Nanofibrous mats are interesting scaffold materials for biomedical applications like tissue engineering due to their interconnectivity and their size dimension which mimics the native cell environment. Electrospinning provides a simple route to access such fiber meshes. This thesis addresses the structural and functional control of electrospun fiber mats. In the first section, it is shown that fiber meshes with bimodal size distribution could be obtained in a single-step process by electrospinning. A standard single syringe set-up was used to spin concentrated poly(ε-caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA) solutions in chloroform and meshes with bimodal-sized fiber distribution could be directly obtained by reducing the spinning rate at elevated humidity. Scanning electron microscopy (SEM) and mercury porosity of the meshes suggested a suitable pore size distribution for effective cell infiltration. The bimodal fiber meshes together with unimodal fiber meshes were evaluated for cellular infiltration. While the micrometer fibers in the mixed meshes generate an open pore structure, the submicrometer fibers support cell adhesion and facilitate cell bridging on the large pores. This was revealed by initial cell penetration studies, showing superior ingrowth of epithelial cells into the bimodal meshes compared to a mesh composed of unimodal 1.5 μm fibers. The bimodal fiber meshes together with electrospun nano- and microfiber meshes were further used for the inorganic/organic hybrid fabrication of PCL with calcium carbonate or calcium phosphate, two biorelevant minerals. Such composite structures are attractive for the potential improvement of properties such as stiffness or bioactivity. It was possible to encapsulate nano and mixed sized plasma-treated PCL meshes to areas > 1 mm2 with calcium carbonate using three different mineralization methods including the use of poly(acrylic acid). The additive seemed to be useful in stabilizing amorphous calcium carbonate to effectively fill the space between the electrospun fibers resulting in composite structures. Micro-, nano- and mixed sized fiber meshes were successfully coated within hours by fiber directed crystallization of calcium phosphate using a ten-times concentrated simulated body fluid. It was shown that nanofibers accelerated the calcium phosphate crystallization, as compared to microfibers. In addition, crystallizations performed at static conditions led to hydroxyapatite formations whereas in dynamic conditions brushite coexisted. In the second section, nanofiber functionalization strategies are investigated. First, a one-step process was introduced where a peptide-polymer-conjugate (PLLA-b-CGGRGDS) was co-spun with PLGA in such a way that the peptide is enriched on the surface. It was shown that by adding methanol to the chloroform/blend solution, a dramatic increase of the peptide concentration at the fiber surface could be achieved as determined by X-ray photoelectron spectroscopy (XPS). Peptide accessibility was demonstrated via a contact angle comparison of pure PLGA and RGD-functionalized fiber meshes. In addition, the electrostatic attraction between a RGD-functionalized fiber and a silica bead at pH ~ 4 confirmed the accessibility of the peptide. The bioactivity of these RGD-functionalized fiber meshes was demonstrated using blends containing 18 wt% bioconjugate. These meshes promoted adhesion behavior of fibroblast compared to pure PLGA meshes. In a second functionalization approach, a modular strategy was investigated. In a single step, reactive fiber meshes were fabricated and then functionalized with bioactive molecules. While the electrospinning of the pure reactive polymer poly(pentafluorophenyl methacrylate) (PPFPMA) was feasible, the inherent brittleness of PPFPMA required to spin a PCL blend. Blends and pure PPFPMA showed a two-step functionalization kinetics. An initial fast reaction of the pentafluorophenyl esters with aminoethanol as a model substance was followed by a slow conversion upon further hydrophilization. This was analysed by UV/Vis-spectroscopy of the pentaflurorophenol release upon nucleophilic substitution with the amines. The conversion was confirmed by increased hydrophilicity of the resulting meshes. The PCL/PPFPMA fiber meshes were then used for functionalization with more complex molecules such as saccharides. Aminofunctionalized D-Mannose or D-Galactose was reacted with the active pentafluorophenyl esters as followed by UV/Vis spectroscopy and XPS. The functionality was shown to be bioactive using macrophage cell culture. The meshes functionalized with D-Mannose specifically stimulated the cytokine production of macrophages when lipopolysaccharides were added. This was in contrast to D-Galactose- or aminoethanol-functionalized and unfunctionalized PCL/PPFPMA fiber mats. / Biofunktionale Materialien gewinnen immer größere Bedeutung in biomedizinischen Anwendungen wie dem künstlichen Ersatz von Knochen oder Blutgefässe. Weiterhin können diese Stoffe