Rotating Drum Collector Research Articles

Optimisation of Electrospinning Parameters for High-Strength Oriented Pan Nanofibre Mats

Abstract This study explores the optimisation of electrospinning parameters to enhance the strength and orientation of polyacrylonitrile (PAN) nanofibre mats, which are pivotal in filtration applications and other areas requiring high-strength, uniformly distributed nanofibres. The focus is on the electrospinning process, particularly on a rotating drum collector, which is instrumental in determining the morphology of nanofibres. Key process variables, including the distance between the collector and the syringe, feed rate, applied voltage, and polymer concentration, have been meticulously examined to understand their influence on the physical properties of PAN nanofibres. Our findings indicate that parameters such as voltage, collector-to-syringe distance, and drum rotation speed (RPM) significantly impact the mechanical performance of the nanofibre mats. The optimised electrospinning conditions produced PAN nanofibre mats with tensile strengths ranging from 1.61 MPa to 21.78 MPa, demonstrating a notable improvement in strength due to controlled fluid dynamics and expulsion of polymer solution during the process.

Aligned electrospun starch-pullulan-protein fibers

Electrospun nanofiber mats with potential utility as functionalized scaffolding for cultivated meat were fabricated from octenyl succinic anhydride (OSA) modified starch, pullulan, and either glycomacropeptide (GMP) or whey protein isolate (WPI). A statistical mixture design was used to establish the influence of polymer composition on spinning dope properties including conductivity, surface tension, shear viscosity, and elasticity and relate these properties to spun fiber morphology. Component composition varied – starch 16–24 %, pullulan 4–6 %, protein 0–10 % – while maintaining the overall polymer content at 30 % w/w. The propensity for fiber beading was inversely associated with a timescale for bead formation dependent on the ratio of viscosity to surface tension and directly to a timescale for fiber solidification/drying altered by adjusting relative humidity. Smooth, continuous nanofibers, average diameter of 461–526 nm, were obtained from mixtures that contained less than 4% (w/w) protein, whereas mixtures with greater than 6% (w/w) protein resulted in fibers with beading. Generally, GMP-containing nanofibers exhibited less beading than WPI-containing nanofibers. Aligned fiber mats were produced using a rotating drum collector at different speeds varying from 3600 to 5600 rpm that may serve to template cell growth.

Aligned polycaprolactone/polyaniline electrospun nanofibers for directing neural stem cell differentiation and neuron arrangement

The use of engineered biomimetic substrates combined with neural stem cells (NSCs) constitutes a promising approach to develop reliable in vitro models of the nervous tissue. The fabrication of scaffolds with suitable compositional, topographical, and electrical properties is crucial for directing neural cell adhesion, differentiation, and arrangement. Herein, we propose the development of electroconductive polycaprolactone/polyaniline (PCL/PANI) electrospun mats as functional substrates for NSC culture. A rotating drum collector was employed to obtain fibers with aligned geometry. According to the results, the increase in alignment contributed to the reduction of fiber diameter and the increase of scaffold mechanical properties in terms of elastic modulus and tensile strength. In vitro experiments demonstrated the ability of PCL/PANI membranes to support NSC attachment and growth, as well as significantly foster neuronal differentiation. Furthermore, the presence of an aligned pattern was shown to effectively influence the arrangement of NSC-derived neurons, confirming the potential of this substrate for the design of a physiologically relevant culture platform for in vitro investigation of the nervous tissue.

Electrospun superhydrophobic polyvinyl chloride /polydimethylsiloxane-nanodiamond nanocomposite with enhanced antifouling and mechanical properties for fresh produce packaging

Food package films serve the important functions of preserving food quality, extending shelf life, and protecting against external contaminants while also providing a barrier to moisture and oxygen. In consideration of the increasing frequency of foodborne outbreaks, there is a growing demand for food packaging films with additional functionality to prevent cross-contamination and the attachment of pathogens, thereby enhancing bacterial safety. Herein, we report a one-step fabrication approach relying on electrospinning of a blend of polyvinyl chloride (PVC) and polydimethylsiloxane (PDMS) together with nanodiamond (ND) on a rotating drum collector for the formation of bacterially antifouling food package films. In this approach, by adjusting the concentrations of PVC, PDMS, and ND and the drum angular velocity, the nanofiber diameter could be tuned in the range of 0.4 μm to 2.0 μm. Furthermore, these process parameters could also be used to modulate the water contact angle on the resultant films, with a minimum contact angle of 136.2 ± 5.6° and a maximum of 159.5 ± 3.8°. The lowest water contact angles were observed for films with bare PVC fibers while the highest contact angles were seen for films with nanocomposite fibers containing ND and PVC/PDMS. Compared with the films with bare PVC, nanocomposite films with ND-PVC/PDMS achieved up to 99.8 % and 99.6 % reduction in bacterial adhesion against S. typhimurium LT2 and Listeria innocua, respectively. The tensile strength of nanofibrous PVC film can be increased from 1.2 ± 0.4 MPa to 4.4 ± 0.3 MPa by the inclusion of PDMS (1:1 wt.%) and further increased to 8.9 ± 0.3 MPa with the additional inclusion of ND (PVC/PDMS/ND 1:1:0.1 wt.%). Considering the notable antifouling properties against bacteria and the improved mechanical characteristics, these nanocomposite films represent a noteworthy step in the development of sustainable and active food packaging solutions for a safer and healthier food supply chain.

