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Encapsulation of nanoparticles using CO2-expanded liquids

DSpace at IIT Bombay

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Title Encapsulation of nanoparticles using CO2-expanded liquids
 
Creator VINJAMUR, M
JAVED, M
MUKHOPADHYAY, M
 
Subject Encapsulation
Supersaturation ratios
Gas expanded liquids
Nanoparticles
FLUIDIZED-BED
RAPID EXPANSION
ANTI-SOLVENT
SUPERCRITICAL SOLUTIONS
CONTROLLED-RELEASE
SUBCRITICAL CO2
FINE PARTICLES
CARBON-DIOXIDE
BETA-CAROTENE
COPRECIPITATION
 
Description A new process for encapsulation based on the principle of precipitation of nanoparticles by pressure reduction of CO2 gas-expanded liquids (PPRGEL) is presented here. Encapsulation has been studied for two types of core solid nanoparticles, namely suspended and in situ produced particles from solution. Mechanisms for both types of encapsulations have been proposed: for the former type deposition happens because of mass transfer from the bulk solution; for the latter type encapsulation happens if the supersaturation profiles of the core and coating solutes are staggered in time in order that the core solute precipitates first and the coating solute deposits on it by mass transfer. A model for the process that includes nucleation and growth has been developed to select systems and process conditions that favor encapsulation. The mechanisms have been experimentally verified at 52 bar and 303 K for (i) encapsulation of suspended nanoparticles of silica with ascorbylpalmitate (AP) dissolved acetone and (ii) encapsulation of in situ produced tartaric acid (TA) nanoparticles with AP, both initially dissolved in acetone. A uniform coating of about 10-20 nm of AP is formed on the 250 nm silica particles. For the two-solute system it is observed that AP deposits on TA resulting in encapsulated particles of an average size of about 520 nm. (C) 2013 Elsevier B.V. All rights reserved.
 
Publisher ELSEVIER SCIENCE BV
 
Date 2014-10-14T12:55:16Z
2014-10-14T12:55:16Z
2013
 
Type Article
 
Identifier JOURNAL OF SUPERCRITICAL FLUIDS, 79216-226
http://dx.doi.org/10.1016/j.supflu.2013.03.004
http://dspace.library.iitb.ac.in/jspui/handle/100/14457
 
Language en