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The construction of multidimensional fillers provides new ideas for the development of composite materials. In this study, one-dimensional (La 0.5 Nb 0.5) x Ti 1-x O 2 ceramic nanorods (x-LNTO NRs) and 1-LNTO ceramic materials with three-dimensional fiber structure network (3D-1-LNTO) were prepared by electrospinning. These materials were used as fillers to prepare x-LNTO NRs/PVDF composites and 3D-1-LNTO/PVDF composites. Compared with the 1-LNTO NPs/PVDF composites, the 1-LNTO NRs/PVDF composites showed better dielectric properties, with a dielectric constant of 40 and a dielectric loss of 0.12 at a fill content of 60 wt%. The 3D-1-LNTO/PVDF composites achieved a high dielectric constant at a low filler content, the composite achieved a dielectric constant of 25 at a fill content of only 10 wt%, which is 2.5 times higher than that of pure PVDF. Compared with x-LNTO NRs, 3D-1-LNTO is more obvious for improving the dielectric properties of composites. The construction of continuous fiber network is the main reason for the enhancement of dielectric constant, and this study provides a new experimental idea for the construction of multi-dimensional high dielectric fillers. [Display omitted] • We prepared 3D-1-LNTO/PVDF composites achieved a high dielectric constant at a low filler content. • The continuous fiber network is an important reason for the increased dielectric properties. • The co-doping ceramic nanomaterials worked as the hybrid filler. • The dielectric constant is about 25 and the dielectric loss is only 0.128 at 1 kHz. [ABSTRACT FROM AUTHOR]

Dielectric materials with ultrahigh energy storage and discharge capabilities have become increasingly vital for high energy efficiency in modern electronics which require immense pulsed power delivery. Ferroelectric polymers offer the benefit of being relatively low-cost, lightweight, and having a lower carbon footprint to produce and maintain in comparison to ceramics. Electrospinning polyvinylidene difluoride (PVDF) nanofibres have proven to produce a highly polarised polymorph, although dielectrics involving these alone often have problems with leakage currents. In this work, multilayer all-polymer laminates were assembled by alternative stacking of poly (methyl methacrylate) (PMMA) thin films and electrospun poly (vinylidene difluoride-co-hexafluoropropylene) (PVDF-co-HFP) membranes, where the nonwoven PVDF-co-HFP nanofibrous membranes were electrospun with an ionic liquid (1-allyl-3-methylimidazolium chloride (AMIM) to eliminate leakage currents and maximize the discharged energy density. The effects of the crystallography, microstructures and interfaces of the multilayer PMMA/PVDF-co-HFP laminates on the energy storage capacity were discussed. [Display omitted] • Electrospinning PVDF-co-HFP nanofibers enhance the electroactive crystal β-phase. • Adding an ionic liquid (AMIM) to PVDF-HFP gives the greatest proportion of β-phase. • Hot pressed layered laminates of PMMA:PVFHA keep a fibrous structure up to 160 °C. • Ferroelectric testing of laminates shows sample homogeneity is key to achieving high U e. [ABSTRACT FROM AUTHOR]

As smart electronics and self-powered devices continue to evolve, the emergence of piezoelectric polymers has sparked significant research interest. In this pioneering project, we have successfully synthesized ZIF-67 particles/tetrabutylammonium hexafluorophosphate (TBAHP)/polyvinylidene fluoride (PVDF) tree-like nanofiber structures for the first time, which was characterized by a large number of branching nanofibers (down to 5 nm) and a uniform diameter trunk fiber (about 400 nm). And the synergistic interaction between these two distinct additives yields exceptional multifunctional properties. By optimizing the quantities of ZIF-67 and TBAHP, we enhanced the β-phase content and piezoelectric performance of PVDF through diameter refinement, interface coupling enhancement, and the introduction of a micro-capacitance mechanism. Notably, the improvements surpassed those achieved with a single additive. Specifically, the piezoelectric energy harvester fabricated using TBAHP/PVDF-TLNMs doped with 0.5 wt% ZIF-67 exhibited an output current of 4.25 μA and a peak voltage of 17.32 V, marking an increase of approximately 1187 % and 831 %, respectively, over pure PVDF nanofiber membranes. Furthermore, the device demonstrated sensitivity to motor movements and effectively harvested energy from diverse bodily motions. [Display omitted] • The designed nanogenerator possessed β-phase content of 89.83 %. • ZIF-67 enhanced interface coupling effect to locally stable all-trans conformation. • The nanogenerator showed great piezoelectricity enhancement for pure PVDF. • Enhanced performance originated from the synergistic effect of TBAHP and ZIF-67. [ABSTRACT FROM AUTHOR]

Polyethylene furanoate (PEF) stands out as a highly promising biopolymer, characterized by its lower melting point and higher flexibility than those of polyethylene terephthalate (PET). Moreover, the enhanced functionality of PEF broadens its potential applications across various domains. Herein, the synergistic integration of PEF with a polymer thermoelectric layer is explored via the formulation of advanced environmentally sustainable materials for prospective utilization in flexible thermoelectric generators for the emerging field of green energy. The fabrication process involves the creation of PEF nonwoven via the electrospinning technique, thereby endowing the PEF with considerable stretchability. Concurrently, the polymer thermoelectric layer is developed by blending dimethyl sulfoxide (DMSO) and d -sorbitol in a poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) solution, followed by drop-casting PEDOT:PSS onto glass substrates. Subsequently, free-standing PEDOT:PSS films are transposed onto PEF nonwoven substrates with a power factor of 17.84 μW m⁻1 K⁻2 and an elongation of 24 % at breaking point. The intimate compatibility between the PEDOT:PSS film and PEF nonwoven substrate is demonstrated by the cyclic bending test results, wherein over 90 % of the original conductivity is maintained after 1000 cycles, thereby highlighting the potential of the developed device as a thermoelectric generator. Finally, a 12-leg thermoelectric generator is fabricated, yielding an output voltage of 3.63 mV and an output power of 34.52 nW under a temperature gradient of 32.3 K. [Display omitted] • A thermoelectric generator with biomass PEF substrate and PEDOT:PSS films. • A stretchable PEF substrate was successfully fabricated with an elongation of 63 %. • A flexible thermoelectric generator generates a maximum power of 34.52 nW. [ABSTRACT FROM AUTHOR]

Electrospinning is a unique technology based on the fabrication of polymer fibers from the solution under an applied electric field. Electrospun membranes are applied in various fields, starting from filter technologies to tissue engineering. Polyalyletherketones (PAEK) is a family of synthetic bioinert polymers characterized by outstanding mechanical performance, high chemical stability, and biocompatibility. In the present study, the effect of electrospinning parameters (collector-to-tip distance, applied voltage, spinning solution flow rate and polymer concentration in the spinning solution) on the morphology of the fabricated polyetherketoneketone (PEKK) membranes as well as their crystal structure, chemical stability and biocompatibility was investigated. Based on 108 combinations of the electrospinning parameters, it was found that minimum concentration of PEKK in the spinning solution in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) required for the fibers' formation is 4 wt %, while the applied voltage providing fibers without defects was found at 20 kV. It was demonstrated that the tested electrospinning regimes allow to fabricate the membranes with average fiber diameter from 0.76 ± 0.29 to 1.46 ± 0.60 μm and porosity from 87 ± 1 to 92 ± 1 %. It was found that electrospinning process has no effect on the chemical structure of PEKK macromolecules. Electrospinning parameters had no effect on crystal structure of PEKK in the fabricated membranes, which was found to be amorphous. The fabricated membranes demonstrated high Young modulus (above 150 MPa) and elongation over 170 %, were stable in strong alkali and acid solutions and biocompatible towards mouse embryonic fibroblasts. [Display omitted] • PEKK FDM-printing waste was recycled to fibers using electrospinning technique. • The regimes for the fabrication of fibers without defects were selected. • The fabricated fibers are chemically stable and biocompatible. [ABSTRACT FROM AUTHOR]

Meeting the criteria of performance and biocompatibility poses a significant challenge in developing polymeric nonwovens for biomedical and filtration purposes. Although non-isocyanate poly(carbonate-urethane)s (NIPCUs) made by transurethane polycondensation are emerging as non-toxic alternatives to isocyanate-based polyurethanes, their fibrous processing is scarce. Therefore, our work focused on preparing electrospun nonwovens from sustainable NIPCUs with an architecture tailored for high mechanical strength. Combining aromatic 4,4′-diphenylmethane bis(hydroxyalkyl carbamate) hard segments and soft oligocarbonate segments imparted strength and flexibility, while incorporating up to 29 wt % of CO 2 into the structure of the NIPCUs. Scanning electron microscopy showed that adjusted electrospinning parameters produced uniform, submicron fibers without defects. FT-IR and NMR spectroscopy confirmed their unchanged composition and molar mass (20–25 kg mol−1) compared to the unprocessed NIPCUs. Differential scanning calorimetry and dynamic mechanical thermal analysis showed that the macromolecular arrangement induced during electrospinning was strongly dependent on the architecture of the polymer. The mechanical performance of the nonwovens, reaching tensile strength above 5 MPa and elongation at break up to 250 %, correlated to their morphological differences. Thus, appropriate modification of the structure and morphology of the NIPCU nonwovens allowed the production of CO 2 -rich submicron fibers with high toughness and flexibility. [Display omitted] • CO 2 -based polymers. • Electrospinning of polyurethanes. • Non-isocyanate aliphatic-aromatic polyurethanes. • Non-isocyanate polyurethanes. • Transurethane polycondensation. [ABSTRACT FROM AUTHOR]

