Fiber Packing Density Research Articles

Influence of Constituents on Strength and Flowability in Ultra High-Performance Concrete

Ultra-High-Performance Concrete (UHPC) boasts superior features like excellent flowability, mechanical properties, and durability. These features are achieved by adopting low water-to-binder ratio (w/b), good particle packing density and high dosage of steel fibers. This study mainly focused on the development of the optimized UHPC mixes by considering locally available materials. The impact of different composition of ordinary Portland cement (OPC) with different CaO/SiO2 ratio (4.31, 4.37, 4.49, 4.53, 4.60 and 4.82) on the compressive strength and flowability were investigated to ensure versatility across projects. The compressive strength of UHPC mixes by using various types of fine aggregates namely, manufactured sand, standard sand, river sand and quartz sand were also investigated. Also, the compressive strength as well as flowability of UHPC were studied by varying the fiber content of 0%, 1%, 1.5%, 2%, 2.5% and 3%. The results reveal that the compatibility of OPCs with varying CaO/SiO2 ratios has minimal impact, whereas different sand types significantly influence both flowability and compressive strength of UHPC mixes. Considering cost, availability & performance, M Sand and quartz sand can be used for the development of UHPC. Also, observed that increase in fiber content enhances the compressive strength while negatively influencing the flowability.

Effect of artificial lung fiber bundle geometric design on micro- and macro-scale clot formation.

The hollow fiber membrane bundle is the functional component of artificial lungs, transferring oxygen to and carbon dioxide from the blood. It is also the primary location of blood clot formation and propagation in these devices. The geometric design of fiber bundles is defined by a narrow set of parameters that determine gas exchange efficiency and blood flow resistance, principally: fiber packing density, path length, and frontal area. These same parameters also affect thrombosis. This study investigated the effect of these parameters on clot formation using 3D printed flow chambers that mimic the geometry and blood flow patterns of fiber bundles. Hollow fibers were represented by an array of vertical micro-rods (380 μm diameter) arranged with three packing densities (40%, 50%, and 60%) and two path lengths (2 and 4 cm). Blood was pumped through these devices corresponding to three mean blood flow velocities (16, 20, and 25 cm/min). Results showed that (1) clot formation decreases dramatically with decreasing packing density and increasing blood flow velocity, (2) clot formation at the outlet of the fiber bundle enhances deposition upstream, and consequently (3) greater path length provides greater clot-free fiber surface area for gas exchange than a shorter path length. These results can help guide the design of less thrombogenic, more efficient artificial lung designs.

Design and optimization of gradient fibrous media using the method of moments

The goal of this work is to optimize the deposition mass distribution of polydisperse particles inside the fibrous media by modifying the distribution of the fiber packing density across filter depth. Two types of gradient fibrous media with linear and exponential fiber packing density distribution along the flow direction were derived. The method of moments was employed to study the transport and deposition characteristics of polydisperse aerosol particles inside the fibrous media. The reliability of the calculated results by the method of moments was confirmed by the numerical simulations based on the discrete phase model (DPM). Results indicate that the gradient fibrous media allows more particles to transport and deposit into the interior of the fibrous media, which improves the uniformity of particle deposition distribution across filter depth. There exists an optimal fiber packing density distribution ratio for the gradient fibrous media where the non-uniformity of deposition mass distribution of polydisperse particles across filter depth is minimized. In this way, uniform deposition distribution along the flow direction can be generally achieved by optimizing the fiber packing density distribution, which will contribute to the optimal design of microstructures for the fibrous filter.

Submicron PAN and nanofiber CTA air filters: Fabrication, optimization, and performance

This study investigates the fabrication, optimization, and performance of submicron polyacrylonitrile (PAN) and nanofiber cellulose triacetate (CTA) air filters produced through electrospinning. PAN fibers with diameters ranging from 379 to 804 nm were generated from PAN/DMF solutions, while genuine CTA nanofibers (65–102 nm) were successfully produced using a recycled CTA polymer and a binary solvent system (DMSO/TCM). The effects of electrospinning parameters, including solution concentration (10–12 wt% for PAN, 8 wt% for CTA), applied voltage (10–16 kV), tip-to-collector distance (16–24 cm), solution supply rate (0.08–0.10 mL/hr), and binary solvent ratio (7:1 to 20:1 DMSO/TCM), on fiber morphology and diameter were systematically examined. Reducing PAN solution concentration and increasing applied voltage effectively decreased fiber diameter, enhancing filtration efficiency. Filtration performance tests revealed that CTA nanofibers outperformed PAN submicron fibers, exhibiting higher quality factors (0.043–0.046 Pa−1) due to their smaller fiber diameters and increased fiber packing density. Decreasing CTA solution supply rate and increasing DMSO/TCM ratio reduced fiber diameter and increased packing density. Longer spinning collection times improved filtration efficiency but increased thickness and pressure drop. The optimization of electrospinning parameters proved crucial for controlling fiber diameter and achieving enhanced filtration efficiency, particularly at the most penetrating particle size (MPPS), which usually covers the ultrafine particle size range. This study provides valuable insights into the development of high-performance air filtration media through the optimization of electrospinning parameters and the utilization of recycled materials.

