A fast and effective way to measure the inner pore size distributions of wetted cotton fibers and their pretreatment performance using time-domain nuclear magnetic resonance.

This study reports the findings from using time-domain nuclear magnetic resonance (TD-NMR) to analyze the pore structures of cotton fibers. Cotton fibers, which swell and soften in water, present challenges for conventional pore measurement techniques. TD-NMR overcomes these by measuring the transverse relaxation time (T2) of water protons within the fibers, indicative of internal pore sizes. We established a T2-to-pore size conversion equation using mixed cellulose ester membranes. This enabled differentiation between strongly bound, loosely bound, and free water within the fibers, and detailed the water distribution. A method for measuring the pore size distribution of wet cotton fiber was developed using TD-NMR. We then examined how various pretreatments affect the fibers' internal pores by comparing their pore size distribution and porosity. Specifically, caustic mercerization primarily enlarges the porosity and size of larger pores, while liquid ammonia treatment increases porosity but reduces the size of smaller pores. This research confirms TD-NMR's utility in assessing cotton fabrics' wet processing performance.

Preparation of high antioxidant nanolignin and its application in cosmetics.

Lignin, as a natural polyphenol, displays anti-oxidant activity by trapping and binding free radicals through its free phenolic hydroxyl groups. However, the most accessible form, industrial lignins, generally has low phenolic hydroxyl content, which severely limits their application value and scenarios. Herein, we showed that potassium-glycerate deep eutectic solvent (PG-DES) treatment can be combined with laccase oxidation to afford prepared high antioxidant lignin nanoparticles (HA-LNPs) with notably improved anti-oxidant activities benefiting from both the enhanced phenolic hydroxyl content 170.8 % and reduced average particle size (59.0 nm). At concentrations as low as 60 µg/mL, HA-LNPs showed favorable effects in promoting collagen formation. When HA-LNPs were used as an active ingredient in the anti-aging mask formulation, the reactive oxygen species (ROS) scavenging activity of mask samples containing 0.4 % HA-LNPs reached 37.2 %. The data suggest great promise of HA-LNPs as a natural antioxidant for formulating in anti-aging skin care products.

Lightweight and robust cellulose/MXene/polyurethane composite aerogels as personal protective wearable devices for electromagnetic interference shielding.

The increasing electromagnetic pollution is urgently needed as an electromagnetic interference shielding protection device for wearable devices. Two-dimensional transition metal carbides and nitrides (MXene), due to their interesting layered structure and high electrical conductivity, are ideal candidates for constructing efficient conductive networks in electromagnetic interference shielding materials. In this work, lightweight and robust cellulose/MXene/polyurethane composite aerogels were prepared by mixing cellulose nanofiber (CNF) suspensions with MXene, followed by freeze-drying and coating with polyurethane. In this process, CNF effectively assembled MXene nanosheets into a conductive network by enhancing the interactions between MXene nanosheets. The prepared aerogel exhibited the shielding effectiveness of 48.59 dB in the X-band and an electrical conductivity of 0.34 S·cm-1. Meanwhile, the composite aerogel also possessed excellent thermal insulation, infrared stealth, mechanical and hydrophobic properties, and can be used as a wearable protective device to protect the human body from injuries in different scenarios while providing electromagnetic interference shielding protection.

Study of reactive dyes and their hydrolyzed forms in a real trichromatic dyeing process by capillary electrophoresis with UV detection.