Affordable lab-scale electrospinning setup with interchangeable collectors for targeted fiber formation

The electrospinning method is increasingly in demand due to its capability to produce fibers in the nanometer to micrometer range, with applications in diverse fields including biomedical, filtration, energy storage, and sensing. Many of these applications demand control over fiber layout and diameter. However, a standard flat plate collector yields random fibers with limited control over diameter and density. Other viable solutions offering a higher level of control are either scarce or substantially expensive, impeding the accessibility of this vital technique. This study addresses the challenge by designing an affordable laboratory-scale electrospinning setup with interchangeable collectors, enabling the creation of targeted fibers from random, aligned, and coiled. The collectors include the standard flat plate and two additional designs, which are a rotating drum and a spinneret tip collector. The rotating drum collector has adjustable speed control to collect aligned fibers and exhibits stability even at high rotational speeds. The spinneret tip collector was designed to produce helically coiled fibers. The setup was validated by directed fiber formation using polycaprolactone (PCL), a biodegradable and FDA-approved polymer. Overall, the uniqueness of the design lies in its affordability, modifiability, and replicability using readily available materials, thus extending the reach of the electrospinning technique.

PAN—Composite Electrospun-Fibers Decorated with Magnetite Nanoparticles

The results of the synthesis of PAN(polyacrylonitrile)-magnetite composite fibers using the electrospinning method are presented. The electrospinning installation included a rotating drum collector for collecting fibers. Magnetite nanoparticles were synthesized using chemical condensation from an iron chloride solution. It was shown that homogeneous Fe3O4 magnetite nanoparticles with particle sizes of 6–16 nm could be synthesized using this method. Magnetite nanoparticles were investigated using X-ray diffraction analyses and transmission electron microscopy. Based on magnetite nanoparticles, composite PAN/magnetite fibers were obtained through electrospinning. The obtained composite fibers were investigated using scanning electron microscopy, X-ray diffraction analyses, and elemental analyses. It was shown that the magnetite nanoparticles were uniformly distributed on the surface of the fibers. A comparison of PAN fibers without any added magnetite to PAN/magnetite fibers showed that the addition of magnetite led to a decrease in the value of the fiber diameter at the same polymer concentration and under the same electrospinning process conditions.

Gas Sensitive Materials Based on Polyacrylonitrile Fibers and Nickel Oxide Nanoparticles

The results of the synthesis of PAN/NiO composite fibers by the electrospinning method are presented. The electrospinning installation included a rotating drum collector for collecting fibers. Nickel oxide nanoparticles were synthesized by solution combustion synthesis from nickel nitrate and urea. It was shown that monophase NiO nanoparticles with average particle sizes of 154 nm could be synthesized by this method. NiO nanoparticles were investigated by X-ray diffraction analysis and scanning electron microscopy. Based on NiO nanoparticles, composite PAN/NiO fibers were obtained by electrospinning. The obtained composite fibers were modified with heat treatment (stabilization and carbonization) processes. Obtained C/NiO fibers were investigated by SEM, and EDAX. It was shown that obtained composite fibers could be used for the detection of acetone and acetylene in air. These results show that C/NiO based electrospun fibers have potential applications in gas sensors.

