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Two novel phenanthroimidazole derivatives were synthesized for efficient three-photon excited fluorescence and absorption. By introducing spirobi [9H-fluorene] to replace fluorene, the three-photon-excited fluorescence and cross-section are significantly enhanced to 3.56 ± 0.15 × 10 −78 cm 6 s 2 photon −2 , which is among the highest reported values for organic molecules. Our results supply a useful method to develop novel materials for applications of three-photon excited fluorescence and absorption. [ABSTRACT FROM AUTHOR]

Recently, cellulose paper based triboelectric nanogenerators (CPTENGs) has gained widely attention due to the development of wearable, green and miniaturized electronic products. Modification of cellulose fibers or paper is a feasible method to improve the output performance of CPTENGs, however, the simple and effective routes to improve the triboelectric property of cellulose paper still remain a challenge. Herein, we report a simple method to prepare PEO/cellulose composite paper (PEO/CCP) via mixing polyethylene oxide (PEO) with cationic cellulose fibers. Benefiting from amino groups and PEO, the composite paper exhibits higher triboelectric positive property and triboelectric charge density, thereby endowing PEO/CCP based TENG with outstanding output performance. The voltage, current and power density peak values of PEO/CCP based TENG exhibited linear relationship with amino groups content; in this instance, the performance of the TENGs can be readily adjusted by the amino groups. The voltage, current and power density of PEO/CCP based TENG can be up to 222.1 V, 4.3 μA, and 217.3 mW•m−2, respectively. Moreover, a human-health detection device based on this TENG can monitor the physiological signals such as eye muscles, respiration, heart beat and wrist pulse, promising potentials for applications in human health-care. • PEO can improve the triboelectric positive property of cellulose paper. • The V OC , I SC and Q SC values of PEO/CCP based TENG exhibits linear relationship with amino groups content. • The PEO/CCP based TENG can yield a maximum V OC and I SC of 222.1 V and 4.3 μA. • A human-health detection device with button battery structure was designed. • The human-health detection device can monitor physiological signals. [ABSTRACT FROM AUTHOR]

Bacteria and virus infections have posed a great threat to public health and personnel safety. For realizing rapid sterilization of the bacteria and virus, electrical stimulation sterilization was adopted to endow cellulose fibers with instantaneous antibacterial and antiviral properties. In the proposed strategy, the fiber is fluffed by mechanical refining, and then by means of the hydrogen bond between hydroxyl and aniline, the polyaniline (PANI) directionally grows vertically along the fine fibers via in-situ oxidative polymerization. Benefiting from the conductive polyaniline nanorod arrays on the fiber stem, the paper made from PANI modified refined fibers (PANI/BCF/P) exhibited excellent antibacterial and antiviral activity, the inhibition rates against S. aureus , E. coli , and bacteriophage MS2 can up to 100 %, 100 %, and 99.89 %, respectively when a weak voltage (2.5 V) was applied within 20 min. This study provides a feasible path for plant fiber to achieve efficient antibacterial and antiviral activity with electrical stimulation, which is of great significance for the preparation of electroactive antibacterial and antiviral green health products. • Refining makes the fiber to be fluffed. • Nanorod arrays can be realized by in-situ growth of PANI on the fine fibers. • Electrical stimulation sterilization is feasible for cellulosic fibers. [ABSTRACT FROM AUTHOR]

Figure C1 KCNF-TENG builds multi-channel, fast-response self-powered wearable sensing systems for human–computer interaction and control hardware. [Display omitted] • kapok cellulose nanofiber film (KCNF) with superior optical, mechanical and biological properties was prepared. • The KCNF dielectric enhancement formed after mechanical treatment significantly improves the electrical output performance of TENG devices. • Self-powered human–computer interaction systems, e.g., five-finger input, smart medicine, and intelligent games, were established. As wearable devices in the fields of medical health, human–computer interaction, and motion detection continue to diversify in their materials and forms, they show vast application potential. Cellulose materials are emerging as prominent materials for fabricating flexible wearable electronic devices because of their favorable skin compatibility, cost-effectiveness, and abundance. However, there is little research on the use of kapok cellulose in wearable electronics. This study addresses this knowledge gap by exploring the high-yield production and waste recycling potential of kapok cellulose. To overcome the limitations of conventional cellulose films, such as poor flexibility, high haze, and limited light transmittance, a kapok cellulose nanofiber film (KCNF) with a transparency of > 90 % and a tensile strain of > 20 % is prepared. The use of the KCNF as a friction electric material in the triboelectric nanogenerator (TENG) improves its electrical output performance by 228 % and permits its comfortable long-term attachment to the skin for self-powered tactile sensing applications, including game control, text input, and smart medical devices. This study demonstrates that the exploration of KCNF materials expands the options available for developing wearable electronic devices with numerous potential applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-layer forming technology can integrate triboelectric material with electrode. • The all CPTENGs can exhibit excellent humidity, acid and alkali resistance. • The CPTENGs can yield a V OC , I SC and power density of 227.1 V, 6.9 μA and 520 mW/m2. • Matching CPTENGs with P-ZISC can obtain a self-charging power system (PSCPS). • The PSCPS can drive some miniaturized electronics for a long time. Triboelectric nanogenerators (TENGs) are regarded as a promising technology to drive the development of flexible/wearable electronics and self-powering sensor. Application of cellulose paper as the triboelectric positive materials makes TENGs more environmentally friendly. However, the limited output performance and stability in harsh environments and oxidation and corrosion of the metal electrodes have limited the practical application of cellulose paper based triboelectric nanogenerators (CPTENGs). Here, we have integrated cellulose paper-based triboelectric material and electrode in one sheet by using multi-layer forming technology in paper industry; the upper triboelectric layer shows excellent triboelectric positive performance, hydrophobicity and acid and alkali resistance, while the bottom electrode exhibits promise conductivity. The all CPTENGs can yield a maximum open-circuit voltage (V OC) of 227.1 V, a short-circuit current (I SC) of 6.9 μA. Furthermore, the V OC values of the all CPTENGs increase from 0.02 V to 225.1 V at the load resistance of 100 Ω∼10 GΩ; and a power density of 520 mW·m−2 is also obtained at a load resistance of 30 MΩ. Moreover, the V OC of CPTENGs not only retains up to 78 % of its initial value at a high relative humidity of 90 %, but also almost maintains unchanged in a wide range of the pH environment (pH = 1∼13). More importantly, the CPTENGs can be readily matched with paper-based zinc supercapacitor (P-ZISC) to act as an all paper based self-charging power system (PSCPS). The PSCPS is capable of driving various miniaturized electronics, such as electronic watch, temperature/humidity indicator, demonstrating its potential application in a sustainable power source for portable and green electronics. [ABSTRACT FROM AUTHOR]

