Nanofibrous Membranes Research Articles

Unlocking the superior flexibility and enhanced catalytic oxidation performance of CoTiO3 nanofibrous membranes through zirconium doping

The development of continuous CoTiO3 (CTO) fibers with prominent catalytic oxidation activity, tunable fibrous structures, and improved recyclability is appealing for application in efficient organic wastewater treatment; however, inescapable flaws remain, such as their inherent brittleness and adverse operability. Herein, a facile and effective strategy is proposed for the fabrication of flexible and mechanically robust CTO nanofibrous membranes through a combination of element doping and sol–gel-assisted electrospinning. Compared with pristine CTO fibers, the resulting zirconium-doped CoTiO3 (ZCTO) nanofibrous membranes displayed remarkably enhanced flexibility and tensile mechanics, which were attributed to their lower crystallinity, smaller grain size, and fewer fiber surface defects. The developed ZCTO fibrous membrane demonstrated exceptional resistance to bending fatigue, retaining a polymer-like bending rigidity of approximately 25 mN even after undergoing 200 reciprocating bending cycles. Furthermore, the incorporation of zirconium into CTO clearly had an advantageous effect on the formation of oxygen vacancies, thereby enhancing the surface adsorption of peroxymonosulfate (PMS), accelerating the electron transfer process, and weakening the peroxy bonds. The tetracycline degradation efficiency of the ZCTO fibers remained at 81.4% within 10 min after 5 continuous cycles. Benefiting from their robust mechanical properties and excellent catalytic activity, the fabricated membranes demonstrated outstanding dynamic catalytic performance under gravity-driven conditions. More importantly, the reported strategy might be adopted and extended to develop a wide range of ceramic fibers with enhanced flexibility and mechanics for catalytic oxidation.

Superhydrophilic and underwater superoleophobic polylactide/cellulose diacetate composite nanofibrous membranes for effective oil-in-water emulsions separation

Electrospun polylactide (PLA) fibrous membranes, characterized by good biodegradability and high porosity, demonstrate significant potential for oily wastewater treatment. However, the inherent hydrophobicity of PLA poses a significant challenge in separating oil-in-water emulsions. Herein, a facile and effective strategy was proposed to fabricate a PLA based nanofibrous membrane for oil-in-water emulsions separation. By combining the electrospinning and nonsolvent-induced phase separation technologies, hydrophilic cellulose diacetate (CDA) networks were in-situ constructed throughout the entire body of PLA fibrous membrane, resulting in a unique hierarchical porous structure. As a result, the obtained PLA/CDA composite nanofibrous membrane exhibited intriguing superhydrophilicity and underwater superoleophobicity, as well as gratifying separation performances for various oil-in-water emulsions solely under the driving force of gravity. Furthermore, the PLA/CDA composite nanofibrous membrane could be easily reused and will not bring out significant environmental concerns after extended use and disposal. We anticipate that this work could pave a way for the development of environmentally friendly membranes for oily wastewater treatment.

Sustained-release of essential oils by polyvinyl alcohol-based nanofibers

Flavored cigarettes are very popular among consumers. However, many essential oils in cigarettes are lost during storage, and the utilization rate of the essential oils during use is low. Therefore, effective packaging and stable sustained release are urgently needed. In this study, a composite electrospun stable nanofiber storage material was prepared for sustained release. Polyethylene glycol, which has good heat storage properties, was selected as the heat storage material to inhibit the release of essential materials during storage. Porous graphene with good thermal conductivity and a porous structure was selected as the heat conductive component to ensure rapid and uniform release. Polyethylene glycol/porous graphene polyvinyl alcohol-mint essential oil sustained-release composite electrospun nanofibers membrane was prepared by electrospinning, and the morphology, composition, thermal properties, and sustained-release properties were tested. The results showed that the composite electrospun nanofiber membrane reduced the loss of mint oil during storage and enabled the rapid release of mint oil at high temperatures. At room temperature, the retention rate of the mint oil was still more than 90% after 120 h, and at a high temperature (75°C) the retention rate was less than 20% after 10 min; that is, 80% of the essential oil material was released within 10 min.

