Sustainability in Wood Products: A New Perspective for Handling Natural Diversity

Low-Temperature Water Evaporation-Mediated Fusion and Densification of Wood for High-Performance and Sustainable Materials

Developing high-performance wood products to replace carbon-intensive structural materials is a key approach to reducing carbon emissions, whereas transforming low-strength wood into high-performance bulk materials through eco-friendly processing techniques is challenging but highly desired. Herein, a facile and sustainable water processing strategy is reported to robustly assemble wood pieces into high-performance bulk materials via delignification, followed by room-temperature water evaporation, eliminating the need for traditional adhesives. As water penetrates and swells the microfibrils, the plasticity of the softened wood is significantly enhanced, thereby facilitating the mutual diffusion of the microfibrils. The strong capillary stresses drive the microfibrils so close that they eventually accomplish molecular-level fusion and densification, which endows self-assembled wood with superior mechanical strength (tensile strength ∼ 535.21 MPa, lap shear strength ∼ 5.02 MPa, and solvent stability). This eco-friendly, water-mediated processing technique paves the way for the development of advanced, sustainable, and high-performance wood products.

The influence of polysiloxane functional groups on phototrophic colonization

Wood is one of the most widely used construction materials. As a natural material, it is susceptible to the damaging effects of environmental factors. Therefore, researchers are developing innovative solutions to protect wooden surfaces from the harmful effects of moisture or biological agents such as algae and fungi. The objective of the current study was to test the effectiveness of four polysiloxane compounds functionalized with hydrophilic and hydrophobic groups as potential agents for the protection of wood surfaces against biocorrosion caused by photosynthesizing microorganisms. The results of the study clearly indicate that the biological properties of the coating are affected not only by the types of functional groups in the polysiloxane but also by their amounts.

Peripheral Evolution of Tanshinone IIA and Cryptotanshinone for Discovery of a Potent and Specific NLRP3 Inflammasome Inhibitor

Natural products (NPs) continue to serve as an invaluable source in drug discovery, and peripheral evolution of NPs is a highly efficient evolution strategy. Herein, we describe a unified "methyl to amide" peripheral evolution of Tanshinone IIA and Cryptotanshinone for discovery of NLRP3 inflammasome inhibitors. There were 54 compounds designed and prepared, while the chemoinformatic analysis revealed that these evolved NP analogues occupy a unique chemical space. Biological evaluation identified 5m as an NLRP3 inflammasome inhibitor, and 5m could directly bind to the NACHT domain of the NLRP3 protein and block the interaction of NLRP3 and ASC, thus suppressing ASC oligomerization and NLRP3 inflammasome assembly. Molecular dynamic stimulations revealed that the amide moiety played a vital role in the binding mode. Moreover, 5m exhibited therapeutical efficacy in sepsis and the NASH mouse model. In conclusion, this protocol provides a new vision of NPs' peripheral evolution and a novel NLRP3 inflammasome inhibitor.

Biopolymer-Derived Carbon Materials for Wearable Electronics

Advanced carbon materials are widely utilized in wearable electronics. Nevertheless, the production of carbon materials from fossil-based sources raised concerns regarding their non-renewability, high energy consumption, and the consequent greenhouse gas emissions. Biopolymers, readily available in nature, offer a promising and eco-friendly alternative as a carbon source, enabling the sustainable production of carbon materials for wearable electronics. This review aims to discuss the carbonization mechanisms, carbonization techniques, and processes, as well as the diverse applications of biopolymer-derived carbon materials (BioCMs) in wearable electronics. First, the characteristics of four representative biopolymers, including cellulose, lignin, chitin, and silk fibroin, and their carbonization processes are discussed. Then, typical carbonization techniques, including pyrolysis carbonization, laser-induced carbonization, Joule heating carbonization, hydrothermal transformation, and salt encapsulation carbonization are discussed. The influence of the processes on the morphology and properties of the resultant BioCMs are summarized. Subsequently, applications of BioCMs in wearable devices, including physical sensors, chemical sensors, energy devices, and display devices are discussed. Finally, the challenges currently facing the field and the future opportunities are discussed.

