Effect of Processing Parameters on the Diameter and Morphology of Electrospun Iron-Modified Montmorillonite (Fe-MMT)/Polycaprolactone Nanofibers

2020 ◽  
Vol 846 ◽  
pp. 14-22
Author(s):  
Gianina Martha A. Tajanlangit ◽  
Leslie Joy L. Diaz

Iron-modified montmorillonite-filled polycaprolactone nanofiber mats were produced via electrospinning with varying applied voltage, flow rate, needle-tip-to-collector distance, and needle diameter. Scanning electron microscopy (SEM) was used to observe fiber morphology and characteristics. The effects of varying process parameters on various fiber characteristics were evaluated using a two-level fractional factorial experimental design. The effect of voltage on fiber diameter differed with varying flow rate. At 32 ml/hr, the average fiber diameter decreased from 518.38 nm ± 289.37 nm to 466.43 nm ± 312.36 nm when the voltage is increased. At 42 ml/hr the effect of voltage on fiber diameter was reversed. The average fiber diameter was also found to decrease from 516.03 nm ± 283.48 nm to 467.96 nm ± 318.07 nm with decreasing tip-to-collector distance at 32 mL/hr flow rate. The variation of the effect of the factors on fiber diameter was mainly due to a significant loss of material observed at 12 kV and 15 cm tip-to-collector distance. Bead formation was observed for all runs with more beads being formed at 12 kV applied voltage and 15 cm tip-to-collector distance. Spherical beads were observed at 12 kV and 15 cm tip-to-collector distance while spindle-like beads were present in nanofiber membranes spun at high voltage and at the combination of low voltage and low tip-to-collector distance. The parameter setting combination of 19 kV, 32 ml/hr flow rate, 10 cm tip-to-collector distance, and 0.514 mm needle diameter yielded the lowest fiber diameter with the least amount of beading and small bead size. Small fiber diameters and less beading provide larger surface area and more exposure of the Fe-MMT particles for more efficient adsorption.

Author(s):  
Jopeth M. Ramis ◽  
Bryan B. Pajarito ◽  
Custer C. Deocaris

The study presents a method on producing defect-free polyvinyl alcohol-gelatin (PVAG) nanofibers by considering multiple morphological characteristics of the produced nanofibers using the Taguchi method. Aside from minimizing the average fiber diameter, the method was also used to produce consistent, monodispersed PVAG nanofibers without the usual defects of beading and splattering. The experiments are performed considering the effect of polymer composition (PVAG ratio and solvent ratio of water, formic acid, and acetic acid H2O:FA:HAc) and process factors (tip-to-collector distance TCD and solution flow rate) on fiber morphology. Fiber morphology is measured in terms of 4 responses: average fiber diameter, standard deviation of fiber diameter, occurrence of beading, and occurrence of splattering. Results show that maximum overall desirability for electrospinning PVAG nanofibers at smallest average diameter and deviation (26.10 ± 9.88 nm) with chance of moderate beading and zero splattering is predicted at PVAG mass ratio of 6.5:3.5, H2O:FA:HAc solvent volume ratio of 4:4:2, TCD of 12.5 cm, and flow rate of 1 ml h-1. Results of confirmatory run agree with the predicted factor levels at maximum desirability, with average fiber diameter and standard deviation measured to be 26.95 ± 6.39 nm. PVAG nanofibers of the confirmatory run are also both bead-and splatter-free. Results suggest the application of Taguchi method can offer a robust and rapid approach in deriving the conditions for production of new and high-quality PVAG nanofibers for tissue engineering scaffolds.


