Generating nanoscale aggregates from colloidal nanoparticles by various aerosol spray techniques

Abstract

Growing interest in the environmental and health effects of engineered nanostructured materials requires accurate control of cluster morphology and size in order to make valid interpretations of nanomaterial toxicity. Pressure-driven atomization/nebulization, ultrasonic generation, and electrospraying are common aerosol generation techniques that are currently used. Electrospray produced monodispersed isolated particles, when the original material was reasonably monodisperse, which may be most suited for use in experiments requiring single-size aerosol population. The technique however requires the use of a conductive solution that may not be suitable in biological experiments. Also, in the generation of single walled carbon nanohorns (SWNHs), we found that electrospray produced an anonymous peak that was not consistent with currently known SWNH nanostructures. This adds to an uncertainty about its utility in nanotoxicological experiments. Though producing controllable larger cluster sizes, ultrasonic generation might be a relatively straightforward process for reproducibly generating nanoparticle aggregates for nanotoxicological research. Note that the ultrasonic generation is not to be confused with sonication that is commonly used to homogenize a colloidal suspension. The aerosol population produced by a pressure-driven atomizer was very broad, suitable for experiments requiring a simple, easy means to deliver/disperse colloidal suspensions where size distribution is not a major concern. Advantages and disadvantages of each method are presented in relation to future toxicology experiments.

• Latex particles
• ultrasonic
• electrospray
• aggregate morphology

Acknowledgements

Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC for the U. S. Department of Energy under Contract No. DE-AC05–00OR22725. A portion of this research was conducted at the Center for Nanophase Materials Sciences as part of a CNMS user project, which is sponsored at Oak Ridge National Laboratory by the Division of Scientific User Facilities, U.S. Department of Energy.