1,721,249 research outputs found
Electrospinning: A versatile processing technology for producing nanofibrous materials for biomedical and tissue-engineering applications
No full textElectrospinning technique has been extensively acknowledged as an efficient and convenient approach for producing functional nanofibrous biomaterials. The performance of the electrospun nanofibers and their nanofibrous membrane can be improved by modifying/combining with active molecules in different ways. The topography and orientation of the fibrous assembly are effectively controlled by modifying the electrospinning setup. Despite the promising characteristics of nanofibers, insufficient mechanical properties, hydrophobic nature, ineffective pore-structure controllability, shrinkage, and distortion are identified as some limitations. Yet, recent studies have been devoted/combined with other approaches to overcome these disadvantages. This chapter summarizes the recent strategies employed to develop advanced electrospun nanofibrous membranes for biomedical and tissue-engineering applications
Cyclodextrin-grafted electrospun cellulose acetate nanofibers via "Click" reaction for removal of phenanthrene
No full textWOS: 000336525400080Beta-cyclodextrin (p-CD) functionalized cellulose acetate (CA) nanofibers have been successfully prepared by combining electrospinning and "click" reaction. Initially, p-CD and electrospun CA nanofibers were modified so as to be azide-p-CD and propargyl-terminated CA nanofibers, respectively. Then, "click" reaction was performed between modified CD molecules and CA nanofibers to obtain permanent grafting of CDs onto nanofibers surface. It was observed from the SEM image that, while CA nanofibers have smooth surface, there were some irregularities and roughness at nanofibers morphology after the modification. Yet, the fibrous structure was still protected. ATR-FTIR and XPS revealed that, CD molecules were successfully grafted onto surface of CA nanofibers. The adsorption capacity of p-CD-functionalized CA (CA-CD) nanofibers was also determined by removing phenanthrene (polycyclic aromatic hydrocarbons, PAH) from its aqueous solution. Our results indicate that CA-CD nanofibers have potential to be used as molecular filters for the purpose of water purification and waste water treatment by integrating the high surface area of nanofibers with inclusion complexation property of CD molecules. (C) 2014 Elsevier B.V. All rights reserved.UBITAK-The Scientific and Technological Research Council of Turkey [110M612]; U FP7-PEOPLE-2009RG Marie Curie-IRG (NANOWEB) [PIRG06-GA-2009-256428]; Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP)Dr. T. Uyar acknowledges TUBITAK-The Scientific and Technological Research Council of Turkey (project #110M612) for funding the research. Dr. T. Uyar also acknowledges EU FP7-PEOPLE-2009RG Marie Curie-IRG (NANOWEB, PIRG06-GA-2009-256428) and The Turkish Academy of Sciences - Outstanding Young Scientists Award Program (TUBA-GEBIP) for partial funding. A. Celebioglu acknowledges TUBITAK-BIDEB for the national Ph.D. scholarship
Surface modification of electrospun cellulose acetate nanofibers via RAFT polymerization for DNA adsorption
No full textWe report on a facile and robust method by which surface of electrospun cellulose acetate (CA) nanofibers can be chemically modied with cationic polymer brushes for DNA adsorption. The surface of CA nanofibers was functionalized by growing poly[(ar-vinylbenzyl)trimethylammonium chloride)] [poly(VBTAC)] brushes through a multi-step chemical sequence that ensures retention of mechanically robust nanofibers. Initially, the surface of the CA nanofibers was modified with RAFT chain transfer agent. Poly(VBTAC) brushes were then prepared via RAFT-mediated polymerization from the nanofiber surface. DNA adsorption capacity of CA nanofibrous web surface functionalized with cationic poly(VBTAC) brushes was demonstrated. The reusability of these webs was investigated by measuring the adsorption capacity for target DNA in a cyclic manner. In brief, CA nanofibers surface-modified with cationic polymer brushes can be suitable as membrane materials for filtration, purification, and/or separation processes for DNA
Development Of Metal-organic Framework (MOF) Functionalized Electrospun Porous Polymer Nanofibers For Enhanced CO2 Capture
