Fluid and Electric Field Simulation and Optimization of the Multi-Vane and Multi-Slit Electrospinning Nozzle

Stanishevsky A.

AbstractElectrospinning is increasingly used as a staple technology for the fabrication of nano‐ and micro‐fibers of different materials. Most processes utilize direct current (DC) electrospinning, and a multitude of DC‐electrospinning tools ranging from research to commercial production systems is currently available. Yet, there are numerous studies performed on electrospinning techniques utilizing non‐DC, periodic electric fields, or alternating current (AC) electrospinning. Those studies demonstrate the strong potential of AC‐electrospinning for the sustainable production of various nanofibrous materials and structures. Although tremendous progress is achieved in the development of AC‐electrospinning over the last 10 years, this technique remains uncommon. This paper reviews the AC‐electrospinning concepts, instrumentation, and technology. The main focus of this review is the most studied, “electric wind” driven AC‐electrospinning technique tentatively named alternating field electrospinning (AFES). The latter term emphasizes the role of the AC electric field's confinement to the fiber‐generating electrode and the absence of a counter electrode in such an electrospinning system. The synopses of AFES process parameters, fiber‐generating spinneret designs, benefits and obstacles, advancements in AC electrospun nano/micro‐fibrous materials/structures and their applications are given, and future directions are discussed.

Liu Y., Liu Y., Liu L., Hao M., Hu X., Wang X., Yang B.

To produce a high quality electrostatic spinneret with low voltage requirements, low energy consumption, and narrow fiber diameter distribution, the mechanical model of the spinning unit of the fractal spiral spinneret was established by using the quadratic fractal spiral parametric equation. The established fractal spiral electrostatic spinning model was imported into COMSOL Multiphysics finite element analysis software, mesh division was performed on the model, multiple spinning units were combined to form the array spinneret, and the optimal parameters of the fractal structure were optimized. However, there are still two sides of the field intensity other than the middle field intensity of the high situation. In order to equalize the field intensity, we used the spinneret properties of the same disc auxiliary electrode and quadratic fractal spiral spinneret in a linear arrangement, and the auxiliary electrode and spinneret distance and spinneret radius of the two important parameters to optimize the simulation, resulting in obtaining a more uniform field intensity distribution of the quadratic fractal spiral spinneret electrospinning equipment. Based on the calculation of the fractional dimension of the Von Koch curve, the fractional dimension of the quadratic fractal spinneret was 1.77. The critical field intensity of the system was calculated to be 2.13 × 106 V/m, and the jet space was 1.22–3.13 mm. The optimized quadratic fractal spinneret model with auxiliary electrode faced the receiving plate in the range of 60° from the left to the right of the spinning sites, –5 to 5 sites, which may emit the spinning jet.

Lee J., Moon S., Lahann J., Lee K.J.

AbstractElectrospinning has received a lot of attention in recent years because it can create nonwoven nanofiber webs with high surface area and porosity. However, the typical needle and syringe‐based electrospinning systems feature poor productivity that has limited their usefulness in the industrial field. Here, current developments in the creation of nanofibers employing nonconventional electrospinning methods, such as needleless electrospinning and syringeless electrospinning, are examined. These alternate electrospinning techniques, which are dependent on numerous polymer droplets of varied shapes, have the potential to match the productivity required for industry‐scale manufacturing of nanofibers. Additionally, they make it possible to produce nanofibers that are difficult to spin using traditional techniques, like electrospinning of colloidal suspensions.

Khatri M., Francis L., Hilal N.

Obtaining fresh drinking water is a challenge directly related to the change in agricultural, industrial, and societal demands and pressure. Therefore, the sustainable treatment of saline water to get clean water is a major requirement for human survival. In this review, we have detailed the use of electrospun nanofiber-based membranes (ENMs) for water reclamation improvements with respect to physical and chemical modifications. Although membrane distillation (MD) has been considered a low-cost water reclamation process, especially with the availability of low-grade waste heat sources, significant improvements are still required in terms of preparing efficient membranes with enhanced water flux, anti-fouling, and anti-scaling characteristics. In particular, different types of nanomaterials have been explored as guest molecules for electrospinning with different polymers. Nanomaterials such as metallic organic frameworks (MOFs), zeolites, dioxides, carbon nanotubes (CNTs), etc., have opened unprecedented perspectives for the implementation of the MD process. The integration of nanofillers gives appropriate characteristics to the MD membranes by changing their chemical and physical properties, which significantly enhances energy efficiency without impacting the economic costs. Here, we provide a comprehensive overview of the state-of-the-art status, the opportunities, open challenges, and pitfalls of the emerging field of modified ENMs using different nanomaterials for desalination applications.

Shi S., Si Y., Han Y., Wu T., Iqbal M.I., Fei B., Li R.K., Hu J., Qu J.