Li metal battery is a promising next-generation power storage devices, but faces the serious safety issues caused by the uncontrolled Li dendrite growth and leakage of the flammable organic electrolyte. Herein, a low-cost CA/PVDF (cellulose acetate/polyvinylidene fluoride) composite membrane is prepared via electrospinning technology for safe lithium metal batteries. This membrane (45 μm) exhibits the high porosity (76.9 %) and excellent thermally stability (>180 °C) preventing the short circuit during abuse. The CA/PVDF-based gel polymer electrolyte (GPE), fabricated with CA/PVDF electrospun membrane swelled by carbonate-based organic liquid electrolyte, delivers the ionic conductivity of 1.82 mS cm−1 and Li + transfer number of 0.506, which achieve uniform Li+ ion electrodeposition and inhibit the formation of lithium dendrites. As the results, the symmetrical cell Li/CA/PVDF-based GPE/Li exhibits the impressive reversible Li stripping/plating behavior over 300 h at 1 mA cm−2 with the capacity of 1 mA h cm−2. Furthermore, the assembled LiFePO 4 /GPE/Li battery exhibits the capacity of 101.2 mA h g−1 at 5C with the capacity retention of 94.6 % after 400 cycles, which exceeds that of traditional liquid electrolytes. This research provides a low-cost gel polymer electrolyte via the electrospinning technique for rechargeable lithium batteries with good electrochemical performance and high security. A low-cost CA/PVDF composite membrane is designed via electrospinning technology for safe lithium metal batteries, which achieves uniform Li+ ion electrodeposition, inhibits formation of lithium dendrites over 300 h and stabilizes the interface between electrode and electrolyte. The assembled LiFePO 4 /CA/PVDF-based GPE/Li battery exhibits the capacity of 101.2 mA h g−1 at 5C with the capacity retention of 94.6 % after 400 cycles. [Display omitted] • A low-cost CA/PVDF composite membrane is prepared via electrospinning technology. • The CA/PVDF-based gel polymer electrolyte delivers the ionic conductivity of 1.82 mS cm−1 and Li + transfer number of 0.506, which achieve uniform Li+ ion electrodeposition. • The assembled Li symmetrical cell exhibits the impressive reversible cycle over 300 h. • LiFePO 4 /GPE/Li battery exhibits the capacity of 101.2 mA h g−1 at 5C with the capacity retention of 94.6 % after 400 cycles. [ABSTRACT FROM AUTHOR]

Here we utilize the layer-by-layer (LbL) technique to homogenously integrate polyelectrolyte (PE) multilayers with multiple different catalytic functionalities inside an electrospun BPM without forming an electrically and/or ionically non-conductive catalyst layer. BPMs were fabricated by coating an electrospun cation exchange layer alternately with polyethyleneimine (PEI)-poly (acrylic acid) (PAA), followed by hot-pressing between pristine electrospun anion and cation exchange layers. This resulted in a BPM having a thin entangled 3D junction with high surface area and well-integrated catalysts. Optical reflectometry shows that the amount of PE catalysts inside the BPM can be controlled by tuning coating parameters such as the amount of bilayers and the ionic strength of the coating solution, where especially a higher ionic strength resulted in a significantly higher mass adsorption. The BPMs coated at higher ionic strength (500 mM NaCl) showed the lowest water dissociation potential of 0.84 V. Furthermore, it was found that incorporating the PE multilayers diminished the effect of the electric field and that the catalytic activity becomes more dominant in facilitating the water dissociation reaction. The advantage of creating a 3D junction using electrospinning in combination with the versatility of the LbL deposition technique allows for further optimization to create high performance BPMs that can be tailored to specific applications. [Display omitted] • Polyelectrolyte (PE) multilayer water dissociation catalysts in electrospun BPMs. • PE deposition can be controlled by the ionic strength in the coating solution. • Integration of PE multilayers results in a considerable decrease in overpotential. • Properties of especially the final PE layer determines the final BPM performance. • Multilayers with the most available functional groups have the lowest overpotential. [ABSTRACT FROM AUTHOR]

With the growing environmental concerns over the use of chemicals and nanomaterials to achieve membrane hydrophobicity, polydimethylsiloxane (PDMS) has emerged as a sustainable and eco-conscious alternative. Introducing PDMS into the doping solution to be used for electrospinning is a simple yet highly efficient means of augmenting the hydrophobicity of the electrospun membrane. Nevertheless, to achieve stable nanofibers and an appropriate structure as a membrane when using PDMS introduction, it is imperative to regulate the polymer concentration. In the present investigation, we explored modifications in the physicochemical characteristics of the membrane, specifically changes in hydrophobicity, upon the addition of PDMS to a 15 % poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) solution. Increasing the amount of PDMS was found to introduce more CH 3 groups to the membrane's surface, but it also had the side effect of enlarging the fiber diameter. Thus, the maximum contact angle improved to 148° with the addition of 10 % PDMS. However, the membrane distillation system using the membrane that included 5 % PDMS exhibited the most stable performance, as it sustained continuous operation for more than 170 h and effectively prevented membrane wetting. [Display omitted] • Addition of PDMS to PVDF-HFP solution to improve hydrophobicity in electrospinning. • A concentration of 15 % PVDF-HFP is required for the stable formation of nanofibers. • PDMS injection led to an improvement in hydrophobicity, but reached a plateau. • A 10 % PDMS injection resulted in the highest contact angle. • The MD performance was optimal with a 5 % PDMS injection. [ABSTRACT FROM AUTHOR]

Fibrous membranes are crucial on the filtration of pollutants from air and water, but continued use can lead to a failure in effectiveness due to pollutant accumulation. To enhance durability, incorporating photocatalytic submicroparticles into these membranes appear as a solution. Here, we prepared a set of polyvinyl difluoride (PVDF) fibrous membranes modified with graphitic carbon nitride (g-C 3 N 4) using three different methodologies. Their photocatalytic efficiency was investigated using phenol as model pollutant compound under visible light irradiation. Using g-C 3 N 4 fibrous membranes modified by electrospinning blend a pseudo first-order kinetic constant (k app) of 2.51 × 10-4 min-1 was observed for phenol degradation after 240 min reaction. Despite minimal particle adhesion the thermal treatment increased k app to 5.41 × 10-4 min-1. The membranes prepared via chemical activation of PVDF exhibited the highest photocatalytic activity (k app of 21.7 × 10-4 min-1). This superior activity was attributed to covalent bonds between PVDF and g-C 3 N 4 , allowing the formation of oxidative species. [Display omitted] • Different approaches of g-C 3 N 4 /PVDF photocatalytic membranes were investigated. • Preparation method significantly affected photocatalytic performance. • Covalent bonding between sided NH 2 - groups of g-C 3 N 4 and PVDF was achieved. • Surface availability affects kinetic rate rather than amount of deposited g-C 3 N 4. • Novel experimental setup for estimating the amount of attached g-C 3 N 4 is presented. [ABSTRACT FROM AUTHOR]

The major limitation of conventional sulfonated polymer proton-exchange membranes (PEMs) is their strong reliance on water molecules for proton conduction, causing a significant reduction in proton conductivity under low-humidity conditions. In this study, a one-dimensional ionogel (IL@Sep) confined within sepiolite (Sep) nanorods was prepared using ionic liquid (1-butyl-3-methylimidazolium trifluoromethanesulfonate) and supercritical CO 2. Subsequently, IL@Sep was blended with a Nafion solution, and electrospinning was used to fabricate the composite fiber PEM suitable for low-humidity environments. The results revealed that the electrospun (ES)-Nafion/IL@Sep composite fiber membrane exhibited significantly enhanced mechanical properties, water absorption, and proton conductivity. At an IL@Sep content of 2 wt%, the Nafion/2IL@Sep membrane exhibited a proton conductivity of 231 mS cm−1 at 80 °C/98 % relative humidity (RH) and 113 mS cm−1 at 80 °C/40 % RH. Moreover, the single-cell assembled with this composite membrane exhibited good gas tightness and achieved a peak power density of 779 mW cm−2 at 60 °C/80 % RH, which was ∼1.45 times that of the Nafion 212 membrane single-cell. This study indicates that electrospinning-assisted ionogel-modified ES-Nafion/IL@Sep composite fiber membranes have potential suitability for use in proton-exchange membrane fuel cells under varying humidity conditions. [Display omitted] • Sep-encapsulated ILs (IL@Sep) were prepared using supercritical CO 2. • Nafion/2IL@Sep membrane-based single-cell achieved a peak power density of 779 mW cm−2 at 60 °C/80 %. • The composite membrane's improved performance was due to the axial alignment of IL@Sep within the Nafion nanofibers. [ABSTRACT FROM AUTHOR]