Green Electrospun Poly(vinyl alcohol)/Gelatin-Based Nanofibrous Membrane by Incorporating 45S5 Bioglass Nanoparticles and Urea for Wound Dressing Applications: Characterization and In Vitro and In Vivo Evaluations.

This study reports the fabrication and characterization of poly(vinyl alcohol) (PVA) and gelatin (Gel)-based nanofiber membranes cross-linked with citric acid (CA) by a green electrospinning method in which nano 45S5 bioglass (BG) and urea were incorporated. Various combinations of PVA, gelatin, and BG were prepared, and nanofiber membranes with average fiber diameters between 238 and 595 nm were fabricated. Morphological, chemical, and mechanical properties, porosity, swelling, water retention, and water vapor transmission rate of the fabricated membranes were evaluated. PVA:Gel (90:10), 15% CA, and 3% BG were determined as the optimum blend for nanofiber membrane fabrication via electrospinning. The membrane obtained using this blend was further functionalized with 10% w/w polymer urea coating by the electrospray method following the cross-linking. In vitro biocompatibility tests revealed that the fabricated membranes were all biocompatible except for the one that functionalized with urea. In vivo macroscopic and histopathological analysis results of PVA/Gel/BG and PVA/Gel/BG/Urea treated wounds indicated increased collagenization and vascularization and had an anti-inflammatory effect. Furthermore, careful examination of the in vivo macroscopic results of the PVA/Gel/BG/Urea membrane indicated its potential to decrease uneven scar formation. In conclusion, developed PVA/Gel/BG and PVA/Gel/BG/Urea electrospun membranes with multifunctional and biomimetic features may have the potential to be used as beneficial wound dressings.

Flexible Piezoelectric Sensor Based on Two-Dimensional Topological Network of PVDF/DA Composite Nanofiber Membrane

Owing to the robust scalability, ease of control and substantial industrial applications, the utilization of electrospinning technology to produce piezoelectric nanofiber materials demonstrates a significant potential in the development of wearable products including flexible wearable sensors. However, it is unfortunate that the attainment of high-performance piezoelectric materials through this method remains a challenging task. Herein, a high-performance composite nanofiber membrane with a coherent and uniformly dispersed two-dimensional network topology composed of polyvinylidene fluoride (PVDF)/dopamine (DA) nanofiber membranes and ultrafine PVDF/DA nanofibers was successfully fabricated by the electrospinning technique. Based on the evidence obtained from simulations, experimental and theoretical results, it was confirmed that the unique structure of the nanofiber membrane significantly enhances the piezoelectric performance. The present PVDF/DA composite nanofibers demonstrated a remarkable piezoelectric performance such as a wide response range (1.5–40 N), high sensitivity to weak forces (0–4 N, 7.29 V N−1), and outstanding operational durability. Furthermore, the potential application of the present PVDF/DA membrane as a flexible wearable sensor for monitoring human motion and subtle physiological signals has also been validated. This work not only introduces a novel strategy for the application of electrospun nanofibers in sensors but also provides new insights into high-performance piezoelectric materials.Graphical

Polyvinylidene fluoride (PVDF) Nanofiber Modified Current Collector in Anode-Free Lithium Battery