Highly Flexible and Foldable Paper-Based Thermoelectric Generator Prepared with Post-Treatment-Free PEDOT:PSS Hybrid Ink

Paper-based thermoelectric (PTE) generators have recently emerged as a green technology that can help alleviate environment pollution and the energy crisis. In this work, a PTE generator was prepared by coating a post-treatment-free thermoelectric ink consisting of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) doped with 1-ethyl-3-methylimidazolium:tricyanomethanide (EMIM:TCM) onto the card paper. By tuning the molar concentration of the EMIM:TCM to 0.17 M and with hot-pressing, the PTE generator showed a decent power factor (PF) value of 6.82 μW m−1 K−2, which was higher than the values of PTE in the literature. This phenomenon could be attributed to the synergistic effect of high-performance thermoelectric ink (i.e., PF = 175 μW m−1 K−2 when deposited on glass slide) and the hot-pressing. The hot-pressing enhanced the packing density of cellulose fibers and the associated PEDOT:PSS hybrid, which enabled the formation of long-range conductive paths. In addition, the PTE had good mechanical stability, indicated by no significant change of the power factor values after cyclic folding 10,000 times. Moreover, the structure of as-prepared PTE could be easily tuned into different shapes that are promising for the preparation of flexible wearable thermoelectric generators.

Optical transparency of electrospun nanofibrous membranes: A study on influencing parameters

AbstractThis paper studies the effects of five parameters, including fiber diameter, crystallinity, thickness, packing density, and surface roughness, on the transparency of electrospun polymethyl methacrylate/polydimethylsiloxane (PMMA/PDMS) nanofibrous membranes after heat treatment. The PMMA/PDMS membranes produced at an electrospinning voltage of 20 kV reaches 54.85% transparency with the diameter 0.759 μm, crystallinity 14.81%, thickness 9.2 μm, roughness 0.659 μm, and packing density α 0.0081% after the heat treatment from 80 to 200°C. In general, the PMMA/PDMS membranes present higher transparency with the decrease of diameter, crystallinity, thickness, roughness, and packing density. The influencing parameters on transparency are first quantified by multiple nonlinear regressions with a R2 of the model equals 0.869. A composite scaled sensitivity (CSSj) analysis shows that the most influential factor is the nanofibrous membrane thickness with a CSSj value of 1, followed by fiber diameter with a CSSj value of 0.515. The CSSj values for packing density, membrane roughness and crystallinity are 0.385, 0.361, and 0.173, respectively. Finally, the nanofibrous membrane transparency is a function of nanofiber material density, fiber diameter, and nanofibrous membrane thickness based on the Chandrasekhar radiative transfer equation and the Rayleigh's Scattering Theory.

BIO13: Effect of Artificial Lung Fiber Bundle Geometric Design on Micro- and Macro-scale Clot Formation