In this study, a flexible piezoelectric sensor based on polyacrylonitrile (PAN), zirconium-based MOF (UiO-66) with nitro (NO 2) and two-dimensional material MXene composite nanofiber film was proposed. When pressure was applied, the three-dimensional structural nanopores were compressed, increasing the intercalation structure between the MXene nanosheets coated in the fibers. The double-packed system produced a higher resistance change under the same pressure load, which can be explained by the fact that the low-conductivity octahedral UiO-66-NO 2 particles acted as a similar "buffer" between the highly conductive MXene. At the same time, a large number of hydrogen bonds between the surfaces of the two fillers enhanced the synergistic effect and promoted the interfacial coupling effect, so that more 31-helical conformation in the PAN matrix was converted into a planar zigzag conformation. This improved the piezoelectric performance and enabled the sensor to have a voltage output of about 200 V in the detection range. And because the polyhedral form of UiO-66-NO 2 particles provided a rougher surface structure, the piezoelectric sensor can achieve a high sensitivity of 5.62 V/N. The other results showed that the dielectric constant of the designed flexible piezoelectric sensor was increased to 2.67, the dielectric loss was kept at a low level of 0.026, and the maximum elongation was 56.03 %. This multi-functional sensor shows great potential in the fields of health and medical treatment, human-computer interaction, etc. [Display omitted] • Flexible film based on PAN/UiO-66-NO 2 /MXene is prepared by electrospinning process. • The content of planar zigzag conformation in PAN improves the piezoelectric performance. • The sensor has outstanding performance in sensitivity (5.62V/N, 0.88V/N). • It exhibits fast response and recovery times (120 ms/53 ms). • It is mainly used in medical health and human-computer interaction. [ABSTRACT FROM AUTHOR]

The effects of polyvinylidene fluoride (PVDF) wt. % and electric fields on the production of PVDF fibers using a novel centrifugal electrospinning design were investigated. High-quality, bead-free fibers with diameter of (0.55 ± 0.04) μm were successfully produced. Fibers with exceptionally high β -phase content of 96.1 % and piezoelectric coefficient, d 33 of (−157 ± 5) pC N−1 were obtained using PVDF amount and electric field of 14.0 wt % and 400 V cm−1, respectively. Under 3.0 N repetitive vertical forces, the fabricated piezoelectric nanogenerator (PENG) exhibited impressive open-circuit voltage, short-circuit current and power density of (32.6 ± 0.7) V, (3.26 ± 0.07) μA and (15.4 ± 0.6) μW cm⁻2, respectively. The production of high and well aligned β -phase in the fibers indicated by good d 33 values are the likely reasons for the excellent performance of the PENG. Ultimately, potential of the fabricated PENG as a self-power supply for low-energy electronic devices was demonstrated. [Display omitted] • A novel design for centrifugal electrospinning to efficiently produce PVDF fibres. • The success of using a low electrical field to enhance the beta-phase content in PVDF fibres. • High V oc signal generated using a PVDF fibre-based PENG. • The potential for replacing lead-based PENGs with fibre-based PENGs as a power supply for low-energy electronics. [ABSTRACT FROM AUTHOR]

A piezoresistive flexible strain sensor was developed using thermoplastic polyurethane elastomers (TPU) as the matrix and carbon nanotubes (CNTs) as conductive fillers. Sensitivity, strain range, and tensile cycling stability were concurrently considered during its design. Electrospun TPU fiber membranes were prepared via electrospinning in this experiment, with controllable fiber diameter achieved by adjusting the rotational speed of the electrospinning receiving drum. CNTs were incorporated into a flexible polymer substrate through suction filtration to create the strain sensor. The support structure of the electrospun film served as a carrier for uniformly adhering conductive particles. Well-dispersed conductive CNTs could more easily achieve uniform loading through the pore size of the electrospun fiber film, thereby forming a conductive layer. This study initially determined the influence of TPU content in the spinning solution on the morphology of the electrospun membrane. Subsequently, the effects of CNT content and electrospinning receiving drum rotational speed on the microstructure of TPU electrospun membranes were investigated, along with their impact on the microstructure, mechanical properties, and sensing performance of CNTs/TPU (CT) flexible strain sensors. The results indicate that the electrospun fiber membrane prepared under the conditions of TPU mass fraction of 20 wt% and rotational speed of 100 r/min has a larger average fiber diameter and a more stable scaffold structure. The CNTs/TPU (CT) sensor, prepared by filtering 10 mL of CNTs with a concentration of 2 mg/mL, exhibited the best mechanical properties, with a tensile strength and elongation at break of 6.22 MPa and 575 %, respectively. Additionally, it demonstrated high sensitivity (GF = 420.17 at 200 % strain) and excellent durability stability (300 cycle tests), enabling quick and accurate responses to movements of various parts of the human body, thereby meeting the basic usage requirements of flexible strain sensors. [Display omitted] • Electrospinning combined with vacuum filtration was used to prepare strain sensors. • The influence of manufacturing process parameters on sensor performance was explored. • The sensor exhibits high sensitivity and excellent mechanical performance. • The sensor demonstrates good stability. • The sensor is capable of effectively monitoring human movement. [ABSTRACT FROM AUTHOR]

Melt electrowriting (MEW) is an advanced additive manufacturing technology that produces high-resolution scaffolds for medical applications. Although there are many valuable parameter groups for MEW, the corresponding principles need to be clarified to improve the success of printing high-fidelity scaffolds. To this end, we investigate the print limit of MEW with respect to the minimum interfiber distance and the maximum print period based on a medical-grade poly(ε-caprolactone) material. The results indicate that relatively large turning loops and low turning speeds improve the print accuracy of the scaffolds; however, excessively large turning loops and low turning speeds result in fiber accumulation on the edge of the scaffolds, resulting in print failure. The turning loops with 500 μm in diameter and turning speeds of 0.625 × CTS (critical translation speed) can achieve well-defined MEW scaffolds with an interfiber distance down to 25 μm. For printing such high-resolution scaffolds, the constant printing process can last one week. Fiber placement gets random when the fiber diameter is larger than 2.5 μm, caused by the melt polymer degradation and shear thinning in the printing process. Additionally, we verify that the method of charge neutralization is not beneficial for improving the fiber overlay. This is a fundamental study clarifying the principles of printing high-resolution MEW scaffolds, being capable of extending the application of the MEW products. [Display omitted] • Ultrahigh-resolution polycaprolactone scaffolds are printed by melt electrowriting. • Theories on improving printing accuracy are established. • The correlations between printing time and print accuracy are elucidated. • Charge neutralization has a limited impact on improving print accuracy. [ABSTRACT FROM AUTHOR]

The development of magnetoactive scaffolds based on piezoelectric polymers is of great interest due to their ability to exert a magnetoelectric effect, their flexibility, and biocompatibility in various prospective applications. This study describes fabrication of novel electrospun magnetoactive scaffolds based on poly(vinylidene fluoride- co -trifluoroethylene) [P(VDF-TrFE)] loaded with a high content (20 or 25 wt%) of magnetite nanoparticles modified by citric acid (Fe 3 O 4 -CA) and data on their structure and physicochemical, mechanical, and magnetic properties as well as a piezoelectric response. The suspension method gave a uniform nanoparticles' distribution in the electrospun scaffolds without any noticeable agglomeration. Raman and infrared spectroscopy and X-ray diffraction analysis indicated that the fabricated pure scaffolds and composite P(VDF-TrFE)/Fe 3 O 4 -CA scaffolds contain both piezoactive phases (β and γ). The composite scaffolds doped with 20 or 25 wt% of Fe 3 O 4 -CA nanoparticles were found to have the highest saturation magnetization, 12.7 and 14.1 emu/g, respectively, superior to that of other PVDF-Fe 3 O 4 –based magnetoactive scaffolds. Besides, the incorporation of 20 or 25 wt% of Fe 3 O 4 -CA nanoparticles substantially decreased total crystallinity of the piezopolymer scaffolds from 60.7% to 46.9% and 42.7%, respectively. Addition of 20 wt% of Fe 3 O 4 -CA nanoparticles also diminished ultimate strength and Young's modulus but improved elongation at break. Meanwhile, in composite P(VDF-TrFE)/Fe 3 O 4 -CA scaffolds loaded with 20 wt% of the magnetic filler, the piezoresponse was similar to that of pure P(VDF-TrFE) scaffolds. Such changes in properties are explained by the interaction between P(VDF-TrFE) polymer chains and the surface of Fe 3 O 4 -CA nanoparticles via hydrogen bonds and dipolar bonds. [Display omitted] • P(VDF-TrFE)/Fe 3 O 4 -CA scaffolds heavily loaded with Fe 3 O 4 -CA nanoparticles were fabricated by electrospinning. • The composite P(VDF-TrFE)/Fe 3 O 4 -CA magnetoactive scaffolds revealed the highest saturation magnetization (14.1 emu/g). • Piezoresponse of P(VDF-TrFE)/Fe 3 O 4 -CA was close to pure P(VDF-TrFE) scaffolds. [ABSTRACT FROM AUTHOR]