nützlich sein, um die Wechselwirkung zwischen Biomaterialien und biologischen Systemen wie Zellen oder Organismen weiter zu erforschen. In diversen Studien konnten Größen wie dreidimensionaler Strukturaufbau, Oberflächentopographie, Mechanik und die Funktionalisierung mit bioaktiven Substanzen als Einflussfaktoren identifiziert werden, welche auf verschiedenen Größenskalen von makroskopisch bis nanoskopisch untersucht wurden und gegenwärtig erforscht werden. Bioinspiriert von Kollagenfasern, die als Strukturmotiv an verschieden Orten im menschlichen Körper vorkommen (z.B. extrazelluläre Matrix) konnte gezeigt werden, dass Fasermatten, die eine ähnliche Größendimensionen wie die vorher erwähnten Kollagenfasern (Ø ~ 500 nm) aufweisen, eine aussichtsreiche Gerüstmatrix darstellen. Eine einfache Methode Fasermatten in diesen Dimensionen herzustellen ist Elektrospinning, wobei typischerweise eine viskose Polymerlösung durch anlegen eines Hochspannungsfeldes verstreckt wird. Obwohl auf diese Weise hergestellte Fasermatten für gewisse Zelllinien eine ideale Zellwechselwirkung aufweisen, ist die Zellbesiedelung solcher Netzwerke, bedingt auch durch die kleinen Porendurchmesser, problematisch und bedarf meistens weiterer Prozessierungsschritte. Diese Arbeit beschäftigt sich mit der einfachen Herstellung von strukturel und funktional kontrollierten Fasersystem mittels Elektrospinning. Der erste Teil behandelt ein Einschrittverfahren zum Elektrospinnen von bimodalen Fasermatten bestehend aus Nano- und Mikrofasern. In Zellstudien mit Epithelzellen konnte gezeigt werden, dass solche Netzwerke tiefer besiedelt werden als Matten bestehend aus unimodalen 1.5 μm dicken Fasern. Des Weiteren wurden diese Fasermatten für fasergerichtete Kristallisation von Kalziumcarbonat und – phosphat benutzt. In einem zweiten Teil wurden 2 Strategien für die Faserfunktionalisierung mit Peptiden und Zuckermolekülen entwickelt. Zum einen wurde gezeigt, dass funktionale Peptidfasern durch Verspinnung einer Mischung von einem Peptid-Polymer-Konjugat mit einem kommerziellen Polymer hergestellt werden konnten. Zusätzlich wurde ein modularer Ansatz für die Herstellung von reaktiven Fasern ausgearbeitet, die anschließend mit Peptiden oder Zuckern funktionalisiert wurden. Die Bioaktivität der Zucker funktionalisierten Fasern konnte durch Zellversuche erfolgreich bestätigt werden.

Damage to synovial joints results in osteochondral defects that only heal with inferior fibrous repair tissue. Since mesenchymal stem cells (MSCs) play a vital role in the natural development, maintenance, and repair of cartilage and bone, tissue engineering strategies to enhance functional regeneration by modulating MSC differentiation are a promising alternative to the limitations and potential complications associated with current conventional therapies. In this work, signals present in the native microenvironment were utilized in fabricating polymer/extracellular matrix composite scaffolds to guide chondrogenic and osteogenic differentiation. In an osteochondral defect environment, interactions exist between bone marrow cell populations. Although MSCs have been extensively utilized for their ability to support hematopoietic stem and progenitor cells (HSPCs), the role of HSPCs in regulating the osteogenic differentiation of MSCs in the bone marrow niche is not well understood, and thus was explored via direct contact co-culture. HSPCs in a low dose with sustained osteogenic induction by dexamethasone accelerated osteogenesis and enhanced mineral deposition, whereas the lack of induction signals affected the spatial distribution of cell populations and minerals. Thus, HSPCs presumably play an active role in modulating the development and maintenance of the osteogenic niche. Since physical signals affect cellular activity, flow perfusion culture was employed to deposit mineralized extracellular matrix (ECM) with different maturity and composition on electrospun poly([varepsilon]-caprolactone) (PCL) microfibers in fabricating mineralized PCL/ECM composite scaffolds. The presence of mineralized matrix induced the osteogenic differentiation of MSCs even in the absence of dexamethasone, and a more mature matrix with higher quantities of collagen and minerals improved osteogenesis by accelerating alkaline phosphatase expression and matrix mineralization. To determine whether PCL/ECM scaffolds can be applied to support the chondrogenic differentiation of MSCs, cartilaginous PCL/ECM composite scaffolds were fabricated. The presence of cartilaginous matrix reduced fibroblastic phenotype and in combination with transforming growth factor-β1 (TGF-β1), further promoted chondrogenesis as evident in elevated levels of glycosaminoglycan synthetic activity. While further investigation is necessary to optimize and test these scaffolds to induce the regeneration of cartilage and bone, this work demonstrates the importance of harnessing signals present in the native microenvironment to modulate chondrogenic and osteogenic differentiation.

