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1. Electrospinning of Heterogeneous Nanofibers: A Review

   https://doi.org/10.1149/2754-2734/ad86cc  

   Regmi, Dinkar; Choi, Jin_Woo; Xu, Jian (October 2024, ECS Advances)

   Electrospinning is a straightforward approach for efficiently creating continuous fibers within the submicron to nanometer size range. Electrospun fibers possess excellent properties like high porosity, large specific surface area, tunable morphology, small diameter, etc., making them desirable in various applications. Because of its various properties, polymer is one of the most used materials as the spinning solution in electrospinning. Electrospun polymeric fibers, by themselves, may serve limited applications. Therefore, they are usually mixed with other materials to serve many applications. There are many ways in which these other materials are mixed with polymers in electrospinning, like doping, surface treatment, functionalization, etc. There are several studies published that report on the various composite fibers produced using electrospinning. However, a review focused solely on the production of heterogeneous fibers, where the electrospun fibers are intrinsically made of more than one material, is lacking. Herein, we review different heterogeneous fibers synthesized using electrospinning and their fabrication methods. 

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2. Gravity-Driven Ultrahigh-Speed Electrospinning for Green Production of Ethyl Cellulose Nanofibers with Tunable Porosity for Oil Absorption

   Hao, Q; Schossig, J; Davide, T; Towolawi, A; Zhang, C; Lu, P (December 2024, ACS Sustainable Chem. Eng.)

   ABSTRACT: Ethyl cellulose (EC) is a biocompatible, renewable, and recyclable material with diverse sources, making it an attractive candidate for industrial applications. Electrospinning has gained significant attention for the production of EC fibers. However, conventional electrospinning methods face challenges such as bead formation, low yield, and the absence of porous internal structures, limiting both the functional performance and scalability. This study presents an optimized approach for producing EC fibers by using a gravity-driven ultrahigh-speed electrospinning (GUHS-ES) system. This system leverages gravity to reshape the Taylor cone morphology during electrospinning, enhancing stability and dramatically increasing throughput. As flow rates increase, the Taylor cone contracts inward, while the tip structure expands and stabilizes, reaching maximum size at ultrahigh flow rates (100−150 mL/h). This unique Taylor cone structure enables a fiber production rate of 24.5 g/h, hundreds of times greater than conventional electrospinning techniques. Another advantage of the GUHS-ES system is its ability to achieve both high diameter uniformity and adjustable porosity. At ultrahigh flow rates, the pore sizes of the EC fibers reached 321 nm. The highly porous structure of EC fibers exhibited an absorption capacity of 56.6 to 110.7 times their weight, exceeding most previously reported oil-absorbing materials and demonstrating high efficacy for rapid waste oil absorption. This green, efficient technology represents a promising advancement for the large-scale production and application of natural polymer fibers with broad implications for sustainable industrial processes. 

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3. Electrospinning Using AC Electric Fields

   https://doi.org/10.1002/marc.202400907  

   Stanishevsky, Andrei (February 2025, Macromolecular Rapid Communications)

   Abstract Electrospinning 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. 

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4. Expanding the Repertoire of Electrospinning: New and Emerging Biopolymers, Techniques, and Applications

   https://doi.org/10.1002/adhm.202101979  

   Madruga, Liszt_Y_C; Kipper, Matt_J (November 2021, Advanced Healthcare Materials)

   Abstract Electrospinning has emerged as a versatile and accessible technology for fabricating polymer fibers, particularly for biological applications. Natural polymers or biopolymers (including synthetically derivatized natural polymers) represent a promising alternative to synthetic polymers, as materials for electrospinning. Many biopolymers are obtained from abundant renewable sources, are biodegradable, and possess inherent biological functions. This review surveys recent literature reporting new fibers produced from emerging biopolymers, highlighting recent developments in the use of sulfated polymers (including carrageenans and glycosaminoglycans), tannin derivatives (condensed and hydrolyzed tannins, tannic acid), modified collagen, and extracellular matrix extracts. The proposed advantages of these biopolymer‐based fibers, focusing on their biomedical applications, are also discussed to highlight the use of new and emerging biopolymers (or new modifications to well‐established ones) to enhance or achieve new properties for electrospun fiber materials. 

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

   https://doi.org/10.1016/j.ohx.2023.e00501  

   Switz, Alexi; Mishra, Aditi; Jabech, Katrina; Prasad, Anamika (March 2024, HardwareX)

   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. 

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