Detecting the concentration of reactive dyes and their hydrolyzed products is essential for controlling the dyeing process and is an important guide for upgrading and improving textile dyeing technology. In this study, capillary electrophoresis (CE) with UV detection was for the first time applied in a real trichromatic dyeing process to provide qualitative and quantitative determination of reactive dyes and their hydrolyzed forms. Here, three original reactive dyes (SES-Cl-red-195, SES-Cl-yellow-145, and SES-Cl-blue-194), their vinyl sulfone forms (VS-Cl-red-195, VS-Cl-yellow-145, and VS-Cl-blue-194), and complete hydrolyzed forms (HES-OH-red-195, HES-OH-yellow-145, and HES-OH-blue-194) could be baseline separated in our developed BGE comprised of 10.0 mol/L Na2B4O7, 15% (V/V) ACN at pH 8.50 that adjusted by 0.50 mol/L H3BO3. The LODs (S/N = 3) of nine analytes ranged from 0.3 to 1.3 mg/L, and high sensitivities were achieved with UV detection. The RSDs of peak area and migration time were in the ranges of 1.4-3.8% and 0.39-1.29%, which indicated the CE methods were reliable for studying different dye forms in complex dye baths, and for evaluating dyeing process quality. Thus, the percentage of dye-uptake in single and trichromatic combination dyes was calculated based on the concentration of the original and their vinyl sulfone and hydrolyzed forms, and the result was consistent with the traditional UV-Vis method.

Green, chemical-free, and high-yielding extraction of nanocellulose from waste cotton fabric enabled by electron beam irradiation.

Recycling and high-value reutilization of waste cotton fabrics (WCFs) has attracted a widespread concern. One potential solution is to extract nanocellulose. Sulfuric acid hydrolysis is a conventional method for the production of nanocellulose with high negative charge from WCFs. However, the recycling and disposal of chemicals in nanocellulose production, along with low yields, remain significant challenges. Consequently, there is a pressing need for a sustainable method to produce nanocellulose at higher yield without the use of chemicals. Herein, we propose a green, sustainable and chemical-free method to extract nanocellulose from WCFs. The nanocellulose displayed a rod-like shape with a length of 50-300 nm, a large aspect ratio of 18.4 ± 2 and the highest yield of up to 89.9 %. The combined short-time and efficient two-step process, involving electron beam irradiation (EBI) and high-pressure homogenization (HPH), offers a simple and efficient alternative approach with a low environmental impact, to extract nanocellulose. EBI induced a noticeable degradation in WCFs and HPH exfoliated cellulose to nano-size with high uniformity via mechanical forces. The as-prepared nanocellulose exhibits excellent emulsifying ability as the Pickering emulsion emulsifier. This work provides a facile and efficient approach for nanocellulose fabrication as well as a sustainable way for recycle and reutilization of the waste cotton fabrics.

Electrothermal Phase Change Composite with Flexibility over a Wide Temperature Range for Wearable Thermotherapy.

Flexible electrothermal composite phase change materials (PCMs) are promising candidates for portable thermotherapy. However, a great challenge remains to achieve high PCM loading while maintaining reasonable flexibility. Herein, the polypyrrole-decorated melamine foam (PPy@MF) was fabricated and thereafter applied to confine binary PCM mixtures composed of a high-enthalpy long-chain polyethylene glycol (PEG4000) and its short-chain homologue (PEG200) to make the novel PPy@MF-PEG4000+200 composite PCM. At a high loading of up to 74.1% PEG4000 and a high latent heat energy storage density of 150.1 J/g, the composite PCM remained flexible at temperature (-20 °C) far below its phase transition point thanks to the plasticine effect of PEG200. The composite also demonstrated good Joule heating performance, providing fast heating from 28 to 70 °C at low applied voltages (4.5-6.0 V). The energy could be stored efficiently and released to maintain the composites at the proper temperature. The electrothermal performance of the composite remained undisturbed during curved or repeated bending, showing good potential to be used for personal thermal management and thermotherapy.

Inferring biophysical properties of membranes during endocytosis using machine learning.

Endocytosis is a fundamental cellular process in eukaryotic cells that facilitates the transport of molecules into the cell. With the help of fluorescence microscopy and electron tomography, researchers have accumulated extensive geometric data of membrane shapes during endocytosis. These data contain rich information about the mechanical properties of membranes, which are hard to access via experiments due to the small dimensions of the endocytic patch. In this study, we propose an approach that combines machine learning with the Helfrich theory of membranes to infer the mechanical properties of membranes during endocytosis from a dataset of membrane shapes extracted from electron tomography. Our results demonstrate that machine learning can output solutions that both match the experimental profile and satisfy the membrane shape equations derived from Helfrich theory. The learning results show that during the early stage of endocytosis, the inferred membrane tension is negative, indicating the presence of strong compressive forces at the boundary of the endocytic invagination. Our method presents a generic framework for extracting membrane information from super-resolution imaging.