<p class="Keywords">In order to coat the layer of the Cu for an anode-free lithium battery (AFLB) and examine AFLB performance, PVDF nanofiber with electrospinning is used. The fabrication time and molecular weight of the nanofiber can be modified. In comparison to conventional models, the AFLB is one of the new model options that provides great energy density at the same battery size. The disadvantages of this new model battery include its limited electrochemical performance and the fact that it is still in its initial stages of manufacturing. Low Coulombic efficiency and uncontrolled dendritic growth are challenges in the growth of AFLB. For the fabrication of nanofiber membranes were synthesized with different types of PVDF Mw 1.300.000 and 534.000, PVDF Nanofibers were made using electrospinning with time variations of 5 hours, 7 hours, and 9 hours, and their thermal, mechanical, and porosity properties were examined. The PVDF Mw 1.300.000 sample had the greatest porosity percentage value which is 47.031% during a 9-hour time. The PVDF Mw 534.000 sample had the highest tensile strength results, with a variation of 2.33 MPa during a 9-hour time. The PVDF Mw 1.300.000 sample had the highest percentage elongation results, 39.7%. The average nanofiber size varies with processing time, with the PVDF Mw 1.300.000 sample having the smallest size at 167.9 nm.</p>

Flexible pressure sensor based on thermoplastic polyurethane/polyvinylidene fluoride nanofiber membranes

The mechanical flexibility of flexible sensors primarily originates from sensitive flexible materials. Therefore, the key to developing new flexible mechanical sensors lies in constructing high-performance sensitive flexible materials. In this study, we employ a coaxial electrostatic spinning technique to prepare thermoplastic polyurethane (TPU)/polyvinylidene fluoride (PVDF) nanofiber membranes (NFM) with a core–shell structure for the construction of flexible piezoelectric mechanosensors. The utilization of TPU/PVDF NFM in flexible mechanosensors for human health monitoring and environmental sensing is investigated. As a result, the excellent performance of this composite membrane was demonstrated by its high mechanical strength and flexibility, resulting in high sensitivity (GF: 0.42 V/kPa), low response time (100 ms), and wide sensing range (0.2∼5.0 kPa). Additionally, The TPU/PVDF NFM not only demonstrates excellent pressure sensing performance but also exhibits exceptional capabilities for human body sensing applications. Therefore, these results highlight that the TPU/PVDF NFM exhibits excellent pressure-sensing properties and holds significant potential for applications in the fields of flexible robotics and wearable devices such as human-computer interfaces, intelligent healthcare systems, and artificial intelligence skin technologies.

Development of reversibly photo-crosslinkable water-stable poly(2-ethyl-2-oxazoline) nanofibers via functionalization with cinnamoyl moieties

Poly(2-ethyl-2-oxazoline) (PEtOx) is a potent member of the versatile poly(2-oxazoline) polymer platform with its high hydrophilicity that could be beneficial in numerous biomedical applications, especially in the form of a nanofibrous membrane. However, its water-solubility limits its application in situations where a stable, nanofibrous morphology is required in aqueous environments. The present work offers a straightforward route towards water-stable PEtOx-based nanofibrous membranes, via post-polymerization functionalization with cinnamoyl moieties (PEtOx-Cin) and photo-crosslinking of the electrospun membranes. It is shown that a UVB treatment does not significantly affect the nanofibrous morphology, while successfully inducing the cinnamoyl dimerization process and hence the formation of a polymeric network, as evidenced by spectral analysis. The hereby crosslinked PEtOx-based nanofibers exhibit a prolonged water-stability (at least 45 days), while, interestingly, intermediate irradiation times yield the best results. Full disintegration of the photo-crosslinked nanofibers in aqueous media could be achieved by subsequent UVC exposure. This is not only due to decrosslinking of the cinnamoyl dimers, but was also found to be due to partial degradation of the polymeric backbone. The investigation of UVB/UVC exposure on pure PEtOx nanofibrous membranes confirmed the photo-degradation of the polymeric backbone by a significant decrease in molar mass as observed by size exclusion chromatography and supported by spectral analysis. The hereby proposed, straightforward route for reversible crosslinking of PEtOx-based nanofibrous membranes and their accessible disintegration will contribute to the promotion of these materials in biomedical applications where a water-stable, nanofibrous morphology combined with high hydrophilicity and easy removal is required.