Purpose of Study: The hollow fiber membrane bundle is the functional component of artificial lungs, transferring oxygen and carbon dioxide to and from the blood. It is also the primary location of blood clot formation and propagation in these devices. The geometric design of fiber bundles is defined by a narrow range of parameters that determine gas exchange efficiency and blood flow resistance, such as fiber packing density, path length, and frontal area. However, these parameters also affect thrombosis. Methodology: This study investigated the effect of these parameters on clot formation using 3-D printed flow chambers that mimic the geometry and blood flow patterns of fiber bundles. Hollow fibers were represented by an array of vertical micro-rods (380 micron diameter) arranged with varying packing densities (40, 50, and 60%) and path lengths (2 and 4 cm), all of which are fiber bundle parameters in commercially available artificial lung devices. Blood was pumped through the device corresponding to three mean blood flow velocities (16, 20, and 25 cm/min), which were scaled from 4 L/min flowrates in an Adult Quadrox oxygenator. Results: Results showed that (1) clot formation decreases dramatically with decreasing packing density and increasing blood flow velocity, (2) clot formation at the outlet of fiber bundle enhances deposition upstream, and consequently (3) greater path length provides more clot-free fiber surface area for gas exchange than a shorter path length. Summary: These results can be used to create less thrombogenic, more efficient artificial lung designs.Figure 1. a) The experimental flow chamber was designed to be 2 or 4 cm and with a packing density of 60%, 50% or 40% rods to simulate the flow path of blood through an artificial lung hollow fiber bundle. (b) The flow circuit involved one-way flow from a syringe pump, connected to the flow chamber and then to a waste container. A manometer measured the pressure drop across each experimental device. (c) The averaged clot volumes from the microCT scans show more clot (red) at the outlets of all devices. There was also less clot in the chambers with a longer path length device, faster flow rate, and less density.

A practical design equation for accurate quantification of CRRT filter design factors and convection effects.

Considering the increasing clinical need for continuous renal replacement therapy (CRRT), further improvement in therapeutic efficacy has become an important focus for researchers. Here, we designed nine CRRT filters with various combinations of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) to evaluate the clearance of middle molecular uremic toxins (MMs) via simulation of an in vitro continuous veno-venous hemodialysis treatment model. We also used Doppler ultrasonography to measure the maximum internal filtration flow rate (QIF-Max) as an aid; this approach facilitated an exploration of the impacts of various design factors on convection effects, while revealing the mechanisms influencing MM removal performance. Furthermore, we constructed a multiple linear regression model of design factors and QIF-Max, then conducted experimental verification. Finally, we proposed an accurate and practical design equation to quantify the design factors influencing CRRT filters and convection effects: , where N/D2 and L/D affect QIF-Max by 15.0% and 85.0%, respectively. This design equation was able to effectively quantify the convection effects of CRRT filters with different design factors, thereby predicting MM removal performance; this convenient design equation can support the development of CRRT-related products.

Pressure Drop Dynamics during Filtration of Mixture Aerosol Containing Water, Oil, and Soot Particles on Nonwoven Filters.

The pressure drop dynamics during the filtration of three-component mixture aerosols are investigated and compared with two and single-component aerosols. The main area of interest is the effect of the addition of a small quantity of liquid (oil) and solid (soot) particles during the filtration of aerosol containing water mist. In addition, calculations of the change in filter mass during oil aerosol filtration have been carried out and compared with the experimental results. The new, improved filtration efficiency model takes into account a better coefficient fitting in the filtration mechanism equations. The limitations in the change in fibre diameter and packing density resulting from the filter loading have been implemented in the model. Additionally, the calculation model employs the fibre size distribution representation via multiple average fibre diameters. The changes in fibre diameter are dependent on each fibre's calculated filtration efficiency. The improved filtration model has been utilised to predict the mass change of the filters during the filtration of pure and mixture aerosols. The pressure drop calculation model based on changes in filter mass has been formulated. The model is then utilised to calculate pressure drop changes resulting from the filtration of the oil aerosol and water and oil mixture aerosol.

Modeling pressure drop values across ultra-thin nanofiber filters with various ranges of filtration parameters under an aerodynamic slip effect

Computational fluid dynamics simulations of fibrous filters with 56 combinations of different fiber sizes, packing densities, face velocities, and thicknesses were conducted for developing models that predict pressure drops across nanofiber filters. The accuracy of the simulation method was confirmed by comparing the numerical pressure drops to the experimental data obtained for polyacrylonitrile electrospun nanofiber filters. In the simulations, an aerodynamic slip effect around the surface of the small nanofibers was considered. The results showed that, unlike in the case of conventional filtration theory, pressure drops across the thin layers of electrospun nanofiber filters are not proportional to the thickness. This might be a critical factor for obtaining precise pressure drops across the electrospun nanofiber filters with extremely thin layers. Finally, we derived the product of drag coefficient and Reynolds number as a function of packing density, Knudsen number, and ratio of thickness to fiber diameter to get the correlation equation for pressure drop prediction. The obtained equation predicted the pressure drops across the nanofiber filters with the maximum relative difference of less than 15%.

