Predicted Fiber Diameters Research Articles

Establishment of Unique Cone Shapes and Universal Shape Parameters toward Predicting Fiber Diameter in Polymer Electrospinning

Establishment of Unique Cone Shapes and Universal Shape Parameters toward Predicting Fiber Diameter in Polymer Electrospinning

Central Composite Design and Response Surface Methodology for Optimizing the Diameter of Electrospun Polyamide-6,6 Nanofiber Mat

Electrospinning is a well-established technique for creating submicron polymer fibers to create distinctive functional nanostructures. Electrospinning parameters including solution concentration, tip-to-collector distance and applied voltage are adjusted to produce nonwovens with variable fiber diameter distributions. This research on the response surface methodology (RSM) is being used to model the diameter of a polyamide-6,6 (PA-6,6) nanofiber mat. The experiments were designed using central composite design (CCD) and RSM, which evaluated the interactions between the operating variables (polymer concentration, applied positive voltage, needle tip to collector distance and spinning angle) on the diameter of the PA-6,6 nanofiber. The average nanofiber diameter increased as the concentration of the PA-6,6 polymer solution increased. The model’s strong regression coefficient ([Formula: see text]) reveals that it did a desirable of predicting the diameter of PA-6,6 fibers. The experimental findings and predicted fiber diameters were in good agreement. The results demonstrate that the optimization of electrospinning process to produce the smallest nanofibers and narrowest diameter distribution ([Formula: see text]) combined effects of 10% polymer concentration, 21[Formula: see text]kV applied positive voltage, 18[Formula: see text]cm needle tip to collector distance and 60[Formula: see text] spinning angle are substantial interacting effects that have an impact on the surface response nanofibers. The results of the research and several mathematical models will offer useful guidelines for choosing parameter settings for electrospinning PA-6,6 to achieve the required fiber diameter. By saving time, effort and money more effectively, this research will expand the field of investigation for the quality of electrospun nanofibers.

A Decade of Melt Electrowriting.

Over the past decade, melt electrowriting (MEW) has established the fundamental understanding of processing (and printer) requirements. Iterative work on parametric development and dissemination of this recent additive manufacturing technology has been performed across many systems and polymers (mainly poly-(ε-caprolactone)), showing similarities and trends. However, the software and hardware ecosystems of MEW are not mature. Further, due to its multi-parametric nature, MEW can be challenging for laboratories to master. This review intends to provide a unique perspective on the dynamic relationship between MEW processing parameters. Such parameters can be divided into 1) those that affect the polymer flow rate to or 2) from the nozzle, and 3) environmental conditions. The most influential parameters for high-quality printing are applied voltage, applied pressure, collector speed, polymer temperature, nozzle diameter, and the conditions that lead to charge buildup (e.g., relative humidity). Other factors such as ambient temperature, nozzle size, and protrusion, collector temperature and conductivity, and collector distance can all affect the process. Success for MEW printing means fibers fall onto the collector according to their pre-programmed path with predicted fiber diameter. Here, the authors elucidate how the dynamic relationship between these parameters can converge into ideal printing conditions to produce scaffolds.

Formation Mechanism of Fibrous Web in the Solution Blowing Process.

Solution blowing (SB) is a widely reported technology that can be used to fabricate fibers at the micro- and nanoscale. To reveal the fibrous web formation mechanism in SB, we improved our previous melt blowing (MB) model to predict fibrous web structures. Then, we fabricated two samples and simulated the same number of virtual samples in the computer to verify the model. Thereafter, we measured the structural parameters including the fiber diameter, fiber orientation, basis weight, and pore size. Our model provides a good prediction of the fiber orientation and basis weight. However, the predicted fiber diameter was slightly smaller than the measured diameter. The experimental pore size distribution was also different from that in the simulated results. The model provides a virtual fabrication process to reveal a fibrous web formation mechanism and finds a similar distribution of these structural parameters between SB and MB.