Breath moisture-induced electroactive nanofibrous membrane for efficient antibacterial and antiviral air filtration

The high humidity environment created by human breath can easily lead to charge loss in the mask's filter and weaken the mask's filtration effect on aerosols containing bacteria and viruses. Therefore, in this study, a breath moisture-induced electroactive nanofibrous membrane was prepared by incorporating Cu/Zn nanoparticles into cellulose acetate/poly (vinyl butyral) fibers. Adjacent Cu/Zn nanoparticles can form galvanic couples that can be activated by human breath to undergo redox discharge reactions, thus imparting moisture-induced electroactivity to nanofibrous membrane. Based on the moisture-induced electroactivity, nanofibrous membrane demonstrated antibacterial rates of 98.32 % against Escherichia coli (E. coli) and 99.06 % against Staphylococcus aureus (S. aureus). Moreover, moisture-induced electroactive nanofibrous membrane significantly reduced the titer of Enterovirus 71 (EV71) transmitted through the respiratory tract within 5 min. The excellent antibacterial and antiviral performance of electroactive nanofibrous membrane can be attributed to the synergistic effect of Cu/Zn’s electrical stimulation (ES) interference on the electrodynamics of bacteria and viruses, the generated reactive oxygen species (ROS), and the released metal ions. Benefiting from the increased surface potential from Cu/Zn galvanic couples, moisture-induced electroactive nanofibrous membrane exhibited a filtration efficiency of 99.61 % for PM0.3 particles while maintaining a low-pressure drop (78 Pa). Meanwhile, electroactive nanofibrous membrane showed excellent wear comfort and non-cytotoxicity. In summary, this moisture-induced electroactive nanofibrous membrane maintains high filtration performance and exhibits excellent antibacterial and antiviral activities, shedding some light on developing novel efficient air filters.

Electrospun poly(l-lactide-co-dl-lactide) nanofibrous scaffold as substrate for ex vivo limbal epithelial cell cultivation

Ultrathin electrospun poly (l-lactide-co-dl-lactide) nanofibrous membranes coated with fibronectin were explored as scaffolds for the ex vivo cultivation of limbal epithelial cells (LECs) for the treatment of limbal stem cell deficiency. The developed scaffolds were compared with the “gold-standard” fibrin gel. The resulting membranes composed of nanofibers possessed a very low thickness of 4 μm and allowed very good optical transparency in the wet state. The fibronectin-coated nanofibrous scaffolds demonstrated LEC expansion and successful cultivation similar to that on fibrin gel. Unlike the regular cobblestone epithelial cell morphology on the fibrin gel, the nanofibrous scaffold presented a mostly irregular epithelial morphology with a shift to a mesenchymal phenotype, as confirmed by the upregulation of profibroblastic genes: ACTA2 (p = 0.023), FBLN1 (p < 0.001), and THY1 (p < 0.001). Both culture conditions revealed comparable expression of stem cell markers, including KLF4, ΔNp63α and ABCG2, emphasizing the promise of polylactide-based nanofibrous membranes for further investigations.

Study on uniformity of multi‐needle electrostatic spinning by auxiliary flow field

AbstractMulti‐needle electrospinning is a simple and general method for mass preparation of nanofiber membrane, which has great industrial potential. However, the bending instability produced in the electrospinning process makes that the deposition uniformity of the nanofiber is still a big concern, resulting in non‐uniform nanofiber membrane, which seriously affects the application of electrospun membrane in environmental filtration, new energy and medical fields. In order to improve the uniformity of nanofiber deposition in multi‐needle electrospinning, an auxiliary flow field system (AFF) is proposed, which can effectively improve the uniformity of nanofiber deposition. After image processing, the uniformity of nanofiber deposition is quantified with the index of grey distribution, and the effectiveness of this method is verified. Combined with the multi‐physical field analysis, the influence mechanism of cross‐wind field on the uniformity of fibre deposition was revealed. By optimizing the experimental parameters, the non‐uniformity of nanofiber deposition was reduced by 49.19%. Based on multi‐needle electrospinning technology, a reliable idea (AFF) and experimental basis are provided for the uniform preparation of nanofiber membrane.