Variation of physical wood properties and effect of dasometric variables in Ochroma pyramidale trees growing in plantation

Physical properties were studied in commercial plantation of balsa established in Costa Rica. Among other variables studied, physical properties varied mainly for tree age, spacing, stand density, diameter, and height of trees, which we named dasometric conditions. The aim of this study was (i) to determine the variation of specific gravity (SG), air-dry density (AD), green density (GD), and green moisture content (GMC), (ii) to know the site effect and dasometric conditions on these properties, and (iii) to establish the relationship between the four physical properties. The results showed that: SG from 0.08 to 0.21, AD from 90 to 250 kg/m3, GD varied 203-274 kg/m3, and GMC from 38.8 to 137.1 %. Tree age affected statistically all physical properties, it was positively correlated with SG, AD, and GD, but negatively correlated with GMC. Diameter breast height and total height were weakly correlated with SG and AD, respectively. Commercial height and stand density were highly correlated with SG and AD, besides stand density was positively correlated with GMC. AD was positively correlated with SG and GD but negatively correlated with GMC. According to the results, balsa tree plantations exhibited significant variation in physical properties (SG, AD, GD, and GMC) in trees aged between 30 and 40 months and this variation was primarily attributed to the site-specific growth conditions, mainly temperature and precipitation. These wood properties can be selected by site and growing conditions.

A Bio-Inspired Perspective on Materials Sustainability

The article explores materials sustainability through a bio-inspired lens and discusses paradigms that can reshape the understanding of material synthesis, processing, and usage. It addresses various technological fields, from structural engineering to healthcare, and emphasizes natural material cycles as a blueprint for efficient recycling and reuse. The study shows that material functionality depends on both chemical composition and structural modifications, which emphasizes the role of material processing. The article identifies strategies such as mono-materiality and multifunctionality, and explores how responsivity, adaptivity, modularity, and cellularity can simplify material assembly and disassembly. Bioinspired strategies for reusing materials, defect tolerance, maintenance, remodeling, and healing may extend product lifespans. The principles of circularity, longevity, and parsimony are reconsidered in the context of "active materiality", a dynamic bio-inspired paradigm. This concept expands the traditional focus of material science from structure-function relationships to include the development of materials capable of responding or adapting to external stimuli. Concrete examples demonstrate how bio-inspired strategies are being applied in engineering and technology to enhance the sustainability of materials. The article concludes by emphasizing interdisciplinary collaboration as a key factor for developing a sustainable and resilient materials economy in harmony with nature's material cycles.

Alcoholysis-induced changes in cell wall surfaces: Structural insights for the effective delignification of lignocellulosic biomass

Alcoholysis (organosolv delignification)-induced changes in cell wall surfaces were investigated to verify whether structural assessments are required for effective delignification. Softwood blocks of Cryptomeria japonica were subjected to alcoholysis at 100-150 °C, which gradually decreased their lignin content. Scanning electron microscopy revealed the emergence of amorphous mesh structures on the intercellular side and their transformation into spherical particles with increasing temperature. In addition, warty layers changed from uneven structures into spherical particles on the lumen side of tracheids. These particles produced in cell walls under harsh alcoholysis conditions, damaging the cell wall layers on both sides. Confocal laser scanning microscopy identified that they were mainly lignin eluted by alcoholysis. Alcoholysis at 130 °C providing the largest specific surface area showed intermediate stages of growth into spherical particles but allowed complete delignification when combined with NaClO2 bleaching. Therefore, the role of the spherical particles, which has so far been debatable, was clarified as causing damage rather than a bleaching accelerant. Focusing only on compositional changes while ignoring structural ones leads to the incorrect identification of optimal conditions that remove lignin but damage the cell walls. Our findings demonstrate that structural considerations are required for effective and noninvasive delignification.

Phenotyping of Drought-Stressed Poplar Saplings Using Exemplar-Based Data Generation and Leaf-Level Structural Analysis

Drought stress is one of the main threats to poplar plant growth and has a negative impact on plant yield. Currently, high-throughput plant phenotyping has been widely studied as a rapid and nondestructive tool for analyzing the growth status of plants, such as water and nutrient content. In this study, a combination of computer vision and deep learning was used for drought-stressed poplar sapling phenotyping. Four varieties of poplar saplings were cultivated, and 5 different irrigation treatments were applied. Color images of the plant samples were captured for analysis. Two tasks, including leaf posture calculation and drought stress identification, were conducted. First, instance segmentation was used to extract the regions of the leaf, petiole, and midvein. A dataset augmentation method was created for reducing manual annotation costs. The horizontal angles of the fitted lines of the petiole and midvein were calculated for leaf posture digitization. Second, multitask learning models were proposed for simultaneously determining the stress level and poplar variety. The mean absolute errors of the angle calculations were 10.7° and 8.2° for the petiole and midvein, respectively. Drought stress increased the horizontal angle of leaves. Moreover, using raw images as the input, the multitask MobileNet achieved the highest accuracy (99% for variety identification and 76% for stress level classification), outperforming widely used single-task deep learning models (stress level classification accuracies of <70% on the prediction dataset). The plant phenotyping methods presented in this study could be further used for drought-stress-resistant poplar plant screening and precise irrigation decision-making.

