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•Conductive superhydrophobic and elastic nanofibrous aerogel were prepared.•The aerogel testified lightweight, superior compressibility and recoverability.•The aerogel exhibited ...splendid self-cleaning and oil/water separation abilities.•The aerogel can be used as a piezoresistive sensor with excellent performance.•Our method may be offer an approach to high-performance multi-functional platform.
Developing a durable, lightweight, and robust aerogel with multifunctional characteristics is greatly desirable but remains challenging these days. Herein, an environment-friendly and original nanofibrous aerogel with integrative performance was constructed through the combination of nanofibrous aerogels’ forming technique and post-treatment modification approach. The obtained aerogel has a hierarchical porous structure consisting of flexible polyacrylonitrile nanofibers (PANF), a functional polyvinyl alcohol (PVA) polymer, conductive carbon nanotubes (CNTs), and hydrophobic octadecylamine functionalized reduced graphene oxide (ODA-rGO), endowing it with ultralow density (20.54 mg cm−3), superior compressibility and recoverability, outstanding fatigue resistance over 1000 cycles. The hydrophobic ODA-rGO coating imparts the hydrophilic PANF/CNT aerogel superhydrophobicity (154°), contributing to a splendid self-cleaning ability. Additionally, the aerogel was capable of realizing excellent oil/water separation performances. Both organic solvents and soybean oil could be adsorbed by the aerogel with high adsorption capacity (36.07 to 65.09 g g−1) and good stable in recycling as a result of its hierarchical porous structure and good hydrophobicity. It was noteworthy that the aerogel composite can be used as a piezoresistive sensor, exhibiting high sensitivity (33 kPa−1 in the range of 0–2 kPa), low detection limit (1% strain), fast response (160 ms), and good durability (over 1000 cycles). Further, it was demonstrated that the composite can be used to monitor various human activities in real time. These advantages make it an excellent candidate for smart garments, high-efficient oil/water separation and human motion detection.
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•The membrane was prepared by using a novel nature-inspired method.•The membrane possesses self-cleaning and antibacterial properties.•The membrane exhibits robust mechanical strength ...and stability.•The membrane features excellent biocompatible and UV-shielding.•Using this membrane can effectively separate various oil-water mixtures.
Fabrication of environmental-friendly, low-cost, and free-standing superhydrophobic nanofibrous membranes with additional functionalities such as self-cleaning and UV-shielding properties is highly demanded for oil-water separation. Herein, we describe the preparation of multifunctional superhydrophobic nanofibrous membrane by using a facile and novel nature-inspired method, i.e., plant polyphenol (tannic acid) metal complex is introduced to generate rough hierarchical structures on the surface of an electrospun polyimide (PI) nanofibrous membrane, followed by modification of poly (dimethylsiloxane) (PDMS). Taking an as-prepared tannic acid − Al3+-based superhydrophobic membrane as an example, it not only exhibits anti-impact, low-adhesive and self-cleaning functions, but also presents excellent performance in the separation of various oil-water mixtures. A high flux up to 6935 l m−2 h−1 with a separation efficiency of over 99% and the oil contents in water below 5 ppm is obtained even after repeating use for twenty separation cycles. Additionally, the membrane exhibits excellent UV-shielding property, attributing to the inherent UV-absorbing ability of tannic acid. Furthermore, the membrane also possesses additional properties including antibacterial activity, good biocompatibility, robust mechanical strength, and excellent resistance to various harsh conditions. These attractive properties of the as-prepared membrane make it a promising candidate for potential applications in industrial oil-contaminated water treatments and oil-water separation.
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•The membrane can perform oily wastewater separation, stay stable under harsh environments and mechanical abrasion.•The modification layer was transparent and achieved UV-resistant ...property as well.•The preparation process was fast, facile and environmental-friendly.
As oily wastewater issues continue to grow, the treatment of oily wastewater has become urgent an emergency. However, present solutions are restricted by the limited performance of materials. An UV-resist and transparent coating consisting of PDMS and ZnO decorated on a highly stable and self-standing polyimide is reported in this work as a potential solution. The obtained fibrous membranes not only allow high-efficiency (higher than 99%) oily wastewater separation but also show superior UV-resistant activity. Moreover, the superoleophilicity and hydrophobicity of the composite membrane were confirmed to be stable under harsh conditions, and the transparent coating layer has the potential to be applied in other fields. The design of the UV-resistant, transparent and superoleophilic nanofibrous membrane is very practical, and will be quite promising for reducing oily environmental contaminations from waters.