Self-cleaning PTFE nanofiber membrane for long-term passive daytime radiative cooling

Passive daytime radiative cooling (PDRC) is an innovative, eco-friendly, and electricity-free cooling strategy that involves spontaneously cooling a surface by reflecting sunlight and radiating heat to cold outer space. Currently, many kinds of research focus on the effects of material design and structure construction on PDRC performance. However, the PDRC suffers a significant challenge of performance degradation arising from surface contamination and poor long-term outdoor durability. Herein, we developed a simple, efficient, and scalable strategy to prepare a superhydrophobic poly-(tetrafluoroethylene) (PTFE) nanofiber membrane (SNM-PTFE) with outstanding radiative cooling and self-cleaning performance for various practical applications. The SNM-PTFE has an average infrared emissivity of 95.8 % and reflects 95.4 % of solar irradiance. It brought about a sub-ambient cooling performance of ∼ 14.4 °C under direct sunlight. Moreover, it demonstrated excellent above-ambient cooling performance by reducing ∼ 9.5 °C under sunlight, which exhibited unprecedented heat dissipation and solar heat-shielding properties. The self-cleaning surface of SNM-PTFE maintained its good cooling performance after being exposed to outdoor conditions for a full month. SNM-PTFE showed great promise for PDRC, which can further extend the application for residential, industrial applications, and human thermal management.

Fabrication of in situ polymerized polyaniline‐based functional nanofibrous structures for flexible electromechanical devices

AbstractRecently, flexible electromechanical devices (EMDs) emerged as alternatives to rigid electronics, promoting polymeric materials over traditional semiconductors. This study develops EMDs using conductive nanofibrous membranes of thermoplastic polyurethane (TPU), polyaniline (PANI), and multi‐walled carbon nanotubes (MWCNTs) in various structures. The fabrication technique included the combination of electrospinning and in situ polymerization to create random and aligned conductive membranes. Morphological, mechanical, thermomechanical, and electrical characterizations were conducted to assess their potential in EMDs applications. Mechanical testing revealed that, in comparison to aligned pure TPU mats, aligned TPU/PANI and TPU/MWCNTs/PANI membranes exhibited maximum strains of 26% and 19%, respectively. Meanwhile, randomly oriented mats, TPU/PANI and TPU/MWCNTs/PANI demonstrated maximum strains of 18% and 27%, respectively. Moreover, incorporating PANI and/or MWCNTs increased the Young's modulus. Thermogravimetric analysis showed thermal stability up to 250°C for all mats, with TPU/PANI mats demonstrating superior stability. Dynamic mechanical analysis revealed that PANI incorporation increased the storage modulus from 119 and 180 MPa to 2012 and 1367 MPa for aligned and random mats, respectively, compared with pure TPU mats. The combination of MWCNTs and PANI yielded moduli of 1501 and 1096 MPa, respectively. All conductive mats exhibited symmetric ohmic behavior, with conductivities varying based on orientation and composition. Specifically, TPU/PANI and TPU/MWCNTs/PANI mats exhibited conductivities of 0.83 and 1.78 S/cm for aligned mats, and 0.35 and 0.67 S/cm for random mats, respectively. Pure TPU, on the other hand, displayed a conductivity of 1.8 × 10−10 S/cm, indicating a significantly lower conductivity compared with the other mats.

Cover Image, Volume 141, Issue 22

The cover image is based on the Research Article Development of crosslinked polyvinyl alcohol nanofibrous membrane for microplastic removal from water by Anandu Nair Gopakumar et al., https://doi.org/10.1002/app.55428image

A unidirectional water-transport antibacterial bilayer nanofibrous dressing based on chitosan for accelerating wound healing

