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A review on polymer nanofibers by electrospinning and their applications in nanocomposites

Electrospinning: a fascinating fiber fabrication technique.

Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon-black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.

Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers

Electrospinning: Applications in drug delivery and tissue engineering

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Preparation and properties of cellulose nanocrystals: Rods, spheres, and network

Three solvents, that is, acetone, acetic acid, and dimethylacetamide (DMAc), with a range of solubility parameter δ, surface tension γ, viscosity η and boiling temperature were used to generate mixtures for electrospinning cellulose acetate (CA) (degree of substitution, DS = 2.45). Although none of these solvents alone enables continuous formation of fibers, mixing DMAc with either acetone or acetic acid produced suitable solvent systems. The 2:1 acetone:DMAc mixture is the most versatile mixture because it allows CA in the 12.5–20% concentration range to be continuously electrospun into fibrous membranes. These CA solutions have η between 1.2 and 10.2 poise and γ around 26 dyne/cm and produce smooth fibers with diameters from 100 nm to ∼1 μm. Fiber sizes generally decrease with decreasing CA concentrations. The nature of the collectors affects the morphology as well as packing of fibers. Fibers collected on paper have more uniform sizes, smooth surfaces, and fewer defects, whereas fibers collected on water are more varied in size. Electrically conductive solid collectors, such as Al foil and water, favor more tightly packed and less porous membranes. Porous collectors, like paper and copper mesh, produce highly porous membranes. The pores in membranes collected on the Al foil and paper are much better interconnected in the planar directions than those in membranes collected on water. There is evidence that electrospinning induces order in the fibers. Deacetylation of CA membranes is more efficient and complete in NaOH/ethanol than in aqueous NaOH, producing DS values between 0.15 and 2.33 without altering fiber surfaces, packing, or organization. The fully regenerated cellulose membranes are similarly hydrophilic as commodity cellulose fibrous matrices but absorb nearly 10 times as much water. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2119–2129, 2002

Ultrafine fibrous cellulose membranes from electrospinning of cellulose acetate

Preparation and characterization of cellulose nanocrystals from rice straw

Chemically and mechanically isolated nanocellulose and their self-assembled structures.

Ultra-light (1.7 to 8.1 mg cm−3) and ultra-porous (99.5 to 99.9%) aerogels have been assembled from cellulose nanofibrils (CNFs) that were defibrillated from rice straw cellulose at 96.8% yield. The as-prepared aerogels, amphiphilic super-absorbents, absorbing 210 and 375 times water and chloroform, respectively, are far superior to any previously reported cellulose aerogel. Vapor deposition with triethoxyl(octyl) silane turned the amphiphilic aerogel more hydrophobic and oleophilic, capable of absorbing 139–356 times non-polar hydrocarbons, polar aprotic solvents and oils, surpassing all previously reported polymeric, cellulosic and carbonaceous aerogels by 2 to nearly 20 times. These aerogels are excellent amphiphilic super-absorbents for selective oil removal and recovery.

/pdf/amphiphilic-superabsorbent-cellulose-nanofibril-aerogels-2ck4f8g3t9.pdf

You-Lo Hsieh

Papers

Preparation and properties of cellulose nanocrystals: Rods, spheres, and network

Ultrafine fibrous cellulose membranes from electrospinning of cellulose acetate

Preparation and characterization of cellulose nanocrystals from rice straw

Chemically and mechanically isolated nanocellulose and their self-assembled structures.

Amphiphilic superabsorbent cellulose nanofibril aerogels