Nanofibres have been the subject of recent intensive research due to their unique properties, especially their large surface-area-to-volume ratio, which is about one thousand times higher than that of a human hair. They also have several other remarkable characteristics, such as flexibility in surface functionality, superior mechanical properties such as stiffness and tensile strength, their capacity to be formed into a variety of shapes, and the fact that they can be produced from a wide range of organic and inorganic polymers. These outstanding properties make polymer nanofibres the optimal candidates for providing significant improvement in current technology and for opening the door to novel applications in many research areas. Electrospinning is a straightforward and inexpensive process that produces continuous nanofibres from submicron diameters down to nanometre diameters. Many researchers have successfully electrospun a variety of polymer solutions into nanofibres. However, electrospinning any polymer solution directly is not straightforward or simple because of the number of parameters that influence the electrospinning process. The characteristics of the electrospun jet and the morphology of the resultant fibres are highly dependent on the properties of the polymer solution. In addition, what are favourable processing conditions for one polymer solution may not be suitable for another solution. A literature review revealed that there is no clear understanding of the behaviour of the electrospun jet and the way in which fibre morphology varies with variations in influential parameters. In addition, reported results contain significant inconsistencies and very little research has examined the effects of electrical parameters such as the electric field, the polarity of the electrode, and the conductivity and permittivity of the solution. Furthermore, no research has been conducted with respect to optimizing the electrospinning process. In this thesis, a comprehensive study was carried out by giving a special attention to the effects of electric field that have not been thoroughly investigated in the past. The electric field between the needle tip and the collector plate was altered by varying the applied voltage, distance between the needle tip and the collector plate, the inner diameter of the needle, and polarity of the voltage. Based on the experimental work, it was found that the behavior of Taylor cone, the length of the straight jet portion, and whipping jet region is highly influenced by the distribution of the electric field between the needle tip and the collector plate. Based on the stability of the Taylor cone, it was concluded that the stable operating region of the electrospun jet is a very narrow region and it is between 0.9 – 1.1kV/mm for the range of experiments that were carried out in this study. The length of the straight jet portion of the electrospun jet shows a linear relationship to the applied electric field at the tip of the fluid droplet and the whipping jet region is influenced by both the electric field at the tip of the fluid droplet and the distance between the needle and the collector plate. A confirmation were made that there must be enough distance between the needle tip and the collector plate (>200mm) to operate over the complete range of voltages without affecting drying of nanofibres. It was also concluded that the morphology and diameter of the collected nanofibres depend significantly on both the length of the straight jet portion and size of the whipping region. The effects of polarity of the applied voltage on the electrospinning process and nanofibre morphology were investigated using the positive, negative, and AC voltages. However, it was found that the electrospinning can not be achieved with the application of 60Hz AC voltage. It was observed that the behavior of Taylor cone, the straight jet portion, and the whipping jet region depend on the polarity of the applied voltage. During the study, it was accomplished that the reason for this different behavior is the disparity of ionization in the polymer solution with the application of positive and negative high voltages. In this thesis, the effects of multi-needle arrangements on the electrospinning process and fibre morphology were also explained. Finite element method (FEM) simulation results revealed that the local electric field strength around each needle tip weakens significantly in the case of multi-needle schemes due to the mutual influence of other needles in the arrangement compared to the single-needle system. The spacing between the needles was varied, and the effects of the needle spacing were examined. The experimental and simulation results were concealed the correlation between the degree of field distortion and the variation in the measured vertical angle of the straight jet portion for different needle spacing. It was concluded that the local field deterioration at the needle tips in multi-needle schemes degrades the electrospinning process significantly and produces