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The extraordinary strength and toughness of arthropod cuticle depend on phenol-amine chemistry and mineral reinforcement. A bio-inspired adhesive was engineered through introducing ...the cost-effective phenolic polymer accompanied with acid-stable montmorillonite mineral into amino-rich soy protein matrix. This adhesive reproduces the outstanding properties of arthropod cuticle, including high toughness and superior strength, and exhibited outstanding stiffness, mold resistance, flame retardancy.
•An arthropod cuticle-inspired bio-based adhesive was prepared by phenol-amine chemistry and mineral enhancement.•The phenol-amine cross-linking and MMT reinforcement improved adhesive’s adhesion strength.•The sacrificial interactions and micro-phase separation enhanced the adhesive’s toughness.•The compatibility of hybrid system endows this adhesive with multi-functionality.
Arthropod cuticles are extraordinarily stiff and strong due to phenol-amine chemistry and mineral reinforcement. Nevertheless, these cuticles require costly dopamine (phenol provider), acid-unstable minerals, enzymes that can be deactivated, making them difficult to imitate in artificial materials. Herein, the arthropod cuticle was mimicked by introducing a low-cost phenolic polymer (DP) and acid-stable montmorillonite into an amino-rich soy protein matrix (SPI) to develop a bio-based adhesive. Fe3+ was chosen as the oxidizing agent to trigger the oxidation of DP without using enzyme, while activating cross-linking between oxidized DP and SPI to cure the adhesive. This covalent cross-linking and mineral reinforcement strategy endowed the adhesive with a bonding strength (1.04 MPa) comparable to industrial-use adhesives, whereas its volatile organic compounds emission was about 10-fold lower than the industrial-use adhesives. The sacrificial bonds and microphase-separated structure formed from the adhesive resulted in a high toughness. Furthermore, this adhesive featured an outstanding stiffness (40.38 GPa), exceeding ten times that of normal plastics. Notably, this adhesive exhibited excellent mold resistance (288 h shelf life) and flame retardancy (level B1 in GB 8624-2012). This efficient, eco-friendly, and low-cost bionic design strategy can advance the enhancement and functionalized modification of underwater adhesives, hydrogel, and composite materials.
Polydopamine (PDA) is a fascinating bioinspired material for the construction of diverse functional materials. In particular, the growing trend of PDA hydrogels clearly reveals the global ...significance and the intense interest of scientific research in this field. The abundant functional groups make PDA serve as the important structural units for covalent or/and non-covalent interactions with polymers, and anchoring of transition metal ions for hydrogels formation. With these benefits, PDA not only endows hydrogels with various functions such as adhesion, photothermal effect, ultraviolet protection, antioxidant ability, antibacterial properties, but also has been rapidly incorporated into a wide range of applications across the biomedical, environment, energy, and electronic fields. This review strives to provide a comprehensive overview of the relevant advances in the field of bioinspired PDA hydrogels. We start to introduce the PDA as the structural units in hydrogels and dedicate a lot of space to discuss their design and PDA functions in the hydrogels. Furthermore, these functions would bring about various interesting applications of the hydrogels. Some key issues in this emerging field have been also exhibited into discussion which will inspire our thinking in functional hydrogels design.
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Pillararene polymers have been widely used as excellent adsorbents for water treatment, but pillararene polymers with ultra-high specific surface area and versatility are still rarely reported. ...Herein, a quaternary ammonium salt modified pillar 5 arene polymer, QPBP 5, with specific surface area of 1844 m2 g−1 was successfully synthesized. Since QPBP 5 has abundant different adsorption sites, it exhibits excellent performance for the simultaneously removal of organic pollutants with different charges from water. The selected three model pollutants, Rhodamine B (RhB, positively charged), Sulfamethazine (SMT, electrically neutral) and Fulvic acid (FA, negatively charged), could be rapidly and efficiently removed from water by QPBP 5 within 10 min, which are much faster than them by most of the reported adsorbents. RhB and SMT are mainly adsorbed through hydrophobic interactions with the QPBP 5 surface, while FA is mainly removed through ion exchange. In addition, QPBP 5 also showed excellent reusability and adsorption performance for the environmentally relevant concentration of pollutants. Furthermore, the quaternary ammonium groups on QPBP 5 makes it a solid disinfectant with excellent antibacterial properties. In conclusion, QPBP 5 is a promising multifunctional adsorbent for the treatment of complex pollutants in water.
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•Quaternary ammonium salt modified pillar 5 arene polymer was synthesized.•The polymer has a specific surface area up to 1844 m2 g−1.•The polymer can efficiently remove contaminants of different charge types.•The polymer showed excellent disinfection properties.
