. Mapping the optical landscape that is accessible from lignocellulosics is shown as an essential step toward their utilization in smart devices. Advanced materials built from sustainable resources, including those obtained from industrial or agricultural side streams, demonstrate enormous promise in optoelectronics due to their potentially lower cost, while meeting or even exceeding current demands in performance. The requirements are summarized for the production and application of plant-based optically functional materials in different smart material applications and the review is concluded with a perspective about this active field of knowledge.

We use dry-jet wet spinning in a coaxial configuration by extruding an aqueous colloidal suspension of oxidized nanocellulose (hydrogel shell) TOCNF combined with airflow in the core. The coagulation of the hydrogel in a water bath result in hollow filaments (HF) that are drawn continuously at relatively high rates. Additionally, Blueberries pruning waste or BPw was dissolved in an ionic liquid, 1-ethyl-3- methylimidazolium acetate ([emim][OAc]) and regenerated into ligno- cellulose filaments with highly aligned nanofibrils (wide-angle X-ray scattering) that simultaneously displayed extensibility (wet strain as high as 39 %). Finally in alkaline conditions we investigate the interplay between cellulose crystallization and aggregation with interfibrillar interactions, shear forces, and the local changes in the medium's acidity. The latter is affected by the CO2 chemisorbed from the surrounding atmosphere, which, combined with shear forces, explain cellulose gelation. Different instrumental techniques are combined to unveil the fundamental factors that limit cellulose gelation and maximize its dissolution in NaOH(aq). The obtained solutions are then proposed for developing green and environmentally friendly cellulose-based materials at different dimensions, such as filaments (1D), films(2D) and printed meshes (3D).

The purpose of this work is to obtain dissolving cellulose fibers that are suitable for the manufacturing of cellulose derivatives. Therefore, the combination of enzymatic and chemical treatments during the bleaching stage (lignin removal) and purification stage (hemicellulose removal) is proposed. The obtained dissolving cellulose was submitted to acetylation reactions, and then acetate films were prepared as an example of end product. Assessing the quality of acetate films, it was concluded that dissolving cellulose fibers had good properties and fulfilled the quality requirements. These satisfactory results were compared with acetate films obtained under same acetylation conditions, but the dissolving cellulose fibers used as a raw material came from a conventional and industrial process. This publication is part of the PID2020-114070RB-I00 (CELLECOPROD) project, funded by MCIN/AEI/10.13039/501100011033. O.J.R. acknowledges funding support by the Academy of Finland through its Center of Excellence Program (2014–2019) “Molecular Engineering of Biosynthetic Hybrid Materials Research”.

Background: Cellulose nanofibrils (CNFs) have emerged as a sustainable and environmentally friendly option for a broad range of applications. The fibrous nature and high biopersistence of CNFs call for a thorough toxicity assessment, but it is presently unclear which physico-chemical properties could play a role in determining the potential toxic response to CNF. Here, we assessed whether surface composition and size could modulate the genotoxicity of CNFs in human bronchial epithelial BEAS-2B cells. We examined three size fractions (fine, medium and coarse) of four CNFs with different surface chemistry: unmodified (U-CNF) and functionalized with 2, 2, 6, 6-tetramethyl-piperidin-1-oxyl (TEMPO) (T-CNF), carboxymethyl (C-CNF) and epoxypropyltrimethylammonium chloride (EPTMAC) (E-CNF). In addition, the source fibre was also evaluated as a non-nanosized material. Results: The presence of the surface charged groups in the functionalized CNF samples resulted in higher amounts of individual nanofibrils and less aggregation compared with the U-CNF. T-CNF was the most homogenous, in agreement with its high surface group density. However, the colloidal stability of all the CNF samples dropped when dispersed in cell culture medium, especially in the case of T-CNF. CNF was internalized by a minority of BEAS-2B cells. No remarkable cytotoxic effects were induced by any of the cellulosic materials. All cellulosic materials, except the medium fraction of U-CNF, induced a dose-dependent intracellular formation of reactive oxygen species (ROS). The fine fraction of E-CNF, which induced DNA damage (measured by the comet assay) and chromosome damage (measured by the micronucleus assay), and the coarse fraction of C-CNF, which produced chromosome damage, also showed the most effective induction of ROS in their respective size fractions. Conclusions: Surface chemistry and size modulate the in vitro intracellular ROS formation and the induction of genotoxic effects by fibrillated celluloses. One cationic (fine E-CNF) and one anionic (coarse C-CNF) CNF showed primary genotoxic effects, possibly partly through ROS generation. However, the conclusions cannot be generalized to all types of CNFs, as the synthesis process and the dispersion method used for testing affect their physico-chemical properties and, hence, their toxic effects.