The development of conductive, soft, ultra-stretchable, and asymmetrically adhesive hydrogels is difficult and essential for both wearable electronics and anti-adhesion tissue dressings. In particular, there is still no simple, effective and universal approach to construct an asymmetrically adhesive multifunctional hydrogel. Here, we first synthesized lignosulfonate sodium (LS)-doped PAA hydrogels with uniform adhesion (adhesive strength: ~30.5 kPa), conductivity (~0.45 S/m), stretchability (up to ~2250%), and low compressive modulus (~20 kPa). In the second step, an oriented soaking of Fe3+ onto the upper surface of the resultant composite hydrogel renders the upper surface non-adhesive. This novel strategy masterfully delivers asymmetric adhesion behavior to the upper and bottom surfaces of the same hydrogel (~0 kPa adhesive strength for the upper surface; strong adhesive strength of ~27 kPa for the bottom surface). The asymmetric adhesive hydrogel has proven to adhere well onto the human skin and achieve waste-barrier. Importantly, this hydrogel assembled pressure sensor demonstrates excellent anti-interference and wearable comfort. [ABSTRACT FROM AUTHOR]

In recent years, various biomacromolecule-based hydrogels have been extensively and deeply studied in the field of wearable electronics. However, the application of lignin-based hydrogels in flexible devices is still in its infancy. This is mainly due to the significant differences in physical and chemical properties of industrially extracted lignin. In order to seek the universal applicability of diversified lignin in the preparation of hydrogel electronics, we mainly paid attention to the natural physical and chemical properties of lignin to discuss feasible solutions for functional gel design. These properties include chemical reactivity, UV shielding, antibacterial, bio-degradability, anti-oxidation, etc. Finally, in view of lignin's unique properties and the demand for high-quality flexible electronics, some insights are proposed regarding the future research and development directions of lignin-based hydrogel electronics. [ABSTRACT FROM AUTHOR]

Ti 3 C 2 T x (MXene), a new kind of 2D ceramic nanosheets, is receiving more and more attention in the fields of medicine, biology, energy, electronics, etc. However, the preparation and application of MXene in hydrogel is still in its infancy period. Here, we review the latest progress (after 2018) related to MXene hydrogels in time. Aiming at the key issue of the dispersion stability of MXene in hydrogel systems, the preparation strategy, mechanism, advantages and disadvantages of MXene hydrogels are sorted out in detail, and the potential application prospects of MXene composite hydrogel are introduced. Finally, future viewpoints are put forward for the dispersion stability challenges that need solving in the design of MXene hydrogel. [ABSTRACT FROM AUTHOR]

The dynamic avalanche instability in the silicon-on-insulator (SOI) lateral insulated-gate bipolar transistors (LIGBT) at low temperature is investigated. The measured results show a time-dependent collector-emitter voltage (V CE) walk event at –40 °C under the OFF-state dynamic avalanche conditions. A charge couple is proposed and TCAD simulations are performed for the mechanism revealing. It is found that the dynamic avalanche instability is closely related to the hole accumulation at the collector-side bottom, the depletion in P-type substrate (P-sub) and the transfer of the breakdown spot. The optimization strategy for the dynamic avalanche stability is drawn based on the revealed mechanism. The V CE walk can be suppressed or eliminated by preventing the dynamic expansion/shrinking behaviour of the depletion layer in substrate or satisfying an equal relationship between the vertical breakdown voltage (BVV) and the lateral breakdown voltage (BVL). With different device types, collector structures, N-drift lengths, BOX thicknesses, substrate biases and substrate types, the V CE walk events at low temperature (–40 °C) are comprehensively discussed in this paper. The V CE walk can be completely eliminated through replacing the P-sub by the N-type substrate (N-sub). • Measured results show a time-dependent collector-emitter voltage walk event at -40oC. • A charge couple is proposed and TCAD simulations are performed for the mechanism revealing. • The dynamic avalanche instability is closely related to the hole accumulation at the collector-side bottom. • The optimization strategy for the dynamic avalanche stability is drawn based on the revealed mechanism. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel molecularly imprinted membrane (Cell/SiO 2 -MIM) with specific selective recognition sites for paclitaxel (PTX) separation. Highlights • A novel molecular imprinting membrane (Cell/SiO 2 -MIM) was prepared. • The Cell/SiO 2 -MIM has a special recognition ability toward paclitaxel (PTX). • The Cell/SiO 2 -MIM showed excellent perm-selectivity and adsorption capacity to PTX. • The excellent stability and reusability of Cell/SiO 2 -MIM were also demonstrated. Abstract Separating the natural product of paclitaxel from its structural analogs still remains a significant challenge. In this work, a novel molecular imprinting membrane (Cell/SiO 2 -MIM) with specific recognition sites was hierarchically constructed for paclitaxel (PTX) separation. Inspired by mussel, inorganic silica nanoparticles (SiO 2 NPs) were introduced onto the surface of the regenerated cellulose membrane as polymerization platform in an attempt to enhance the permeation flux of the membrane. The specific recognition sites of PTX were constructed on the nanoscale silica surface through the bulk polymerization of vinylpyridine in the presence of PTX as templates, leading to the membrane with the selective recognition ability for the target molecule (PTX). The as-synthesized imprinting membrane exhibited excellent selective adsorption capacity and perm-selectivity towards PTX, with the maximum adsorption amount and separation factor of 46.36 mg/g and 3.77, respectively. Moreover, after six consecutive adsorption and desorption cycles, the membrane maintained the excellent stability and reusability, which facilities its potential application in an industrial scale. [ABSTRACT FROM AUTHOR]