Effect of Yarn Physical Properties on Fiber Migration and Packing Density of Cotton/Acrylic Blended Yarns

In the scope of the study, the effect of fiber blending ratio, yarn count and twist coefficient on fiber migration, packing density and diameter of the cotton/acrylic blended yarns were investigated. The yarn samples with 75-25%, %50-50%, 40-60% cotton-acrylic blending ratios were produced with three different yarn numbers; 20/1 Ne, 24/1 Ne, 30/1 Ne and three twist coefficients; 3.5 α, 4 α, 4.5 α. Thus, totally 27 yarn samples were obtained. The yarn cross-sectional samples were sliced with microtome. The image frames of yarn cross-sections were acquired via digital microscope. The yarn packing density was calculated by using image processing algorithm and the fiber migration was determined via cross-section images. The results were evaluated statistically.

Effects of hollow fiber packing density and housing shape on the albumin filtration performance of CRRT filters

Continuous renal replacement therapy (CRRT) has become the most commonly used acute blood purification therapy for critically ill patients. As a key point of extracorporeal blood circulation, the CRRT filter plays a decisive role in therapeutic efficacy. However, few in vitro studies have been conducted on CRRT filters, particularly concerning the effects of design factors on filter effectiveness and safety profile; no comprehensive evaluation system has been established. Here, we designed nine CRRT filters with various combinations of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) and introduced a high-frequency sampling pressure monitor to accurately monitor small changes in transmembrane pressure (TMP) and ultrafiltration rate (UFR) over time. We also used concentration polarization mass transfer resistance (Rc), change in sieving coefficient (S) of albumin over time, and amount of albumin removed (Mfld) to investigate the effects of two design factors on albumin filtration performance and analyze the mechanism of protein filtration performance over time, thereby establishing a comprehensive in vitro evaluation system to explore the safety profile of CRRT filters. Our results showed that the nine CRRT filters designed with different combinations of PD (50%, 55%, and 60%) and L/D ratio (2.9, 5.3, and 9.3) were able to maintain stability in terms of hemodynamics and water permeability; the lowest Mfld was PD = 60% and L/D ratio = 9.3, which indicates that design factor optimization can effectively control albumin filtration, thereby improving the safety profile of CRRT filters.

Numerical investigation of fiber orientations and homogeneity in powder bed fusion of fiber/polymer composites

ABSTRACT The packing characteristics of fiber/polymer powder in powder bed fusion additive manufacturing exhibit a high correlation with the mechanical behaviours of printed composite parts such as homogeneity and anisotropy. A discrete element model has been developed to investigate the packing characteristics of glass fiber/polyamide 12 (PA12) powder, which include fiber orientations, fiber homogeneity, and packing density. The predicted probability distributions of fiber orientations in the powder bed are comparable with those measured in glass fiber–reinforced PA12 composites printed via multi jet fusion. Three types of fibers with different length distributions are adopted to study the effects of the fiber length distribution on their packing characteristics. The simulation results reveal that a large average fiber length is beneficial to fiber alignment in the powder spreading direction but lowers the fiber homogeneity and packing density of the powder bed. Furthermore, varying the fiber length can provide an effective way to regulate fiber orientations in the powder packing process, which would help achieve satisfactory anisotropic mechanical properties for composite parts.

A new expression for inertial particle collection efficiency by nanofibers with slip effect

The inertial particle filtration process of nanofibers in slip/transitional flow regime is studied by numerical methods. Effects of fiber Knudson number (Knf), fiber packing density (C), interception parameter (R), and particle Stokes number (St) on particle filtration performance are investigated. Results indicate that particle trajectories for slip flow are much closer to the fiber surface when compared to those with non-slip flow condition, which leads to a higher particle collection efficiency under slip flow condition than the case of no-slip flow. Particle collection efficiency improves as slip effect increases, especially for small and weak inertial particles, whereas, it is weakly related to slip effect for particles with large size and high-inertia. Particle deposition distribution on fiber surface is found to be negligibly influenced by slip effect. Based on the simulation results, a reliable prediction expression for particle collection efficiency of nanofibers due to the combination effects of inertial impaction and interception is developed in the range of 0.05 ≤ Knf ≤ 2, 0.01 ≤ C ≤ 0.1, 0.01 ≤ R ≤ 0.5, 0.1 ≤ St ≤ 10.