Nanoparticle-sensitized photoporation is an upcoming approach for the intracellular delivery of biologics, combining high efficiency and throughput with excellent cell viability. However, as it ...relies on close contact between nanoparticles and cells, its translation towards clinical applications is hampered by safety and regulatory concerns. Here we show that light-sensitive iron oxide nanoparticles embedded in biocompatible electrospun nanofibres induce membrane permeabilization by photothermal effects without direct cellular contact with the nanoparticles. The photothermal nanofibres have been successfully used to deliver effector molecules, including CRISPR-Cas9 ribonucleoprotein complexes and short interfering RNA, to adherent and suspension cells, including embryonic stem cells and hard-to-transfect T cells, without affecting cell proliferation or phenotype. In vivo experiments furthermore demonstrated successful tumour regression in mice treated with chimeric antibody receptor T cells in which the expression of programmed cell death protein 1 (PD1) is downregulated after nanofibre photoporation with short interfering RNA to PD1. In conclusion, cell membrane permeabilization with photothermal nanofibres is a promising concept towards the safe and more efficient production of engineered cells for therapeutic applications, including stem cell or adoptive T cell therapy.
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•Basic principle of electrospun nanofiber membranes for air filtration is demonstrated.•Characteristics and advantages of electrospun natural bio-based nanofiber membranes are ...analysed.•Comprehensive performance of electrospun natural polymer nanofiber membranes in air filtration is discussed.•Limitations, modification strategies and future perspectives are presented.
Currently, air pollution as a thorny issue has been affecting the atmospheric environment and human health for a long time. Air filtration is a crucial and effective method to improve the air quality. The nanofiber membranes fabricated by electrospinning technology have play a prospective role in the field of air filtration due to their porous structure, high specific surface area, controllable morphology and multi-functional fiber surface. The excessive utilization of traditional air filter materials prepared from non-degradable polymers or glass fibers poses huge challenges to environmental protection. Supported by the advantages of wide availability, environmental sustainability, biocompatibility and biodegradability, natural polymers have become good candidates to substitute traditional synthetic polymers for manufacturing air filtration media. In this review, the necessity and mechanism of air filtration are firstly introduced. On this basis, it is proposed to evaluate the performance parameters of nanofiber membranes prepared by electrospinning technology in air filtration. In addition, in view of the restrictions of traditional air filtration materials, the valuable prospects of eco-friendly and sustainable natural bio-based materials are introduced in detail, as well as the diverse categories and comprehensive performance of their nanofiber membranes prepared by electrospinning technology in removing air pollutants. Given that the research summary of this review, we finally deliberate the remaining problems and future challenges.
Recent development of flexible and self-healable electro-conductive hydrogels (ECHs) are considered as promising soft materials towards intelligent applications. Nonetheless, realizing the integrated ...features of high electro-conductivity, viscoelasticity and mechanical toughness, as well as inherent mouldability, fast self-healing ability, and ideal electrochemical properties is still challenging. Herein, we report a kind of multifunctional ECHs based on a polyvinyl alcohol-borax (PVAB) hydrogel and carbon nanotube-cellulose nanofiber (CNT-CNF) nanohybrids that combines the conductivity of CNTs and template function of CNFs. CNFs serve as dispersant to uniformly stabilize CNTs in suspension. As-prepared CNT-CNF nanohybrids are uniformly dispersed into PVAB to construct freeze-standing CNT-CNF/PVAB composite hydrogels. Owing to a conductive and reinforcing dual-network structure, the compression stress (∼93 kPa) and storage modulus (∼7.12 kPa) of CNT-CNF/PVAB are 2.7 and 1.9-fold larger than those of CNF/PVAB. CNT-CNF/PVAB also exhibits low density (∼1.1 g cm−3), high water content (∼95%), pH sensitivity, intrinsic mouldability and 20s self-healing capability. The solid-state supercapacitor assembled by PVAB-based hydrogels has a specific capacitance of 117.1 F g−1 and a capacitance retention of 96.4% after 1000 cycles. The self-healable and flexible supercapacitor demonstrates an ideal capacitance retention (∼98.2%) after ten damaging/self-healing cycles and a capacitance retention (∼95%) after 1000 cycles under various deformation.