Highlights • [Amim][Cl] and [Bmim][Cl] was more suitable for preparing quality film. • A decrease of DP resulted in a higher crystallinity index. • Crystal structure governs the properties of the film. Abstract Three ionic liquids (ILs) with increasing dissolution power, 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-allyl-3-methylimidazolium chloride ([Amim][Cl]), and 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]), were selected for cellulose dissolution and film preparation through regeneration. The physical properties of the films were investigated, and the correlation between the IL used and the film properties was evaluated. The results indicated that the superior cellulose dissolution system, [Emim][Ac], had the most difficult regeneration process (i.e., more time was required for gel formation), followed by [Amim][Cl], and [Bmim][Cl]. On the other hand, the film produced from [Amim][Cl] had the highest crystallinity, transparency, and tensile strength, followed by the films produced from [Bmim][Cl] and [Emim][Ac]. It was inferred that stronger and more ordered molecular arrangements and inter-molecular interactions preferentially occurred during cellulose regeneration from [Amim][Cl] than during cellulose regeneration from [Bmim][Cl] and [Emim][Ac]. [ABSTRACT FROM AUTHOR]

[Display omitted] • GCOS with high DS was firstly synthesized in an acid-free aqueous medium. • The MIC of GCOS against S. aureus and E. coli is only 1/8 of COS. • GCOS-CFs show excellent antibacterial and antiviral activity. • Antibacterial and antiviral activities of GCOS-CFs are stable to water and heat. The worldwide spread of COVID-19 has put a higher requirement for personal medical protective clothing, developing protective clothing with sustained antibacterial and antiviral performance is the priority for safe and sustaining application. For this purpose, we develop a novel cellulose based material with sustained antibacterial and antiviral properties. In the proposed method, the chitosan oligosaccharide (COS) was subjected to a guanylation reaction with dicyandiamide in the presence of Scandium (III) triflate; because of the relatively lower molecular weight and water solubility of the COS, GCOS (guanylated chitosan oligosaccharide) with high substitution degree (DS) could be successfully synthetized without acid application. In this instance, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the GCOS were only 1/8 and 1/4 of that of COS. The introduction of GCOS onto the fiber endowed the fiber with extremely high antibacterial and antiviral performance, showing 100% bacteriostatic rate against Staphylococcus aureus and Escherichia coli and 99.48% virus load reduction of bacteriophage MS2. More importantly, the GCOS modified cellulosic fibers (GCOS-CFs) exhibit excellent sustained antibacterial and antiviral properties; namely, 30 washing cycles had negligible effect on the bacteriostatic rate (100%) and inhibition rate of bacteriophage MS2 (99.0%). Moreover, the paper prepared from the GCOS-CFs still exhibited prominent antibacterial and antiviral activity; inferring that the sheeting forming, press, and drying process have almost no effect on the antibacterial and antiviral performances. The insensitive of antibacterial and antiviral activity to water washing (spunlace) and heat (drying) make the GCOS-CFs a potential material applicable in the spunlaced non-woven fabric production. [ABSTRACT FROM AUTHOR]

Robust superhydrophobic and superoleophilic cellulose- g -PFOEMA filter paper membranes were fabricated via surface grafting of poly(perfluorooctylethyl methacrylate) (PFOEMA) using atom transfer radical polymerization (ATRP). The surface chemical compositions, morphologies and wettability of cellulose- g -PFOEMA with different degree of graft ratio (DG) were investigated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and contact angle (CA) measurement. IR and XPS showed that PFOEMA were introduced into surface of filter paper. The superhydrophobicity of filter paper increased with amount of PFOEMA grafted. When DG of grafted PFOEMA was higher than 11.2%, the superhydrophobicity reached a steady state and the measured water contact angle was about 157°. The PFOEMA-grafted filter paper exhibited excellent chemical resistance toward a wide range of pH solution from 1 to 12. Cellulose- g -PFOEMA is convenient for oil/water separation with efficiency higher than 95%. The excellent reusability and stability make cellulose- g -PFOEMA filter paper membrane a promising candidate in the applications of oil spillage cleanup and the separation of oil/water mixture. [ABSTRACT FROM AUTHOR]