As a piezo-polymer, the most contribution of polar phases (β-, γ-phases) to the piezoelectricity of polyvinylidene fluoride (PVDF) has been researched. Herein, a new type PVDF/tetrabutylammonium hexafluorophosphate (TBAHP) tree-like nanofiber membrane (TLNM) with high polar phase content and numerous fine branch fibers was successfully developed via electrospinning. PVDF-TLNMs exhibited mass branch fibers whose diameters of less than 50 nm. The β-phase content of 88.94 % disclosed piezoelectric polarization ability in the presence of TBAHP and tree-like structure. The best output current and voltage of flexible PVDF-TLNMs based piezoelectric nanogenerators (PENGs) could reach 2.04 μA and 4.08 V at 0.07 mol L−1 TBAHP, which increased the current of pure PVDF by approximately six times and a 217 % improvement to voltage output. Likewise, the peak power density of 0.07 mol L−1 PVDF-TLNM was 13 times above that of pure PVDF-NM. The significant reduction of internal resistance occurred after the addition of TBAHP. Such significant enhancements for electrical output depended on the high β-phase content, originated through TBAHP induced self-alignment of electric dipoles in PVDF polymer and high extent of mechanical drawing. The new kind of PVDF-TLNMs-base PENGs can provide a large scope for the ideas of smart wearable devices. [Display omitted] • A tree-like piezoelectric membrane was fabricated via electrospinning. • The tree-like piezoelectric nanogenerator possessed β-phase content of 88.94 %. • The nanogenerator showed great piezoelectricity enhancement for pure PVDF. • Enhanced performance originated from branch fibers and interfacial interaction. [ABSTRACT FROM AUTHOR]

This paper addresses the pressing concern of environmental deterioration by investigating innovative solutions for tackling water pollution in aquatic ecosystems. Various hazardous pollutants, such as dyes, pharmaceuticals, heavy metals, and pesticides, pose significant threats to both the environment and human health. To combat these issues, in this work we explored the synthesis of composite nanofibers using copper sulfide (CuS) nanoparticles and cellulose acetate (AC) polymer matrix through a gas-liquid sulfurization process. The resulting nanocomposites were used to fabricate nanofibers by the electrospinning technique. The morphological analyses revealed a transition from ribbon-like structures to cylindrical forms as nanoparticle concentration was increased. Chemical analysis confirmed the presence of CuS nanoparticles within the composite nanofibers. XRD studies indicated a covellite crystal structure of the CuS nanoparticles. TGA analysis revealed a coordination complex formation between nanoparticles and dimethylformamide. Optical properties showed variations in band gap energies, from 1.76 to 1.9 eV, as nanoparticle concentration changed. Photocatalysis studies demonstrated that the composite nanofibers exhibited enhanced adsorption and degradation of methylene blue dye under solar irradiation. Overall, this study contributes to understanding the potential application of CuS/AC composite nanofibers for environmental remediation. [Display omitted] • Composite of copper sulfide (CuS) and cellulose acetate (AC) nanofibers (CuS/AC). • The composite exhibited absorption and photocatalytic properties in MB degradation. • Nanofibers and nanoparticles composites are crucial in remediation applications. [ABSTRACT FROM AUTHOR]

The usage of plastic bottles in large quantities will cause serious pollution to the environment due to its poor biodegradability. The recycling of plastic waste with high added value for expanded applications needs to be explored and the poor mechanical properties should be resolved at the meantime. Herein, plastic waste was recycled into flexible nanofiber electrode based on electrospinning associated with acidified carbon nanotubes loaded inside/outside and electrodeposition of nano-MnO 2 film outside. The fabricated plastic waste-based composites could be directly used as a supportable electrode with high conductivity, multistage aperture structure and efficient pseudo-capacitance. And the further assembled symmetric supercapacitors exhibited excellent flexibility, high energy capacity as the specific capacitance of 118.8 mF/cm2 at a scan rate of 10 mV/s and desirable cycle stability as 97.6 % capacitance retention over 5000 charge/discharge cycles. The strategies presented herein help alleviate the white pollution problem and realize the recycling and utilization of waste plastic products with high added value, which is a cost-effective and sustainable option to promote circular economy. [Display omitted] • Plastic waste could be recycled and utilized with high added value. • Flexible nanofiber based on plastic waste was prepared by electrospinning. • High conducting Activated C-multiwalled C nanotubes were dispersed on nanofibers. • Dense layer of MnO 2 loaded on the nanofibers provide extra pseudo-capacitance. • Flexible supercapacitor was assembled based on PT-C@MnO 2 electrode. [ABSTRACT FROM AUTHOR]

Waterproof breathable membranes (WBMs) have attracted intense research interest due to their wide applications, however, there are still great challenges in effectively preparing WBMs with desirable waterproofness, breathability and elasticity. Here, a facile and scalable fabricating strategy combining electrospinning and electrospraying is proposed to manufacture nanofiber WBMs, which are comprised of both hydrophobic thermoplastic polyurethane (TPU) nanofibers and inter-fiber polyvinyl butyral (PVB) bonding containing a short perfluoroalkyl hydrophobic agent. The obtained composite nanofiber membranes showed durable water/oil repellent properties against ultrasonic washing and abrasion. The interconnected fibrous structure together with liquid repellent surface have endowed the WBMs with comprehensive properties with hydrostatic pressure of 73.7 kPa, water vapor transmission rate of 6.88 kg m−2 d−1, outstanding tensile strength of 25.72 MPa and large elongation at break of 217%, which have exceeded the majority of their nanofiber counterparts. This work could provide a novel approach for the preparation of waterproof and breathable membranes with balanced structural stability, waterproofness and wearing comfort, especially suitable for the personal protective material application. [Display omitted] • Waterproof nanofiber membranes are fabricated by a one-step electrospinning/electrospraying process. • Electrospraying of PVB forms inter-fiber bonding between TPU nanofibers. • The inter-fiber bonding structure contributes to improved mechanical strength and large hydrostatic pressure. • The nanofiber WBMs demonstrate high washing and abrasion durability. [ABSTRACT FROM AUTHOR]

In this study, we proposed a flexible piezoelectric sensor made of gradient multilayer polyacrylonitrile (PAN) MXene/Molybdenum disulfide (MoS 2) nanocomposites prepared by layer-by-layer electrospinning technology. Each layer of the composite film was formed by adding different mass ratios of MXene and MoS 2 (MXene: MoS 2 = 4:1, 2:1, 1:1) as filler materials, with a constant content of MXene (2% of the PAN matrix), and the concentration of MoS 2 increases progressively from the inner layer to the outer layer. In addition, a heterojunction structure was formed using MXene and MoS 2 , which formed hydrogen bonds with –CN on PAN, thereby enhancing their interaction. By employing this novel concept of gradient multilayer and 2D/2D heterostructure, the interface coupling effect could be effectively promoted, and more 31−helical conformations could be transformed into planar zigzag conformations, significantly improving the dielectric, ferroelectric, and piezoelectric properties of the multilayer composite fiber films, thereby enhancing its output performance. With the gradient multilayer structure, the piezoelectric sensor exhibited excellent voltage sensitivity (14.9 V/N). The piezoelectric sensor detected body movement during basketball shooting and offered excellent breathability for enhanced comfort. It shows promise for use in health monitoring, electronic skin, and human-computer interaction. [Display omitted] • PAN gradient multilayer fiber films prepared by layer-by-layer electrospinning. • The 2D/2D heterostructures formed by MXene and MoS 2 enhance the properties. • By varying MoS 2 content, forming a gradient multilayer structure, and enhancing interfacial coupling. • The film is applied as a wearable sensor, making the wearer comfortable. • Heterostructure and gradient multilayer interact with each other simultaneously. [ABSTRACT FROM AUTHOR]

In the present study, a fluorescent optosensor containing a molecularly imprinted polymer in combination with electrospinning was employed for selective recognition of 2,4-dichlorophenoxyacetic acid (2,4-D). Free radical polymerization was carried out on the surface of polyethersulfone (PES) nanofibers as a substrate using a monomer, initiator, template and a polymerizable 1,8-naphthalimide derivative as the fluorogenic monomer. PES nanofiber@fluorescent molecularly imprinted polymer (PES nanofiber@FMIP) was produced by means of UV curing. The magnetic PES nanofiber@FMIP was developed in the same manner as the magnetic Fe 3 O 4 nanoparticles were exerted in the electrospinning of the PES nanofiber. The imprinting factor (IF) was considered 1.97 as a selective character of PES nanofiber@FMIP versus PES nanofiber@FNIP. The developed sensor was able to selectively determine 2,4-D in a linear range of 1 × 10−7-1 × 10−3 M with limit of detection (LOD) of 1.01 × 10−8 M. The results confirmed that PES nanofiber@FMIP was satisfactorily able to determine trace concentrations of 2,4-D. Image 1 • Novel MIP based fluorescent optosensor was prepared on the PES nanofiber surface. • The rapid UV curable fluorescence MIP was prepared via free radical polymerization. • Magnetic PES nanofiber@FMIP was prepared on the surface of magnetic PES nanofibers. • The optosensor has linear range of 1 × 10−7-10−3 M and limit of detection 1.01 × 10−8 M. • Adsorption of 2,4-D on nanofiber@FMIP and nanofiber@FNIP obey Freundlich isotherm. [ABSTRACT FROM AUTHOR]