2013 ◽  
Vol 845 ◽  
pp. 985-988 ◽  
Author(s):  
N.H.A. Ngadiman ◽  
M.Y. Noordin ◽  
Ani Idris ◽  
Denni Kurniawan

Fabrication of nanofibers using electrospinning has recently attracted much attention for various applications due to its simplicity. Electrospinning has the ability to produce nanofibers within 100-500 nm. Some applications require certain fiber diameter. As a relatively new process, there are many electrospinning parameters that are believed to influence the nanofibers diameter. The purpose of this review is to identify and discuss the effect of some of those parameters, i.e. concentration, spinning distance, and applied voltage, and volume flow rate, to the nanofiber diameter during electrospinning process. It was concluded that fiber volume flow rate is proportional to fiber diameter while there is no agreement in reports on other parameters.


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1439
Author(s):  
Hua-Wei Chen ◽  
Min-Feng Lin

In this study, composite nanofibers (SF/PCL/CS) for the application of dressings were prepared with silk fibroin (SF), polycaprolactone (PCL), and chitosan (CS) by electrospinning techniques, and the effect of the fiber diameter was investigated using the three-stage Taguchi experimental design method (L9). Nanofibrous scaffolds were characterized by the combined techniques of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), a cytotoxicity test, proliferation tests, the antimicrobial activity, and the equilibrium water content. A signal-to-noise ratio (S/N) analysis indicated that the contribution followed the order of SF to PCL > flow rate > applied voltage > CS addition, possibly owing to the viscosity and formation of the beaded fiber. The optimum combination for obtaining the smallest fiber diameter (170 nm) with a smooth and uniform distribution was determined to be a ratio of SF to PCL of 1:2, a flow rate of 0.3 mL/hr, and an applied voltage of 25 kV at a needle tip-to-collector distance of 15 cm (position). The viability of these mouse fibroblast L929 cell cultures exceeded 50% within 24 hours, therefore SF/PCL/CS could be considered non-toxic according to the standards. The results proposed that the hydrophilic structure of SF/PCL/CS not only revealed a highly interconnected porous construction but also that it could help cells promote the exchange of nutrients and oxygen. The SF/PCL/CS scaffold showed a high interconnectivity between pores and porosity and water uptake abilities able to provide good conditions for cell infiltration and proliferation. The results from this study suggested that SF/PCL/CS could be suitable for skin tissue engineering.


2020 ◽  
Vol 859 ◽  
pp. 239-243
Author(s):  
Nawinda Chinatangkul ◽  
Sirikarn Pengon ◽  
Suchada Piriyaprasarth ◽  
Chutima Limmatvapirat ◽  
Sontaya Limmatvapirat

The aim of this study was to develop the electrospun shellac (SHL) and hydroxypropyl cellulose (HPC) blended nanofibers for drug carrier application. The effects of polymer solution and electrospinning parameters, including SHL-HPC ratio, HPC concentration, applied voltage and flow rate, on the appearance of fibers were investigated. Based on the results, electrospun fiber was not obtained when a solution of HPC alone was employed. However, the fibers would be obviously fabricated as SHL was added to the HPC solution. An increase in the SHL ratio in SHL-HPC blended solution could accordingly lead to a remarkable enhance in the fiber diameter. In addition, the continuous nanofibers with less beads were gradually formulated when the HPC concentration was increased. The electrospinning parameters seemed to be significant. The elevation of infusion rate from 0.5 to 1 mL/h would contribute to the preparation of thick fibers with the diameters enlarging from 666.9 to 843.5 nm. With the applied voltage increasing from 15 to 30 kV during the electrospinning process, the fabrication of small nanofibers with the diameters reducing from 843.5 to 741.6 nm would be conducted. In this study, monolaurin (ML), a broad antimicrobial agent, was encapsulated into the SHL-HPC carrier for the purpose of drug delivery application. Regarding the result, the loaded concentration of ML could not be enhanced by introducing HPC to the SHL fibers.