Herein, an ionic liquid/water (IL/w) system was developed to separate hemicelluloses from the chemical pulp with enhanced efficiency by employing xylanase. In the traditional IL/w process, when the water content was in the range 20-15%, the extraction of hemicelluloses was 71–80%. However, the highly efficient hemicelluloses removal was always accompanied with an increased cellulose loss. In this regard, xylanase (X) pretreatment was introduced to facilitate the IL/w process for improving the separation selectivity/efficiency of the hemicelluloses. In the case of the IL/w-20 (water content is 20%) procedure, X 30 (30 mg/g xylanase) pretreatment could increase hemicelluloses removal from 71 to 78%, while the separation selectivity increased from 11.0 to 43.8. Additionally, X pretreatment also reduced IL usage/charge to achieve the same degree of hemicelluloses removal. [ABSTRACT FROM AUTHOR]

The worldwide outbreak of SARS-CoV-2 has attracted extensive attention to antibacterial and antivirus materials. Cellulose is the most potential candidate for the preparation of green, environmentally friendly antibacterial and antiviral materials. Herein, modified cellulosic fibers with sustained antibacterial and antiviral performance was prepared by introducing chitosan oligosaccharide onto the fibers. The two-step method is proved to be more effective than the one-step method for enhanced chitosan oligosaccharide loadings and antibacterial and antiviral activity. In this instance, the modified fibers with 61.77 mg/g chitosan oligosaccharide loadings can inhibit Staphylococcus aureus and Escherichia coli by 100 % after contacting with bacteria for 12 h and reduce the bacteriophage MS2 by 99.19 % after 1 h of contact. More importantly, the modified fibers have washing durable antibacterial and antiviral activity; the modified fibers have 100 % antibacterial and 98.38 % antiviral activity after 20 washing cycles. Benefiting from the excellent performance of the individual fibers, the paper prepared from the modified fibers show great antibacterial (100 %) and antiviral performance (99.01 %) and comparable mechanical strength. The modified fibers have potential applications in the manufacture of protective clothing and protective hygiene products. • Chitosan oligosaccharide is used to prepare cellulosic fibers with antibacterial and antiviral performance. • Two-step method is proved to be effective in COS loadings and antibacterial and antiviral performance. • The modified fibers show excellent antibacterial and antiviral activity. • The modified fibers show excellent antibacterial and antiviral durability against washing. • The paper made from modified fibers still exhibits excellent antibacterial and antiviral performance. [ABSTRACT FROM AUTHOR]

Cellulose and its derivatives have received much attention as green raw materials to prepare ultrafiltration membranes. However, the inferior performance (low rejection, poor anti-fouling etc.) hinders their development. To improve the preparation of cellulose based ultrafiltration membrane and its performance, in this study, we developed a facile strategy to fabricate cellulose acetate ultrafiltration membranes by adding methyl acetate (MAC, as a co-solvent) to N, N-dimethylacetamide (DMAc). The results show that the pore morphologies of the membrane can be regulated by adjusting the DMAc to MAC ratio. Under optimal conditions, the pure water flux can reach 188.0 L/m2h, with the BSA rejection ratio of 95.2 %, which is about 20 % higher than the control. Furthermore, the anti-fouling and long-term stability of ultrafiltration membranes have improved significantly. The above results support the conclusion that using a mixed solvent by adding MAC to DMAc is effective for tuning the pore structure of cellulose-based ultrafiltration membrane, hence, improving its performance for water purification. • A method of using MCA as cosolvent to regulate CA membrane structure was proposed. • The water flux of the membrane reached 188.0 L/m2h. • The BSA rejection of the membrane reached 95.23 %. • The anti-fouling and long-term stability of membranes have improved significantly. [ABSTRACT FROM AUTHOR]

To further explore the factors that resist hemicelluloses degradation and release, the chemical composition and molecular weight (MW) in both the interior and exterior portions of the hydrothermally pretreated bamboo substrates were characterized. The chemical composition analysis showed that pretreatment made the lignin tend to accumulate on the exterior surface of the bamboo chips; and therefore gave rise to a large difference of lignin content between exterior and interior. Along with the degradation of hemicelluloses, the difference of hemicelluloses content in both the exterior and interior part became small. On the contrary, the hemicelluloses from the both exterior and interior portions had an invariable MW in the early stage of pretreatment; whereas, the difference of hemicelluloses MW between the exterior and interior part increased with the pretreatment continue, indicating low MW of hemicelluloses in the interior portion. Long time pretreatment promoted increasingly lignin covering on the surface of the chips; the lignin coatings might act as a hydrophobic layer blocking the access of the degraded hemicelluloses. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cocklebur structured fiber design was developed for polypyrrole modified fibers. • Formation of fibrous polypyrrole on the modified-fiber surface with high yield. • An all-in-one paper supercapacitor was produced with the papermaking technology. • Electrodes and separator were integrated by the inter-layer bonding of paper. In the era of miniaturization, low-cost, high mechanical stability and lightweight are the pre-requisites for the commercialization of smart-wearable supercapacitors (SCs). For this purpose, light-weight, binder-free, sustainable cellulose based thin-films with conductive polymers such as polypyrrole (PPy) have attained considerable attention. However, the delamination of the conductive materials in sandwich-type structures of SCs, particularly during the cyclic bending process at high current densities, is a great challenge for wearable SCs. To circumvent the problem of delamination of conductive materials, multi-layer forming concept that consists of three sequential steps (forming, pressing and drying) in papermaking technology has inspired us to prepare mechanically ultra-stable paper electrodes towards for wearable SCs. For this reason, we firstly adopted the multi-layer concept to design all-in-one paper flexible SCs by integrating PPy-modified cellulose fibers as electrodes, and un-modified cellulose paper as a separator. More importantly, a cocklebur like structure of PPy-modified cellulose fiber has been attained by the virtue of the strong inter-molecular hydrogen bonding between free hydroxyl groups on the surface cellulose fibers and PPy, resulting in increased PPy loading, and thus enhancing the electrochemical properties of the all-in-one paper supercapacitor. Furthermore, these hydroxyl groups facilitate the inter-layer bonding of the paper structure in the subsequent pressing and drying processes, favoring the integration of the electrodes and separator. Benefiting from the multi-layer forming concept and suitable morphology of PPy- modified cellulose, we have prepared an ultra-thin (150 μm) all-in-one paper SC with high areal specific capacitance (up to 562 mF cm−2), high energy density (up to 3.1 mWh cm−3) and high-power density (up to 414.9 mW cm−3). Moreover, the all-in-one paper SC shows excellent flexibility, with negligible specific capacitance loss by bending at 0° to 180° angles after repeating 1000 times. The proposed concept and supercapacitor fabrication process is scalable and can be readily implemented in a modern paper industry. [ABSTRACT FROM AUTHOR]