No full text105 pagesThe climate math is clear: carbon capture and storage (CCS) and carbon dioxide removal (CDR) must scale up to gigatons annually to mitigate climate change reach net-zero emissions and meet the Paris Agreement's goal of limiting the global temperature rise to 1.5 °C. Policy makers, business executives, investors, and the general public are beginning to see the importance of addressing climate change, and this is speeding up the implementation of CCS in many parts of the world. Numerous ongoing endeavors to capture CO2, a substantial greenhouse gas, depend on liquid chemical sorption employing strong alkaline bases or amines to reversibly bound CO2, where the sorbent is regenerated via heated desorption. In recent times, solid-state methods including silica aerogels, activated carbon, and amine sorbents attached to supports have become relevant. Both categories of CO2 collecting technologies have challenges related to selectivity, water rejection, energy consumption, transport limitations, and longevity. As part of the worldwide CCS and CDR endeavor, we aim to design long-lasting, efficient, and subsequently industrially developable carbon capture system for post-combustion capture (PCC) and atmospheric direct air capture (DAC) of CO2. This work explores novel modifications to foundational metal-organic frameworks (MOFs), particularly UiO-66, along with its applications to PCC and DAC. This work is also focused on development of a novel method to encapsulate these MOFs in composite nanofibrous membranes leading to superior CO2 capture capacities (over 1 mmol/g of sorbent) and simplistic reversibility. This would be achieved by tailoring the chemistry, hydrophobicity, porosity, and morphology of highly loaded amine-based metal organic framework/porous organic polymer composite nanofibers (such as UiO-66/PIM-1), using facile synthesis and gas-assisted electrospinning
LAYERED-BY-LAYERED POLYIMIDE COATED SEPARATOR VIA ELECTRPSPRAY AND ELECTROSPINNING METHODS FOR LITHIUM-ION BATTERIES
No full text49 pagesIn order to improve the safety of lithium-ion batteries, polyimide (PI) are introduced to be coated on polyethylene (PE) separator to enhance its thermal and mechanical properties simultaneously via electrospray as well as electrospinning methods. Layer- by-layered structure separators were prepared with a layer of E-spray coating firstly and E-spinning coating secondly. Specifically, spray coating is responsible for heat resistance due to its uniformity and high molten point. Meanwhile, fibers produced by electrospinning play an very important role in increasement of mechanical strength. All electrospray conditions were optimized in order to get the best quality of coating and the morphology of the coating surface prepared under different conditions were compared by scanning electron microscope (SEM). At the same time, heat shrinkage test and dynamic mechanical analysis (DMA) test were also conducted to see if PE separator’s thermal as well as properties achieved our goals. What’s more, Fourier- transform infrared spectroscopy (FT-IR) was also applied in my project to make sure there is no structural changes after plasma treatment that is beneficial to combination between spray and fiber coatings. Finally, electrochemical characterization of cells with prepared separators were conducted in order to prove the practicability of lithium-ion batteries.2026-09-0
Bio-Functionalization of Cotton Nonwovens by Electrospinning/ Electrospraying of Curcumin-Cyclodextrin Inclusion Complexes
No full textThe use of natural bioactive molecules, such as curcumin, has become increasingly popular in wound healing due to its antibacterial and antioxidant properties. However, the low solubility of curcumin has limited its applications. To overcome this issue, starch-derived cyclodextrin, such as hydroxypropyl-γ-cyclodextrin (CD), has been utilized to encapsulate curcumin and enhance its solubility. In this study, inclusion complexes of curcumin (Cur) and hydroxypropyl-γ-cyclodextrin (CD/Cur) were coated onto non-woven cotton fabrics to gain the fast-release property. The citric acid (CA) was used as a cross-linking reagent to form poly-CD, in which poly-CD/Cur structure can provide a slow release of curcumin. The optimized solutions (CD/Cur and poly-CD/Cur) can generate the nanofibers (NF) and nanobeads (NB), by using electrospinning and electrospraying methods, respectively, which were collected onto the nonwoven-cotton substrate. Time-dependent in vitro release test demonstrated that the CD/Cur has improved the solubility of curcumin in an aqueous environment and has fast release ability, while the cross-linked poly-CD/Cur exhibited slow-release characteristics, particularly in a weakly acidic environment. The NF structures showed higher release and maximum release percentages of curcumin compared to the NB structures. In vitro, antioxidant assays also demonstrated that both NF and NB samples exhibited excellent antioxidant activity, poly-CD/Cur and CD/Cur, illustrating slow and fast free radical scavenging effects, respectively. In summary, the poly-CD/Cur nanostructures with nonwoven-cotton substrates have excellent slow-controlled release ability, and CD/Cur nanostructures show excellent fast-release ability. All samples have the potential as a wound healing biomaterial due to the unique properties of curcumin, cyclodextrin, and their nanostructures
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