Superstrong, sustainable, origami wood paper enabled by dual-phase nanostructure regulation in cell walls

Constructing a crystalline-amorphous hybrid structure is an effective strategy to overcome the conflict between the strength and toughness of materials. However, achieving such a material structure often involves complex, energy-intensive processing. Here, we leverage the natural wood featuring coexisting crystalline and amorphous regions to achieve superstrong and ultratough wood paper (W-paper) via a dual-phase nanostructure regulation strategy. After partially removing amorphous hemicellulose and eliminating most lignin, the treated wood can self-densify through an energy-efficient air drying, resulting in a W-paper with high tensile strength, toughness, and folding endurance. Coarse-grained molecular dynamics simulations reveal the underlying deformation mechanism of the crystalline and amorphous regions inside cell walls and the failure mechanism of the W-paper under tension. Life cycle assessment reveals that W-paper shows a lower environmental impact than commercial paper and common plastics. This dual-phase nanostructure regulation based on natural wood may provide valuable insights for developing high-performance and sustainable film materials.

Ecuadorian Woods: Building Material Selection Using an Entropy-COPRAS Comparative Analysis Based on the Characterization of Ecuadorian Oak and Guayacan Timber

Considering that global awareness for sustainable development has risen to face environmental damages, different building materials have been considered from a mechanical perspective. In this sense, considering the richness of South America regarding its woods, the Guayacan and the Ecuadorian oak timbers have not been previously characterized. The present research has performed mechanical, thermal, and moisture content characterizations to acknowledge the benefits of considering these materials for the building industries. In this sense, Guayacan has been shown to have lower thermal conductivity, making it ideal for thermal insulation; the oak from Manabi showed the best compressive strength; while the oak from El Oro stands with the best tensile strength; and the oak from Loja showed the best modulus of elasticity. On the other hand, all the materials were compared by multicriteria decision methods to select the best, by using the COPRAS method driven by the objective entropy-weighted method, showing that the oak from Loja is the best choice considering the advantage that presents with the modulus of elasticity. In this sense, it is concluded that regarding the mechanical properties, there is not much difference for the compression, bending, and tensile strength; nevertheless, for the modulus of elasticity the oak from Loja stands out, making it a factor to be considered in the selection of a wood for building applications that is corroborated through multicriteria decision methods.

Self-Assembled MXene Supported on Carbonization-Free Wood for a Symmetrical All-Wood Eco-Supercapacitor

As an emerging two-dimensional (2D) material, MXene has garnered significant interest in advanced energy storage systems, yet the stackable structure, poor mechanical stability, and lack of moldability limit its large-scale applications. To address this challenge, herein, the self-assembly of MXene on carbonization-free wood was obtained to serve as high-performance electrodes for symmetrical all-wood eco-supercapacitors by a steam-driven self-assembly method. This method can be implemented in a low-temperature environment, significantly simplifying traditional high-temperature annealing processes and generating minimal impact on the environment, human health, and resource consumption. The environmentally friendly steam-driven self-assembly strategy can be further extended into various wood-based electrodes, regardless of the types and structures of wood. As a typical platform electrode, the optimized MXene@delignified balsa wood (MDBW) achieves high areal capacitance and specific capacitance values of 2.99 F cm-2 and 580.55 F g-1 at an extensive mass loading of 5.16 mg cm-2, respectively, with almost loss-free capacitance after 10,000 cycles at 50 mA cm-2. In addition, an all-solid-state symmetrical all-wood eco-supercapacitor was further assembled based on MDBW-20 as both positive and negative electrodes to achieve a high energy density of 19.22 μWh cm-2 at a power density of 0.58 mW cm-2. This work provides an effective strategy to optimize wood-based electrodes for the practical application of biomass eco-supercapacitors.