Cellulose-based membranes have emerged as an attractive alternative to non-biodegradable petrochemical materials. An important drawback, however, is that cellulose-based membranes are prone to biofouling. Silver nanoparticles (AgNPs) encapped with polyacrylic acid were conjugated with the chitosan/cellulose composite films to enhance the antimicrobial activities. Using the 1-ethyl-3-(3-dimethylaminopropyl) carbodii-mide hydrochloride and N -hydroxysuccinimide as biocoupling agents, AgNPs with an average size of 9 nm were distributed evenly in the film without agglomeration. The presence of AgNPs in the chitosan/cellulose–AgNPs composite films was further confirmed by X-ray diffraction measurements. Fourier transform infrared spectroscopy analysis supported the presence of amide bonds between the primary amino groups of chitosan and the carboxylic residues of coordination to silver nanoparticles. The antimicrobial properties of the chitosan/cellulose and chitosan/cellulose–AgNPs composite films were determined using the disk diffusion tests with Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). As compared to the chitosan/cellulose composite films, the chitosan/cellulose–AgNPs composite films showed significantly improved antimicrobial activities. [ABSTRACT FROM AUTHOR]

• Novel SiC/Pyrrolic-N doped carbon material have been synthesized from bamboo. • Inherent SiO 2 moieties in natural bamboo has been used as a sacrificial template. • The synergy of SiC and Pyrrolic-N has been demonstrated for Faradaic redox reactions. • Natural bamboo-based carbon materials deliver capacitance of 369 F g−1 at 0.5 A g−1. • Bamboo-based carbon materials deliver 100% capacitance retention after 5000 cycles. It is still challenging to prepare porous carbon materials following a facile, green and universal sacrificial template method from renewable biomass. For this purpose, bio-renewable bamboo is a natural silicon reservoir containing a significant amount of inherent silica that can act as a natural sacrificial template for the formation of porous carbon materials as well as a dopant. Herein, we firstly report the SiC/N dual doped bio-renewable carbon material via a facile, natural sacrificial template method. In this newly developed method, the inherently available SiO 2 nanoparticles have been utilized as the natural sacrificial template for creating the multi-porous architecture as well as for the generation of structural defects in the form of SiC nano-species. Additionally, the inherent nitrogen functional groups give rise to the formation of only pyrrolic-N species after pyrolysis. Furthermore, dual doping of SiC and pyrrolic-N species stimulate the faradaic redox reaction during the charge/discharge process and further increase the rate capability at higher current density with excellent electrochemical stability. Hence, the synergistic effect of SiC and N-pyrrolic dually doped carbon network gives rise to the formation of promising electrode material towards supercapacitors. Benefiting from the above unique features, the supercapacitor with the SNAC-1 electrode material delivers excellent capacitive behavior (369 F g−1 at 0.5 A g−1) in 1 M H 2 SO 4 electrolyte with 100% capacitance retention after 5000 charge–discharge cycles. More prominently, the all-solid state, symmetric supercapacitors assembled by SNAC-1 show outstanding capacitance of 162 F g−1 at 0.5 A g−1 and reveal high energy density (∼5.41 W h kg−1 at 0.5 kW kg−1 power density) and excellent cyclic stability. This work provides an ideal sustainable solution from bamboo source to prepare porous SiC/N composites for cost-effective supercapacitor's electrode materials. [ABSTRACT FROM AUTHOR]

Highlights: [•] Carboxymethyl cellulose (CMC) was oxidized to form dialdehyde CMC (DCMC). [•] Guanidine hydrochloride (GH) was grafted onto the DCMC to obtain DCMC-GH. [•] The coating of DCMC-GH onto paper resulted in the improvement of paper strength. [•] The DCMC-GH-coated paper exhibited excellent antimicrobial activities. [Copyright &y& Elsevier]