Author(s):  
Yuanyuan Duan ◽  
Lohitha Kalluri ◽  
Megha Satpathy ◽  
Yuanyuan Duan

Background: Poly lactic-co-glycolic acid (PLGA) has been widely investigated for various biomedical applications, such as craniofacial bone regeneration, wound dressing and tissue engineering. Electrospinning is a versatile technology used to produce micro/nanoscale fibers with large specific surface area and high porosity. Purpose: The aim of the current study is to prepare PLGA nanofibers using electrospinning for guided tissue regeneration/guided bone regeneration applications. The objective of this study is to determine the appropriate electrospinning parameters such as applied voltage, flow rate, spinneret-collector distance and polymer solution concentration for preparation of PLGA fibrous membrane and their effect on the mean fiber diameter of the electrospun fibers. Method: PLGA pellets were dissolved in Hexafluoroisopropanol (HFIP) in various concentrations overnight using a bench rocker. The resulting PLGA solution was then loaded into a syringe and electrospinning was done by maintaining the other parameters constant. Similarly, various fibrous mats were collected by altering the specific electrospinning parameter inputs such as applied voltage, flow rate and spinneret-collector distance. The morphology of the fibrous mats was characterized using Scanning Electron Microscope. The mean fiber diameter was assessed using ImageJ software and the results were compared using one-way ANOVA. Results: We obtained bead-free uniform fibers with various tested solution concentrations. One-way ANOVA analysis demonstrated significant variation in mean fiber diameter of the electrospun fibers with altering applied voltage, solution concentration, flow rate and spinneret-collector distance. Conclusion: The above-mentioned electrospinning parameters and solution concentration influence the mean fiber diameter of electrospun PLGA nanofibers.


2013 ◽  
Vol 849 ◽  
pp. 337-342 ◽  
Author(s):  
Narissara Kulpreechanan ◽  
Tanom Bunaprasert ◽  
Ratthapol Rangkupan

Electrospinning of polycaprolactone (PCL) in a mixed solvent of dichloromethane (DCM)/dimethylformamide (DMF) with 1:1 volumetic mixing ratio was studied. The effects of solution concentration (5-30 %w/v), applied voltage (10-25 kV), solution flow rate (0.1-2.0 mL/h) and collecting distance (10, 20 cm) on fiber formation and morphology were investigated. The size of PCL fibers obtained were in the range of 10s nm-2.6 μm with either bead on string or smooth fiber morphology. In this study, the solution concentration strongly affected fiber size exponentially. The fiber size also increased with an increase in solution flow rate. The applied voltage and the collecting distance have no or minimal effect on PCL fiber size.


2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Fuat Topuz ◽  
Tamer Uyar

Cyclodextrin (CD) nanofibers have recently emerged as high-performance materials owing to their large surface area-to-volume ratio, along with the presence of high active CD content for their applications in drug delivery and water treatment. Even though there are several studies on the polymer-free electrospinning of CD molecules of different types, the effects of electrospinning process parameters on the morphology and diameter of the resultant fibers have not addressed yet. In this study, the influence of electrospinning process variables on the morphology and diameter of the resultant CD nanofibers is systematically studied using two different solvent systems, i.e., water and N, N-dimethylformamide (DMF). On adjusting the electrospinning process parameters (i.e., electrical field, flow rate, tip-to-collector distance (TCD), and needle diameter), uniform CD nanofibers could be produced from aqueous and DMF solutions. Generally, the electrospinning of thicker fibers was observed by increasing the applied voltage and flow rate due to higher mass flow. Increasing TCD boosted the fiber diameter. Likewise, the use of needles with larger diameters resulted in the electrospinning of thicker fibers from DMF solutions, which might be attributed to higher viscosity due to reduced shear rate.