Size-structure-property relationship of wood particles in aqueous and dry insulative foams

Three size-fractionated samples of pine beetle-killed wood particles were used to prepare lightweight insulative foams. The foams were produced by foam-forming an aqueous slurry containing wood particles (125-1000 μm), a polymer binder, and surfactant, followed by oven drying. The effect of wood particle size on the aqueous foam stability, structure, and performance of insulative foams was investigated. While all aqueous foams were highly stable, aqueous foam stability increased with decreasing particle size. For dry foams, the cell size distribution was similar for all particle sizes as it was primarily controlled by the surfactant; differences occurred within the cell wall structure. A size-structure-property relationship was identified using x-ray micro-computed tomography where smaller particles produced lighter cell wall frameworks, leading to lower densities and decreased thermal conductivity and compressive strength. Larger particles produced denser cell wall frameworks that were more resistant to deformation, although all dry foams had sufficient mechanical properties for use as insulation panels. Thermal conductivity for all wood particle size-fractionated samples was <0.047 W m-1 K-1 making the foams similar to expanded polystyrene/polyurethane and supporting their use as thermal insulation in buildings.

Bottom-Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis

Linear d-glucans are natural polysaccharides of simple chemical structure. They are comprised of d-glucosyl units linked by a single type of glycosidic bond. Noncovalent interactions within, and between, the d-glucan chains give rise to a broad variety of macromolecular nanostructures that can assemble into crystalline-organized materials of tunable morphology. Structure design and functionalization of d-glucans for diverse material applications largely relies on top-down processing and chemical derivatization of naturally derived starting materials. The top-down approach encounters critical limitations in efficiency, selectivity, and flexibility. Bottom-up approaches of d-glucan synthesis offer different, and often more precise, ways of polymer structure control and provide means of functional diversification widely inaccessible to top-down routes of polysaccharide material processing. Here the natural and engineered enzymes (glycosyltransferases, glycoside hydrolases and phosphorylases, glycosynthases) for d-glucan polymerization are described and the use of applied biocatalysis for the bottom-up assembly of specific d-glucan structures is shown. Advanced material applications of the resulting polymeric products are further shown and their important role in the development of sustainable macromolecular materials in a bio-based circular economy is discussed.

Construction of wood-PANI supercapacitor with high mass loading using "pore-making, active substance-filling, densification" strategy

Wood-conducting polymer materials have been widely used as supercapacitor electrode; however, it remains challenging to achieve a simple method to improve the homogeneity of the conductive material on wood and to reach high mass loading. Herein, a novel "pore-making, active substance-filling, densification (dissolution, in-situ polymerization of polyaniline (PANI), self-shrinking)" strategy is proposed for the preparation of wood electrodes with a high mass loading (41.4 wt%) and homogeneity. Ingeniously, ZnCl2 as a dissolving agent and pore-making agent to treat delignified wood can generate more pores on the wood, which is more conducive to the penetration of aniline small molecules, besides, the dissolved fine fibers can be entangled with more PANI, which can improve the loading and homogeneity of PANI. After drying treatment, there will be shrinkage again, playing a certain physical densification effect on the large lumen. The optical electrode was RWP2 showing high electrochemical performance (2328.9 mF/cm2, 1 mA/cm2), and stability (5000 cycles, 89.3 %). Moving forward, the RWP2//RWP2 SSC showed an excellent energy density of 164.24 μwh/cm2 at a power density of 250 μw/cm2. Remarkably, the simple and versatile strategy of designing wood-based materials with high mass loading provides new research ideas for realizing multifunctional applications.

Structural, mechanical, wear and anticorrosive properties of CrSiCN coatings used for industrial woodworking applications

The woodworking applications are a fast-growing field that aims to create advanced coatings with superior wear resistance, reduced friction, and robust corrosion protection. Chromium silicon carbonitride (CrSiCN) coatings have emerged as a promising solution that offers a unique combination of properties ideal for various industrial applications. The C/N ratio significantly influences the coatings' mechanical and tribological properties. By optimizing the C/N ratio, this research aims to reveal new insights for CrSiCN coatings, enhancing their application in environments that require durability, efficiency, and longevity. In this paper, the effect of the C/N ratio on the structural, mechanical, and corrosion resistance of CrSiCN coatings deposited by cathodic arc evaporation on different steel substrates was studied. The main purpose was to enhance the mechanical and anticorrosion properties of the CrSiCN coatings and to select the optimum parameters for the deposition of layers with superior properties. The results showed that the final properties can be tailored by choosing specific deposition conditions. In this case, the C/N ratio proved to be critical since coatings with higher carbon content presented enhanced corrosion resistance, being able to withstand operating conditions similar to real-life.

