Electrospun Technique Research Articles

Indium-doped BiFeO₃ gas sensors for the high-sensitivity and selective SO₂F₂ detection

A novel gas sensor based on In-doped BiFeO3 was devised to enhance the sensitivity and selectivity for detecting sulfur hexafluoride (SF6) decomposition products, specifically sulfuryl fluoride (SO2F2). The sensor was fabricated using an electrospun technique and hydrothermal approach followed by low-temperature pyrolysis at 250°C, achieving a single-phase BiFeO3 perovskite structure. The In-doped BiFeO3 sensor exhibits remarkable sensitivity (17.8) with a detection limit of 100 ppm for SO2F2 and outstanding selectivity, effectively minimizing responses to the interfering gases. The In-doping into the BiFeO3 results in uniform tubular nanofibers with an increased specific surface (63.53 m2g−1) area, larger pore size (38.17 nm), and reduced grain size. The microstructural enhancements, along with the catalytic activity of In nanoparticles and the formation of p/n junctions facilitating charge transfer and diffusion, lead to the improved sensing capabilities such as lower operating temperatures, higher gas responses, and moderate response/recovery times. This sensor design is tailored for the practical indoor and on-road detection of SO2F2 in industrial applications, contributing to the creation of smart and sustainable urban environments by ensuring a safe and healthy atmosphere.

Fabrication of bacterial cellulose/PVP nanofiber composites by electrospinning.

This study aimed to address a significant challenge in the application of bacterial cellulose (BC) within tissue engineering and regenerative medicine by tackling its inherent insolubility in water and organic solvents. Our team introduced a groundbreaking approach by utilizing zinc sulfate (ZnSO4) as a solvent to render BC soluble, a novel contribution to the literature. Subsequently, the obtained soluble BC was combined with varying concentrations of polyvinylpyrrolidone (PVP). Notably, we pioneered the fabrication of BC/PVP composite scaffolds with customizable fiber surface morphology and regulated degradation rates through the electrospun technique. Several key parameters, such as PVP concentration (8%, 15%, 12%, and 20% w/v), applied voltage (22, 15, and 12 kV), and a fixed nozzle-collector distance of 10 cm with a flow rate of 0.9 mL/h, were systematically evaluated so as to find the optimum parameter created BC/PVP product with electrospun. For electrospun BC/PVP products, a voltage of 12 kV was found to be optimal. Intriguingly, our findings revealed enhanced cell adhesion and proliferation in BC/PVP electrospun products compared with using PVP membranes alone. Specifically, cell viability for PVP and PVP/BC electrospun products was determined as 50.73% and 79.95%, respectively. In terms of thermal properties, the BC/PVP electrospun product exhibited a mass loss of 82.6% at 380°C, while PVP alone experienced 90.2% mass loss at around 280°C. Furthermore, the protein adhesion capacities were measured at 62.3 ± 1.2 μg for PVP and 99.4 ± 2 μg for BC/PVP electrospun products, whereas product showed no biodegradation over 28 days and had notable water retention capacity. In conclusion, our research not only successfully attained nanofiber morphology but also showcased enhanced cell attachment and proliferation on the BC/PVP electrospun product.

Production and antioxidant activity of electrospun polylactic acid (PLA) nanofibrous mats containing naringenin (NAR) for potential wound healing applications