Abstract The rapid development of TE generators for harvesting energy from the human body has made new demand on its TE performance and wearability. In this context, electrospinning and in situ synthesis process are employed to fabricate Ag NPs coated PEDOT:PSS/PVA flexible self-supporting nanofiber film. The introduction of Ag NPs not only creates a great quantity of organic–inorganic interfaces which make an increase both in charge transfer channels and phonon scattering, but also greatly improve the mechanical properties of nanofiber film. As a result, the electrical conductivity has been greatly improved without losing too much Seebeck coefficient of the composite film, a maximum power factor up to 1.2 μW m−1 K−2 at room temperature is achieved. A flexible TE generator consisting of 5 strips is designed using the as-prepared composite film and can produce an output voltage of 3.43 mV at a 30.1 K temperature difference. Graphical abstract Image 1 Highlights • Flexible self-supporting TE nanofiber film was prepared by electrospinning and post-treatment. • The σ of the nanofiber film can be increased from 0.67 to 41.5 S cm-1 without losing too many S and maintaining low κ.. • The introduction of Ag NPs enhances the tensile strength and the Young's modulus to 13.5 MPa and 746.82 MPa respectively. • A TE generator was successfully fabricated used the as-prepared TE nanofiber films. [ABSTRACT FROM AUTHOR]

Abstract In order to improve the removal ability of chitosan (CS) to heavy metal ions, in this study, rich amino-functionalized CS electrospun membranes have been prepared. During the efficient synthesis, poly (glycidyl methacrylate) (PGMA) and polyethylenimine (PEI) were sequentially grafted on the surface of CS electrospun membrane. The success of introduction of amino-group on the CS were confirmed by X-ray diffractometer (XRD), attenuated total reflection-fourier transform infrared (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The ability of remove heavy metal ions (Cr(VI), Cu(II) and Co(II)) of the as-prepared membrane (CS-PGMA-PEI) was investigated. The adsorption equilibrium of the heavy metal ion solutions was rapidly established in 60 min. Adsorption kinetics analysis reveals that the adsorption process of CS-PGMA-PEI electrospun membrane was dominated by a Pseudo-second-order model. Its adsorption isotherm can be described by the Langmuir model. The maximum adsorption capacities calculated by Langmuir model were 138.96, 69.27 and 68.31 mg g −1 for Cr(VI), Cu(II) and Co(II), respectively. The adsorption ability of CS-PGMA-PEI electrospun membrane toward metal ions was found in an order of Cr(VI) > Cu(II) > Co(II). CS-PGMA-PEI membrane also exhibited a good reproducibility and stability. Our study may provide a way to synthesize membranes for water purification. Graphical abstract The PEI-grafted CS (named as CS-PGMA-PEI) electrospun membrane was demonstrated by the following steps: (1). In order to expose the amino groups on the surface of the chitosan, the CS/PEO electrospun membrane was immersed in water to remove the PEO; (2). Poly (glycidyl methacrylate) (PGMA) and polyethylenimine (PEI) were sequentially grafted onto the CS electrospun membrane by a ring-opening reaction of epoxy groups with amino groups to obtain PEI-immobilized CS membrane; (3). A series of batch adsorption experiments were carried out to determine the adsorption performance. Image 1 Highlights • The PEI-grafted chitosan electrospun membrane has been prepared. • The adsorption ability of CS-PGMA-PEI electrospun membrane is in an order of Cr(VI) > Cu(II) > Co(II). • The CS-PGMA-PEI electrospun membrane exhibited good regenerability and stability for heavy-metal removal. [ABSTRACT FROM AUTHOR]

Abstract In this work, we successfully prepared multifunctional boron nitride nanosheets (BNNS)/polyvinyl alcohol (PVA) nanofiber membranes. Using sulfanilic acid (SA) as a medium, hexagonal boron nitride (h-BN) were exfoliated into SA-functionalized BNNS through dry ball-milling process followed with liquid-phase exfoliation based on Lewis acid-base interaction. The f-BNNS/PVA composite nanofiber membranes with different loading amounts of f-BNNS were prepared through electrospinning. The results demonstrated the electrospun f-BNNS/PVA composite nanofiber membranes show high mechanical properties and thermal conductivities. The yield and ultimate tensile strengths of f-BNNS/PVA composite nanofiber membrane at 5 wt% loading amount can reach ∼8.56 and ∼11.37 MPa. Meantime, the thermal conductivity of f-BNNS/PVA composite nanofiber membrane with 10 wt% loading amounts of f-BNNS is ∼0.7328 W/(m•K), almost 6.47 times higher than that of neat PVA membrane. Besides, the f-BNNS/PVA composite nanofiber membrane can also be used as a filtration membrane for fast malachite green (MG) absorption and separation of MG and rhodamine B dyes. Graphical abstract Image 1 Highlights • Sulfanilic acid facilitates the exfoliation and functionalization of boron nitride nanosheets. • Electrospun functionalized boron nitride nanosheet/PVA nanofiber membranes were prepared. • The membrane processes high mechanical property and thermal conductivity. • The membrane can be used for fast separating the mixed dye of malachite green and rhodamine B. [ABSTRACT FROM AUTHOR]

Abstract Formation of single fibres of polymer nanocomposite PVDF-HFP containing MWCNT by Pyro-EHD electrospinning is reported for the first time. Pyro-EHD gives the chance to drawing fibres directly from a viscous polymeric solution containing MWCNT, with respect to classical electrospinning in which highly viscous materials have strong limitation due to the clogging effect. This method allows achieving an electrical conductivity of the fibres considerably higher with respect to the bulk state. The improvement of the electrical conductivity is of one order of magnitude and the electrical percolation threshold is reduced from 2.5 to 0.3 wt%. We also show that the MWCNT are highly oriented in the longitudinal direction of the fibres, producing the improvement in the electrical properties of the composite. Graphical abstract Image Highlights • Pyro-electrospinning is used to produce nanocomposite microfibres. • Fibres electrical percolation threshold is lowered respect to films. • Carbon nanotubes are highly oriented in the longitudinal direction of the fibres. [ABSTRACT FROM AUTHOR]

Abstract Polyvinyl alcohol nanocomposite containing immobilized [Mn(Br 4 TPP)OAc] complex on bio inspired copper oxide was prepared by an electrospinning method (PVA@CuO-MnP). This novel heterogeneous biocatalyst based on Carthamus tinctorius plant was characterized by TEM, SEM, AFM, EDAX, elemental analysis and FTIR spectroscopy. Thermostability and amount of supported porphyrin complex on copper oxide loading on PVA was determined by thermogravimetric. This electrospun PVA@CuO-MnP nanofiber were estimated that the CuO-MnP had with average size of 70 nm distributing on PVA with the size between 65 and 80 nm. We first succeeded the new possibility of nanofiber applications in atom-efficient synthesis of bis (1 H -indol-3-yl)methanes in excellent yields under solvent-free conditions. A structurally diverse set of aldehydes and 1H-indole or 2-methylindole was transformed into desired products regardless of the substituents electronic nature. The products were isolated easily from green media, and the catalyst could be reused several times without any appreciable decrease in catalytic activity. Graphical abstract Image 1 Highlights • Bio-copper oxide was synthesized using Carthamus tinctorius plant. • A novel electrospun immobilized manganese complex on copper oxide based polyvinyl alcohol nanofiber was synthesized. • First electrospun catalyst nanofiber for synthesis Bis (1 H -indol-3-yl)methanes was reported. [ABSTRACT FROM AUTHOR]

Abstract In this work, electrospun membranes of biodegradable polylactic acid and hydrosoluble collagen with multilevel architectures were fabricated by pattern template electrospunning method. The performances influenced by constituent of electrospun matrix and multilevel structures of electrospinning membranes were discussed. The mechanical properties and hydrophilicity were improved both by blending nature collagen and inducing the multilevel structures. The multilevel-architecture membranes were seeded by L929 fibroblast cells with phenotypic shape and guided growth according to pattern orientation. Cells infiltration through the fibers, cell attachment, and proliferation with fiber membranes were observed during the process. More interestingly, for further investigation of promotion the cell infiltration by multilevel structures, the electrospinning membranes were processed into tubular scaffold with 3D print scaffold. The in vivo result confirmed the scaffold favourable biocompatibility and improved tissue regeneration behaviors in vivo. The novel biodegradable membranes and scaffolds will be applicable for tissue engineering based upon their particularly multilevel architectures, which acts to support and guide cell growth in regular way. Graphical abstract Image 1 Highlights • Multilevel architectural mats were fabricated by pattern electrospinning method. • The stereocomplexzation of PLA promoted to form uniform morphology of fibers. • The mechanical properties and hydrophily were improved both by blending collagen and inducing multilevel structures. • Cells penetration through the fibers, cell attachment, and proliferation with fiber mats were observed. [ABSTRACT FROM AUTHOR]