Probing the complexity of wood with computer vision: from pixels to properties

We use data produced by industrial wood grading machines to train a machine learning model for predicting strength-related properties of wood lamellae from colour images of their surfaces. The focus was on samples of Norway spruce (Picea abies) wood, which display visible fibre pattern formations on their surfaces. We used a pre-trained machine learning model based on the residual network ResNet50 that we trained with over 15 000 high-definition images labelled with the indicating properties measured by the grading machine. With the help of augmentation techniques, we were able to achieve a coefficient of determination (R2) value of just over 0.9. Considering the ever-increasing demand for construction-grade wood, we argue that computer vision should be considered a viable option for the automatic sorting and grading of wood lamellae in the future.

Nanocrystalline iron hydroxide lignocellulose filters for arsenate remediation

Harmful levels of environmental contaminants, such as arsenic (As), persist readily in the environment, threatening safe drinking water supplies in many parts of the world. In this paper, we present a straightforward and cost-effective filtration technology for the removal of arsenate from potable water. Biocomposite filters comprised of nanocrystalline iron oxides or oxyhydroxides mineralized within lignocellulose scaffolds constitute a promising low cost, low-tech avenue for the removal of these contaminants. Two types of iron oxide mineral phases, 2-line ferrihydrite (Fh) and magnetite (Mt), were synthesized within highly porous balsa wood using an environmentally benign modification process and studied in view of their effective removal of As from contaminated water. The mineral deposition pattern, minerology, as well as crystallinity, were assessed using scanning electron microscopy, transmission electron microscopy, micro-computed X-ray tomography, confocal Raman microscopy, infrared spectroscopy, and X-ray powder diffraction. Our results indicate a preferential distribution of the Fh mineral phase within the micro-porous cell wall and radial parenchyma cells of rays, while Mt is formed primarily at the cell wall/lumen interface of vessels and fibers. Water samples of known As concentrations were subjected to composite filters in batch incubation and gravity-driven flow-through adsorption tests. Eluents were analyzed using microwave plasma optical emission spectroscopy (MP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). By subjecting the filters to a flow of contaminated water, the time for As uptake was reduced to minutes rather than hours, while immobilizing the same amount of As. The retention of As within the composite filter was further confirmed through energy-dispersive X-ray mappings. Apart from addressing dangerously high levels of arsenate in potable water, these versatile iron oxide lignocellulosic filters harbor tremendous potential for addressing current and emerging environmental contaminants that are known to adsorb on iron oxide mineral phases, such as phosphate, polycyclic aromatic hydrocarbons or heavy metals.

3D Printed Cellulose Nanofiber Aerogel Scaffold with Hierarchical Porous Structures for Fast Solar-Driven Atmospheric Water Harvesting

Hygroscopic salt-based composite sorbents are considered ideal candidates for solar-driven atmospheric water harvesting. The primary challenge for the sorbents lies in exposing more hygroscopically active sites to the surrounding air while preventing salt leakage. Herein, a hierarchically structured scaffold is constructed by integrating cellulose nanofiber and lithium chloride (LiCl) as building blocks through 3D printing combined with freeze-drying. The milli/micrometer multiscale pores can effectively confine LiCl and simultaneously provide a more exposed active area for water sorption and release, accelerating both water sorption and evaporation kinetics of the 3D printed structure. Compared to a conventional freeze-dried aerogel, the 3D printed scaffold exhibits a water sorption rate that is increased 1.6-fold, along with a more than 2.4-fold greater water release rate. An array of bilayer scaffolds is demonstrated, which can produce 0.63 g g-1 day-1 of water outdoors under natural sunlight. This article provides a sustainable strategy for collecting freshwater from the atmosphere.

Room-temperature phosphorescent materials derived from natural resources

Room-temperature phosphorescent (RTP) materials have enormous potential in many different areas. Additionally, the conversion of natural resources to RTP materials has attracted considerable attention. Owing to their inherent luminescent properties, natural materials can be efficiently converted into sustainable RTP materials. However, to date, only a few reviews have focused on this area of endeavour. Motivated by this lack of coverage, in this Review, we address this shortcoming and introduce the types of natural resource available for the preparation of RTP materials. We mainly focus on the inherent advantages of natural resources for RTP materials, strategies for activating and enhancing the RTP properties of the natural resources as well as the potential applications of these RTP materials. In addition, we discuss future challenges and opportunities in this area of research.