Excessive accumulation of exudate from wounds often causes infection and hinders skin regeneration. To handle wound exudate quickly and prevent infection, we developed an antibacterial Janus nanofibrous dressing with a unidirectional water-transport function. The dressing consists of a hydrophilic chitosan aerogel (CS-A) as the outer layer and a hydrophobic laurylated chitosan (La-CS) nanofibrous membrane as the inner layer. These dressings achieved excellent liquid absorption performance (2987.8 ± 123.5 %), air and moisture permeability (997.8 ± 23.1 g/m2/day) and mechanical strength (5.1 ± 2.6 MPa). This performance was obtained by adjusting the density of CS-A and the thickness of the La-CS membrane. Moreover, the dressing did not induce significant toxicity to cells and can prevent bacterial aggregation and infection at the wound site. Animal experiments showed that the dressing can shorten the inflammatory phase, enhance blood vessel generation, and accelerate collagen deposition, thus promoting wound healing. Overall, these results suggest that this Janus dressing is a promising material for clinical wound care.

Surface segregation of rigid polyarylene ether amidoxime on polyurethane nanofiber into hierarchical membranes as substrate of flexible SERS nanosensor for sulfamethoxazole detection

Electrospun polymeric nanofibrous membranes are emerging as the promising substrates for preparation of flexible SERS nanosensors due to their intrinsic nanoscale surface roughness, easy scalability as well as rich surface reactivity. Although the nanofiber membranes prepared from high performance thermoplastics exhibit good mechanical stability, the SERS nanosensors based on these substrates normally have lower signal-to-noise ratio because of the interference from background Raman signals of aromatic moieties. Herein, we synthesized an optically transparent polyurethane (PU) and rigid polyarylene ether amidoxime (PEA), which were electrospun into core-shell nanofibers membranes with a “beads-on-web” morphology. Furthermore, the PU-PEA membranes were coated with ultra-thin silver layer and thermally annealed to prepare the flexible SERS nanosensor without any background noises. In addition, the Raman enhancement of SERS nanosensor can be readily improved by tuning of PU-PEA composition, silver thickness as well as thermal annealing temperature. Finally, the optimized SERS nanosensor enables label-free detection of sulfamethoxazole as low as 0.1 nM with a good reproducibility and detection performance in real water sample. Meanwhile, the optimized SERS nanosensor shows long term anti-biofouling capacity. Thanks to its facile fabrication, competitive analytical performance and resistance to biofouling, the current work basically open new way for design of flexible SERS nanosensors for biomedical applications.

Preparation, Air Filtration Performance of a Fluorinated Polyimide/Polyacrylonitrile Nanofibrous Membrane by Electrospinning.

This paper reports the successful fabrication of a new nanofibrous membrane, F-PI/PAN, through electrospinning of polyacrylonitrile (PAN) and fluorinated polyimide (F-PI). The nanofibrous membrane exhibits comprehensive properties for high-temperature filtration and robust PM2.5 (particulate matter with an aerodynamic equivalent diameter of 2.5 microns or less) removal. The introduction of F enhances the hydrophobicity of the PI. The relationship between the hydrophobic performance and the filtration performance of particles is investigated. The chemical group of the composite membrane was demonstrated using FITR, while the surface morphology was investigated using field emission scanning electron microscopy. The TGA results indicated good thermal stability at 300 °C. Various ratios of F-PI membranes were prepared to characterize the change in properties, with the optimal mass ratio of F-PI being 20 wt%. As the proportion of F-PI increases, its mechanical and filtration efficiency properties and hydrophobicity become stronger. The contact angle reaches its maximum of 128 ± 5.2° when PAN:F-PI = 6:4. Meanwhile, when PAN:F-PI = 8:2, the filtration efficiency reaches 99.4 ± 0.3%, and the elongation at break can reach 76%. The fracture strength can also reach 7.1 MPa, 1.63 times that of the pure PAN membrane.