In tissue engineering applications, the use of natural compounds without undesired side effects is highly preferred compared to chemical drugs. Flavonoids, polyphenolic compounds distributed widely in plant-based foods, exert diverse biological effects in cultured cells and in vivo. Flavonoids exhibit anti-inflammatory, antioxidant, anti-mutagenic, anti-cancerous, antiproliferative, and proapoptotic activities, enzyme modulating activities with minimal toxicity issues. Naringenin (4′,5,7-trihydroxyflavanone) (NAR) is a flavonoid belonging to the class flavanone, predominantly found in grape fruit, bitter orange, and other citrus fruits. It has very prominent pharmacological actions like antitumor, vasoprotective, antihypertension, antiviral, and dantishockactions. As NAR can scavenge reactive oxygen species, its use in wound dressing studies is increasing. In recent years, many studies have been carried out to produce nanofibrous materials by the electrospinning method. Electrospun nanofibers have very large surface areas, controllable pore sizes, and tunable drug release profiles. Several biocompatible polymers with excellent biocompatibility and biodegradability including polylactic acid (PLA) have been widely used for the synthesis of nanofibers using the electrospun technique. In this study, nanofibers were obtained by adding NAR at different concentrations into PLA by electrospinning technique. Morphological (Scanning electron microscopy, SEM), molecular interaction (Fourier transform infrared spectroscopy, FT-IR), thermal analysis (Differential scanning calorimetry, DSC), antioxidant activity, and physical analysis were carried out after the production process. Meanwhile, the PLA nanofibers showed the largest swelling value of 220% after immersion in phosphate buffer saline (PBS) solution for 10 days. Overall, this study demonstrates that our PLA/NAR nanofiber mats are attractive candidates for wound dressing material research and application.

Silk Fibroin/ZnO Coated TiO2 Nanotubes for Improved Antimicrobial Effect of Ti Dental Implants.

The aim of the present research is to develop a novel hybrid coating for a Ti dental implant that combines nature-inspired biomimetic polymers and TiO2 nanostructures with an entrapped ZnO antimicrobial agent. ZnO was used in other studies to cover the surface of Ti or Ti-Zr to reduce the need of clinical antibiotics, prevent the onset of peri-implantitis, and increase the success rate of oral clinical implantation. We developed an original coating that represents a promising approach in clinical dentistry. The titanium surface was first anodized to obtain TiO2 nanotubes (NT). Subsequently, on the NT surface, silk fibroin isolated from Bombyx mori cocoons was deposited as nanofibers using the electrospun technique. For an improved antibacterial effect, ZnO nanoparticles were incorporated in this biopolymer using three different methods. The surface properties of the newly created coatings were assessed to establish how they are influenced by the most important features: morphology, wettability, topography. The evaluation of stability by electrochemical methods in simulated physiological solutions was discussed more in detail, considering that it could bring necessary information related to the behavior of the implant material. All samples had improved roughness and hydrophilicity, as well as corrosion stability (with protection efficiency over 80%). The antibacterial test shows that the functional hybrid coating has good antibacterial activity because it can inhibit the proliferation of Staphylococcus aureus up to 53% and Enterococcus faecalis up to 55%. All Ti samples with the modified surface have proven superior properties compared with unmodified TiNT, which proved that they have the potential to be used as implant material in dentistry.

Promoting bone regeneration via bioactive calcium silicate nanowires reinforced poly (ε-caprolactone) electrospun fibrous membranes

Bone defects arise from tumors, trauma and congenital disease cause permanent damage to patients. Electrospun technique has attracted great attentions since it can produce nano-/micro-fibers continuously, Furthermore, materials prepared by electrospun can mimic the structure of natural extracellular matrix which play a good biomimetic effect and affect cell behaviors. Our study aimed to fabricate bioactive calcium silicate nanowires reinforced poly (ε-caprolactone) (CS-PCL) composite electrospun fibrous membranes (EFMs) to promote bone regeneration. To prepare CS-PCL composite electrospun fibrous membranes, firstly, hydrothermal treatment was applied to prepare CS nanowires. Secondly, CS were added into PCL solution to fabricate CS-PCL EFMs. The results indicated that the addition of CS into PCL can improve the mechanical properties and hydrophilicity of EFMs. In addition, cell adhesion, proliferation, alkaline phosphatase (ALP) activity and the expression of osteogenic genes were also improved via FAK/JNK/p38 signaling pathways. Lastly, according to the bone regeneration results in skull defect areas, the bone healing effect was significantly enhanced after the addition of CS nanowires. In conclusion, the fabricated CS-PCL EFMs can be a great candidate for bone regeneration.