Clogging performance of micro/nanofibrous laminated composite air filter media

The performance of fibrous filter media relies on factors such as particle capture efficiency, pressure drop and clogging time. Fiber diameter, porosity and packing density are important web-based factors to improve final filtration performance. In this study, composite nonwoven webs were produced using spunbonded, meltblown and electroblown mats to obtain filter media with different fiber diameter, porosity and packing density. Such a layered composite approach caused huge differences in porosity and packing density, which resulted with improved clogging performance. The average fiber diameter was found to be 65 ± 19.4 nm for electroblown layer ( N), while that was 1.17 ± 0.38 μm for meltblown (M) and 17.64 ± 2.65 μm for spunbond (S) layers. NM (nanofiber+meltblown) configuration provided 12–13% lower mean flow pore size, which resulted in faster clogging compared to NS (nanofiber + spunbond) mats. The thicker nanofibrous layer resulted in lower pore size and quality factor. Additionally, the composite samples showed a faster-rising pressure drop than the thick microfibrous mats due to smaller pores that clogged quickly. It was also shown that nanofiber coating causes a linear increase in pressure drop with dust loading, while microfibrous samples exhibited smooth plateau and linear increase after clogging point. Nanofiber layer facilitates cake formation which causes more difficult airflow, and lower dust holding capacity. Among the layered composite mats, the NM configurations were found to be more advantageous due to higher initial filtration efficiency and almost similar dust loading performance.

Effect of hollow fiber packing density and housing shape on the solute removal performance of CRRT filters for acute blood purification

Continuous renal replacement therapy (CRRT) has a good therapeutic effect in a variety of diseases, such as acute kidney injury. CRRT filters should feature small membrane surface area, excellent water permeability and solute removal performance for long-term use. Solute removal performance depends on the physicochemical structure of the dialysis membrane as well as on the housing design. On the basis of the same hollow fiber membrane, optimizing the housing design can maximize the performance of the dialysis membrane. In this article, we experimentally demonstrated the influence of hollow fiber packing density (PD) and housing shape (effective hollow fiber length (L) and inner housing diameter (D) ratio (L/D ratio)) on the performance of CRRT filters. In each continuous hemodialysis mode and post-diluted continuous hemodiafiltration mode, we tested nine CRRT filters with the same high-flux membrane but with different PDs (50%, 55%, and 60%) and L/D ratios (2.9, 5.3, and 9.3), and we evaluated the effect of different combinations of the two design factors on solute clearance. Our results showed that unlike with the clearance of small molecular weight solutes, the clearance of medium molecular weight solute was obviously affected by PD and L/D ratio, and the design providing the best removal of medium molecular solutes among the nine experiments was PD = 60% and L/D ratio = 9.3. This article will help address the lack of research on CRRT filter housing design as well as lead to the development of higher performance filters for acute blood purification.

Prediction and analysis of properties of ramie fiber staple yarn reinforced unsaturated polyester composite based on fiber packing density

The limitation of plant fiber length can be overcome by using staple spinning to achieve continuity on short fibers. Ramie fiber staple yarn reinforced unsaturated polyester composites (RSYCs) were fabricated with ramie fiber and unsaturated polyester matrix. The unique fiber packing density of staple yarn must be tackled first to reflect the structure of RSYCs. The relationship between fiber packing density of staple yarn and fiber volume fraction of composite was evaluated to investigate the effect of fiber packing density on properties and predict the tensile strength of RSYCs using the rule of mixture. A scanning electron microscope illustrated fiber packing density of staple yarn. When the twist factor was 380 with the optimal yarn count of 80 tex, the fiber packing density was 19.9% higher than that at 260. Compared with the minimum tensile strength of RSYCs at 120 tex, the maximum of RSYCs at 380 was 399.2 MPa, improved by 238.6%. Measured by dynamic mechanical analysis, the viscoelastic rigidity and damping property of RSYCs was the best at 380, with the storage modulus of 31.9 GPa at 40 °C and the tan delta of 0.1226 at 80.59 °C. Compared with the neat resin and ramie fiber, the onset temperature of weight loss of RSYCs tested by thermogravimetric was reduced. The increasing fiber packing density significantly reduced the resin permeability of RSYCs, according to the contact angle and ultrasonic nondestructive testing results. There is no doubt that the obtained fiber packing density possessed great potential for promoting the development of RSYCs.