Customizable High-Contrast Optical Responses: Dual Photosensitive Colors for Smart Textiles.

Smart textiles demonstrating optical responses to external light stimuli hold great promise as functional materials with a wide range of applications in personalized decoration and information visualization. The incorporation of high-contrast, vivid, and real-time optical signals, such as color change or fluorescence emission, to indicate light on/off states is both crucial and challenging. In this study, we have developed a dual output photosensitive dye system possessing photochromic and photofluorescent properties, which was successfully applied to the dyeing and finishing processes of cotton fabrics. The design and fabrication of this dye system were based on the unique photoinduced proton transfer (PPT) principle exhibited by the water-soluble spiropyran (trans-MCH) molecule. The dual output response relies on the open-/closed-loop mechanism, wherein light regulates the trans-MCH molecule. Upon excitation by UV or visible light, the dye system and dyed fabrics display significant color changes and fluorescence switching in a real-time and highly reversible manner. Moreover, diverse photosensitive color systems can be tailored by direct blending with commercially available water-soluble dyes. By integrating high-contrast dual optical outputs into this scalable, versatile, and reversible dye system, we envisage the development and design of smart textiles capable of producing high-end products.

Effect of Al2Cu constituent layer thickness discrepancy on the tensile mechanical behavior of Cu/Al2Cu/Al layered composites: a molecular dynamics simulation.

Nano-polycrystalline Cu/Al2Cu/Al layered composites with different layer thicknessesdof single-crystal Al2Cu constituent are constructed. The effects ofdon the strength and fracture modes of nano-polycrystalline Cu/Al2Cu/Al layered composites are systematically investigated by molecular dynamics simulations. The uniaxial tensile results show that the ultimate strength and fracture mode of the nano-polycrystalline Cu/Al2Cu/Al layered composites do not change monotonically with the change of single crystal Al2Cu constituent layer thicknessd, the ultimate strength peaking atd= 2.44 nm, and the toughness reaching the optimum atd= 4.88 nm. The improvement of deformation incompatibility between Cu, Al and Al2Cu components increases the ultimate strength of polycrystalline Cu/Al2Cu/Al laminated composites. Due to the high activity of Cu dislocation and the uniformity of strain distribution of single crystal Al2Cu, the fracture of nano-crystalline Cu/Al2Cu/Al layered composites changes from brittleness to toughness. This study is crucial to establish the organic connection between microstructure and macroscopic properties of Cu/Al layered composites. To provide theoretical basis and technical support for the application of Cu/Al layered composites in high-end fields, such as automotive and marine, aerospace and defense industries.

A one-pot approach to prepare stretchable and conductive regenerated silk fibroin/CNT films as multifunctional sensors.

Silk fibroin (SF)-based materials are characterized by their outstanding biocompatibility and biodegradability and are considered as the most promising candidates for next-generation flexible electronics. In order to generate such devices, SF can be mixed with carbon nanotubes (CNTs) which feature excellent mechanical, electrical, and thermal properties. However, obtaining regenerated SF with homogeneous dispersion of CNTs in a sustainable manner represents a challenging task, mainly due to the difficulty in overcoming van der Waals forces and strong π-π interactions that hold together the CNT structure. In this study, a one-pot strategy for fabricating SF/CNT films is proposed by designing SF as a modifier of CNTs through non-covalent interactions with the assistance of aqueous phosphoric acid solution. Glycerol (GL) was introduced, endowing the SF/GL/CNT composite film with excellent flexibility and stretchability. The sustainable strategy greatly simplifies the preparation process, avoiding dialysis of SF and the use of artificial dispersants. The as-fabricated SF/GL/CNT films showed an excellent mechanical strength of 1.20 MPa and high sensitivity with a gauge factor of up to 13.7 toward tensile deformation. The composite films had a sensitive monitoring capability for small strains with detection limits as low as 1% and can be assembled into versatile sensors to detect human movement. Simultaneously, the composite films showed a superb thermosensitive capacity (1.64% °C-1), which satisfied the requirement of real-time and continuous skin temperature monitoring. We anticipate that the presented one-pot strategy and the prepared composite films could open a new avenue for forthcoming technologies for electronic skins, personal health monitoring, and wearable electronics.