Enhancing the osteogenic differentiation of aligned electrospun poly(L-lactic acid) nanofiber scaffolds by incorporation of bioactive calcium silicate nanowires

Bone defects cause serious psychological and economic burden to patients. Artificially bone repairing materials bring hope to the treatment of bone defects. Electrospun technique has attracted great attention since it can fabricate fibers from nano- to micro- scale continuously. Scaffolds fabricated by electrospun can mimic the structure of extracellular matrix which is beneficial to cell adhesion and migration. Researches have showed that bioactive ions (such as silicon and calcium ions) can promote bone regeneration. In addition, physical cues can affect cellular behavior such as cell adhesion and differentiation. In this study, two kinds of calcium silicate – adopted poly (L-lactic acid) (CS-PLLA) electrospun scaffolds with random/aligned structures were prepared by electrospun to promote bone regeneration. The integration of CS nanowires improved the biological property of PLLA electrospun scaffolds. Furthermore, in vitro results indicated that aligned 1 wt% CS adopted PLLA (PCA1) electrospun scaffolds with better physical properties and facilitated cell adhesion, improved alkaline phosphate (ALP) activity and the expression of osteogenic genes (Osteopontin (OPN), Collagen type 1 (Col-1) and Bone morphogenetic protein-2 (BMP-2)) compared with random 1 wt% CS adopted PLLA (PCR1) electrospun scaffolds. In conclusion, the prepared PCA1 electrospun scaffolds might be a potential candidate for bone regeneration in defect areas.

Electrospun polyfunctional quasi-tricolor nanoribbon and array

By integrating a coaxial spinneret with a tri-axial parallel spinneret, a distinctive monoaxis//coaxis//monoaxis parallel spinneret is firstly constructed. A novel flexible one-dimensional nanoribbon (abbreviated as NR), very like the tricolor and thus named as quasi-tricolor NR, is firstly designed and prepared via electrospun technique by the distinctive spinneret. As a case study, {[Tb(TTA)3(TPPO)2] (abbreviated as TbTT)/PMMA}//{[CoFe2O4/PMMA]@[polyaniline (PANI)/PMMA]}//{anthracene/rhodamine B/PMMA} quasi-tricolor NR and array (named as QNA for short) are prepared. Each quasi-tricolor NR is made up of left and right sides of green luminescent [TbTT/PMMA] NR and blue-red luminescent [anthracene/rhodamine B/PMMA] NR, respectively, and the middle of magnetic-conductive [CoFe2O4/PMMA]@[PANI/PMMA)] coaxial NR. The quasi-tricolor NR as the building unit with unique quadri-partitioned structure restricts the conductive polymer, luminescent materials and magnetic nanoparticles in their own spatial domains, which effectively avoid unfavorable effects among various functions and ensure strong luminescence and high conductive aeolotropy of the array. Luminescent-magnetic-conductive trifunctionality is highly integrated. Moreover, energy transfer among luminescent materials is regulated by the aid of special structure of NR and thus white light emission (abbreviated as WLE) is realized by the combination of terbium complexes with dyes. The conductive aeolotropy and magnetism of the QNA can be respectively modulated by varying the contents of PANI and CoFe2O4. The highest conductance ratio in two perpendicular directions can reach 108 when PANI content is 70 %. The quasi-tricolor NR can be extended to assemble other functions to avoid adverse mutual interferences to achieve poly functions.