Revealing Novel Power Laws and Quantization in Electrospinning Considering Jet Splitting—Toward Predicting Fiber Diameter and Its Distribution Part II Experimental

Blends of poly‐ϵ‐caprolactone (PCL) with two different molar masses are deliberately varied to change viscosity independent of polymer concentration enabling to separate viscosity and a direct concentration dependence of the fiber diameter in the electrospinning process. Multiple distributions as a result of jet splitting are determined and analyzed. The existence of essentially two modes in fiber diameter frequency distribution, the base mode and the split mode, is revealed, whereas the scaling laws for each mode can be validated according to the latest theory. Finally, the theoretical predicted upper limit of the ratio of standard deviation of fiber diameter and average fiber diameter is validated.

Effects of electrospinning parameters on peanut protein isolate nanofibers diameter

ABSTRACT Electrospinning technology is a common method for preparing ultrafine fibers and nanofibers. Using natural or synthetic polymers as raw materials, fibers with diameters ranging from tens of nanometers to several microns can be prepared. Using hexafluoroisopropanol as solvent, electrospinning was applied to peanut protein, and the resulting fiber morphology was observed by scanning electron microscopy. Using the Box–Behnken design for the response surface method, the solution concentration, voltage, and spinning speed were selected as the three main influencing factors, the peanut protein isolate(PPI) fiber diameter was the object of investigation, and the second-order multiple regression model was established through regression analysis. The results showed that solution mass fraction had the most significant effect on fiber diameter, followed by voltage and spinning speed. The optimal conditions obtained by the simulated annealing algorithm were, as follows: Solution mass fraction, 10%; voltage, 16 kV; spinning speed, 0.6 mL/h. The predicted fiber diameter was 151 nm and the actual fiber diameter obtained experimentally was 164 nm. The fiber diameter predicted by the model was in good agreement with the real value, indicating that the model effectively predicted the diameter of electrospun PPI fiber. The use of response surface methodology to design experiments is of great significance for nanofiber preparation by electrospinning technology.

Using artificial neural networks to model and interpret electrospun polysaccharide (Hylon VII starch) nanofiber diameter

AbstractPresent work was aimed to develop an artificial neural networks (ANN) model to predict the polysaccharide‐based biopolymer (Hylon VII starch) nanofiber diameter and classification of its quality (good, fair, and poor) as a function of polymer concentration, spinning distance, feed rate, and applied voltage during the electrospinning process. The relationship between diameter and its quality with process parameters is complex and nonlinear. The backpropagation algorithm was used to train the ANN model and achieved the classification accuracy, precision, and recall of 93.9%, 95.2%, and 95.2%, respectively. The average errors of the predicted fiber diameter for training and unseen testing data were found to be 0.05% and 2.6%, respectively. A stand‐alone ANN software was designed to extract information on the electrospinning system from a small experimental database. It was successful in establishing the relationship between electrospinning process parameters and fiber quality and diameter. The yield of smaller diameter with good quality was favored by lower feed rate, lower polymer solution concentration, and higher applied voltage.

Revealing Novel Power Laws and Quantization in Electrospinning Considering Jet Splitting—Toward Predicting Fiber Diameter and Its Distribution

Revealing Novel Power Laws and Quantization in Electrospinning Considering Jet Splitting—Toward Predicting Fiber Diameter and Its Distribution

Revealing Novel Power Laws and Quantization in Electrospinning Considering Jet Splitting—Toward Predicting Fiber Diameter and Its Distribution

AbstractA novel physical model is proposed relating fiber diameter and its distribution to various process parameters. Power laws are derived taking into consideration, applied voltage, viscosity, charge density, surface tension, and jet splitting. It is recommended how researchers should analyze their data to separate various effects. In particular, it is possible to predict not only the fiber diameter but also its distribution.

Modeling 3D melt electrospinning writing by response surface methodology

Three-dimensional (3D) melt electrospinning writing (MEW) is a promising technique for 3D printing of porous scaffolds with well-defined geometrical features. The diameter of electrospun fibers strongly affect the achievable resolution and consequently several other physical, mechanical, and structural properties of the fabricated scaffold. However, there are a few process parameters which significantly affect the size of electrospun fibers. In this study, response surface methodology (RSM) was used to investigate the critical and optimized process parameters and their interaction effects on the desired fiber diameter. Four process parameters, including collector speed, tip-to-collector distance, applied pressure, and voltage were studied considering their practical ranges. The results showed that all the parameters except the applied voltage had a significant effect on the printed fiber diameters. A generalized model for the interaction effects of the parameters was introduced which can be used as a framework for selecting the process parameters to achieve the desired fiber diameter. The developed model was validated by choosing random process parameters and printing three-dimensional scaffolds. The results confirm that the predicted fiber diameters match closely with the actual fiber diameters measured directly from the printed scaffold.