Smooth‐rough asymmetric PLGA structure made of dip coating membrane and electrospun nanofibrous scaffolds meant to be used for guided tissue regeneration of periodontium

AbstractA surgical procedure for the repair of damaged periodontal tissue is Guided Tissue Regeneration (GTR), which involves the use of a barrier membrane to prevent soft tissue ingrowth and create a space for slow regeneration of periodontium and bone. GTR membrane should have pores able to facilitate the diffusion of fluids, oxygen, nutrients, and bioactive substances for cell growth, but also be impermeable to epithelial cells or gingival fibroblasts, which could overpopulate the defect space and inhibit infiltration and activity of bone‐forming cells. In this paper, a bilayer PLGA membrane was realized by coupling the dip coating and electrospinning techniques. The rough layer of the double‐sided structure was electrospun on the previously prepared smooth dip‐coated membrane. A rotating drum collector at two rotating speeds was used to generate different fibers orientation. The bilayer membrane with different superimposed surfaces was successfully fabricated and characterized from a morphological, physicochemical, and the mechanical point of view. Performed analyses revealed that the membrane possesses suitable properties, especially from mechanical point of view, for its possible use as a scaffold for the GTR of periodontum. A high fiber alignment and improved mechanical properties with respect to available GTR membranes characterized the product resulting from this study.

Optimization of high‐quality carbon fiber production from electrospun aligned lignin fibers

AbstractIn recent years, investigating lignin as an alternative carbon fiber precursor has received immense research attention as a way to reduce the cost and replace the unsustainable conventional petroleum‐based precursors for carbon fiber production. The predominant challenge for lignin‐based carbon fibers is its low mechanical performance compared to conventional ones. In this work, mechanical properties of electrospun lignin carbon fiber mats were shown to be considerably enhanced via alignment of the submicron fibers. Over 60% of the fibers were aligned via a rotating drum collector utilized during fiber production. The main electrospinning parameters, namely electric field, rotating speed, and flow rate were optimized with the Box–Behnken method to enhance mechanical properties with reduced fiber diameter and improved fiber alignment. The optimal electrospinning process parameter was achieved at 2000 rpm collection speed, 80 kV/m electric field, and 440 nl/s flow rate. The lignin carbon fibers produced under the optimized condition exhibited elastic modulus of 3145.47 ± 917.75 MPa, tensile strength of 18.78 ± 6.11 MPa, and average fiber diameter of 697.07 ± 96.41 nm. The analysis on the interactions between electrospinning parameters has laid a solid foundation for the production of high‐quality carbon fibers from lignin precursor.

Understanding multiscale structure-property correlations in PVDF-HFP electrospun fiber membranes by SAXS and WAXS.

Electrospinning is a versatile technique to produce nanofibrous membranes with applications in filtration, biosensing, biomedical and tissue engineering. The structural and therefore physical properties of electrospun fibers can be finely tuned by changing the electrospinning parameters. The large parameter window makes it challenging to optimize the properties of fibers for a specific application. Therefore, a fundamental understanding of the multiscale structure of fibers and its correlation with their macroscopic behaviors is required for the design and production of systems with dedicated applications. In this study, we demonstrate that the properties of poly(vinylidene fluoride-co-hexafluoro propylene) (PVDF-HFP) electrospun fibers can be tuned by changing the rotating drum speed used as a collector during electrospinning. Indeed, with the help of multiscale characterization techniques such as scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS), we observe that increasing the rotating drum speed not only aligns the fibers but also induces polymeric chain rearrangements at the molecular scale. Such changes result in enhanced mechanical properties and an increase of the piezoelectric β-phase of the PVDF-HFP fiber membranes. We detect nanostructural deformation behaviors when the aligned fibrous membrane is uniaxially stretched along the fiber alignment direction, while an increase in the alignment of the fibers is observed for randomly aligned samples. This was analyzed by performing in situ SAXS measurements coupled with uniaxial tensile loading of the fibrous membranes along the fiber alignment direction. The present study shows that fibrous membranes can be produced with varying degrees of fiber orientation, piezoelectric β-phase content, and mechanical properties by controlling the speed of the rotating drum collector during the fiber production. Such aligned fiber membranes have potential applications for neural or musculoskeletal tissue engineering.

Confined crystallization and chain conformational change in electrospun poly(ethylene oxide) nanofibers