Author(s):  
Omer San ◽  
Sinan Eren Yalcin ◽  
Oktay Baysal

A micropump is an essential component of a microfluidic lab-on-a-chip device, especially for their biomedical applications. Based on their actuation method to drive the fluid flow, pumps may be categorized as mechanical or non-mechanical devices. In our proposed paper, we will report our comparative study of the most promising micropumps in each of these categories: a piezoelectrically-actuated micropump (PAμP) and an electroosmotic micropump (EOμP). A PAμP requires relatively high applied voltage, but provides high flow rates and has emerged to be the dominant type of micropump in biomedical applications. A valveless diffuser-nozzle micropump, driven by an oscillating membrane, has an important advantage, since the fabrication of any additional moving part, such as a check valve, would add significantly to its cost and render a more failure-prone device. The piezoelectrically actuated, valveless micropumps use moving mechanical parts to pump fluid and control the flow with optimized actuation frequency and applied voltage. In the present study, the microflow-structure interaction in the PAμP is modeled using an arbitrary Lagrangian-Eulerian method including a parametric study of applied voltage and frequency. An EOμP consists of multiple micron-scale channels in parallel that are subjected to the electroosmotic effect. However, a major drawback in the conventional design of an EOμP is the need for a high driving voltage to increase the flow rate or to overcome the back pressure. In the present study, a low-voltage EOμP is proposed and computationally modeled. Our simulations are performed in order to study the low-voltage EOμP for its various flow rate and back pressure characteristics. In the proposed paper, we will discuss our comparisons of PAμP and EOμP, with respect to their actuation mechanisms, applied voltages, pump sizes, flow rates and back pressures.


2021 ◽  
pp. 004051752110039
Author(s):  
Peng Chen ◽  
Qihong Zhou ◽  
Ge Chen ◽  
Qian Zhang ◽  
Shaozong Wang

There is a strong coupling relationship between the process parameters of electrospun polyacrylonitrile (PAN) and its fiber diameter. By examining the mechanism of influence, the quality of electrospun products can be significantly improved and controlled. In this study, a novel idea for predicting and optimizing electrospun PAN process parameters was proposed. First, the control equation of the electrospun PAN was established based on the incompressible Navier–Stokes equation, and the volume force (generated via electric field force, gravity, and surface tension) and jet velocity during electrospinning were solved and analyzed via simulation software. Then, grey correlation analysis was used to calculate the correlation among the three process parameters (applied voltage, feed rate, and distance between the needle and collector) of the electrospun PAN, volume force, jet velocity, and average fiber diameter. Subsequently, the effect of simultaneous changes in multiple process parameters on the average fiber diameter was examined based on the response surface method, and a prediction model was established. Finally, the experimental results indicated that the model can predict the average fiber diameter when multiple process parameters are simultaneously changed. The model predicted the average fiber diameter with an error of only 0.28%, and the optimized minimum fiber average diameter was 235.3 nm (the applied voltage was 12 kV, the distance between the needle and collector was 15.6 cm, the feed rate was 0.37 mL/h). This study provides a theoretical basis for the on-line monitoring of the electrospun PAN.


2011 ◽  
Vol 6 (4) ◽  
pp. 155892501100600 ◽  
Author(s):  
Rohit Uppal ◽  
Gita N. Ramaswamy

In order to manufacture cellulose submicron fibers, electrospinning of cellulose was tried with different solvents. Alpha-cellulose did not dissolve in 6% (w/w) sodium hydroxide/4%urea aqueous solution. Alpha-cellulose solution in 85% phosphoric acid was not spinnable at an applied voltage between 15kV to 25 kV and at a spin length of 4 to 6 inches. Electrospinning of alpha-cellulose in N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent mixture could be performed at an applied voltage of 28 kV and at a spin length of seven inches during spinning and at an ambient temperature of 380C. The degree of crystallinity of the cellulose submicron fibers was found to be 37.88%. The number average fiber diameter of cellulose submicron fibers from 1.25% (w/w) cellulose solution in the N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent was found to be 207 nm and the number average fiber diameter of cellulose submicron fibers from 2.5% (w/w) cellulose solution in the N-methylmorpholine-N-oxide/N-methyl-pyrrolidinone/water solvent mixture was found to be 243 nm.


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