We pre- sent results of an interesting system formed by core-shell fibers constituted by poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA), and its morphology and thermal characterization. In this study, we investigate how electrospinning parameters can affect coaxial fibers characteristics. Figure 1 shows a schematic representation of different fiber morphologies that can be obtained when coaxial eletrospinning is employed, for example, coaxial fibers made of a polymeric material shell and a non-electrospinnable material core (A) coaxial fibers made of two different electrospinnable materials (B) and tubular fibers prepared by removal of the inner material after coaxial electrospinning (C).Ĭoaxial electrospun fibers have been shown to be useful in gene delivery, drug delivery, bioactive molecules delivery and sensors, for example. The electrospinning technique has grown particularly due to the possibility of combining different materials in a single system, resulting in a large interest in potential application as membranes for filtration, scaffolds for tissue engineering and systems for encapsulation of active compounds. These solutions are, however, injected from two different coaxial capillary channels, resulting in a structure with two distinct environments. In order to obtain fibers with different core-shell compositions, two or more polymeric solutions may be used. Recently, advances in the electrospinning technique have allowed the production of different fibrillar structures, for example, fibrous tubes, core-shell nanofibers and membranes with different compositions. Possible to obtain fibers with different diameters and structures according to a specific application. Changing adequately the process parameters, it is The technique is based on the application of an electrical field in a polymer solution, and, nowadays, it is considered one of the most efficient techniques to fabricate high performance nanofibers mats, with distinct advantages like high surface area in relation to volume and porosity. These core-shell fibers presented improved hydrophilicity as compared with monolithic PLA fibers.Ĭore-Shell Fibers, Electrospinning, Poly(Lactic Acid), Poly(Vinyl Alcohol)Įlectrospinning is a simple method to produce mats of fibers with diameter which can reach the nanometer scale. Nevertheless, fibers with smaller average diameter could also be produced (200 nm). The increase in the PLA solution flow rate increases the diameter of the core-shell fiber which reaches up to 1.7 μm. The morphology of these fibers was dependent on the flow rate of both core and shell solutions, and homogeneous and smooth surface was only attained when the flow rate of the external PLA solution was 4 times the flow rate of the internal PVA solution. This type of structure was also confirmed by means of transmissions electron microscopy. FTIR-ATR and contact angle measurements also suggested imprisonment of the PVA core within the PLA shell. Scanning electron microscopy analyses of these structures showed that the PLA shell can present certain porosity depending on the process condition. Received 19 January 2015 accepted 10 February 2015 published 15 February 2015Ĭoaxial electrospinning process was used to produce biodegradable membranes made of core- shell fibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. This work is licensed under the Creative Commons Attribution International License (CC BY). Institute of Macromolecules, Federal University of Rio de Janeiro, Rio de Janeiro, BrazilĮmail: * © 2015 by authors and Scientific Research Publishing Inc.
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