Traditional textiles are conductive to breed germs that might cause infection or unpleasant odor, especially in public hygiene products. Moreover, biosafety, environmental protection and cost are crucial considerations for antimicrobial materials. Herein, we developed a biocompatible microcapsules/nanofibrous membrane using eco-friendly and facile strategy. The microcapsules loaded with the Epigallocatechin and gallate (EGCG) were synthesized through an ion-crosslinking reaction between chitosan (CS) and sodium tripolyphosphate (TPP). Additionally, the addition of octadecyl trimethyl ammonium chloride (STAC) could further enhance the antibacterial activity. Following that, the microcapsules were combined with the polycaprolactone (PCL) nanofibers. The resultant composite nanofibrous membrane exhibits a slow release effect, an enjoyable deodorant activity, and strengthened antibacterial activity through contact-killing and biocide-releasing. Besides, the membrane behaved a low degradation rate, without compromising its mechanical and hydrophilic properties after a 20-day degradation. These findings provided a biocompatible and practical approach for antimicrobial and odor-proof material for hygienic and sanitary products. [Display omitted] • Introduce quaternary ammonium salt-modified chitosan microcapsules to obtain enhanced antibacterial activity. • The electrospun nanofibers can offer a further encapsulation of catechins. • A synergistic antibacterial effect of the contact biocide and the release of antibacterial agents. • An eco-friendly, biosafety, and low cost strategy for antibacterial and deodorant hygienic products. [ABSTRACT FROM AUTHOR]

Modern-day requirements for efficient, eco-friendly, and self-powered devices have resulted in a growing interest in piezoelectric polymers among the scientific community. Polyvinylidene fluoride (PVDF) is an excellent electroactive polymer that is flexible, with high mechanical strength, thermal stability, and biocompatibility. The relatively low cost and easiness to be fabricated into thin pliable films made PVDF one of the most studied polymers for the development of nanogenerators and wearable sensors. The piezoelectric properties and therefore the energy harvesting and sensing capabilities of PVDF are distinct characteristics of its electroactive polar phases, especially the β phase. Hence, several PVDF-based nanocomposites that could achieve a high β phase fraction have been widely explored. Electrospinning is one of the best methods for manufacturing such PVDF-based nanocomposite films. This article, therefore, highlights essential information about different electrospinning parameters which help to enhance the β phase in PVDF. The review then progresses into the recent developments and technological advances of electrospun PVDF-based nanocomposite devices in energy harvesting and sensing applications. The piezo-, pyro-, and triboelectric properties of PVDF allow the fabrication of conventional and hybrid nanogenerators. The later can harvest energy simultaneously from multiple sources, sense various fluctuations in their surroundings, and transmit the acquired data immediately when integrated with Bluetooth or wireless devices. They are fine models of self-powered, portable, multifunctional, and sustainable engineering. Finally, a peek into the other possible applications of electrospun PVDF-nanocomposite fibers is also made. Overall, the review aims to illustrate the innovative research and developments of PVDF fiber-based devices and the relevance and prospects they hold as future green sources of energy. [Display omitted] [ABSTRACT FROM AUTHOR]

Epoxy/polycaprolactone (PCL) blends containing cationic photo-initiator were prepared by both solution and melt blending. These materials were processed by solvent casting, solution electrospinning (SE), melt electrowriting (MEW), and Fused Deposition Modeling (FDM) 3D printing. The final materials were obtained after UV curing at room temperature. FTIR, and gel content measurements showed that all the materials were crosslinked and that the PCL was part of the network. The shape memory abilities (measured by DMA experiments) depended on the processing technique. Thus, the fixity and recovery ratios were optimal for electrospun fibers, while the 3D printed sample was not able to recover any shape, probably because of the poor adhesion between the printed layers. According to AFM images, samples obtained by MEW and 3D printing produced materials with spherulitic morphology, while solution electrospinning rendered fibers with Shish-Kebab-type crystalline morphology. The latter was highly anisotropic, and many chains were oriented along the nanofiber axis interdispersed with amorphous regions where the epoxy resin formed covalent links with the PCL chains. This morphology conferred extraordinary solvent resistance and shape memory properties to the electrospun mats. The latter manifested a very high affinity towards chloroform, and accordingly, they displayed potential applications as chloroform sensors. [Display omitted] • Cationically photo-polymerized Epoxy/Polycaprolactone blends processed by solution electrospinning, melt electrowriting, and 3D printing • Solution electrospinning fibers presented Shish-Kebab morphology with many chains oriented along the nanofiber axis • Nanofibers presented better fixity and recovery ratio in addition to improved solvent resistance. [ABSTRACT FROM AUTHOR]

Abstract The hydrophobic nature of the substances has served as important tools for governing the spatial behaviors of various fibrous substances depending on their affinities to oils or organic liquids. Herein, electrospun two-dimensional (2D) polyacrylonitrile (PAN) fiber mat was converted into three-dimensional (3D) mesh by hydrogen gas foaming technique using aqueous sodium borohydride (NaBH 4) solution, which on heating at high temperature under a nitrogen atmosphere produced ultra-light, low density, hydrophobic 3D carbon scaffold with distinct affinities to oil phases. The fibrous materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectra. Specific surface area and porosity of the fiber were analyzed by the Brunauer-Emmett-Teller (BET) technique. The carbon scaffold exhibit dominance as absorbents for selectively separating oils such as diesel, canola oil, xylene, and n-hexane with absorption capacity from 68.71 g g−1 to 131.33 g g−1. More interestingly, the absorbed oils were readily collected by simple mechanical squeezing and the recovered 3D carbon scaffold could be reused for the successive absorptions. This carbon scaffold could be a versatile platform to offer a kind of efficient and selective absorbent material for absorption of oils or organic liquids from the water. Graphical abstract Image Highlights • Electrospinning technique was employed to fabricate 2D PAN fiber mat. • 3D PAN fiber mesh was obtained from the 2D mat by neutral gas foaming technique. • The pyrolysis of 3D fiber mesh was performed to get hydrophobic 3D PAN-based carbonized fiber. • 3D carbon fiber scaffold was exploited for the successful sorption of oils from oil/water emulsion. [ABSTRACT FROM AUTHOR]

Abstract This paper reports the effects of hydrogen bonding on the starch granule dissolution, spinnability of the starch solution, and the properties of the electrospun starch fibers. Dissolution behaviors of the starch granules in dimethyl sulfoxide (DMSO) and water mixed solvents are characterized by confocal laser microscope, differential scanning calorimetry (DSC), and rheologic measurement. The starch granules are dissolved in the 100%DMSO or 6%H 2 O/94%DMSO solvent, resulting in good electrospinnability. On the other hand, the gelatinization behavior is observed for the starch granules in the 22%H 2 O/78%DMSO solvent, resulting in poor fiber formation during electrospinning. Infrared spectroscopy, DSC, x-ray diffraction, and mechanical property characterizations of the electrospun starch nanofibers suggest that the water content in the solvent plays an important role in the properties of the nanofibers. The dissolution behavior, electrospinnability, and the properties of the electrospun nanofibers are explained by the effects of the DMSO and H 2 O molecules on the ubiquitous hydrogen bonds in starch. Highlights • Ratio of dimethyl sulfoxide and water in the mixed solvent affects dissolution of starch. • High water content results in gelatinization and poor electrospinnability of the starch solution. • Aprotic dimethyl sulfoxide dissociates hydrogen bonds of starch, resulting in uniform nanofiber. • Water in solvent affects formation of hydrogen bonds and properties of the electrospun nanofibers. [ABSTRACT FROM AUTHOR]

Abstract Stereocomplex polylactide (sc-PLA) nanofibers with the average diameter of 367 nm were prepared by the conductivity-controlled electrospinning using 7 wt% PLA solution in the mixed solvents of dichloromethane and pyridine. The sc-PLA nanofibers were used as reinforcement materials for poly(l -lactide) (PLLA) to fabricate a self-reinforced PLA composite, while the fibers were compounded into the PLLA by compression molding. Thermomechanical and optical properties of the resulting self-reinforced PLA composites were investigated. It was found that highly transparent (above 75%) self-reinforced PLA composites were obtained up to the sc-PLA fiber concentration of 15 wt%. Also, at higher temperature in the rubbery state, the storage moduli of the composites increased by adding sc-PLA nanofibers. At the fiber concentration of 15 wt%, the storage modulus of the composite became 70 MPa, which was 24.1 times higher than that of the original pure PLLA. It was therefore concluded that the self-reinforced PLA composite with high transparency and high thermomechanical properties was successfully obtained. Graphical abstract Image 1 Highlights • Stereocomplex polylactide (sc-PLA) nanofibers were fabricated by electrospinning. • sc-PLA nanofibers were compounded into PLLA to get self-reinforced PLA composite. • Composite film still kept its high transparency at 15 wt% of sc-PLA nanofibers. • Storage modulus was significantly increased by compounding sc-PLA nanofibers. [ABSTRACT FROM AUTHOR]