This study focused on understanding the confined crystallization of poly(ethylene oxide) (PEO) in electrospun nanofibers. The effect of thermal treatment on PEO crystallization was also studied. An electrospinning process with a rotating drum collector enabled stretching and aligning of polymer chains, which resulted in the formation of a planar zigzag conformation. The confined environment in nanofibers facilitated an ordered crystal arrangement, resulting in an increase in the degree of crystallinity with a decrease in the fiber diameter. By contrast, large fibers extended solvent evaporation, which resulted in large crystallite sizes. The confined geometry and mechanical force provided by a rotating collector induced the preferred crystal orientation parallel to the fiber axis. Upon thermal annealing, the stretched PEO chains relaxed, resulting in a change from the metastable zigzag conformation to a stable helical conformation. Thermal treatment monotonically increased the melting temperature, degree of crystallinity, and crystallite size of PEO nanofibers regardless of the fiber diameter but did not influence the orientation of the organized crystals. The confinement effect on the chain conformation and crystallization behavior of poly(ethylene oxide) (PEO) in electrospun nanofibers was investigated. The PEO chains in electrospun nanofibers were tightly packed and exhibited a zigzag conformation. Increasing the fiber diameter reduced the packing of polymer chains, resulting in increases in the melting temperature and crystallite size. Thermal treatment relaxed the stretched chains, which induced a change from the metastable zigzag conformation to a stable helical conformation. Additionally, the melting temperature, degree of crystallinity, and crystallite size increased with increasing annealing temperature.

Aligned Nanofiber-Guided Bone Regeneration Barrier Incorporated with Equine Bone-Derived Hydroxyapatite for Alveolar Bone Regeneration.

Post-surgery failure of dental implants due to alveolar bone loss is currently critical, disturbing the quality of life of senior dental patients. To overcome this problem, bioceramic or bone graft material is loaded into the defect. However, connective tissue invasion instead of osteogenic tissue limits bone tissue regeneration. The guided bone regeneration concept was adapted to solve this problem and still has room for improvements, such as biochemical similarity or oriented structure. In this article, an aligned electrospun-guided bone regeneration barrier with xenograft equine bone-derived nano hydroxyapatite (EBNH-RB) was fabricated by electrospinning EBNH/PCL solution on high-speed rotating drum collector and fiber characterization, viability and differentiation enhancing properties of mesenchymal dental pulp stem cell on the barrier was determined. EBNH-RB showed biochemical and structural similarity to natural bone tissue electron microscopy image analysis and x-ray diffractometer analysis, and had a significantly better effect in promoting osteogenesis based on the increased bioceramic content by promoting cell viability, calcium deposition and osteogenic marker expression, suggesting that they can be successfully applied to regenerate alveolar bone as a guided bone regeneration barrier.

Fabrication and vibrational energy harvesting characterization of flexible piezoelectric nanogenerator (PEN) based on PVDF/PZT

In this study, polyvinylidene difluoride (PVDF) is doped with different volume levels (10, 20, 30 vol %) of lead zirconate titanate (PZT), and neat PVDF (undoped) electrospun nanofibres are prepared by aligning them through the electrospinning process with a rotating drum collector. All of the produced nanofibres are characterized by X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR). The piezoelectric nanogenerator (PEN) devices are fabricated by placing the PVDF/PZT electrospun nanofibres as the dielectric material between two conductive plates. The vibrational energy harvesting analyses of the PEN are defined by taking measurements under various resistive loads. At 15 Hz excitation frequency, the maximum output power of PEN with PVDF+10 vol %PZT reaches 6.35 μW by increasing the power to 85% under a resistive load of 1MΩ, while the PEN with β-PVDF has the electrical power of 3.44 μW at the same load. The PEN based energy generation is a promising source of clean energy generation from mechanical vibrations for powering portable microelectronic applications without an external power supply.

Gaseous flow focusing for spinning micro and nanofibers

We apply the gaseous flow focusing principle to produce fibers of polyvinylpyrrolidone down to the nanometer scale. The polymer solution is injected in front of a glass converging micronozzle through which a high-speed air stream flows. The air stream sucks and drags the liquid forming a meniscus whose tip emits a thin jet. The jet flies while whipping until it solidifies due to the solvent evaporation. The resulting fiber is deposited on a rotating drum collector. Gaseous Flow Focusing Spinning does not require any additional source of energy. It proves to be stable and robust, and produces fibers over hours with hardly any interruptions for wide ranges of gas pressures and liquid flow rates. Fibers with diameters of the order of 100 nm are produced for sufficiently low polymer concentrations. Their sections are circular and uniform in diameter. The standard deviation of the diameter distribution ranges from around 20%–40% of the corresponding mean value.

Raising the steaks ‐ a taste of what's to come

Raising the steaks ‐ a taste of what's to come

A Flexible Piezoelectric Nanogenerator Based on Aligned P(VDF-TrFE) Nanofibers.

