Enhancement of Surfactants in Nanoparticles Produced by an Electrospray Aerosol Generator |
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| Authors: | Amanda C. MacMillan John B. Morrison Christopher W. Harmon Sergey A. Nizkorodov |
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| Affiliation: | 1. Department of Chemistry , University of California , Irvine , California , USA;2. Department of Chemistry , University of California , Irvine , California , USA;3. Department of Chemistry , Humboldt State University , Arcata , California , USA |
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| Abstract: | Electrospray aerosol generators (EAGs) disperse conducting solutions into air, promptly neutralize the particles to remove the excess charge, and evaporate the residual solvent with a dry air flow. For solutions containing multiple solutes, the particles may become enhanced in the more surface-active solutes. The extent of the enhancement was estimated for nanoparticles electrosprayed from a solution containing NaCl and surfactant sodium dodecyl sulfate (SDS) mixed in a 9:1 weight ratio. A tandem particle mobility analyzer was used to quantify the hygroscopic growth factor (GF). The relative fractions of NaCl and SDS in the particles were estimated from the measured GFs assuming that NaCl and SDS take up water independently of each other. The nanoparticles were considerably enhanced in SDS relative to the starting solution, with the NaCl:SDS weight ratio increasing with the distance from the EAG electrified capillary tip to the neutralizer, and reaching ～1:1 at the longest distances probed. The enhancement in SDS likely occurred during particle fission events as particles traveled from the capillary to the neutralizer. This study has practical ramifications for aerosol nanotechnology and aerosol-assisted drug delivery, which rely on EAG as an instrument of choice for nanoparticle generation. Copyright 2012 American Association for Aerosol Research |
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