considerable variation in the fibre morphology even though the influence of needle spacing on the average jet current and the fibre diameter are not very significant. In this work, the effects of conductivity and ionic carriers on the process of electrospinning and hence on the morphology of nanofibres were studied using polyethylene oxide (PEO) and polyacrylic acid (PAA) aqueous solutions. Different salts including lithium chloride (LiCl), sodium chloride (NaCl), sodium fluoride (NaF), sodium bicarbonate (NaHCO3), potassium chloride (KCl), and cesium chloride (CsCl) were added in different concentrations to the polymer solutions for introducing different ionic carriers into the solution. The results showed that the average fiber diameter decreases with increase in the conductivity of the solution. In addition, it was discovered that the formation of Taylor cone highly depends on the conductivity in the polymer solution. Formation of multi-jets at the fluid droplet when the conductivity of the polymer solution is increased during the electrospinning was also observed. These behaviors were completely explained using the distribution of the surface charge around the electrospun jet and the variation in the tangential electric field along the surface of the fluid droplet. The stretching of the polymer jet can be related to the amount of ionic carries and the size and mobility of positive and negative ions. The increasing amount of ionic carriers and smaller size positive ions enhance the stretching of the electrospun jet. In contrast, the lesser diameter negative ions decrease the stretching of the electrospun jet. The morphology of electrospun nanofibres can also be varied by altering the type of ionic carriers. A charge modifier, which is a container that is used to hold a solvent surrounding the needle tip during the electrospinning, was introduced to facilitate the electrospinning of insulating and high conductivity polymer solutions. The co-axial flow of the filled solvent on the outer surface of the polymer solution helps to induce enough surface charges during electrospinning and it also keeps the electric field tangential to the fluid surface during the process. Therefore, the introduction of charge modifier greatly enhanced the electrospinning behavior of highly insulating and conductive polymer solutions and liquids. The developed charge modifier method was verified by using sodium alginate which is a biopolymer that cannot electrospin alone due to its high electrical conductivity and silicone rubber which is an insulating liquid polymer at room temperature. One of the most commonly used theoretical model of the electrospinning process was modified to incorporate the non-uniform characteristics of the electric field at the tip of the needle. The non-uniform electric field between the needle tip (spinneret) and the collector plate was calculated based on the charge simulation technique (CST). It gives a better representation of the true electrospinning environment compared to the uniform field calculation in the existing model. In addition, a localized approximation was used to calculate the bending electric force acting on the electrospinning jet segments. It was also introduced a constant velocity to initiate the electrospinning jet during simulation. The incorporated modifications gave better results that closely match with the real electrospinning jet. The modified electrospinning model was used to understand the effects of parameters on the electrospinning process and fibre morphology.

In this study, with near-field electrospinning technique of PVDF (Polyvinylidene fluoride) piezoelectric nano-fibers and the additional multiwalled-carbon nanotubes(MWCNT), both mechanical strength and piezoelectric characteristics of a single nano-fiber were discussed. Then the behavior of piezoelectric fiber actuators was realized using inverse piezoelectric effect. Near-field electrostatic technology can be used to fabricate PVDF piezoelectric fibers with an excellent piezoelectric property compared with film structures due to a higher piezoelectric coefficient and energy conversion efficiency. It is more suitable to produce micro transducers. By adjusting velocity of a fully parametric x-y stage, DC voltage, and the distance between the needle and collection plate, the morphology and polarization intensity of piezoelectric fiber can fully be controlled. In addition, the optimal parameters of PVDF solution such as PVDF powder weight percentage and MWCNT were also discussed. From the observation of XRD (X-ray diffraction), it reveals a high diffraction peak at 2£c=20.8¢X of piezoelectric crystal £]-phase structure. Finally, the actuation property was tested using DC voltage supply, and fiber has significant deflection in the experiment. The vertical deflection can be observed and compared with model solution of piezoelectric cantilever structure. In the fiber¡¦s direct piezoelectric effect, the result shows that fiber can produce an open circuit voltage of 15mV under a low frequency vibration of 7Hz.