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In this study, we report the design and fabrication of a novel biocompatible sponge with excellent antibacterial property, making it a promising material for wound dressings. The sponge is formed by ...grafting amoxicillin onto regenerated bacterial cellulose (RBC). It was observed that the grafted RBC could enhance the antibacterial activity against fungus, Gram-negative, and Gram-positive bacteria. The morphology of strains treated with the grafted RBC and fluorescent stain results further demonstrated the antibacterial ability of the fabricated sponge. Moreover, a cytocompatibility test evaluated in vitro and in vivo illustrates the nontoxicity of the prepared sponge. More importantly, the wound infection model reveals that this sponge can accelerate the wound healing in vivo. This work indicates the novel sponge has the huge potential in wound dressing application for clinical use.
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•A combined reinforcing and conductive network with a 3D hierarchical structure was constructed in NR by introducing well-dispersed CNF-PANI complexes.•The CNF-PANI/NR elastomer ...exhibited high flexibility, strength, stretchability and conductivity.•The elastomer-based sensor could monitor the real-time motion of human body, and the elastomer-based electrode demonstrated promising electrochemical performances.
The wide-ranging applications of electroconductive elastomers in next-generation soft electronics demand more renewable bio-based materials derived from natural forest crops than the non-sustainable materials currently available. However, it still remains a critical challenge to construct an effective, stable and continuous conductive network in a non-conductive elastomer matrix with enhanced mechanical properties and desired electrochemical performances especially using natural polymer. Here, we report a novel type of electroconductive hybrid elastomers based on a natural rubber (NR) matrix and nanostructured CNF-PANI (cellulose nanofibers-polyaniline) complexes that synergizes the conductive nature of PANI and the biotemplate role of CNFs. The CNF-PANI complexes with ideal dispersity and high aspect ratio are synthesized through in situ oxidative polymerization of aniline monomers on the surface of CNF templates, which are further uniformly dispersed into NR latex to synthesize CNF-PANI/NR elastomers with a hierarchical 3D network structure through a latex cocoagulation process. The incorporation of sustainable and biodegradable CNFs can not only built a reinforcing network, but also support the hierarchical 3D conductive network in NR matrix. The final bio-based elastomers with a homogeneous texture exhibited intrinsic flexibility, enhanced mechanical properties (tensile strength up to 9.7 MPa, Young’s modulus up to 10.9 MPa), decent stretchability (elongation at break up to 511%), low density (∼1.16 g cm−3) and ideal conductivity (up to 8.95 × 10-1 S m-1). The highly sensitive and repeatable strain-sensor integrated by the elastomer with 8 phr of PANI could monitor the real-time motion of human body. The specific capacitance of elastomer-based electrode with 20 phr of PANI can reach up to 110 F g-1 at a current density of 0.3 A g-1, and its capacitance degradation is less than 22% after 1200 cycles, exhibiting promising electrochemical properties. The multifunctional elastomers synthesized through a facile, scalable and green approach in this work promotes the advanced applications of bio-based materials including CNFs and NR in prospective soft electronics, such as strain sensors and flexible electrodes.
Schematic diagram illustrating the application for air filtration membranes.
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Air pollution has become a major environmental concern given the ever increasing levels of particulate ...matter (PM) and the increased in treatment-resistant bacterial and viral strains. Major efforts are therefore required into the development of air filtration and purification technology as well as novel, alternative antiviral and antibacterial treatment modalities. Here, we report an environmentally friendly method for the generation of multifunctional poly(vinyl alcohol)/poly(acrylic acid) (PVA-PAA) composite membranes via green electrospinning and thermal crosslinking. Superhydrophobic silica nanoparticles were then incorporated into the fibers resulting in a rough surface, after which AgNO3 was introduced, resulting in the formation of Ag nanoparticles through UV reduction. The PVA-PAA-SiO2-Ag NPs membranes were found to possess high air filtration performance (with >98% filtration efficiency for PM2.5) as well as potent antibacterial and antiviral activities. The green synthesis approach avoids the use of hazardous organic solvents, thereby bypassing any potential toxicity concerns caused by organic solvent residues. These newly designed PVA-PAA-SiO2 NPs-Ag NPs nanofibrous membranes with many superior features (e.g. high filtration efficiency, high tensile strength, biological compatibility, and antibacterial properties) can be applied in eco-friendly air filtration materials, in particular for personal air filtration devices.
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