In situ preparation of alendronate-loaded ZIF-8 nanoparticles on electrospun nanofibers for accelerating early osteogenesis in osteoporosis

Applying guided bone regeneration membrane (GBRm) to treat bone defects in osteoporotic patients remains a challenge, as they cannot restore the fundamental balance between osteoblasts and osteoclasts, resulting in the ineffectiveness of osteoporotic bone injury treatment. Herein, a multifunctional polycaprolactone/gelatin (PG)-blended membrane embedded with alendronate-loaded zeolitic imidazolate framework-8 (Aln/Zif-8) nanoparticles was fabricated by electrospun technique and a simple solution-phase synthesis. Surface characterizations confirmed the successful synthesis of PG/Aln-Zif-8 nanofibers endowed with excellent mechanical strength. The release kinetics analysis showed the synergistic effects of the coordination bonds among Aln, zinc ions (Zn2+), and organic ligands played a critical role in regulating the initial burst release and delayed release of Aln and Zn2+, respectively. The in vitro results of MC3T3-E1 and RAW264.3 cells demonstrated that the PG/Aln-Zif-8 membranes possessed superior anti-osteoporosis and osteoinductive properties. Furthermore, the PG/Aln-Zif-8 samples also exhibited significant bactericidal properties against both Staphylococcus aureus and Escherichia coli. The in vivo results further confirmed that PG/Aln-Zif-8 membranes had superior osteoinduction abilities, contributing to the accelerated osseointegration in the osteoporosis model. Altogether, these new bioinspired surface modifications highlight the promising alternative for fabricating multifunctional MOFs on electrospun membranes to accelerate early osteogenesis in osteoporosis.

Glutathione Immobilized Polycaprolactone Nanofiber Mesh as a Dermal Drug Delivery Mechanism for Wound Healing in a Diabetic Patient

Glutathione (GSH) is an anti-inflammatory and antioxidant biomolecule. Polycaprolactone (PCL) nanofiber mesh (NFM) is capable of the attachment and release of biomolecules for prolonged periods and has the potential as a transdermal drug delivery system during wound healing for a diabetic patient. Our earlier study found that high levels of sugar in diabetic male mice were significantly decreased by daily doses of glutathione administered on the mice. Furthermore, oxidative stress found in diabetic male mice led to the total depletion of glutathione levels in the body’s organs (pancreas, spleen, epididymis, and testis). The objective of this study was to attach GSH with PCL NFM for the controlled release of GSH biomolecules for long periods of time from the fiber mesh into a diabetic body. This study produced PCL NFM using an electrospun technique and tested it on mice to evaluate its efficiency as a dermal drug delivery mechanism. This study dissolved GSH (2.5 mg/mL) with phosphate-buffered saline (PBS) and glutaraldehyde (GLU) solution to create GSH-PBS and GSH-GLU complexes. Each complex was used to soak PCL NFM for 24 h and dried to create PCL-GSH-PBS and PCL-GSH-GLU meshes. Fiber morphology, degradation, fibroblast cell proliferation, cytotoxicity, and GSH release activities from each mesh were compared. Fibroblast cell adhesion and cytotoxicity tests found excellent biocompatibility of both GSH-immobilized PCL meshes and no degradation until 20 days of the study period. The disk diffusion method was conducted to test the antibacterial properties of the sample groups. Release tests confirmed that the attachment of GSH with PCL by GSH-GLU complex resulted in a steady release of GSH compared to the fast release of GSH from PCL-GSH-PBS mesh. The disk diffusion test confirmed that PCL-GSH-GLU has antibacterial properties. The above results conclude that GSH-GLU immobilized PCL NFM can be a suitable candidate for a transdermal anti-oxidative and anti-bacterial drug delivery system such as bandage, skin graft for wound healing application in a diabetic patient.

Atomically dispersed cobalt in core-shell carbon nanofiber membranes as super-flexible freestanding air-electrodes for wearable Zn-air batteries