This study used electrospinning to fabricate a polyvinylidene fluoride (PVDF) piezoelectric nanofiber harvesting device with interdigitated electrode to capture ambient energy. According to d33 mechanical-electric energy conversion mode, the energy harvesting device can be applied on the low frequency ambient vibration and impact abilities for the transformation mechanical energy into electrical energy effectively. First, the PVDF powder was mixed in acetone solution uniformly and the dimethyl sulfoxide (DMSO) was mixed with multi-walled carbon nanotube (MWCNT) to prepare PVDF macromolecular solution. The mixed solution was filled in a metals needle injector and contacted hundreds of voltage. After the PVDF drop in the needle was subjected to high electric field, the drop overcame surface tension of the solution itself, then extremely fine PVDF fiber was formed and spun out. The electrospun was collected orderly using X-Y digital control stage and the linear diameter of electrospun can be controlled easily by adjusting the travelling speed of the stage. In the spinning process, as affected by stretching strain and electric field at the same time, the PVDF piezoelectric fiber resulted in electric polarization and transformed £] piezoelectric crystal phase, in which the dipoles are oriented in the same direction. Furthermore, MWCNT was added to improve the mechanical properties of fiber and increase £] phase, to enhance the tensile strength and piezoelectric property of PVDF fiber effectively. Finally, the photolithography was used to fabricate interdigitated electrodes with 100£gm gap on the flexible PI substrate. The PVDF fibers, with a length and diameter of approximately 1cm and 700-1000nm, were aligned on interdigitated electrodes and packaged with the PI film. In order to increase the conversion efficiency of piezoelectric fiber in d33 mode, the PVDF fibers were repolarized in a high electric field. The results showed that the PVDF fiber energy harvesting device can generate 15mV open-circuit voltage under low frequency vibration of 4Hz and generate above 30mV open-circuit voltage under 6Hz vibrations. As compared with the piezoelectric fiber not repolarized by interdigitated electrode, its output voltage was increased by1- 2 times.

In this study, a cylindrical near-field electrospining (CNFES) process will be used to fabricate permanent piezoelectricity of polyvinylidene fluoride (PVDF) piezoelectric fibers, and a piezoelectric fiber harvesting device with parallel electrode was fabricated to capture ambient energy. First, the PVDF powder was mixed in acetone solution uniformly and the dimethyl sulfoxide (DMSO) was mixed with fluorosurfactant to prepare PVDF macromolecular solution. The PVDF macromolecular solution was filled in a metals needle injector and contacted a high power supply, after the PVDF drops in the needle was subjected to high electric field, the drops became a Taylor cone and overcame surface tension of the solution itself, extremely fine PVDF fiber was formed and jetted out. The fibers were collected numerous and quickly by homemade cylindrical collector and the diameter of fiber could be controlled easily by adjusting the rotating speed of the cylinder and the electric field. From the observation of XRD (X-ray diffraction), it reveals a high diffraction peak at 2£c=20.7¢X of piezoelectric crystal £]-phase structure by adjusting PVDF concentrations and DC voltage. By providing 7Hz shake and 0.23% strain, the piezoelectric fiber harvesting device with parallel electrode could generate 76mV; by providing 7Hz shake and 0.14% strain, the device could generate 1.1nA.

Nanochannel devices have been explored over the years with wide applications in bio/chemical analysis. With a dimension comparable to many bio-samples, such as proteins, viruses and DNA, nanochannels can be used as a platform to manipulate and detect such analytes with unique advantages. As a prerequisite to the development of nanochannel devices, various nanofabrication techniques have been investigated by many researchers for decades. In this dissertation, three different fabrication approaches for nanochannels are discussed, including a novel scanning coaxial electrospinning process, a heat-induced stretching approach and a standard contact photolithography process. The scanning coaxial electrospinning process is established based on conventional electrospinning process. A coaxial jet, with the motor oil as the core and spin-on-glass-coating/PVP solution as the shell, is deposited on the rotating collector as oriented coaxial nanofibers. These nanofibers are then annealed to eliminate the core material and form the hollow interior. Silica nanochannels with an inner diameter as small as 15 nm were obtained. The heat-induced stretching approach includes using commercially available fused silica tubings to create nanochannels by thermal deforming. This method and the electrospinning technique both focus on fabricate one-dimensional nanochannels with a circular opening. Fluorescent dye was used as a testing sample for single molecule detection and electrokinetic analysis in the resultant nanochannels. Another nanochannel device described in this dissertation has a deep-shallow step structure. It was fabricated by standard contact lithography, followed by etching and bonding. This device was applied as a powerful detection platform for surface-enhanced Raman spectroscopy (SERS). The experiment results proved that it is able to highly improve the sensitivity and efficiency of SERS. The SERS enhancement factor obtained from the device is 108. Moreover, the molecule enrichment effect of this device provides an extra 105 enhancement. The detection can be efficiently finished within minutes after simply loading the mixture of analytes solution and gold nanoparticles in the device. The sample consumption is in micro-liter range. Potential applications in diagnostics, prognositics and water pollutants detection could be achieved using this device.