In Nature, there are a large range of tough, strong, lightweight and multifunctional structures that can be an inspiration to better performing materials. This work presents a review of structures ...found in Nature, from biological ceramics and ceramics composites, biological polymers and polymers composites, biological cellular materials, biological elastomers to functional biological materials, and their main toughening mechanisms, envisaging potential mimicking approaches that can be applied in advanced continuous fibre reinforced polymer (FRP) composite structures. For this, the most common engineering composite manufacturing processes and current composite damage mitigation approaches are analysed. This aims at establishing the constraints of biomimetic approaches development as these bioinspired structures are to be manufactured by composite technologies. Combining both Nature approaches and engineering composites developments is a route for the design and manufacturing of high mechanical performance and multifunctional composite structures, therefore new bioinspired solutions are proposed.
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•Review of structures found in Nature and their main toughening mechanisms, envisaging potential mimicking approaches;•Summary of engineering manufacturing solution capable to mimic biological material structures;•Proposal of new bioinspired solutions combining both, Nature solutions and engineering developments to achieve high mechanical performance and multifunctional composite materials.
1. The prominent new place of ecosystem services in environmental policy, land management and land planning requires that the best ecological knowledge be applied to ecosystem service quantification. ...Given strong evidence that functional diversity underpins the delivery of key ecosystem services, assessments of these services may progress rapidly using a trait-based approach. 2. The trait-based approach shows promising results, especially for plant trait effects on primary production and some processes associated with carbon and nitrogen cycling in grasslands. However, there is a need to extend the proof of concept for a wider range of ecosystems and ecosystem services and to incorporate not only the functional characteristics of plants but those of other organisms with which plants interact for the provision of ecosystem services. 3. The five papers in this Special Feature illustrate how some of the key conceptual and methodological challenges can be resolved, and provide a range of case studies across three continents. Relevant plant functional traits depict different axes of variation including stature, the leaf economics spectrum, and associated or independent variations in root or stem traits. The application of the trait approach to ecosystem processes underpinned by interactions between plants and other biota is illustrated for soil micro-organisms and granivorous invertebrates. There is strong evidence for the biomass ratio hypothesis (i.e. prevalent effects of the traits of dominant species through the community-weighted mean), along with less prevalent and more complex effects of heterogeneous trait values between species (i.e. functional divergence). 4. Synthesis. Together, the five papers in this Special Feature illustrate how trait-based approaches may help elucidate the complexity of ecological mechanisms operating in the field to determine ecosystem service delivery. To address scientific and management questions about the provision of multiple services, progress is needed in understanding how functional trade-offs and synergies within organisms scale up to interactions between ecosystem services. Service-oriented ecosystem management within the context of global change, or ecological restoration, remains a major challenge, but trait-based understanding opens new avenues towards more generic, integrated approaches.
Chitosan (CS) has been extensively studied because of its biocompatibility, biodegradability, low toxicity, and good film-forming properties. However, pristine CS has relatively low UV resistance, ...antioxidant, and antibacterial properties, and is thus not suitable for food packaging. In this study, multifunctional tannic acid (TA) was incorporated into pristine CS to overcome its limitations. Two neutralization conditions with different pH (pH 7.4 using phosphate-buffered saline (PBS) and pH 8.5 using Tris buffer) were employed to prepare CS-TA composite films. The chemical and structural characteristics of the composite films were analyzed through Fourier-transform infrared, UV–visible, and X-ray photoelectron spectroscopies. At the higher neutralization pH of 8.5, the covalent crosslinking between CS and TA increased because more TA was transformed into quinone form. In addition, the Schiff base reaction was predominant when neutralized with PBS (pH 7.4), whereas the Michael addition reaction was predominant when neutralized with Tris buffer (pH 8.5). The CS-TA composite films exhibited better mechanical, thermal, antioxidant, and antibacterial properties than those of pristine CS. Furthermore, the packaging film of the composite effectively reduced enzymatic browning and water loss from bananas. The findings suggest that the CS-TA composite films can be used as active packaging materials for long-term food storage owing to their excellent mechanical, antioxidant, and antibacterial properties.
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•Chitosan (CS)-based films can replace plastic films used in packaging.•Covalently corss linked CS/tannic acid (TA) composite films are mechanical strong.•CS-TA composite films have excellent antioxidant and antibacterial properties.•CS-TA packaging films increase the spoilage-free storage period of bananas.