• This work represents the first-ever attempt of introducing specific carbon nanofiber-based membranes which is truly flexible via electrospun technique. • Due to good integration of Zn/Co-ZiFs and fiber precursor, the Co-N 4 sites are atomically dispersed in the crosslinked flexible nanofibers. • A correlation between flexibility and high-efficiency of air-electrodes for Zn-air batteries is elucidated, opening a new area of structure-based design and development of carbon nanofibers by core-shell electrospinning approach. Highly efficient and flexible air-electrodes play a vital role in the development of solid-state metal-air batteries for wearable electronic devices. However, the practical application of air-electrodes is impeded by the multistep synthesis and poor flexibility. Herein, metal/nitrogen co-doped carbon nanofiber membranes are synthesized by integrated core-shell electrospun, in which Co-N 4 sites are atomically dispersed in the porous shell and specific carbon nanofibers with super-flexibility form backbones in the core. Owing to a high specific surface area, a 3D porous network structure and atomically dispersed Co-N 4 active sites, as-prepared membranes demonstrate a remarkable bifunctional electrocatalytic performance towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with a low potential gap of 0.719 V. Furthermore, the flexible Zn–air battery featuring a freestanding air-electrode by as-fabricated membranes displays an outstanding open-circuit voltage (1.461 V), a high peak power density (60.3 mW cm −2 ) and an ultra-narrow and stable discharge-charge voltage gap of 0.61 V under different bending angles, which are among the best values reported for self-supported flexible Zn-air batteries. This work paves a new way to prepare integrated freestanding air-electrodes as power sources for flexible electronic devices. .

Nanotechnology-Assisted, Single-Chromophore-Based White-Light-Emitting Organic Materials with Bioimaging Properties.

White-light-emitting (WLE) organic materials, especially small molecules comprising a single chromophoric unit, have received much attention due to their tremendous use in modern-day electronic devices and biomaterials. They can increase the efficiency and lifetime of devices compared to the currently used combination approach. Herein, we explored a small symmetric push-pull organic molecule Hexyl-TCBD with a single 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) chromophoric unit containing urea as a key functional group on an acceptor-donor∼donor-acceptor (A-D∼D-A) backbone for its ability to show white-light emission in solution as well as in the solid state. The luminescence was absent in the solid state due to the H-bonding- and π-stacking-driven quenching processes, while emission behavior in solution was tunable with variable CIE chromaticity index values via hydrogen (H)-bonding-governed disaggregation phenomena. Translation of WLE from the Hexyl-TCBD solution to a solid state was demonstrated by utilizing nonemissive polystyrene (80 wt % with respect to the chromophore) as the matrix to obtain WLE nanofibers (made by the electrospun technique) via segregating the molecules. The optical microscopy study validated the WLE nanofibers. The presence of multicolor photoluminescence, including white light, could be fine-tuned through various excitation wavelengths, solvent polarities, and polystyrene matrices. Furthermore, the detailed photophysical studies, including lifetime measurements, indicated that the inherent intramolecular charge transfer (ICT) bands of Hexyl-TCBD exhibit better ICT state stabilization by space charge distribution through the modulation of H-bonding between urea groups. Finally, a cytotoxicity study was performed for Hexyl-TCBD on normal and cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay to explore bioimaging applications in biosystems. MTT results revealed significant toxicity toward cancer cells, whereas normal cells exhibited good biocompatibility.

Fabrication of biopolymer nanofibers from natural sources

The methods available for the disposal of synthetic polymers are not advanced in an environment-friendly way. Consequently, their waste persists as a non-degradable pollutant that discharges toxic substances, which have now reached the deepest parts of the ocean. As an alternative, biopolymers such as polylactic acid, polyhydroxyalkanoates, and poly(butylene succinate), synthesized from natural sources such as plants, animals, and microbes, are an eco-friendly option, as they are biodegradable and a better option to shift from synthetic polymer dependency. The fabrication of electrospun nanofibers (NFs) using biopolymers is a novel approach, by which new ideas have been proposed in various fields, such as agriculture, biomedical, food packing, textiles, adsorption, drug delivery, three-dimensional printing, etc. Electrospun NFs are receiving increasing attention due to their diverse properties, including flexibility. This review provides a perception of the novel biopolymers that are currently utilized by the electrospun technique and their various applications.

