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Needleless Electrospun Nanofibers for Drug Delivery Systems
Published in K.M. Praveen, Rony Thomas Murickan, Jobin Joy, Hanna J. Maria, Jozef T. Haponiuk, Sabu Thomas, Electrospun Nanofibers from Bioresources for High-Performance Applications, 2023
Jolius Gimbun, Ramprasath Ramakrishnan, Praveen Ramakrishnan, Balu Ranganathan
Independent and dependent process parameters were discussed. These parameters were not of much different to the conventional needle based technique. In terms of polymer properties, chemical moiety and concentration played a critical role. Solvent played a role in terms of the intrinsic properties of the solution, that is, electrical conductivity, surface tension, dielectric constant, and viscoelastic components. These parameters are very much qualitatively measurable with precision and accuracy therefore scaling up is very easy. The equipment process parameters being applied, namely high voltage and jet travel distance between the electrodes are adjustable and controllable with good accuracy. Roller speed played a critical role in terms of nanofiber properties. In contrast to conventional needle based electrospinning technique, in this roller based electrospinning technique, new quantitative measurement parameters were evaluated: Taylor cone density per surface area, spinning performance for one Taylor cone, total spinning performance, the fiber diameter uniformity coefficient (FDUC), and the non-fibrous area coefficient (NFA) [12]. Bundled formation of nanofibers was observed using roller electrospinning technique and bundle formation increased the throughput of the electrospinning process, hence making this innovative technology very productive leading to the potential for commercialization [13].
Nanotextiles and Recent Developments
Published in Asis Patnaik, Sweta Patnaik, Fibres to Smart Textiles, 2019
Rajkishore Nayak, Asimananda Khandual
Fabrication of nanofibres by electrospinning using rotational setup dates back to 1980s (Simm et al. 1979). Roller electrospinning process was first developed by Jirsak et al. (2009) at Technical University of Liberec (Czech Republic), as shown in Figure 18.9 (Sasithorn and Martinová 2014). The mechanism of formation of Taylor cones on the surface of roller was described by Lukas et al. (2008). Cengiz and Jirsak (2009) studied the effect of tetraethylammoniumbromide salt on the spinnability of PU nanofibres by roller electrospinning. The roller electrospinning setup consisted of a rotating cylinder to spin nanofibres directly from the polymer solution. An aluminium rotating roller was partially immersed in the PU solution contained in a PP dish. The rotating roller was applied with high voltage, and the collector was grounded. It was found that the salt concentration had an important effect on conductivity, viscosity, fibre diameter and morphology.
Multiple-jet electrospinning methods for nanofiber processing: A review
Published in Materials and Manufacturing Processes, 2018
Hanna Sofia SalehHudin, Edzrol Niza Mohamad, Wan Nor Liza Mahadi, Amalina Muhammad Afifi
Besides wires and coils, other geometries are also used as spinnerets in free-surface electrospinning. An electrospinning method using a rotating cylinder spinneret was invented by Jirsak et al.[118] and commercialized by Elmarco Company in the Czech Republic under the name Nanospider™. Figure 22 shows a typical setup for the rotating cylinder or roller electrospinning. Similar to the rotating wire electrospinning, the rotating cylinder is coated with a thin solution in a liquid bath, and a critical voltage is applied to generate multiple jets and start the electrospinning process.[119] Roller electrospinning, however, produces thicker fibers and requires a higher voltage supply compared to traditional single-needle electrospinning.[120] Wu et al.[121] also developed a roller electrospinning setup with a modified collector to produce patterned fibers at high production rates. Nurwaha and Wang[122] analyzed and compared the performance of rotating cylinder, spiral coil, and straight wire spinnerets in terms of operating parameters and fiber properties. Instead of using a liquid bath, a splashing technique was used to distribute the solution onto the rotating cylinder. Between the three methods, the cylinder spinneret was found to have the lowest voltage requirement and produced fibers with the smallest average diameter. Pokorny et al.[123] also performed electrospinning using a stationary vertical cylindrical rod spinneret, with the solution provided using a syringe. The setup does not require a collector as nanofibrous clouds were formed in the space above the vertical electrode as a result of supplying AC rather than DC voltage.