The Experts below are selected from a list of 8421 Experts worldwide ranked by ideXlab platform
Gary L Bowlin - One of the best experts on this subject based on the ideXlab platform.
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ElectroSpinning jets and nanofibrous structures
Biomicrofluidics, 2011Co-Authors: Koyal Garg, Gary L BowlinAbstract:ElectroSpinning is a process that creates nanoFibers through an electrically charged jet of polymer solution or melt. This technique is applicable to virtually every soluble or fusible polymer and is capable of Spinning Fibers in a variety of shapes and sizes with a wide range of properties to be used in a broad range of biomedical and industrial applications. ElectroSpinning requires a very simple and economical setup but is an intricate process that depends on several molecular, processing, and technical parameters. This article reviews information on the three stages of the electroSpinning process (i.e., jet initiation, elongation, and solidification). Some of the unique properties of the electrospun structures have also been highlighted. This article also illustrates some recent innovations to modify the electroSpinning process. The use of electrospun scaffolds in the field of tissue engineering and regenerative medicine has also been described.
Koyal Garg - One of the best experts on this subject based on the ideXlab platform.
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ElectroSpinning jets and nanofibrous structures
Biomicrofluidics, 2011Co-Authors: Koyal Garg, Gary L BowlinAbstract:ElectroSpinning is a process that creates nanoFibers through an electrically charged jet of polymer solution or melt. This technique is applicable to virtually every soluble or fusible polymer and is capable of Spinning Fibers in a variety of shapes and sizes with a wide range of properties to be used in a broad range of biomedical and industrial applications. ElectroSpinning requires a very simple and economical setup but is an intricate process that depends on several molecular, processing, and technical parameters. This article reviews information on the three stages of the electroSpinning process (i.e., jet initiation, elongation, and solidification). Some of the unique properties of the electrospun structures have also been highlighted. This article also illustrates some recent innovations to modify the electroSpinning process. The use of electrospun scaffolds in the field of tissue engineering and regenerative medicine has also been described.
Randolph V Lewis - One of the best experts on this subject based on the ideXlab platform.
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modifications of spider silk sequences in an attempt to control the mechanical properties of the synthetic Fibers
Journal of Materials Science, 2007Co-Authors: Florence Teule, William A Furin, Alyssa R Cooper, Joshua R Duncan, Randolph V LewisAbstract:Bacteria were genetically engineered to produce two spider silk protein variants composed of basic repeat units combining a flagelliform elastic motif ([GPGGX]4) and a major ampullate silk strength motif ([linker/poly-alanine]. The secondary structures of the pure recombinant proteins in solution were determined by circular dichroism. The data presented suggest that the nature of the 5th and 10th amino acid (X) in the [GPGGX]2 elastic motif and temperature have an impact on the amount of β-sheet structures present in the proteins. More specifically, increasing temperatures seem to be positively correlated with β-sheet formation for both proteins and this state is irreversible or reversible when both X (5th and 10th) in the elastic motif are hydrophilic or hydrophobic respectively. Moreover, each pure silk-like protein was able to spontaneously self-assemble into films from aqueous solutions. Two kinds of synthetic Fibers were made by pulling Fibers from these preassembled films as well as Spinning Fibers from each protein resolubilized in HFIP. The mechanical data show that the pulled Fibers are far tougher than the spun Fibers suggesting a better fiber organization.
Jiurong Liu - One of the best experts on this subject based on the ideXlab platform.
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fabrication of silica supported zro2 mesoporous Fibers with high thermal stability by sol gel method through a controlled hydrolysis condensation process
Microporous and Mesoporous Materials, 2010Co-Authors: Luyi Zhu, Xinqiang Wang, Jiurong LiuAbstract:Abstract Silica-supported ZrO 2 mesoporous Fibers with high thermal stability and fine-tuning mesostructure were successfully fabricated by sol–gel method. Triblock co-polymer of Pluronic P-123 was used as the structure-directing agent. The self-induced acid environment of ZrOCl 2 ·8H 2 O in ethanol solution was utilized so as to avoid a rapid hydrolysis process and obtain viscous sol precursors for Spinning Fibers. Meanwhile, the different amounts of KAc were added to adjust such acid environment and control the hydrolysis–condensation process. Silica content of up to 50 mol% was incorporated into the mesoporous zirconia-based framework, providing materials with high surface areas, uniform pore sizes, and pore ordering. The micellization of Zr species dominate the self-assembly process, while the competitive hydrolysis–condensation process between Zr and Si species determined the final mesostructure properties. The obtained Fibers were characterized by XRD, FTIR, TG-DTA, UV–Vis diffuse reflectance spectra (UV–Vis DRS), N 2 adsorption, SEM and HRTEM measurements.
Young Moo Lee - One of the best experts on this subject based on the ideXlab platform.
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microporous pvdf membranes via thermally induced phase separation tips and stretching methods
Journal of Membrane Science, 2016Co-Authors: Jeong F Kim, Jun Tae Jung, Ho Hyun Wang, Suk Young Lee, Theodore Moore, Aldo Sanguineti, Enrico Drioli, Young Moo LeeAbstract:Abstract Microporous polyvinylidene difluoride (PVDF) hollow fiber membranes were fabricated via a thermally-induced phase separation (TIPS) method using an environmental-friendly hydrophobic solvent, acetyl tributyl citrate (ATBC, tradename Citroflex ® A4 ). To maximize membrane tensile strength, the TIPS method was fully utilized by Spinning Fibers with high polymer content. It was observed that the fiber quality was significantly affected by the dope and bore flow rates and compositions, and an appropriate Spinning range was established. The prepared membranes were subsequently stretched to tune the porosity, mean pore size, permeability, tensile strength, and fiber strain. A design of experiment (DOE) analysis was conducted using a 3-factor quadratic model to optimize the stretching conditions and to understand the effects of the parameters and interactions thereof. The permeability of the stretched membranes improved by a factor of 35 (15.1–538 L m −2 h −1 bar −1 ), and the tensile strength increased from 7.2 MPa to 8.4 MPa at the expense of the fiber strain. The DOE analysis revealed that the stretching ratio positively affects the permeability and porosity but decreases the fiber strain. On the other hand, it was determined that the stretching temperature positively influences the permeability and fiber strength. The stretched membranes exceeded the PVDF performance upper bound prepared by the TIPS method. The membranes were primarily in the α-phase polymorph, and stretching the Fibers up to 40% at 90 °C did not induce any detectable β-phase crystals. The proposed preparation method offers a feasible and sustainable alternative to fabricate hollow Fibers membranes with high tensile strength and high permeability.