Triboelectric nanogenerators (TENGs) have been investigated as a promising device to harvest mechanical energy into electricity. At present, paper-based triboelectric nanogenerators (P-TENGs) have been widely researched because paper features with lightweight, low cost, abundance, renewability and biodegradability. In this paper, the operating principles and operation modes of TENGs, the development progress and performance enhancement routes of P-TENGs are comprehensively reviewed. Additionally, the overview, challenges and opportunities of P-TENGs applications are also presented. [ABSTRACT FROM AUTHOR]

Abstract: Green bamboo was hydrolyzed over a range of durations at different temperatures. A simple pseudo-homogeneous irreversible first order kinetic model was developed to describe pentosan solubility during steam treatment of green bamboo. To avoid the influence of soluble pentosan during heating process, kinetic parameters were effectively dissolved based on the data in the reacting process. Moreover, the pentosan solubility during heating process was also well modeled by numerical algorithm method. According to the origin of H factor, a modified parameter called steam treatment factor (f(P)) was proposed in this paper based on the determined kinetic constants. Finally, residual pentosan in whole process could be predicted properly based on the f(P) and the introducing of potential hydrolysis degree (h d). After using f(P) to combine reaction temperature and time into a single factor, comparative result showed that steam treatment is more effective for removing pentosan compared with hot water extraction. [Copyright &y& Elsevier]

Abstract: Perdeuterated pyridinium chloride–DMSO-d6 is an effective solvent system for whole cell biomass dissolution and NMR characterization. Employing this solvent system, semi-quantitative 13C–1H heteronuclear single quantum correlation (HSQC) spectroscopy of untreated, steam, dilute acid and lime pretreated poplar biomass samples was readily accomplished. In an effort to demonstrate the efficacy and usefulness of this fairly new characterization technique, relative spectral intensities of the untreated and pretreated biomass samples were evaluated and compared. From the relative signal intensities of hemicelluloses in each system it was observed that hemicelluloses are being removed in various pretreatment conditions, but complete dissolution of hemicellulose was observed only with acid pretreatment. The relative changes in lignin subunits after pretreatment were estimated from the volume integration of resolved cross peaks of various lignin subunits. The degradation of lignin was observed in all pretreatments, though more significant changes were noticed after dilute acid and lime pretreatment. HSQC analysis results were in agreement with the composition analysis of pretreated biomass samples. Thus, this methodology broadens the application of whole cell NMR analysis in biofuel research. [Copyright &y& Elsevier]

Keeping in view the huge demands of green and flexible supercapacitors to further digitalize and electrify human community, it is imperative to develop cost-effective and eco-friendly solutions. Herein, we report a sequential protocol to fabricate flexible, lightweight and inexpensive cellulose fiber thin film electrode based on vertically aligned polyaniline (PANI) nano-dendrites@fiber for supercapacitors. In this process, the mechanical shearing not only induces the branched architecture on cellulose fibers, but also promotes the subsequent growth of vertically aligned nano-dendrites of PANI on the cellulose fibers with increased PANI loading. The high fibrillation caused by mechanical shearing and the well-ordered growth of vertically aligned PANI dendrites on cellulose fibers make the resultant PANI@Paper hierarchically porous with high specific surface area, conductivity, mechanical strength and flexibility. The PANI@Paper based supercapacitor demonstrates excellent specific capacitance of 296 Fg-1 at 1 Ag-1 and areal capacitance of 5017 mF cm−2 at 10 mA cm−2. Furthermore, a solid-state supercapacitor based on PANI@Paper demonstrates excellent capacitance (282 Fg-1 at 1 Ag-1), high energy density (2.5 Wh kg−1) and power density of (0.3 kW kg−1). Impressively, all-paper supercapacitor fabricated with PANI@Paper and commercial paper shows remarkable capacitance (271 Fg-1 at 1 Ag-1) and flexibility while maintaining the electrochemical stability. [Display omitted] • Novel vertically aligned PANI nano-dendrimers@CF as a flexible electrode for SCs. • Synthesis of PANI nano-dendrimers@CF via mechanically enhanced polymerization method. • PANI nano-dendrimers@CF based electrodes for the mass production of all-paper SCs. • The PANI@Paper electrode delivers excellent areal capacitance of 5017 mF cm−2. [ABSTRACT FROM AUTHOR]

• The asymmetric hydrogel is adjusted and assembled by lignin and cellulose derivatives. • The hydrogel exhibits completely asymmetric adhesion, strength, and electriferous. • The hydrogel-based sensor has excellent skin adaptability and application stability. • The hydrogel can be applied to self-adhesive bioelectrodes and self-powered sensors. Mechanical adaptability, great wearability, application stability, and self-powered sensing characteristics are important requirements for hydrogel-based strain sensors. In this study, a novel double-layer hydrogel was fabricated with asymmetrical adhesion, strength, and electriferous properties. Wherein, the lignosulfonate sodium (LS)-borax mediated bottom hydrogel layer exhibits excellent softness (Young's modulus: ~14.2 kPa) and skin-adhesion (Adhesive strength: ~18.7 kPa) while the quaternary hydroxyethyl cellulose (QHEC) mediated top hydrogel layer demonstrates great mechanical strength (Young's modulus: ~101.3 kPa) and non-adhesive (Adhesive strength: ~2.2 kPa) properties. These complementary asymmetrical adhesion and strength properties endow the hydrogel-based sensor with exceptionally stable sensing performance and adaptive wearability; moreover, the lignocellulosic materials utilization plays a significant role in the designability, antibacterial and biodegradable properties. In addition, the synergy of negative LS (-) and positive QHEC (+) particles enables the double-layer hydrogel great self-powered sensing because of the directional movement of free ions initiated by the external mechanical stimulus. This study presents a hierarchical design idea of wearable electronics, which will have potential applications in many fields from wearable bioelectrodes to self-powered sensors. [ABSTRACT FROM AUTHOR]