Optimization of biodegradable PEG/PLGA nanofiber mats electrospinning process for anti‐adhesion application

ABSTRACTElectrospinning is a direct, continuous, and useful technique to prepare nanofiber by applying electrostatic forces. In this study, poly(lactic‐co‐glycolic acid)/poly(ethylene glycol) (PLGA/PEG) nanofiber mats were prepared, and electrospinning process was optimized to obtain appropriate fiber diameter and hydrophilicity for anti‐adhesion application. Optimization of applied voltage, PEG content, and feeding rate was investigated using response surface methodology. A total of 15 trials were designed to optimize the parameters. Fiber diameter was measured using scanning electron microscopy. Individual and interactive effects of the solution properties were determined. Moreover, the adequacy of the models was verified by validation experiments. For anti‐adhesion test, a nanofiber mat was produced based on the suggested optimum electrospinning conditions. Results showed that optimum fiber diameters were obtained using 7.5% PEG content, applied voltage of 19 kV, and flow rate of 3 mL/h. Experimental results were in good agreement with the predicted fiber diameters. Furthermore, a rat model of sidewall defect‐cecum abrasion was employed to investigate the efficacy of PEG/PLGA in preventing postoperative peritoneal adhesions. Hence, this study provides an overview on the fabrication of PLGA/PEG nanofibers with targeted diameter, which may be used in anti‐adhesion. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46282.

Numerical modeling, simulation, and experimental validation of predicting fiber diameter in wide‐slot positive‐pressure spunbonding process

An air‐drawing model of polypropylene (PP) polymer and an air jet flow field model in wide‐slot positive‐pressure spunbonding process are established. The influences of the density and the specific heat capacity of polymer melt at constant pressure changing with polymer temperature on the fiber diameter have been studied. The predicted fiber diameter agrees with the experimental data as well. The effects of the processing parameters on the fiber diameter have been investigated. The air jet flow field model is solved by means of the finite difference method. The numerical simulation computation results of distribution of the fiber diameter match quite well with the experimental data. The air‐drawing model of polymers is solved with the help of the distributions of the air velocity. It can be concluded that the higher air velocity and air temperature can yield the finer fibers diameter. The higher inlet pressure, longer drawing segment length, smaller air knife edge, longer exit length, smaller slot width, and smaller jet angle can all cause higher air velocity and air pressure along z‐axis position, which are beneficial to the air drawing of the polymer melt and thus to reduce the fiber diameter. The experimental results show that the agreement between the predicted results and the experimental measured data is very better, which verifies the reliability of these models. Also, they reveal great prospects for this work in the field of computer‐assisted design (CAD) of spunbonding process. POLYM. ENG. SCI., 58:1371–1380, 2018. © 2017 Society of Plastics Engineers

A physical–mathematical model for the prediction of fiber diameter of the polyethylene terephthalate (PET) spunbonding nonwoven fabrics

A mathematical model of air drawing of a polyethylene terephthalate (PET) polymer in a spunbonding nonwoven process was established and solved by introducing the numerical computational results of the air jet flow field of the attenuator. The predicted fiber diameters, crystallinities, and birefringences agreed well with the experimental data. The air jet flow field model was solved and simulated by means of the finite difference method. The numerical simulation computation results of distributions of the air velocity matched quite well with the experimental data. The air drawing model of the polymer was solved with the help of the distributions of the air velocity measured by a particle image velocimetry. The effects of the processing parameters on the fiber diameters, measured with the aid of an image analysis method, are further discussed. A lower polymer throughput rate, higher polymer melt initial temperature, higher air initial temperature, higher air initial speed, lower venturi gap, higher air suction speed, and higher quench pressure can all produce finer filament fibers. The results demonstrated the great prospects for this research in the field of computer‐assisted design (CAD) in the spunbonding technology field. POLYM. ENG. SCI., 58:1213–1223, 2018. © 2017 Society of Plastics Engineers

Numerical simulation and experimental investigations of air drawing model and air jet flow field model in wide slot positive pressure spunbonding process