High-tensile chitin films regenerated from cryogenic aqueous phosphoric acid.

The abuse of non-renewable fossil resources and the resulting plastic pollution have posed a great burden on the environment. Fortunately, renewable bio-macromolecules have shown great potential to replace synthetic plastics in fields ranging from biomedical applications, and energy storage to flexible electronics. However, the potential of recalcitrant polysaccharides, such as chitin, in the above-mentioned fields have not been fully exploited because of its poor processability, which is ultimately due to the lack of suitable, economical, and environmentally friendly solvent for it. Herein, we demonstrate an efficient and stable strategy for the fabrication of high-strength chitin films from concentrated chitin solutions in cryogenic 85 wt% aqueous phosphoric acid (aq. H3PO4). The regeneration conditions, including the nature of the coagulation bath and its temperature are important variables affecting the reassembly of chitin molecules and hence the structure and micromorphology of the films. Uniaxial orientation of the chitin molecules by applying tension to the RCh hydrogels further endows the films with enhanced mechanical properties of up to 235 MPa and 6.7 GPa in tensile strength and Young's modulus, respectively.

Facile construction of photocatalytic cellulose-based sponge with stable flotation properties as efficient and recyclable photocatalysts for sewage treatment.

Dispersion and recycling of powdered nano-photocatalysts for water purification is still not an easy task. The self-supporting and floating photocatalytic cellulose-based sponges ware conveniently prepared by anchoring BiOX nanosheet arrays on cellulose-based sponge's surface. The introduction of sodium alginate into the cellulose-based sponge significantly enhanced the electrostatic adsorption of bismuth oxygen ions and promoted the formation of bismuth oxyhalide (BiOX) crystal nuclei. Among the photocatalytic cellulose-based sponges, the sponge (BiOBr-SA/CNF) modified with bismuth oxybromide displayed excellent photocatalytic ability for photodegrading 96.1 % rhodamine B within 90 min under 300 W Xe lamp irradiation (λ > 400 nm). The loading of bismuth oxybromide on cellulose-based sponge's surface improves the flotation stability of the cellulose-based sponge. Benefiting from excellent load fastness of bismuth oxybromide nanosheet and flotation stability of BiOBr-SA/CNF sponge, after 5 cycles of recycling, the photodegradation rates of BiOBr-SA/CNF sponge to rhodamine B remained above 90.2 % (90 min), and it also has excellent photocatalytic degradation effect on methyl orange and herbicide isoproteron. This work may provide a convenient and efficient method to construct self-supporting and floating photocatalytic sponges using cellulose based materials as substrates for sewage treatment.

Rapid activation of peroxymonosulfate with iron(â ¢) complex for organic pollutants degradation via a non-radical pathway.

Developing high-performance catalytic systems for eliminating contaminants effectively in water has received a lot of attention. However, the complexity of practical wastewater poses a challenge for degrading organic pollutants. Non-radical active species with strong resistance to interference have shown great advantages in degrading organic pollutants under complex aqueous conditions. Herein, a novel system was constructed by Fe(dpa)Cl2 (FeL, dpa = N, N'-(4-nitro-1,2-phenylene) dipicolinamide) activating peroxymonosulfate (PMS). The mechanism study verified that the FeL/PMS system had high efficiency in producing high-valent iron-oxo and singlet oxygen (1O2) to degrade various organic pollutants. In addition, the chemical bonding between PMS and FeL was elucidated by the density functional theory (DFT) calculations. The FeL/PMS system could remove 96% Reactive Red 195 (RR195) in 2 min, which was much higher than other systems involved in this study. More attractively, the FeL/PMS system demonstrated general resistance to interference from common anions (Cl-, HCO3-, NO3- and SO42-), humic acid (HA) and pH changes and were thus compatible with various natural waters. This work provides a new approach for producing non-radical active species, which is a promising catalytic system for water treatment.

