New Horizons in Modeling and Simulation of Electrospun Nanofibers: A Detailed Review (original) (raw)
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Mathematical Models of Bead-Spring Jets during Electrospinning for Fabrication of Nanofibers
Electrospinning is a popular technique to produce structures in the form of nanofibers. These nanofibers can be used for many applications such as filtration composites, insulator and energy storage. The technique is based on the electrostatic force that acts on the polymeric solution. However, during the electrospinning process the liquid jet shows unstable behavior. This problem causes the random formation of nanofibers. This article focuses on the mathematical models to describe the dynamics behavior of the fluid jet in the electrospinning process. There are a lot of different parameters in the model. Variation in these parameters results in a change in jet behaviors. This brief review is a summary of the authors' recent work. The Reneker's model and Wu's model are used to describe the dynamics behavior of the jet used in electrospinning.
Mathematical modeling in electrospinning process of nanofibers: a detailed review
Electrospinning represents an efficient and versatile technique for fabrication of very thin fibers from polymers or composites. Various polymers have been successfully electrospun into ultrafine fibers in recent years mostly in solvent solution and some in melt form. The efficiency of this process can be improved by adjusting the composition of the solution and the configuration of the electrospinning apparatus, such as voltage, flow rate etc., therefore optimizing the alignment and morphology of the fibers produced. In addition, several applications demand well-oriented and diameter and porosity controlled nanofibers. Thus, recently there has been great interest to optimize this method in order to solve the problems that make electrospinning uncontrollable. Mathematical and theoretical modeling and simulating procedure will permit to offer an in-depth insight into the physical understanding of complex phenomena uring electrospinning d and might be very useful for managing contributing factors toward increasing production rate. In this review article, we give a general outlook of the most common mathematical models for electrospinning, which have been introduced so far, and briefly point out their weak points.
Journal of Applied Polymer Science, 2016
Electrospinning allows the production of ultrafine nanofibers through the stretching of a charged polymer jet with an external electrostatic field. In this study, we derived a simplified and accurate model relating the processing parameters, including the solution volumetric flow rate (Q), the applied electric field (E), and the polymer concentration, to the final fiber diameter. The model takes into consideration the jet behavior starting at the stable region and moving to the bending instability region. We validated the model experimentally by performing the electrospinning process with a polyacrylonitrile/N,N-dimethylformamide solution with different ranges of concentrations (8-11 wt %), Qs (900-1320 lL/h), and Es (88,889-113,889 V/m). The final fiber diameter was measured with scanning electron microscopy. The model predicted the fiber diameter with a relative error of less than 10%.
Analytical – FE simulation of a multi-jet electrospinning process to predict material flow
Simulation Modelling Practice and Theory, 2015
Electrospinning is a technology used for the production of nanometric fibers starting from a solution of material spun by a needle in an electrostatic field. The jet starts from a needle and its diameter is reduced thanks to the instability of the process that stretch the fiber till nanometric dimension. The productivity of a single needle is very low so multiple needles facing the same collector is the simplest and most used apparatus to achieve an adequate productivity. However jets so produced repel each other making their path diverge from the axis of the needles; this effect can be corrected introducing a system of electrostatic lenses. As soon as the diameter of the filament is commonly tens of nanometers the FE simulation of the process in the work area is nearly impossible due to the very large number of elements required. This paper presents an hybrid approach that couple together an analytical analysis with an FE approach in order to reduce the computational time. The developed model is able to predict the divergence of electrospun multi-jets with and without the corrective effect of an electrostatic lens. The developed approach has been validated thanks to laboratory experimental tests that has proven its accuracy. A simulated test campaign using the Design of Experiment approach has been performed to create a mathematical model to predict the deflection of the filaments with different process parameters.
Modeling Electrospinning of Nanofibers
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A fast discrete model for the simulations of thin charged jets produced during the electrospinning process is derived, based on an efficient implementation of the boundary element method for the computation of electrostatic interactions of the jet with itself and with the electrodes. Short-range electrostatic forces are evaluated with slender-body analytical approximations, whereas a hierarchical force evaluation algorithm is used for long-range interactions. Qualitative comparisons with experiments is discussed.
Experiments and modelling of electrospinning process
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Very thin liquid jets can be obtained using electric field, whereas an electrically-driven bending instability occurs that enormously increases the jet path and effectively leads to its thinning by very large ratios, enabling the production of nanometre size fibres. This mechanism, although it was discovered almost one century ago, is not yet fully understood. In the following study, experimental data are collected, with the dual goal of characterizing the electro-spinning of different liquids and evaluating the pertinence of a theoretical model.
Thermo-electro-hydrodynamic model for electrospinning process
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Abstract Ultra-fine polymer fibers, obtained by electrospinning, have a wide range of potential applications such as fluid filtration, biomedicine, catalyst supports, drug delivery, tissue engineering, nanowires, to just say few. Yet theoretical modeling the spinning process remains a bottleneck severely hampering further improvement in both quality and efficiency. This paper establishes a mathematical model to explore the physics behind electrospinning.
Electrospinning Method Used to Create Functional Nanocomposites Films, 2018
Electrospinning, the most favorable process of obtaining nanofibers, is capable of processing solution or melt polymers, ceramic materials or metals in many morphological variants, thus providing diverse functionalities. The chapter reviews the main ways in which nanofibers' characteristics can be influenced by solution parameters, process parameters and ambient conditions, afterwards focusing on the role of some of the most significant electrospinning parameters (applied voltage, flow rate, nozzle to collector distance) on the diameter of the nanofibers. Experimental studies to model the influence of process parameters in the case of electrospinning polyetherimide solutions are presented. Response surface methodology and MATLAB simulation software have been used to obtain the mathematical models that indicate the most favorable parameters.
Multiple jets in electrospinning: experiment and modeling
Polymer, 2005
The electric forces are the main factor responsible for the characteristic jet path and stretching in electrospinning. The present work describes the results of the experimental investigation and modeling of multiple jets during the electrospinning of polymer solutions. Realistic configurations of the external electric field between the electrodes were employed, as well as the linear and non-linear, Upper-Convected Maxwell, models were used to describe the viscoelastic behavior of the polymer jets. The results demonstrate how the external electric fields and mutual electric interaction of multiple charged jets influence their path and evolution during electrospinning. q
Nonlinear Langevin model for the early-stage dynamics of electrospinning jets
Molecular Physics, 2015
We present a non-linear Langevin model to investigate the early-stage dynamics of electrified polymer jets in electrospinning experiments. In particular, we study the effects of air drag force on the uniaxial elongation of the charged jet, right after ejection from the nozzle. Numerical simulations show that the elongation of the jet filament close to the injection point is significantly affected by the non-linear drag exerted by the surrounding air. These result provide useful insights for the optimal design of current and future electrospinning experiments.