Abstract Electrospun nanofiber is regarded as a promising candidate for many high-end applications due to its advantageous unique structure. Ultrafine fiber and good mechanical property are essential to ensure its performance. In this work, tunable ultrafine diameter and significantly enhanced mechanical strength of electrospun Styrene-butadiene-styrene tri-block copolymer (SBS) membrane are attained by means of the addition of LiBr into SBS solution dissolved in tetrahydrofuran/dimethylformamide (THF/DMF). Solution conductivity is found to grow in two steps with the increasing lithium bromide (LiBr) concentration and a critical point is observed at the ultralow concentration of 0.005 wt%, sharp increase below it but modest increase above it. Interestingly, the diameter of electrospun fiber shows a significant reduction with increase of LiBr concentration below this critical point but minor fluctuation above this. Welded structure is observed between adjacent fibers and the degree of welding goes deeper with increase of salt concentration. Accordingly, the mechanical strength of electrospun membrane is gradually enhanced and reaches to the highest value of 5.7 MPa at the critical concentration, with enhancement of 134% in comparison with pure electrospun SBS membrane, and then declines when further adding LiBr. TEM observation confirms more oriented and distinct self-assembly domains in the finer fibers, which contribute greatly to the property enhancement for electrospun SBS membrane obtained below critical concentration. The finding of critical concentration is important for the preparation of high performance electrospun membrane by adding salt in the spinning solution. Graphical abstract Image Highlights • The relationship of electrospun fiber diameter and salt concentration was depicted in a wide range. • A critical salt concentration of decreasing fiber diameter was revealed. • Mechanical strength of SBS electrospun membrane was enhanced most at the critical concentration. [ABSTRACT FROM AUTHOR]

Abstract Electrospinning is a valuable production method for nanoscale polymeric fibers. A major limitation of the technology is the requirement for high molecular weight polymers as a major part of the matrix. Many applications would benefit from flexibility in the materials for electrospinning, including pharmaceuticals, wearable devices and diagnostics, and structured fibers with particles included that are larger than the fiber size. To realize these more advanced functional composites, a strong understanding of how particle inclusion affects the electrospinning process and mat properties is essential. In this work, we examine materials systems containing polymers and microparticles, focusing on how inclusion of particles affects the electrospinnability and morphology of the fiber. The primary factors that influence electrospinnability and morphology are the particle density, particle aggregation, and size ratio of the fibers to the particles. These results provide a platform for product design for new electrospun materials with high loadings of functional particles. Graphical abstract Image 1 Highlights • 10 μm particles can be electrospun when suspended in polymer solutions, with loadings of up to 66 wt% particles in fibers. • The factors that influence electrospinnability and morphology are the particle density, aggregation, and fiber:particle size. • This study provides a platform for product design for new electrospun materials with high loadings of functional particles. [ABSTRACT FROM AUTHOR]

Abstract Unique coplanar β -conformation of polyfluorene, endowed with long effective conjugated length, is promising to form ordered and oriented structures that can result in improved carrier mobility, polarization emission and excellent spectral stability. Herein, a series of polydiarylfluorenes of different side-chains (PHDPF, PODPF or PNDPF) and poly (9-vinylcarbazole) composite nanofibers were prepared via electrospinning approach. It is observed that β -phase can be obtained in PODPF electrospun nanofibers whereas absent in those of PHDPF and PNDPF systems. It can be demonstrated that the optimal chain length for polydiarylfluorenes to β -conformation is an octyl side chain in electrospinning. In contrast with the electrospun nanofibers, there was no β -phase in the corresponding spin-coated film. For the β -phase electrospun nanofibers, the fluorescence quenching sensitivity on 2, 4-dinitrotoluene (DNT) vapor was obviously higher than that of amorphous electrospun nanofibers and spin-coated film, respectively. Synergistic molecular design and electrospun processing may offer a fascinating strategy for the control of polymer conformation to the adjustment of nano and micro optical devices such as organic fluorescence sensors, lasers and light-emitting diodes. Graphical abstract Image 1 Highlights • β-phase can be obtained in PODPF/PVK electrospun nanofibers whereas absent in PODPF/PVK spin-coated film. • The sensing sensitivity of β-phase nanofibers was higher than that of amorphous electrospun nanofibers and spin-coated film. • The optimal chain length to β-conformation in the polydiarylfluorene electrospun nanofibers is an octyl side chain. • Synergetic molecular design and electrospinning offer a strategy for polymer conformation control to optical devices. [ABSTRACT FROM AUTHOR]

To develop tissue engineering scaffolds that possess similar morphological structures to natural extracellular matrices (ECMs) is a major technological challenge. Herein, the feasibility of utilizing polycaprolactone (PCL) as biocompatible and biodegradable binding agent to fabricate electrospun three-dimensional (3D) scaffolds has been demonstrated. The obtained 3D scaffolds are soft while elastic, and they possess interconnected and hierarchically structured pores with sizes in the range from sub-microns to hundreds of microns; hence, they are morphologically similar to natural ECMs thus well suited for cell functions and tissue formation. It is envisioned that various thermoplastic polymers could be fabricated into 3D nanofibrous scaffolds/structures by first making blend nanofibers with PCL followed by processing via the thermally induced (nanofiber) self-agglomeration (TISA) method and finally being thermally stabilized, and the resulting electrospun 3D nanofibrous scaffolds/structures might to be useful for a variety of applications (particularly those related to tissue engineering). [ABSTRACT FROM AUTHOR]

In this work, electrospun mats made from miscible poly(ε-caprolactone) (PCL)/poly(ester amide) (PEA) blends were prepared, for the first time. The well-known immiscibility issues between these two type of polymers were overcome through the synthesis of a novel tailor-made compatibilizer blocky PEA, comprising well defined PCL and PEA8L6 blocks (PCL-PEA8L6). The PCL-PEA8L6 was synthesized for the first time in this work and was characterized in terms of its chemical structure and thermal properties. Regarding the mats, it was found that their properties (morphology, porosity, wettability, thermomechanical) can be easily adjusted by the ratio of the components of the mixture to be electrospun. Increasing amounts of PEA led to more hydrophilic mats, with enhanced in vitro degradability, both hydrolytic and enzymatic. The in vitro cytotoxicity tests carried out with normal human dermal fibroblasts (NHDF) revealed that the samples do not elicit any acute adverse effect on the cells. Moreover, the NHDF were able to grow and proliferate in the surface of the electrospun mats. The data presented in this contribution is a proof-of-concept that can be used to address immiscibility issues between different types of polymers broadly used in biomedical applications. [ABSTRACT FROM AUTHOR]

Bio iron oxide was synthesized from natural Sesbania sesban plant and modified by a molybdenum complex (Fe 2 O 3 /MoSB). Fe 2 O 3 /MoSB was deposited on polyvinyl alcohol (PVA) using a conventional single nozzle electrospinning technique (PVA/Fe 2 O 3 /MoSB). TEM, SEM, AFM, FT-IR, TGA, EDAX, and elemental analysis were used to determine fiber compositional information. The catalytic efficiency of electrospun PVA/Fe 2 O 3 /MoSB nanofiber in the oxidation of alcohols was exploited. The green reactions were conducted at solvent free conditions as a green media in the presence of H 2 O 2 to have the desired aldehydes and tert-butyl hydrogen peroxide to obtain acid products in high yields and excellent selectivity. The survival of this nanocomposite was investigated and it could be reused and recycled in consecutive runs. [ABSTRACT FROM AUTHOR]

In this study, electrospun nanofiber was continuously sandwiched between two rubber rollers at high temperature (150 °C). The prepared nanofiber support layer possessed a pore size of 0.4 μm (with narrow distribution) and a fiber diameter of 292 ± 94 nm. Afterward, an interfacial polymerization was employed to deposit the selective polyamide layer on the nanofiber support layer. For the first time, engineered osmosis (EO) was used as a platform for verifying the presence of a polyamide selective layer on a nanofiber support layer. We found that the membrane prepared exhibited an excellent combination of permeability (30 L/m 2 h) and selectivity (17 g/m 2 h and 0.57 g/L) under a net pressure of 49 bar at the EO platform. The membrane developed can be applied to generate renewable energy using the EO process. In addition, the EO method can be used to detect selective polymer having a nano-scale thickness. [ABSTRACT FROM AUTHOR]