A systematic phytochemical investigation of Pteris wallichiana J. Agardh resulted in the isolation of twenty compounds, including five sesquiterpenes (1 – 5), six flavonoids (6 – 11), seven phenolic acids (12 – 18) and two fatty acids (19 and 20). Their structures were deduced from MS, NMR and ORD data. This is the first report of compounds dehydropterosin B (2), (2 R ,3 S)-pterosin C (4), (2 R ,3 R)-pterosin L (5), apigenin (6), luteolin (7), luteolin-7- O -glucoside (10), caffeic acid (13), vanillin (14), 3,4-dihydroxybenzaldehyde (15), chlorogenic acid (17), 3,5-dicaffeoylquinic acid (18), suberic acid (19) and azelaic acid (20) from P. wallichiana and of compounds 15 , 19 and 20 from the family Pteridaceae. Furthermore, a chemotaxonomic study of the isolates was performed. • A phytochemical study of P. wallichiana led to isolation of twenty compounds. • Compounds 2 , 4 – 7 , 10 , 13 , 14 , 17 and 18 were first found from P. wallichiana. • Compounds 15 , 19 and 20 were first found from the family Pteridaceae. • P. wallichiana has a close chemotaxonomic relationship with other Pteris species. [ABSTRACT FROM AUTHOR]

• LBL-NF-CS/BCM were prepared by combining layer-by-layer assembly with spraying. • Chitosan was added to a cellulose casting solution to gain positive cationic charge. • LBL-NF-CS/BCM exhibited excellent NCl filtration performance at ultra-low pressure. Cellulose is a renewable, biodegradable, biocompatible, and sustainable material. A bamboo cellulose-based nanofiltration membrane (LBL-NF-CS/BCM) was prepared with a combination of layer-by-layer assembly and spraying methods. The chemical structure, morphology, and surface charge of the resultant LBL-NF-CS/BCM composite membranes were characterized based on Thermo Gravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy Scanning (XPS). The nanofiltration performance of the LBL-NF-CS/BCM composite membranes was evaluated using 500 ppm NaCl solutions under 0.3 MPa pressure. It was found that the LBL-NF-CS/BCM composite membranes had a rejection rate of about 36.11 % against a 500 ppm NaCl solution under the conditions tested, and membrane flux of about 12.08 L/(m2 h) was reached. The combined layer-by-layer assembly and spraying provides a scalable and convenient process concept for nanofiltration membrane fabrication. [ABSTRACT FROM AUTHOR]

• MXene can catalyze the ultrafast preparation of hydrogels by redox reaction. • MXene can regulate the internal structure and properties of the hydrogel. • Composite hydrogel has great stretchability (1400%) and recoverability. • Composite hydrogel can be used as a bioelectronic with adjustable adhesion. Re-stacking of 2D Ti 3 C 2 T X (MXene) nanosheets seriously limits their applications and development of effective strategies to overcome this issue remains challenging. Thus, an efficient method was proposed to rapidly fabricate (<20 min) a MXene nanosheets-catalyzed self-assembled, poly-acrylic acid (PAA) hydrogel with excellent conductivity, stretchability (~1400%), and anti-aggregation (>60 d) properties. In the proposed strategy, in-situ growth of TiO 2 nanoparticles (NPs) on MXene surfaces could effectively overcome the nanosheets restacking in solvents. Moreover, the reductive TiO 2 @MXene nanosheets not only catalyze the dissociation of the initiator generating sufficient radicals by redox reaction to initiate the ultrafast polymerization of AA monomers without heating, but also cross-link polymer chains (via chemical bonding) to produce hydrogel in a time scale of minutes instead of hours. Therefore, the MXene-catalyzed ultrafast self-assembly design effectively overcame the problem associated with the re-aggregation of nanosheets in hydrogels. More importantly, the structural, mechanical, swelling, adhesive, and conductive performances of the hydrogel could be adjusted by altering the TiO 2 @MXene contents. This strategy should be extended to almost all types of MXene-radical polymerized hydrogels with tunable structures and performances that have potential applications in the field of wearable bioelectronics. [ABSTRACT FROM AUTHOR]

Phytochemical study of Pteris ensiformis Burm. resulted in the isolation of eleven compounds, including three sesquiterpenoids (1 – 3), one alkaloid (5), one amino acid (6), one flavonoid (7), four phenolic acids (4 , 8 , 9 and 10), and one coumarin (11). Structures of these compounds were deduced from the ESI-MS and NMR data. This is the first report on the isolation of compounds 1 , 2 , 7 and 11 from P. ensiformis , compounds 6 and 9 from the genus Pteris , and compound 5 from the family Pteridaceae. In addition, a detailed discussion of the chemotaxonomic significance of these compounds was presented. • P. ensiformis was found to contain various kinds of chemical constituents. • Four compounds including two pterosins, one flavonoid and one coumarin were first isolated from P. ensiformis. • L -phenylalanine and isoferulic acid were first isolated from the genus Pteris. • Nicotinamide was first isolated from the family Pteridaceae. • A close chemotaxonomic relationship between P. ensiformis and other Pteris species was found. [ABSTRACT FROM AUTHOR]