An air drawing model of polymers and a model of the air jet flow field model in wide slot positive pressure spunbonding process are established. The air jet flow field model is solved by means of the finite difference method. The numerical simulation computation results of distributions of the air velocity match quite well with the experimental data. We find that the variation of the density and the specific heat capacity of polymer melt at constant pressure with polymer temperature have much effects on fiber diameter. The newly developed formulas were incorporated into a spunbonding theoretical model to predict the fiber diameter of nonwoven web. The air drawing model of polymer is solved with the help of the distributions of the air velocity measured by a Particle Image Velocimetry (PIV). The predicted fiber diameters agree with the experimental data well. It can be concluded that the higher air pressure, higher air velocity and air temperature can yield the finer fibers diameter. The higher inlet pressure and smaller jet angle will all cause higher x-axis position of air velocity and air pressure, which are beneficial to the air drawing of the polymer melt and thus to reducing the fiber diameter.

Experimental study and numerical simulation the air jet flow field of a dual slot sharp blunt die in the melt blowing nonwoven process

In this work, the physical model of a polymer in a melt blowing process is established and solved by introducing the numerical computation results of the air jet flow field of the dual slot sharp inset die. The influence of the melt blowing processing parameters and the die design parameters on the fiber diameter is also studied. A lower polymer throughput rate, higher polymer melt initial temperature, higher air initial temperature, higher air initial velocity, smaller angle between slot and axis of the spinneret, smaller width of the die head, and larger width of the slot can all produce finer fibers. At the same time, the air jet flow field model of the dual slot sharp inset die of polypropylene polymer nonwovens fabrics in melt blowing process was also established. The air jet flow field model was solved by using the finite difference method. The computational simulation results of the distributions of the z‐components of air temperature and air velocity along the spinline during melt blowing process are in accordance with the experimental data. The air drawing model of melt blowing process was simulated by means of the numerical simulation results of the air jet flow field. The predicted fiber diameter agree with the experimental data. The effects of the air initial velocity and air initial temperature on the fiber diameter were studied and discussed. The results demonstrate that a higher air initial velocity and a higher air initial temperature are beneficial to the air drawing of the polymer melt and thus to reduced fiber diameter. The results show the great potential of this research for computer assisted design in melt blowing nonwoven process and technology. POLYM. ENG. SCI., 57:417–423, 2017. © 2016 Society of Plastics Engineers

Evaluation of Electrospinning Process Parameters of Poly Lactic-Co-Glycolic Acid and Hydroxyapatite Nanocomposite Nanofibrous Scaffolds

Electrospinning recognized as a simple and inexpensive process for producing continuous polymeric nanofibers with diameters ranging from several micrometers down to tens of nanometers. In this study, an electrospun nanofibrous scaffolds based on lactic-co-glycolic acid (PLGA) and nanohydroxyapatite (nano-HA) was developed. The fiber morphology and mean fiber diameter of prepared nanofibers were investigated by scanning electron microscopy. FTIR analysis demonstrated that there were strong intramolecular interactions between the molecules of PLGA and nano-HA. A more systematic understanding of process parameters was obtained and a quantitative relationship between electrospinning parameters and average fiber diameter was established by using response surface methodology. A response surface function was empirically determined by central composite design using fiber diameter as an observed response and the electrospinning parameters such as concentration, distance, applied voltage, temperature and flow rate as variables. The regression coefficient of the model was found to be 0.938. The predicted fiber diameter was in good agreement with the experimental result. PLGA/nano-HA nanofibrous scaffolds could be good candidates for tissue engineering applications.

Fabrication of curcumin-loaded gum tragacanth/poly(vinyl alcohol) nanofibers with optimized electrospinning parameters