In this study, a one-step electrospinning method was developed for the fabrication of polyamide nanofibrous mats with controllable structure and enhanced wetting behavior. The effects of the concentration of Triton X-100 as the surfactant, as well as formic acid and dichloromethane solvents on characteristics of electrospun nanofibrous mats were investigated. The fibers' diameter and pore size distribution of mats were deliberated by scanning electron microscopy. Furthermore, to characterize the wettability of fibers, the roughness of their surface was evaluated by atomic force microscopy along with measuring the droplets contact angle on the mats surface. The results revealed that adding the surfactant not only improved the electrospinning of nanofibers, but also increased the mat hydrophilicity. Furthermore, changing the polymer solvent altered the mat roughness and consequently its wettability. In general, adjusting the nanofibers' roughness and diameter, mat pore size distribution, and water contact angle could increase the water permeability through the mat. [ABSTRACT FROM AUTHOR]

Tissue engineering strategies are constantly in search of novel scaffold materials that can accelerate cell adhesion, growth and proliferation. In this context, poly(vinyl formal) (PVF), a biodegradable and water absorbing polymer derived from poly(vinyl alcohol) was explored as a potential scaffold material for neural regeneration. No prior attempts have been made to fabricate electrospun fibrous scaffolds from PVF for tissue engineering applications and this forms the focus of the present study. The electrospinning conditions were optimized to obtain defect-free PVF microfibres with an average diameter of 4.4 ± 0.7 μm. The microfibres exhibited a uniform nanoporous surface and a solid core that augmented neuronal cell adhesion and neurite extension. The fibres were brittle and exhibited a 50% degradation in physiological pH and temperature. The viability of hippocampal neuronal cells cultured on the scaffold showed a progressive increase with time revealing its promise as a scaffold material for neural tissue engineering. [ABSTRACT FROM AUTHOR]

This paper describes a new system for NIR light-triggered, localized release of drugs. The system consists of biocompatible/degradable poly(ε-caprolactone) (PCL)-based fibers having a core loaded with doxorubicin (DOX) and a sheath incorporated with indocyanine green (ICG) as a NIR-absorbing agent together with a biocompatible/degradable, phase-changeable fatty acid. Upon NIR irradiation, the photothermal agent will generate heat to raise the local temperature of the fibers. When the temperature is above the melting point of the fatty acid, nano-pores will be generated in the fibers. This response to NIR irradiation allows the instant release of DOX from the fibers through the pores, leading to the significant enhancement of anticancer activity in combination with the hyperthermia effect arising from the photothermal agent. [ABSTRACT FROM AUTHOR]

The ability to prepare Polydiacetylenes based materials in the polyvinylidene fluoride matrix polymer is interesting due to the combination of colorimetric and electrical signaling. The new PVDF/PDA composite nanofibers were prepared via the electrospinning method. The self-assembly of diacetylene monomers (PCDAs) occurred during the electrospinning process. The assembled diacetylene monomers in the PVDF nanofibres were further polymerized to form PDA. Full factorial experimental design was applied to investigate the influence of PVDF concentration and PCDA content on the morphology of nanofibers. The colorimetric transitional of the uniform and beadless PVDF/PDA nanofibers were studied as a function of temperature. The crystal polymorphism of these structures were evaluated using Fourier transform infrared, differential scanning calorimetry, and wide angle X-Ray diffraction. The piezoelectric response of the PVDF/PDA nanofibers in the red and blue phases was also measured. The results showed that a combination of colorimetric and piezoelectric responses is available with composite nanofibers of PVDF/PDA. The polymorphism investigation demonstrated that assembled PCDAs have the effect of inhibiting the growth of non-polar α phase crystals, while promoting the growth of polar β phase. Moreover, the electrospun PVDF/PCDA nanofibers after UV-irradiation and formation of PDA exhibited greater intensity of β-phase in comparison to that before irradiation. However, the red phase of PVDF/PDA nanofibers indicated less fraction of β-phase than the blue phase. The blue-to-red color transition of PVDF/PDA composite nanofibers accompanied by the variation of piezoelectric response could open new avenues for many sensor applications. [ABSTRACT FROM AUTHOR]

Electrospun polymer fibers have attracted great attention in recent years because of their unique properties and applications in various areas such as tissue engineering and drug delivery. It remains a great challenge, however, to understand the morphology and property changes of electrospun polymer fibers induced by post-treatment, especially thermal annealing. In this work, we investigate the morphology evolution of electrospun polystyrene (PS) fibers thermally annealed on poly(vinyl alcohol) (PVA) films. Driven by the surface and interfacial tensions, the PS fibers transform to a series of regularly aligned anisotropic particles embedded in the PVA films via a Rayleigh instability-type transformation. From the in-situ observed optical microscopy (OM) images, higher growth rates of undulated amplitude can be obtained for thinner PVA films, revealing the effect of the underlying glass substrates. [ABSTRACT FROM AUTHOR]

Membranes prepared by electrospinning nonwoven mats have been receiving an increasing amount of interest recently with potential applications as water filtration membranes, drug delivery mats, and environmental sensors. Innovations in membrane processing and characteristics enabled by electrospinning could impact the industry. In this investigation, we demonstrate the effects of changing the chain length of an α , ω -bis( 2 -carboxymethyl)poly(ethylene glycol) (PEG diacid) crosslinker on the physical properties of electrospun poly(vinyl alcohol) (PVA) nanofibrous mats. Analysis of as-spun PVA mats showed average fiber diameters of 0.13 ± 0.02 μm with average pore areas of 1.67 ± 0.51 μm 2 . Average fiber diameters for mats crosslinked with a shorter PEG diacid (M n = 250) were 0.20 ± 0.04 μm with average pore areas of 0.64 ± 0.18 μm 2 . Similarly, mats crosslinked with a longer PEG diacid (M n = 600) had average fiber diameters of 0.22 ± 0.04 μm with average pore areas of 0.44 ± 0.23 μm 2 . Further studies on the durability of the mats showed dramatic improvements in the Young's modulus, the stress at break, and the strain at break that increased with the length of the crosslinker. Developing further knowledge regarding the enhancement and control of electrospun membranes can help improve the field of electrospun membranes with great potential for water purification and can reveal new opportunities for existing technologies moving forward. [ABSTRACT FROM AUTHOR]

The electrodynamics of the polymer melt as well as its effects on fiber spinnability in the framework of laser-heated melt electrospinning was investigated. We challenge the classic views in the aspects of the molten Taylor-cone, the thinning process, and the jet deformation. A temperature-voltage phase diagram was constructed to distinguish the regimes of the bending, the whipping, and the break-up of the jet. These jet kinematics are significantly dependent on the molten Taylor-cone, the jet thinning, and the forces exerted on the jet. The surface tension restricts the growth of the jet while it can be safely neglected after jet initiation. Jet breaks up periodically at the tip of Taylor-cone if the polymer viscosity is too low or the elongation rate is not high enough to stretch the jet. The elongation rate for each segment of the jet keeps almost constant at a certain melt temperature, while the elongation rate increases and the solidification point of the jet shifts from the Taylor-cone to the target with increasing melt temperature. An analytic equation is proposed to estimate the jet diameter along the spinline before jet solidifies. Additionally, the experiment of coiling proved that the electrical and the elastic as the dominant forces for bending are gradually replaced by the inertial and the viscous forces for whipping. [ABSTRACT FROM AUTHOR]

Herein, we describe the successful construction of novel electrospun fibermats from the cross-linkable copolymer poly (acrylamide)- co -poly (diacetone acrylamide) ( PAM- co -PDAAM ) with the molar ratio of acrylamide and diacetone acrylamide units 8:2 ( PAM- co -PDAAM(8:2) ) by in situ cross-linking during electrospinning with the bifunctional cross-linker adipic dihydrazide (ADH). As the cross-linking reactions between the ketone groups in PAM- co -PDAAM(8:2) and the hydrazide groups in ADH (in pH 6–8 aqueous buffer) is one of the bio-orthogonal reactions that are inert for various functional groups in biomacromolecules, stable encapsulation of green fluorescent protein and α-chymotrypsin at the inside of constituent nanofibers was successfully achieved without losing the original biological activities. Aqueous buffer is the only solvent through all process of fibermat construction, and combination of bioorthogonal reactions is optimum for the construction of fibermats that encapsulate biomacromolecules. The examples presented in this study should provide fascinating insight for future biomacromolecule-encapsulated fibermat research. [ABSTRACT FROM AUTHOR]

The development of nanocellulose and nanocellulose-based composites and materials has attracted significant interest in recent decades because they show unique and potentially useful features, including abundance, renewability, high strength and stiffness, eco-friendliness, and low weight. This review addresses critical factors in the manufacturing of nanocellulose composites, followed by introducing and comprehensively discussing various nanocellulose composite processing techniques. The review also provides advances on rubber and thermoset polymer matrices, such as unsaturated polyester resin, formaldehyde resins, and polyethylene terephthalate, used to reinforce cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs). The paper concludes with new findings and cutting-edge studies on electrospun nanocellulose composites. Different aspects, including preparation methods, morphology, mechanical behavior, thermal properties, and barrier action, as well as comparisons of CNC- and CNF-reinforced rubbers or thermoset polymers and electrospun composites, are investigated. [ABSTRACT FROM AUTHOR]