Today, ceramic, polymer, and composite nanofibers are among the most charming materials for nanotechnology. Because of their small characteristic dimension, high surface area, and microstructural features, they provide unique mechanical, optical, electronic, magnetic, and chemical properties for an extensive variety of materials applications. Electrospinning provides an effective way of the nanofiber production in a nanometer scale. This technique utilizes a high voltage DC to create a strong electric field and a certain charge density in a viscous solution contained in a pipette. As a result, fibers with diameters ranging from the micrometer to nanometer are formed from this charged solution. This study deals with, the fabrication of alumina borosilicate ceramic nanofibers using electrospinning technique. Alumina borosilicates contain important components having intriguing characteristics for many applications and have been widely studied with different compositions. In this study, alumina borosilicate/PVA solution was prepared using the conventional sol-gel method. Polyvinyl alcohol (PVA) was added into this solution to increase the viscosity for electrospinning. After the alumina borosilicate/PVA solution was electrospun into fibers, high temperature sintering was carried to obtain ceramic alumina borosilicate fibers. The products were characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform-infrared spectroscopy (FT-IR), and thermogravimetric/differential thermal analysis (TG-DTA) techniques.

In this study a microbial polyester, poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and its blends were wet or electrospun into fibrous scaffolds for tissue engineering. Wet spun fiber diameters were in the low micrometer range (10-50 &amp / #956 / m). The polymer concentration and the stirring rate affected the properties the most. The optimum concentration was determined as 15% (w/v). Electrospun fiber diameters, however, were thinner. Solution viscosity, potential, distance between the syringe tip and the collector, and polymer type affected the morphology and the thickness of beads formed on the fibers. Concentration was highly influential / as it increased from 5% to 15% (w/v) fiber diameter increased from 284 &plusmn / 133 nm to 2200 &plusmn / 716 nm. Increase in potential (from 20 to 50 kV) did not lead to the expected decrease in fiber diameter. The blends of PHBV8 with lactide-based v polymers (PLLA, P(L,DL-LA) and PLGA (50:50)) led to fibers with less beads and more uniform thickness. In vitro studies using human osteosarcoma cells (SaOs-2) revealed that wet spun fibers were unsuitable because the cells did not spread on them while all the electrospun scaffolds promoted cell growth and penetration. The surface porosities for PHBV10, PHBV15, PHBV-PLLA, PHBV-PLGA (50:50) and PHBV-P(L,DL)LA were 38.0&plusmn / 3.8, 40.1&plusmn / 8.5, 53.8&plusmn / 4.2, 50.0&plusmn / 4.2 and 30.8&plusmn / 2.7%, respectively. Surface modification with oxygen plasma treatment slightly improved the cell proliferation rates. Consequently, all scaffolds prepared by electrospinning revealed a significant potential for use in bone tissue engineering applications / PHBV-PLLA blend appeared to yield the best results.

Nanofibers, which have high surface area to volume ratio and better mechanical properties, are nanomaterials that both industry and scientists have started to show great attention in the last two decades. They are used in many areas such as life and filtration sciences, sensors, and composite reinforcement etc. Among five main production types, electrospinning is the best candidate for further development with a wide range of opportunities to be applied to all types of polymers and ceramics. This method uses electrically charged jet of polymers or liquid states of polymers to produce fibers from micro dimensions down to nano dimensions. Electrospinning setup has mainly three parts / (i) an AC/DC high voltage equipment which creates high electrical potential, (ii) a syringe, and (iii) a collecting screen. The purpose of this study is to electrospin polystyrene/butyl rubber blends and to investigate the effects of electrospinning parameters on the fibers produced. In this study, polystyrene/butyl rubber blends were electrospun by changing the applied voltage, the tip-to-collector distance, the flowrate, and the butyl rubber content in the fiber. Finally, morphology of electrospun fibers was characterized by SEM. The average fiber diameters varied from 760 nm to nearly 10 &micro / m. Increasing butyl rubber content in the fiber resulted in a decrease in the final fiber diameter. Increasing applied voltage also caused a decrease in the final fiber diameter. The tip-to-collector distance did not affect the average fiber diameter. Increasing flowrate yielded fibers with larger diameters. Finally, the addition of non-ionic surfactant decreased the average fiber diameter.