Additional file 1. Analysis of covariance (ANCOVA).

openaire: EC/H2020/788489/EU//BioELCell Cellulose nanofibrils (CNFs) have emerged as sustainable options for a wide range of applications. However, the high aspect ratio and biopersistence of CNFs raise concerns about potential health effects. Here, we evaluated the in vivo pulmonary and systemic toxicity of unmodified (U-CNF), carboxymethylated (C-CNF), and TEMPO (2,2,6,6-tetramethyl-piperidin-1-oxyl)-oxidized (T-CNF) CNFs, fibrillated in the same way and administered to mice by repeated (3x) pharyngeal aspiration (14, 28, and 56 mu g/ mouse/aspiration). Toxic effects were assessed up to 90 days after the last administration. Some mice were treated with T-CNF samples spiked with lipopolysaccharide (LPS; 0.02- 50 ng/mouse/aspiration) to assess the role of endotoxin contamination. The CNFs induced an acute infammatory reaction that subsided within 90 days, except for T-CNF. At 90 days post-administration, an increased DNA damage was observed in bronchoalveolar lavage and hepatic cells after exposure to T-CNF and C-CNF, respectively. Besides, LPS contamination dose-dependently increased the hepatic genotoxic effects of T-CNF.

FinnCERES is a Competence Centre formed between Aalto University and VTT Technical Research Centre of Finland (www.finnceres.fi). This combination yields a unique combo of highly ranked fundamental and applied research in the area of forest-sourced materials. In addition, the strength of the alliance derives from its state-of-the-art research infrastructure including pilot capabilities, and global research and industrial networks. We aim at holistic material sustainability considering today’s demands on the smart use of biomass. In the current materials design, the specific inherent properties and added value of lignocellulosics are emphasised even more than merely their renewable origin or biodegradability. We consider plants as our future material bank since cell wall components, structure and functions are an endless source for inspiration for the materials science and engineering. The aim of the research programme is to bridge the gap between fundamental and applied research as well as to provide a fast track for scientific findings towards real innovations and industrial implementation. This presentation highlights the latest scientific advances from the research programme which is divided into five major research themes: 1) Fundamentals: Interactions and advanced characterisation, 2) Future biorefineries, 3) Clean air and water, 4) Lignocellulosics beyond plastics, and 5) Electronics, optics, and energy applications. In addition, the recent progress and actions within the FinnCERES Ecosystem including the Boreal Alliance will be communicated.

Colored solar cells suffer from lower efficiency due to reflection and absorption losses by coatings. By studying different types of coatings on solar cells, the spectrum parameters impacting the solar cell efficiency were identified. A collection of color coatings was fabricated and characterized using spectrophotometry and colorimetric photography. The coatings include commercial absorption filters, commercial distributed bragg reflectors, lab-made interference coatings, and cellulose nanocrystal coatings. Commercial single junction and multijunction solar cells were used to measure the impact of the color coatings on solar cell performance. Structural colors were found to result in the highest brightness to color loss ratio. Structural colors do not fade provided that the structure is not compromised. Color loss in single junction solar cells is a result of the proportion of reflected light in the absorption range of the material. Multijunction solar cells were strongly affected by current mismatch losses, where narrow reflection peaks resulted in high efficiency losses. Structural color coatings made using cellulose nanocrystals exhibited low and broad reflection peaks that produced bright colors and maintained high performance of single junction and multijunction solar cells, retaining up to 83 % of the reference power obtained in the absence of a color coating., 24 pages, 12 figures

Funding Information: This work was supported by the Eastman Chemical Company and was performed, in part, at the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation (award number ECCS-1542015). The AIF is a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), a site in the National Nanotechnology Coordinated Infrastructure (NNCI). Publisher Copyright: © 2021 Elsevier Inc. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Hypothesis: Waterborne sulfopolyesters have gained considerable interest as coating materials due to their excellent film-forming and optical properties. Their commercial use has been limited, however, due to their fragile nature. Incorporating cellulose nanofiber (CNF), a sustainable biopolymer, into the polymer matrix is expected to enhance the mechanical integrity of the nanocomposite as these two components synergistically interact. Experiments: In this study, we have investigated the suspension and film characteristics of three sulfopolyesters varying in charge density, glass transition temperature and molecular weight, as well as their mixtures with CNF. We have performed steady-shear rheology on mixtures with different CNF loading levels, and resulting films have been subjected to quasistatic uniaxial tensile and water contact-angle tests to elucidate the effects of CNF on mechanical and surface properties. Findings: Addition of CNF to waterborne polyester promotes shear-thinning behavior that remains unaffected by the CNF content. Solid films cast from these suspensions possess enhanced mechanical properties, as well as tailorable surface hydrophilicity, depending on composition and film-drying temperature. Tensile tests reveal that films containing 10 wt% CNF display the greatest mechanical improvements, suggesting the existence of a previously unidentified Goldilocks composition window.