Electrospinning is a significant micro/nanofiber processing technology and has been rapidly developing in the past 2 decades. It has several applications, including advanced sensing, intelligent manufacturing, and high-efficiency catalysis. Here, multifunctional protective membranes fabricated via electrospinning in terms of novel material design, construction of novel structures, and various protection requirements in different environments are reviewed. To achieve excellent comprehensive properties, such as, high water vapor transmission, high hydrostatic pressure, optimal mechanical property, and air permeability, combinations of novel materials containing nondegradable/degradable materials and functional structures inspired by nature have been investigated for decades. Currently, research is mainly focused on conventional protective membranes with multifunctional properties, such as, anti-UV, antibacterial, and electromagnetic-shielding functions. However, important aspects, such as, the properties of electrospun monofilaments, development of "green electrospinning solutions" with high solid content, and approaches for enhancing adhesion between hydrophilic and hydrophobic layers are not considered. Based on this systematic review, the development of electrospinning for protective membranes is discussed, the existing gaps in research are discussed, and solutions for the development of technology are proposed. This review will assist in promoting the diversified development of protective membranes and is of great significance for fabricating advanced materials for intelligent protection.

Li Y., Zhu J., Cheng H., Li G., Cho H., Jiang M., Gao Q., Zhang X.

Electrospinning, considered as a low-cost and straightforward approach, attracts tremendous attention because nanofibrous materials with functional properties prepared by it can be widely applied in numerous fields, including rechargeable batteries, filtration, and distillation. This paper aims to provide a comprehensive review of the latest advances in developing this unique technique, which starts with a brief introduction of the advantages of electrospinning and highlights ongoing research activities, followed by its principles and progress. Afterward, the corresponding properties of electrospun nanofibers are discussed. A future vision regarding challenges and perspectives in this area is proposed at the end. It is believed that this review would provide an extensive and comprehensive reference to utilize this advanced technique to generate novel nanofibers performing in high demanding areas.

Partheniadis I., Nikolakakis I., Laidmäe I., Heinämäki J.

Electrospinning (ES) is a convenient and versatile method for the fabrication of nanofibers and has been utilized in many fields including pharmaceutical and biomedical applications. Conventional ES uses a needle spinneret for the generation of nanofibers and is associated with many limitations and drawbacks (i.e., needle clogging, limited production capacity, and low yield). Needleless electrospinning (NLES) has been proposed to overcome these problems. Within the last two decades (2004–2020), many research articles have been published reporting the use of NLES for the fabrication of polymeric nanofibers intended for drug delivery and biomedical tissue engineering applications. The objective of the present mini-review article is to elucidate the potential of NLES for designing such novel nanofibrous drug delivery systems and tissue engineering constructs. This paper also gives an overview of the key NLES approaches, including the most recently introduced NLES method: ultrasound-enhanced electrospinning (USES). The technologies underlying NLES systems and an evaluation of electrospun nanofibers are presented. Even though NLES is a promising approach for the industrial production of nanofibers, it is a multivariate process, and more research work is needed to elucidate its full potential and limitations.

Liu Z., Zhao J., Zhou L., Xu Z., Xing J., Feng Q.

Background: In recent decades, nanofiber-based materials have been considered as one of the top interesting fundamental materials for academic studies and practical applications. However, the electrospinning, as the most popular method for manufacturing nanofibers, is plagued by its low productivity. The first patent about electrospinning was emerged in 1934 and the needleless electrospinning is regarded as one of the most promising methods to realize the high throughput of nanofibers. Methods: This review compares the recent needleless spinning technologies from limited liquid surfaces to free liquid surfaces for improvement of nanofiber throughput. The aim of this review is to reveal the merits and drawbacks of recent methods in practical employment. The view focuses also on the future concern of the needleless electrospinning. Results: The current needleless electrospinning is featured with the properties: 1) high throughput; 2) lower voltage supply for the stable spinning process; 3) narrow fiber diameter distribution, followed by the drawbacks of poor long-term spinning process and limitation of a good bonding of low voltage supply. Conclusion: This review provides an update on needleless electrospinning methods for high throughput of nanofibers for industrial applications.

Baydas S., Karakas B.

A Bezier curve is significant with its control points. When control points are given, the Bezier curve can be written using De Casteljau's algorithm. An important property of Bezier curve is that e...

Xue J., Wu T., Dai Y., Xia Y.

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Ali U., Niu H., Khurshid M.F., Abbas A., Lin T.

In this study, a popular mace-shaped (cylinder with thorn arrays on the curved surface) spinneret is used for electrospinning of nanofibers. Compared with the cylinder with a smooth surface, the po...

Wang X., Xu W.

In this study, a conical wire coil was used as spinneret to launch a novel needleless electrospinning. Multiple polymer jets were observed on the surface of the coil in the electrospinning process. Productivity of the nanofibers can be enhanced to >2.5 g/h by using this novel nozzle. The fiber productivity and diameter together with diameter distribution were dependent on the concentration of the polymer solution, applied voltage, and collecting distance. This novel concept of using wire coil as the electrospinning nozzle depicts a model of large-scale needleless electrospinning system for nanofiber production.

Vinet B., Garandet J.P., Cortella L.

The pendant drop method, used in an ultrahigh vacuum drop tube, allowed new determinations of the liquid surface tension of the refractory metals. After a description of the melting apparatus, the amazing reproducibility in terms of droplets masses (≂0.6%) observed is discussed herein. Evidence is given of the harmful action of hydrogen bubbles contained in the commercial rods. Working with very thin wires (down to 0.3 mm), a variation curve for the Harkin’s correction factor of Tate’s law in its untabulated range is proposed. The validity of the representation of this factor is discussed via a dimensional analysis. Finally, new values of σLV for pure Re (2.510 J m−2), W (2.310 J m−2), Ta (2.010 J m−2), Nb (1.840 J m−2), Ir (2.140 J m−2), and Zr (1.435 J m−2) are proposed.