Soil stability and aggregates are important drivers of soil fertility and microbial diversity and are highly vulnerable to land degradation. However, the role of soil aggregates in driving the ...responses of microbial functional diversity and multiple ecosystem services and functions (multifunctionality) to further degradation (e.g., fertilization) remains largely unexplored and poorly understood. In this study, we used soils from long-term experiments involving inorganic and organic fertilization treatments to investigate the role soil aggregates (microscale) play in driving microbial functional gene diversity (via GeoChip) and the activity of multiple extracellular enzymes in an agricultural ecosystem. We found that microbial functional gene diversity has a significant and positive relationship with soil multifunctionality, which is enhanced in soil aggregates by organic fertilizer but is reduced by inorganic fertilizer. We also found that soil aggregate fractions indirectly controlled multiple ecosystem functions via changes in functional diversity. Smaller soil aggregates with higher resource availability (carbon and nitrogen) supported more ecological functions than larger aggregates under contrasting fertilizer management regimes. Soil multifunctionality is regulated by the differences in resource availability and not by microbial functional gene composition, which suggests that microbial functional diversity contributed more to multifunctionality than gene composition. Random forest analysis and structural equation modeling indicated that soil carbon and nitrogen and microbial functional diversity together determined the multifunctionality, whereas soil traits have more standardized total effects than functional diversity. Our study highlights that soil aggregation stratifies soil nutrition and microbial functional diversity, which leads to the differentiation of aggregate ecosystem multifunctionality.
•Microbial functional diversity positively regulates soil multifunctionality.•Microbial diversity contributes more to multifunctionality than taxonomic traits.•Soil aggregate size may indirectly and negatively determine multifunctionality.•Organic and inorganic fertilizers have opposite effects on multifunctionality.•Soil nutrition and functional diversity together control multifunctionality.
•Structure-directed growth and morphology of multifunctional metal–organic frameworks are well discussed.•The structural changes and morphological differences of MOFs would be induced by composition ...modification.•Various strategies are summarized from the perspectives of precursors, substrates, and synthetic methods.•Multifunctional MOFs show breakthrough performance in environmental protection and energy engineering.•Potential challenges in the controllable preparation and practical applications of MOFs are discussed.
Metal-organic frameworks (MOFs) have attracted much attention in the whole materials science due to their structural tunability that endows precise size and morphology control. Meanwhile, hierarchical MOFs and their derivatives possess fascinating physicochemical properties with their special morphology, controllable nanostructure, ultra-high porosity, and large specific surface area, which have been widely used in the environment and energy fields. Here, the recent advances in controlled synthesis will be comprehensively introduced, mainly focusing on the transformation of MOF morphology and structure based on the following factors, such as precursors, substrates, and synthesis methods. Furthermore, the progress of relevant MOF applications, including gas storage and separation, dye adsorption, heterogeneous catalysis, and fuel cells, is described to emphasize the intrinsic structure–property relationship. Lastly, the challenges and intractable dilemmas arising in their controlled synthesis and performance applications are also briefly discussed.
Boreal forests carry out functions that are critical to global biogeochemical cycling and climate regulation. Soil microbial diversity has been reported to drive multiple functions simultaneously ...(multifunctionality) in drylands and temperate ecosystems, however, the role and importance of bacterial and fungal diversity in driving multiple soil functions in boreal forest ecosystems remains poorly understood. We collected soils from 58 plots across upland and lowland (swamp) habitats in a boreal forest ecosystem to evaluate the linkages between fungal/bacterial diversity and multiple soil functions. Fungal and bacterial diversity were determined using 18S rDNA and 16S rDNA amplicons sequencing, and functions related to nutrient cycling (dissolved inorganic and organic nitrogen and carbon, nitrification) and climate regulation (CO2 and N2O emissions) were measured. The results showed that fungal but not bacterial richness was positively related to soil multifunctionality. We further used structural equation modelling to identify the effects of fungal and bacterial communities, and other environmental variables (moisture, pH, soil organic carbon and habitat types) on multifunctionality. Our model predicted 65.0% of the variation in soil multifunctionality, and confirmed that along with moisture and habitats, fungal richness and community composition were significantly and positively associated with multifunctionality. Finally, we identified specific fungal genera strongly associated with soil multifunctionality, and saprotrophic fungi were especially important for maintaining multiple soil functions. Our results suggest that potential losses in fungal diversity could result in reductions in soil functions particularly linked to nutrient cycling and climate regulation in boreal forests.
•Microbial richness was higher in upland compared to lowland habitats of boreal forests.•Soil functions related to global change were mostly similar among habitats.•Fungal richness was more important than bacteria for multifunctionality.•R-strategy fungi are more likely to control soil functions associated with global change.
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