Photoinduced Absorption Spectroscopy of Photoelectrocatalytic Methylene Blue Oxidation on Titania and Hematite: The Thermodynamic and Kinetic Impacts on Reaction Pathways.

Photoelectrochemical oxidation of methylene blue is investigated, with particular focus on the difference in kinetics and thermodynamics of decoloration and mineralization employing photoinduced absorption spectroscopy. Hematite and titania photoanodes are used for the comparison of both reactions, which is determined to be associated with the depth of the valence band (3.2 vs 2.5 V for titania and hematite, respectively). Methylene blue is mineralized by the titania photoanode, however it is only oxidized to small fragments by hematite. Such difference is related to the valence band potential that provides the thermodynamic driving force for photogenerated holes in both materials. In addition, the kinetic competition of water oxidation is found to occur on titania by controlling the pH of the electrolyte. In the pH 14 electrolyte, mineralization of methylene blue is suppressed due to the faster and dominant kinetics of water oxidation, in contrast to the complete mineralization in the near neutral electrolyte where water oxidation kinetics are modest. These results clearly address the importance considering both thermodynamic and kinetic challenges of methylene blue oxidation, which has been thought to be an easy molecule to oxidize, as the model reaction in the application of photo(electro)catalysis using metal oxides.

Highly stretchable porous regenerated silk fibroin film for enhanced wound healing.

Silk fibroin (SF) has received interest in tissue engineering owing to its biocompatibility, biodegradability, and favorable mechanical properties. However, the complex preparation, brittleness, and lack of pores in the structure of the silk fibroin film limit its application. Herein, we show that facile dissolution of SF in aqueous phosphoric acid followed by regeneration in aqueous ammonium sulfate ((NH4)2SO4) could afford highly stretchable films with nano-pores formed in the nonsolvent-induced phase separation process. The named phase separation, which determines the morphology and mechanical properties of the regeneration silk fibroin (RSF) films, is highly dependent on the (NH4)2SO4 concentration as well as the initial concentration of the SF solution. Therefore, the RSF films exhibit a tunable pore size ranging from 230 to 510 nm and excellent stretchability with tensile strain up to 143 ± 16%. Most interestingly, the RSF films were shown to support the proliferation of human skin fibroblasts in vitro as well as speed up full-thickness skin wound healing in a rat model. This work establishes an easy and feasible method to access porous RSF membranes that can be used for wound dressing in clinical settings.

Fabrication of Fe-BTC on aramid fabrics for repeated degradation of isoproturon.

Catalytic degradation is a promising and ideal technology in environmental remediation. Among them, catalytic oxidation and photocatalysis respectively based on catalysts and photocatalysts both trigger broad interests because of their high removal activity. However, the reusability of the powder catalysts still faces substantial challenges. Here, a simple strategy is proposed to load Fe-BTC catalyst on aramid fabrics (AF) to construct Fe-BTC MOF @ aramid fabric (Fe-BTC@AF) composite materials with layer-by-layer in situ self-assembly methods. The experimental results illustrated that 98% isoproturon could be removed by Fe-BTC@AF20 with oxidant H2O2, while the single Fe-BTC@AF20 could photo-degrade 99% isoproturon within 7 h. Meanwhile, it could sustain a high degradation rate of more than 80%, even if it had gone through 5 degradation cycles. Thus, the Fe-BTC@AF composite has a significant advantage in the recycling ability for degradation of isoproturon, which will have potential applications in the efficient removal of organic contaminants in water.

Composite hydrogel based oxidated sodium carboxymethyl cellulose and gelatin loaded carboxymethylated cotton fabric for hemostasis and infected wound treatment.