Aligned P(VDF-TrFE) nanofibers are successfully fabricated by advanced electrospinning. The aligned feature of the nanofibers is achieved by using parallel electrodes, which is fabricated by lithography and wet etching, and a rotating drum collector. Scanning electron microscope (SEM) images show that the nanofibers are highly ordered with a smooth surface and uniform diameter. X-ray diffraction (XRD) and Fourier Transform Infrared spectrum (FTIR) tests indicate that the fibers contain high β phase content. The nanogenerator based on aligned P(VDF-TrFE) nanofibers exhibits good electric performance with a maximum output voltage as high as 12 V and peak-peak short circuit current about 150 nA, highlighting the potential application of P(VDF-TrFE) on self-powered and wearable devices.

CUSTOMIZATION OF ELECTROSPINNING FOR TISSUE ENGINEERING

This paper deals with two electrospinning technologies: the melt electrospinning with a customized jet head, adapted from the fused deposition modeling (FDM) 3D printer, in comparison with the standard solution electrospinning, aiming at fabrication of tissue engineering scaffolds. The resulting fibers are compared. The influence of the collector properties on those of the fabricated scaffold is investigated. The resulting electrospun fibers exhibit different characteristics such as morphology and thickness, depending on the technology. The micro-fibers are produced by the melt electrospinning with an inbuilt 3D printer jet head, whereas the solution electrospinning has produced nano- and micro-fibers. The scaffolds fabricated on the rotating drum collector exhibit a more ordered structure as well as thinner fibers than those produced on the stationary plate collector. Further investigations should aim at fabrication of porous hollow fibers and tissue engineering scaffolds with controlled porosity and properties.

Influence of Nanofiber Orientation on Morphological and Mechanical Properties of Electrospun Chitosan Mats.

This work explored the use of chitosan (Cs) and poly(ethylene oxide) (PEO) blends for the fabrication of electrospun fiber-orientated meshes potentially suitable for engineering fiber-reinforced soft tissues such as tendons, ligaments, or meniscus. To mimic the fiber alignment present in native tissue, the CS/PEO blend solution was electrospun using a traditional static plate, a rotating drum collector, and a rotating disk collector to get, respectively, random, parallel, circumferential-oriented fibers. The effects of the different orientations (parallel or circumferential) and high-speed rotating collector influenced fiber morphology, leading to a reduction in nanofiber diameters and an improvement in mechanical properties.

Cilostazol-Loaded Poly(\u03b5-Caprolactone) Electrospun Drug Delivery System for Cardiovascular Applications

PurposeThe study discusses the value of electrospun cilostazol-loaded (CIL) polymer structures for potential vascular implant applications.MethodsBiodegradable polycaprolactone (PCL) fibers were produced by electrospinning on a rotating drum collector. Three different concentrations of CIL: 6.25%, 12.50% and 18.75% based on the amount of polymer, were incorporated into the fibers. The fibers were characterized by their size, shape and orientation. Materials characterization was carried out by Fourier Transformed Infrared spectroscopy (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In vitro drug release study was conducted using flow-through cell apparatus (USP 4).ResultsThree-dimensional structures characterized by fibers diameter ranging from 0.81 to 2.48 μm were in the range required for cardiovascular application. DSC and XRD confirmed the presence of CIL in the electrospun fibers. FTIR and Raman spectra confirmed CIL polymorphic form. Elastic modulus values for PCL and the CIL-loaded PCL fibers were in the range from 0.6 to 1.1 GPa. The in vitro release studies were conducted and revealed drug dissolution in combination with diffusion and polymer relaxation as mechanisms for CIL release from the polymer matrix.ConclusionsThe release profile of CIL and nanomechanical properties of all formulations of PCL fibers demonstrate that the cilostazol loaded PCL fibers are an efficient delivery system for vascular implant application.

Membrane desalination using surface fluorination treated electrospun polyacrylonitrile membranes with nonwoven structure and quasi-parallel fibrous structure

Polyacrylonitrile (PAN) solution was electrospun into fibrous membranes with nonwoven structure and quasi-parallel fibrous structure using a rotating drum collector. Surface fluorination treatment technique was applied to transform the intrinsically hydrophilic PAN membranes into hydrophobic membranes. A set of surface fluorination treated electrospun PAN membranes were tested for membrane desalination (MD) using a lab-scale air gap membrane desalination system. The results show that it is promising to use intrinsically non-hydrophobic membranes in MD after surface fluorination modification based on permeate flux and salt rejection ratio. In the MD application, we found that the fiber orientation combing with the flow direction of the feed could affect the mass transfer performance. The quasi-parallel fiber alignment, surface fluorination treatment, liquid entry pressure, permeate flux, and mass transfer coefficient were studied in detail in this work.