Thermo-responsive microneedles patch for transdermal drug delivery via squeezing in diabetic foot ulcers

Microneedle (MN) patches could be a promising treatment for diabetic foot ulcers that plague thousands of people worldwide. While reducing skin resistance or increasing driving force can accelerate the efficiency of transdermal drug delivery with conventional MN patches, it can create toxic chemical residues or require the help of additional devices. Herein, a thermo-responsive microneedles patch (TMN) with high biocompatibility without additional equipment is proposed. The TMN consisted of a bilayer microneedles composed of sodium alginate (SA)-g-poly(N-isopropylacrylamide) layer (SA-g-PNIPAM) loaded with sucrose octasulfate sodium salt (SOS) and hyaluronic acid layer and a polycaprolactone/chitosan nanofiber membrane loading with tetracycline hydrochloride (TH) and SOS. PNIPAM accelerates drug release by extruding the drug through a volumetric phase transition in response to temperature changes, and TH and SOS promote wound healing by inhibiting bacterial growth and promoting vascular regeneration and epithelial formation. The results showed that the drug release of TMN was significantly faster, with the drug release rate of more than 80% in the 10th h, and the antibacterial rate of TMN could reach 800%. In addition, TMN had good biocompatibility and good healing effects in vivo, which may be helpful for the design of multifunctional dressings in the future.

Zwitterionic functional layer modified electrospun polyurethane nanofiber membrane incorporating silver nanoparticles for enhanced antibacterial applications

Nanofiber materials, with their porous nature and high specific surface area, can effectively adsorb and capture bacteria. Additionally, their antibacterial properties can be enhanced by incorporating substances with antibacterial effects and by surface modification with special chemical functional groups. Therefore, this study uses the electrospinning method to prepare polyurethane (PU) nanofiber antimicrobial membranes. Silver nanoparticles (AgNPs) will be incorporated into the PU nanofiber membranes through a green reduction method, followed by atmospheric plasma treatment to graft the zwitterionic material (2-methacryloyloxyethyl phosphorylcholine, MPC) with quaternary ammonium functional groups onto the surface. This process will result in the production of PMPC@PU/AgNPs nanofiber antimicrobial membranes. The results show that MPC grafted onto the surface of PU/AgNPs nanofiber membranes exhibits better antibacterial capability against Escherichia coli than the pristine PU/AgNPs nanofiber antimicrobial membranes, with an antibacterial efficiency reaching 99.68 ± 0.07 %. This is attributed to the synergistic effect provided by the combination of AgNPs within the PU nanofibers and the surface grafting of zwitterionic materials, leading to an antibacterial effectiveness close to 100 %. Therefore, the prepared PMPC@PU/AgNPs nanofiber antimicrobial membrane demonstrates the potential for applications in public health, specifically in areas such as food packaging materials, membrane filters and the biomedical field.

Hairy quaternary ammonium-functionalized metal organic framework integrated in polyacrylonitrile nanofiber membrane for efficient removal of arsenate

In this work, the metal–organic framework (MOF) particles (i.e., UiO-66-NH2) was covalently modified with poly(4-vinylpyridine) (P4VP) through surface-initiated atom transfer radical polymerization (SI-ATRP) method. The hair MOF product, referred to as UiO-66-g-P4VP, was then subjected to quaternization with 1-bromoethane, resulting in UiO-66-g-qP4VP (quaternized P4VP is denoted as qP4VP). Finally, these UiO-66-g-qP4VP particles were incorporated into a polymer matrix made of polyacrylonitrile (PAN) to develop a nanofibrous composite membrane using the electrospinning technique. After modification of quaternized P4VP, the surface of the MOFs carry strong positive charges. Therefore, the electrospun UiO-66-g-qP4VP/PAN nanofiber membrane can serve as an adsorbent in efficient removal of negatively charged arsenate through strong electrostatic interactions. The adsorptive efficacy of the nanofiber membrane exhibited considerable stability within the pH spectrum extending from 4 to 10, indicating that the membrane could potentially maintain its functionality across a broad range of pH conditions. Our developed approach opens up an avenue for manufacturing of polyelectrolyte-functionalized MOF nanofiber membranes, which hold great promise for application in water remediation.