This paper focuses on using response surface methodology (RSM) and artificial neural network (ANN) to optimize the diameter of Gum tragacanth (GT)/poly(vinyl alcohol) (PVA) nanofibers. However, producing curcumin-loaded GT/PVA nanofibers with using these optimized conditions is another aim. RSM methodology based on four variables (voltage, feed rate, distance between nozzle and collector, and solution concentration) with three levels and ANN technique were compared for modeling the average diameter of nanofibers. In the RSM method, the individual and interaction effects between the parameters on the average diameter of nanofibers were determined using Box-Behnken design (BBD). Data sets of input–output patterns were used for training the multilayer perceptron (MP) neural networks trained with back-propagation algorithm for modeling purpose. Experimental results for both ANN and RSM techniques showed agreement with the predicted fiber diameter. High-regression coefficient between the variables and the response displayed that the performance of RSM for minimizing diameter of nanofibers was better than ANN. Based on response surface model, optimum conditions (polymer concentration of 4.2% (w/v), distance between the capillary and collector 20 cm, applied voltage of 20 kV and flow rate of 0.5 mL/h) were obtained for producing GT/PVA nanofibers with minimized diameter. Then curcumin-loaded GT/PVA nanofibers were produced with acquired optimum condition and the effect of curcumin concentration (3 and 5% (w/v)) on the morphology, diameter and biological properties of nanofibers was investigated.

Optimization of mechanical and structural properties of PVA nanofibers

In the present study, nanoscaled poly (vinyl alcohol) (PVA) fibers were prepared by electrospinning. An attempt has been made to examine the effects of different process parameters on the mean fiber diameter and tensile strength of poly (vinyl alcohol) nanofibers. Mean fiber diameter and strength of nanofibers were investigated by scanning electron microscopy and universal testing machine, respectively. Response surface methodology was used to establish a quantitative basis for the relationships between the electrospinning parameters such as solution concentration, applied voltage and spinning distance with the diameter of prepared nanofibers and their tensile strength to predict the optimum conditions. The relationships between the responses and the variables were visualized by contour plots. According to the results, solution concentration was found to be the most significant parameters affecting nanofiber diameter. There was no significant difference between the effects of parameters on tensile strength. The fiber diameter increased, but tensile strength decreased by increasing the concentration of the polymer solution. The predicted fiber diameter and strength were in good agreement with the experimental results.

Investigation of drug release from paclitaxel loaded polylactic acid nanofibers

Objective(s): In this study, drug loaded electrospun nanofibrous mats were prepared and drug release and mechanism from prepared nanofibers were investigated. Materials and Methods: Paclitaxel (PTX) loaded polylactic acid (PLA) nanofibers were prepared by electrospinning. The effects of process parameters, such as PTX concentration, tip to collector distance, voltage, temperature and flow rate on the mean diameter of electrospun PTX loaded PLA nanofibers were investigated. Scanning electron microscopy (SEM) was used to investigate the fiber morphology and mean fiber diameter of prepared nanofibers. Response surface methodology was used to model the average diameter of electrospun PLA/PTX nanofibers. Results: The predicted fiber diameter was in good agreement with the experimental result. In Vitro drug release in phosphate buffer solution (PBS) and acetate buffer for the produced samples showed that diffusion is the dominant drug release mechanism for PTX loaded ubers. Conclusion: Electrospinning was shown to be very promising approach to the formulation of Paclitaxel in order to enhance its release in a sustained and prolonged manner.

Doxorubicin release from optimized electrospun polylactic acid nanofibers

Electrospinning has been known as an efficient method for fabrication of polymer nanofibers. In this study, an electrospun nanofibrous mats based on polylactic acid with a defined release using doxorubicin was developed. The effects of process parameters, such as concentration, distance, applied voltage, temperature and flow rate on the mean diameter of electrospun doxorubicin-loaded polylactic acid nanofibers were investigated. The fiber morphology and mean fiber diameter of prepared nanofibers were investigated by scanning electron microscopy. Differential scanning calorimetry was employed to identify the presence of doxorubicin within nanofibers. Response surface methodology based on a five-level, five-variable central composite design was used to model the average diameter of electrospun polylactic acid/doxorubicin nanofibers. Mean fiber diameter was correlated to these variables by using a polynomial function at a 95% confidence level. The coefficient of determination of the model was found to be 0.93. The predicted fiber diameter was in good agreement with the experimental result. Differential scanning calorimetry results showed that the doxorubicin was loaded into the nanofibers successfully. In vitro drug release in phosphate-buffered solution and acetate buffer for the optimized and non-optimized samples demonstrated that diffusion is the dominant drug release mechanism for drug-loaded fibers. The initial burst release was observed for non-optimized nanofibers compared to optimized nanofibers. Optimized drug-loaded polylactic acid nanofibers could be good candidates for biomedical applications.