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Nanomaterials and supercritical fluids
No full textThe interest in the preparation and application of nanometer size materials is increasing since they can exhibit properties of great industrial
interest. Several techniques have been proposed to produce nanomaterials using supercritical fluids. These processes, taking advantage of the specific
properties of supercritical fluids, are generally flexible, more simplified and with a reduced enviromental impact. The result is that nanomaterials
with potentially better performances have been obtained.
We propose a critical review of the supercritical based techniques applied to the production of nanoparticles, nanofibers, nanowires, nanotubes,
nanofilms and nanostructured materials. The most relevant characteristics of each process and the kind of nanomaterial that can be produced are
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Light-emitting diode based shifted-excitation Raman difference spectroscopy (LED-SERDS)
No full textFluorescence interference is a common problem in Raman spectroscopy. A low-cost solution using shifted-excitation Raman difference spectroscopy (SERDS) with a light-emitting diode (LED) is presented. A conventional dielectric bandpass filter is employed to narrow the spectral bandwidth of the LED radiation and to stabilize its wavelength. Moreover, angle-tuning of the filter allows the wavelength to be controlled and shifted in order to record SERDS spectra. �� 2013 The Royal Society of Chemistry
Nanostructured polymer-iron oxide microparticles for drug delivery systems produced by supercritical assisted atomization
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Supercritical assisted atomization to produce nanostructured chitosan-hydroxyapatite microparticles for biomedical application
No full textSupercritical assisted atomization (SAA) has been applied to the production of coprecipitates formed by hydroxyapatite nanometric particles and chitosan, used as binding agent.Precipitation temperatures between 90. ��C and 110. ��C have been used and a chitosan concentration lower than 20. mg/mL has been required to avoid microparticle coalescence. Furthermore, to obtain a good compromise between particle size and hydroxyapatite loading, a gas to liquid ratio of 1.8 was adopted. The best operating conditions for particle diameter and coprecipitate stability were: precipitation temperature 110. ��C, chitosan concentration in the starting solution 10. mg/mL, that produced spherical composite microparticles with a mean diameter of 0.6. ��m and a loading efficiency of about 91%. The nanostructure and particle surface roughness has been modulated varying hydroxyapatite percentages in the starting suspension. The results obtained have been explained in terms of suspension stabilization and atomization efficiency. Possible biomedical applications for these powders are described. �� 2013 Elsevier B.V
Supercritical assisted atomization: Effect of operative conditions on PVP microparticle size and morphology
No full textSupercritical Assisted Atomization: effect of operative conditions on PVP particle size and morphology
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