Preparation, Characterization and Antibacterial Activity of Malva Sylvestris L. Seed Extract Containing Novel Electrospun PVA Nanofibers

Medicinal plants have been a great source for pharmaceutical agents. However, prossessing these raw sources to turn into therapeutic drugs requires highly complex technologies and expensive methods. Malva sylvestris L. is a commonly used vegetable in traditional and ethnoveterinary medicine because of its antimicrobial and anti-inflammatory properties. Therefore, in this study we used PVA/M. sylvestris L. seed (MSs) extract biocomposites to produce nanofibers with electrospun technique. M. sylvestris L. seed extracts were prepared and divided into fractions with 20% ACN. The metabolites in MSs extract characterized by Q-TOF LC-MS. Biocomposites with different ratios of both polymer and extract were prepared for nanofiber production. Bionanofibers have been produced from these biocomposites with optimized electrospinning conditions and their morphological analysis has been performed using SEM and FTIR techniques. Nanofibers had average diameters within the range of ∼180–244 nm. They were also found to have antibacterial activity against several microorganisms including Gram-negative (P.aeruginosa and E.coli) and Gram-positive (S.aureus and E.faecalis) bacteria. These newly generated bionanofibers with antibacterial properties hold great potential to be used in medical applications and food packaging.

Spring assisted triboelectric nanogenerator based on sepiolite doped polyacrylonitrile nanofibers

Triboelectric nanogenerators (TENGs) are suitable devices for converting small mechanical movements into electrical power. TENGs are inexpensive, easy to manufacture, and have a wide range of uses, but their energy efficiency is low for use in commercial products. In this study, sepiolite doped polyacrylonitrile (PAN) and ethyl cellulose/Polyvinylpyrrolidone nanofibers are tested as negative and positive dielectric layers, respectively, to improve output performance of TENGs. In the experiments, spring assisted TENG was employed to obtain higher power density and electrospun technique was used to produce flexible nanofiber dielectrics. According to the results, different sepiolite contents (1, 3, and 5 wt%) increase tribo-potential of PAN nanofiber by expanding the surface area and dielectric constant of the dielectric layers. The optimized electrical performance are 486 V open circuit voltage and 45 mW (28.125 W/m2) maximum power density for 3 wt% sepiolite doped PAN nanofiber. The proposed nanofibers can be efficiently used as the dielectric layers of contact mode TENGs to supply self-powered electronic devices.

Stretchable strain and temperature sensor based on fibrous polyurethane film saturated with ionic liquid

Stretchable strain sensor and temperature sensor are two essential components for the integration of wearable electronics and electrical skins, which have great potentials in healthcare monitoring, human motion monitoring and human-machine interfaces. Up to now, it is still a challenge to fabricate the stretchable and multifunctional sensor with both the capabilities of strain sensing and temperature sensing by an effective and economical method. Herein, a simple route is provided to design multifunctional sensors with high sensing performances for strain and temperature, which combines the electrospun technique and ultrasonication anchoring technique. Specifically, fibrous thermoplastic polyurethane (TPU) film is fabricated by electrospun technique at first, and then is saturated by ionic liquid (IL) to design the stretchable sensor. Attributed to the stable response and fast reconstruction of conductive pathways of ionic liquid under the stretching-releasing process, the TPU/IL sensor can serve as strain sensor, which exhibits various merits, including fast response time of 67 ms, ultra-low detection limit (0.1%), ultra-wide sensing range from 0.1% to 400% and excellent durability for long-term usage. In addition, it is noteworthy that TPU/IL sensor has great advantages in temperature sensing, which possesses a lowest temperature accuracy of 0.5 °C. This work provides a novel route for manufacturing stretchable multifunctional sensor with both temperature and strain sensing functions, which may accelerate the development of the emerging wearable electronics and electrical skins.

