Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio

São Carlos, Brazil

Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio

São Carlos, Brazil
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Picciani P.H.S.,Federal University of Rio de Janeiro | Medeiros E.S.,Federal University of Paraiba | Pan Z.,U.S. Department of Agriculture | Pan Z.,University of California at Davis | And 4 more authors.
Macromolecular Materials and Engineering | Year: 2010

Conducting electrospun fiber mats based on PLA and PAni blends were obtained with average diameter values between 87 and 1 006nm with PAni quantities from 0 to 5.6 wt.-%. Structural characteristics of fiber mats were compared to cast films with the same amount of PAni and studied by SEM, SAXS, and AFM. Thermal properties of fiber mats and cast films were compared by DSC analyses. Mechanical properties of fiber mats were also evaluated. It was found that electrospinning process governs the crystal structure of the fibers and strongly affects fiber properties. New properties of PLA/PAni blends are reported due to the size fiber reduction. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Costa R.G.F.,Federal University of São Carlos | Ribeiro C.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio | Mattoso L.H.C.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio
Journal of Applied Polymer Science | Year: 2013

Mixed rutile-anatase TiO2 nanoparticles were synthesized by hydrothermal treatment under acidic conditions and incorporated into poly(vinyl alcohol) (PVA). These nanocomposites were electrospun to produce nanofibers of PVA/TiO2, which were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The photocatalytic degradation of Rhodamine B and degradation of the polymer by UV-C lamps were also investigated. The results showed that TiO2 nanoparticles did not change the morphology and thermal behavior of the nanofiber polymer, but were effective in modifying the UV absorption of PVA without reducing its stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Copyright © 2012 Wiley Periodicals, Inc.


Costa R.G.F.,Federal University of São Carlos | Costa R.G.F.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio | Ribeiro C.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio | Mattoso L.H.C.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio
Science of Advanced Materials | Year: 2010

Poly(vinyl alcohol) (PVA)/silver (Ag) nanocomposite fibers were prepared by electrospinning in a onepot process. The fibers were characterized by SEM, EDS, XRD and UV-Vis diffuse reflectance spectroscopy. The antibacterial activities of the nanofibers were investigated. The SEM images showed that the diameter of electrospun fibers with 10 wt% PVA attained average values around 90 nm. The X-ray diffraction patterns, the EDS spectrum and the UV-Vis diffuse reflectance spectra confirmed the presence of the silver nanoparticles on the fibers. These nanofibers showed good values of antibacterial activities against Staphylococcus aureus (87.8%) and Escherichia coli (85.0%). © 2010 American Scientific Publishers.


Picciani P.H.S.,Federal University of Rio de Janeiro | Medeiros E.S.,Federal University of Paraiba | Venancio E.C.,Federal University of ABC | Soares B.G.,Federal University of Rio de Janeiro | Mattoso L.H.C.,Laboratorio Nacional Of Nanotecnologia Aplicada Ao Agronegocio
Sensor Letters | Year: 2016

Electrospinning is easy and relatively inexpensive method for producing ultra thin fibers that has been successfully employed to spin a wide range of polymers. One of the great advantages of the electrospinning process is the ability to produce ultrathin fibers whose applications range from biomedical materials to sensors and actuators. In this work, conductive electrospun fibers of polyaniline (PAni)/poly(lactic acid) (PLA) blends were produced in various diameters and compositions. Electroactive PAni/PLA fiber mats were deposited onto interdigitated microelectrodes (IME) and their electrical response to relative humidity (RH) in atmosphere and different KCl concentration in water (5, 10, 15, 20, 50 mM) were studied by impedance measurements. Scanning electron microscopy results showed that PAni/PLA fibers, with diameter ranging from 100 nm to 1000 nm, were successfully deposited onto interdigitated microelectrodes by electrospinning. The obtained sensors showed high sensitivity in both gas and liquid media. Sensitivity also changed as a function of the amount polyaniline present in the blend. Finally, a PCA approach was employed to evaluate the ability of a specific set of sensors in distinguishing among RH values and successive ppm increments of KCl concentration in water. Copyright © 2016 American Scientific Publishers All rights reserved.

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