The restacking tendency of 2D Ti 3 C 2 T X (MXene) sheets is the main obstacle preventing their application as functional materials in hydrogel. Herein, we fabricated novel ultra-stable 3D MXene-polyacrylamide (PAM) nanocomposite hydrogels inspired by the structure of a spider web. In particular, MXene nanosheets were uniformly located in a gel medium by precise alignment of sonication treatments, followed by the in-situ self-assembly of PAM hydrogel. In this instance, the MXene nanosheets are well-confined and trapped (via strong interactions) by the interwoven spider web-like structure of the PAM chains, which grow in-situ on the surface of the nanosheets. This approach proved effective to solve problems associated with the poor stability of MXene nanosheets in the hydrogel; more prominently, the tight cross-linked structure endows the MXene-PAM hydrogel with anti-compressive and anti-swelling capabilities; the continuous distribution of MXene nanosheets connected by the PAM network creates electron transport pathways and proton transport bridges in the hydrogel. Therefore, the hydrogel can be employed as a temperature and strain sensor or as a component of moist-electric nanogenerator. Image 1 • A temporary alignment and permanent in-situ fixation design was proposed. • Spider web-inspired anti-aggregation robust MXene hydrogel was constructed. • The DFT study predicts the formation for the bionic networks. • The hydrogel can be employed as sensor or moist-electric nanogenerator. [ABSTRACT FROM AUTHOR]

• The redox SL-Fe3+ chelates can shorten the hydrogel gelation time by 99.67%. • The hydrogel obtained stretchable, conductive, adhesive, and UV-blocking properties. • The green SL-Fe3+ chelates imparts excellent self-healing properties of the hydrogel. • The rapid preparation of soft multifunctional coatings electronics was proposed. Developing an ecological and economical method for fabrication and application of polymer hydrogels is important for the hydrogel/coating electronics. Here, a dynamic oxidation and coordination system composed of sulfonated lignin (SL) and Fe3+ was introduced to assemble multifunctional Fe-SL-g-polyacrylic acid (PAA) hydrogel at 20 ℃ in a time scale of minutes instead of hours. The SL-Fe3+ system can rapidly activate the ammonium persulfate (APS, initiator), and then it instantaneously provides abundant semiquinone and hydroxyl radicals to accelerate the formation of polymer chains. Moreover, the functional SL-Fe3+ chelates can also reversibly crosslink the polymer chains to form multifunctional hydrogels. Surprisingly, the resultant hydrogel obtained charming extension ratio (up to 1680%), conductivity (up to 7.0 × 10-2 S·m−1), and adhesive strength (up to 36.4 kPa). This technology was also applied to rapidly fabricate a transparent (up to 81%, thickness: 2 mm), UV-blocking (up to 99.7%, thickness: 2 mm), adhesive, and conductive hydrogel coating on substrates. Besides, the dynamic coordination inside the hydrogel imparts desirable self-healing capabilities to damaged network, with up to 98.5% recovery in conductivity and 85.7% in extension ratio. In short, this technology based on the sustainable SL-Fe3+ system greatly facilitates the rapid and low-cost preparation of multifunctional hydrogel/coatings, which have promising industrial applications in human–machine electronics. [ABSTRACT FROM AUTHOR]

• The TRO application allows a reduction of NaOH with comparable hemicellulose extraction. • The TRO/CCE procedure can make the cellulose fiber more flexible and more accessible. • The reactivity of dissolving pulp is related to accessibility of cellulose materials. The development of effective separation of hemicelluloses from fully bleached cellulosic pulp fibers is conducive to the development and utilization of high value-added cellulose products. In this study, Turkey Red Oil (sulfonated castor oil) (TRO), a renewable source, was proposed to facilitate hemicelluloses separation from chemical pulp in cold caustic extraction (CCE). As expected, TRO application can significantly promote hemicelluloses separation in the CCE process. By contrast to the traditional CCE process, TRO/CCE could decrease the hemicelluloses content from 9.1 to 6.1%, while the hemicelluloses removal selectivity increased from 72.5 to 82.3% and efficiency, increased from 52.4 to 68.1%. Moreover, without sacrificing hemicelluloses removal, the TRO utilization can reduce the alkaline consumption and therefore preserve the cellulose I crystal from conversion to cellulose II. Additionally, the TRO/CCE procedure made the cellulose fiber more flexible and more accessible to react with CS 2 and therefore a high Fock reactivity. [ABSTRACT FROM AUTHOR]

• Cefaclor yield of 91% was obtained in DES-buffer (7:3, v/v) co-solvent system. • Penicillin acylase immobilized on magnetic nanocrystalline cellulose was prepared. • The introduction of DES enhanced the yield and selectivity of cefaclor synthesis. Deep eutectic solvent (DES), has been considered as a new type of green solvent applied in enzymatic systems. Here, we reported DES-buffer co-solvent as a novel reaction medium for high efficient synthesis of cefaclor by penicilin acylase immobilized on magnetic nanocrystalline cellulose. Effect of DES composition, DES-buffer ratio, temperature, pH, substrate ratio and substrate concentration was systematically investigated. In co-solvent consisting of choline chloride (ChCl):glycol-buffer (7:3, v/v), conversion of 7-ACCA was 94%, synthesis to hydrolysis ratio was 1.8, and yield of cefaclor reached 91%, higher than that in aqueous buffer with optimized yield of 84%, showing the great potential of DES as organic solvent alternative. To the best of our knowledge, this is the first example of biosynthesis of cefaclor in the DES-buffer co-solvent. [ABSTRACT FROM AUTHOR]