Fatigue-Free Electrodes Enabled Joule Heating Device for Wearable Thermotherapy

Wearable Joule heating devices have received tremendous attention from researchers due to their applications in personal thermal management systems, like thermal management cloth, and healthcare application, such as wearable thermotherapy. Permeability, stretchability, dynamic stability, and conductivity are essential factors for electrothermal heating devices. Wearable devices usually work under cyclic loading of low stain, so fatigue, mechanical failure induced by cyclic loading at low strain level, is a common disease for metal electrodes. Fatigue-free materials are of great importance to ensure robustness for long-term application. Stretchable electrodes, such as noble metal nano mesh, conductive fillers-based elastomer and metal nanowires have been used to fabricate wearable heater. Liquid metal (LM) has also attracted lots of attention due to its high conductivity and fluidity at room temperature. Such fluidity not only makes LM attractive materials for flexible devices, but also render LM fatigue-free attribute. Many manufacturing methods, such as direct ink writing, screen printing and spray coating have been applied to fabricate LM based electrodes for flexible devices. Recently, electrospun technique have also been applied to fabricate LM particles doped polymer fibers, but LM based conductive fiber electrodes have not yet been fabricated using electrospun process. Here, a LM particles embedded fibers network electrode is fabricated using electrospun method, followed by wrapping a polymer layer on the fiber surface. The LM particles embedded in the electrospun fibers form interconnected network, which exhibits excellent electrical conductivity, high mechanical stretchability, and good fatigue performance. Such network electrode could be directly used as a Joule heater, which is permeable, stretchable and fatigue-free. High conductivity of the electrodes ensures low driving voltage for this electrothermal heating devices. High stretchability of the electrode ensures good Joule heating performance at high strain level. In addition, the uniform fibers size could induce large-scale uniform heating. The LM fiber electrodes could be cut into various patterns to fit curvilinear surface of human skin. Also, the ultrathin and compliant nature of the LM fiber electrode enable seamless attachment with human skin, which could ensure high thermal transfer efficiency. The combination of good electrical and mechanical performances of the LM fiber-based Joule heater enable long-term wearable thermotherapy.

Electrospun SnO2 and its composite V2O5 nanofibers for thermoelectric power generator

Nanofibers have attracted attention in the field of thermoelectric (TE) because of their remarkable properties; abundance, lightweight with the high-surface area-to-volume ratio, low thermal conductivity, mechanically stable, and non-toxic. In applications, like TE wearable device for energy harvesting, development of new composite nanofibers holds more significant potential with the targeted specifications. In our research, we have investigated for the first-time fiber nanocomposites for the application of wearable power generator in terms of TE energy. The electrospun technique attracts in the development of nanostructured materials in the field of thermoelectric power generation. The significance of this paper is to flourish the wearable device materials of 1D vanadium oxide/tin oxide (V2O5/SnO2) composite nanofibers synthesized using sol–gel method followed by electrospinning process. The structural and morphology properties of SnO2 fibers belong to tetragonal structure and nanocomposite relates to tetragonal (SnO2) and orthorhombic (V2O5) structure, diameter in the range of 100–400 nm. The high-surface area to volume ratio of nanofiber allowed more significant phonon scattering and enhance the efficiency. The nanofiber exhibits the outstanding TE properties of the Seebeck coefficient and power factor of 20–100 V/K and 0.3–1.6 µW/K2m at room temperature to 400 K, which is the highest among the fiber SnO2 and its composites. The nanofibers integration on wearable devices paves the way towards ultralight, thermally stable, tunable density and mechanically flexibile are unique, where nanocomposite offers a new opportunity to thermoelectric applications.