Optimization of pressure and time of composite products molding at the temperature of minimum binder viscosity

The technological process of composite products’ molding consists in giving them non-a reversible shape using shape-generating molding tools through polymerization of the binder at a certain temperature and pressure varying in time. The paper deals with the research of technological parameters of the most common practical method of molding products made of polymeric composite materials, pre-formed of prepregs. The mathematical model of filling with a binder of inter-fiber space of the reinforcing material for the polymeric composite material with the varying fiber packing densities, from quadratic to hexagonal one, depending on the type of reinforcing material, has been further developed. A new method for optimization of the pressure and time of composite products’ molding at the temperature of the minimum binder viscosity has been developed. The method is implemented by analytical dependencies, which establish the optimal time intervals and pressure of molding on the section of the temperature and time diagram, associated with the ability of the operating equipment (oven, autoclave) to provide the maximum possible rate of temperature rise in order to “soften” the binder in prepreg to its minimum viscosity. It is shown that energy consumption for the re-formation of the tetragonal structure of the polymeric composite material into hexagonal one is ten times higher than the costs for the tetragonal structure formation. For example, re-formation of the tetragonal structure at volume content of the binder of 0.4 into dense hexagonal structure requires 66.7 times increase in pressure. Obtained results allow establishing the economically feasible level of pressure and time of composite products’ molding while ensuring their specified quality.

Development of high-performance filter from Agave americana fibre/polyacrylonitrile nanofibre membrane for Cd, Pb (II) and organic contaminants removal from aqueous solution

Constructing an easily recyclable and reusable filter is highly efficient for removing Cd, Pb2+ and organic contaminants from aqueous solution. This study investigates the optimization of Cd, Pb2+ adsorption process by thiol functionalized Agave americana fibre. Additionally, polyacrylonitrile (PAN) nanofibre membrane is used as a substrate to filter the organic contaminants. The properties of adsorbents are characterized by various techniques such as Attenuated Total Reflection- Fourier transforms infrared spectroscopy (ATR-FTIR), tensile tester and scanning electron microscopy (SEM). The filter’s performance has been investigated with three variables of thiol functionalized fibre packing density, length of the functionalized fibre and nanofibre spinning time. The fibre packing density and nanofibre spinning time are the most significant parameters that affect all responses. The impact of independent variables on responses has been critically analysed. The optimized filter is identified by regression analysis. The developed filter satisfies heavy metal ion adsorption (Cd, Pb2+) and organic contaminants.

Improved porosity of electrospun poly (Lactic-Co-Glycolic) scaffolds by sacrificial microparticles enhances cellular infiltration compared to sacrificial microfiber.

Electrospinning is a technique used to fabricate nano-/microfiber scaffolds for tissue engineering applications. However, a major limitation of electrospun scaffolds is the high packing density of fibers that leads to poor cellular infiltration. Thus, incorporation of a water soluble sacrificial porogen, polyethylene oxide (PEO), was utilized to fine-tune the porous fraction of the scaffolds and decrease fiber packing density. Poly(lactic-co-glycolic) acid (PLGA) scaffolds were either co-electrospun with sacrificial PEO microfibers or co-electrosprayed with sacrificial PEO microparticles at three different extrusion rates to control the relative morphology and dose of PEO. A dose-dependent response in PLGA scaffold bulk porosity and pore area was noted as PEO content was increased. Notably, PLGA scaffolds after removal of sacrificial PEO microparticles significantly increased the porous fraction and pore area approximately 8, 10, and 14% and 46, 20, and 33μm2, respectively, relative to the analogous PEO microfiber scaffold. The tensile properties of the more porous PLGA scaffolds after PEO microparticle removal, remained stable for all extrusion rates of PEO tested, relative to the PLGA scaffolds after PEO microfiber removal. Histological analysis revealed that removal of PEO microparticles significantly increased the depth of cellular migration through the PLGA scaffolds, relative to PEO microfiber scaffolds, with maximum migratory depths of 1120μm versus 150μm over 28 days, respectively. Additionally, depth of cellular infiltration responded dose-dependently in the PEO microparticle scaffolds, whereas in the PEO microfiber scaffolds there was no correlation. Further analysis with Masson's Trichrome staining and electron microscopy revealed that collagen density and depth of deposition substantially increased in PLGA scaffolds after removal of PEO microparticles relative to PEO microfibers. Thus, this study demonstrates an effective strategy to control the porous fraction of electrospun scaffolds via the incorporation of sacrificial PEO microparticles, without significant decreases in mechanical properties, thereby enhancing cellular infiltration and subsequent extracellular matrix deposition.