The fabric-based wound dressings are hard to maintain a moist environment for wound healing while the hemostatic property and gas permeability of some hydrogel-based wound dressings are not ideal. This study first put forward a strategy of checkerboard-pattern wound dressing: 1) preparing the base fabric with hemostatic property, 2) printing multifunctional hydrogels onto one side of the base fabric to form checkerboard patterns, 3) modifying the other side of the base fabric to be hydrophobic. In this manner, the composite dressing not only maintained the advantages of hydrogels, but also inherited good mechanical property, hemostatic property, and gas permeability from the base fabric. Here, the cotton fabric was carboxymethylated to be MCF. To obtain multifunctional hydrogel, sodium carboxymethylcellulose was oxidated to introduce aldehyde groups to form Schiff base with amino groups in gelatin, besides, dopamine and Ag nanoparticles were introduced to endow the hydrogel with antioxidant property and antibacterial activity. The multifunctional hydrogel was printed onto one side of MCF, subsequently, the deposition of paraffin made the other side of this dressing become hydrophobic. The good performance of the obtained dressing in hemostatic process and wound healing demonstrated its potential in the field of wound treatment.

Low-dimensional transition metal sulfide-based electrocatalysts for water electrolysis: overview and perspectives.

Hydrogen prepared by electrocatalytic decomposition of water ("green hydrogen") has the advantages of high energy density and being clean and pollution-free, which is an important energy carrier to face the problems of the energy crisis and environmental pollution. However, the most used commercial electrocatalysts are based on expensive and scarce precious metals and their alloy materials, which seriously restricts the large-scale industrial application of hydrogen energy. The development of efficient non-precious metal electrocatalysts is the key to achieving the sustainable development of the hydrogen energy industry. Transition metal sulfides (TMS) have become popular non-precious metal electrocatalysts with great application potential due to their large specific surface area, unique electronic structure, and rich regulatory strategies. To further improve their catalytic activities for practical application, many methods have been tried in recent years, including control of morphology and crystal plane, metal/nonmetal doping, vacancy engineering, building of self-supporting electrocatalysts, interface engineering, etc. In this review, we introduce firstly the common types of TMS and their preparation. Additionally, we summarize the recent developments of the many different strategies mentioned above for efficient water electrolysis applications. Furthermore, the rationales behind their enhanced electrochemical performances are discussed. Lastly, the challenges and future perspectives are briefly discussed for TMS-based water dissociation catalysts.

Morphology-Controlled Synthesis of Polyphosphazene-Based Micro- and Nano-Materials and Their Application as Flame Retardants.

Common flame retardants, such as halogen-based materials, are being phased-out owing to their harmful environmental and health effects. We prepared poly-(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) microspheres, nanotubes, capsicum-like nanotubes, and branched nanotubes as flame retardants. An increase in reaction temperature changed the morphology from nanotubes to microspheres. A PZS shape had a positive effect on the flame retardancy of polyethylene terephthalate (PET). The PZS with a capsicum-like nanotube morphology had the best flame retardancy, and the PET limiting oxygen index increased from 25.2% to 34.4%. The flame retardancy capability was followed by PZS microspheres (33.1%), branched nanotubes (32.8%), and nanotubes (32.5%). The capsicum-like nanotubes promote the formation of highly dense and continuous carbon layers, and they release a non-combustible gas (CO2). This study confirms polyphosphazene-based flame retardants as viable and environmentally-friendly alternatives to common flame retardants. It also presents a novel and facile design and synthesis of morphology-controlled nanomaterials with enhanced flame retardant properties.

Integrated Janus cellulosic composite with multiple thermal functions for personalized thermal management.

The effective integration of multiple thermal functions into one material is highly attractive in personal thermal management, taking the complex application environment into consideration. Herein, a multifunctional Janus cellulosic composite encompassing superior electrical heating, energy storage, thermal insulation, and infrared camouflage performance was firstly developed by integrating Janus cellulose nanofibers (CNF) aerogel, polypyrrole (PPy), and polyethylene glycol (PEG). In practice, the active heating-thermal regulation layer (PPy@CNFphilic-PEG) of multifunctional Janus cellulosic composite is faced inward to provide heating on-demand through the joint action of the electrically conductive PPy and thermally regulative PEG. The outward-facing hydrophobic aerogel layer (CNFphobic) serves as the thermal insulator, which simultaneously enables infrared camouflage by reducing heat loss to the environment via infrared radiation. This work presents an effective and facile strategy toward multifunctional Janus materials for efficient personal thermal management, showing great promise for potential applications, such as thermal comfort, infrared camouflage, and security protection.