Electrospun Polycaprolactone Nanofibrous Webs Containing Cu–Magnetite/Graphene Oxide for Cell Viability, Antibacterial Performance, and Dye Decolorization from Aqueous Solutions

Fine powder of magnetite nanoparticles (MNPs) was doped with different contents of copper (Cu) through a mat of graphene oxide (GO) nanosheets. These compositions were incorporated into electrospun nanofibrous membranes of polycaprolactone (PCL). Mechanical properties were measured, and examining the ability of these nanofiber membranes to remove methylene blue (MB) dyes from aqueous solutions was also assessed. TEM of the resulting nanofibers has a diameter of the order of 300 nm. Moreover, the morphological features of membranes showed that diameters were varied upon the variation of dopant (Cu ions) starting from 0.35–1.06 μm and 1.8–3.9 μm at no Cu reaching 0.19–0.45 μm and 0.75–1.42 μm for the highest contribution of Cu, whereas GO scattered grains of 0.56–1.5 μm were detected. The tensile strength was changed accordingly and reached around 8.96 ± 0.45 MPa, while the toughness achieved 4.69 ± 0.29 MJ/m3 at the highest additional dopant. The designed nanofibrous membrane was able to remove 95.1% MB after 36 min of continuous exposure, while the reusability indicated that the composition was stable after 5 times of removal with efficiency around 90.1% for the 0.8Cu–MNPs–GO@PCL. The antibacterial efficiency was also investigated against both E.coli and S. aureus, and the inhibition zone recorded around 11.4 ± 1.5 and 11.1 ± 1.7 mm in dark and 15.6 ± 2.1 and 13.6 ± 1.8 mm, respectively, at the highest contribution of Cu dopant. This behavior of the manipulated nanofibrous membrane indicates that tailoring of multi-functional nanomaterials could be reached via designing scaffold-based electrospun technique.

Development of Sunlight-Driven Reduced Graphene Oxide (rGO)/CeO₂-CuO Nanofibrous Photocatalyst for Efficient Removal of Organic Dyes.

A hybrid nanofibrous membrane photocatalysts was developed through electrospinningcarbonization method. In this work, the hybrid membrane with p-n hetero-structure consisting of CeO₂ and CuO metal-oxide nanoparticles was prepared by a hierarchical and facile approach through electrospun technique and stabilized by hydrothermal process. The obtained heterogeneous photocatalyst membrane was studied for its catalytic properties by performing several experiments using test solutions of anionic Congo red (CR) and cationic methylene blue (MB) dyes, respectively. The as-prepared Graphene-CeO₂/CuO intercalated polyacrylonitrile nanofibrous (GCPNs) membrane is characterized by using various analytical techniques and its photocatalytic degradation properties was studied by conducting batch studies and validated using the kinetics models. Furthermore, the functional group transformation, electronic transition state, binding energy values and chemical oxidation state of the GCPNs membrane before and after degradation was investigated by spectroscopic studies. The optical properties of the GCPNs membrane was further analysed by UV-VIS diffuse reflectance spectroscopy (DRS). Also, the enhanced photo-degradation behaviour of the p-n hetero-structure due to the suppression of the recombination rate of the photogenerated electron-hole pairs was confirmed by photoluminescence studies (PL). These investigations implied that the developed photocatalyst GCPN membrane follows the pseudo first-order kinetics having higher reaction rate constant. Comprehensively, the GCPN has varying dye removal capacity of 90-98% for Congo red and 30-90% for Methylene blue in which the photocatalytic degradation capacity increases with increase in dye concentration and time. The reusability studies supported the sustainability and durability of the photocatalytic membrane for longer lifetime and practical value. Henceforth, nanotechnology-based cutting-edge technology offers novel hybrid nanomaterials having excellent properties that are pre-requisite for the development of sunlight mediated nano-photocatalytic reactors in the commercial applications.

High Performance Dye-Sensitized Solar Cells Based on Electrospun MoS2-Carbon Nanofiber Composite Counter Electrode

MoS2-carbon nanofiber composites were prepared via electrospun technique with ammonium thiomolybdate(VI) and PVP. The effects of thermal pretreatment on the morphology of material were studied. The results demonstate that the composite nanofiber with pretreatment shows a uniform diameter and lots of small size MoS2 particles inside with porous structure. When the composites was used as counter electrodes in dye-sensitized solar cell, a maximum efficiency of 5.7% has been achieved due to the combination of electrical conductivity and catalysis ability from MoS2-carbon nanofiber composites.