Validation of TiO₂ particle-size distribution measured by scanning mobility particle sizer

In the latest Vision2020 roadmap (http://www.chemicalvision2020.org/ nanomaterialsroadmap.html), a key need identified across the nanomanufacturing industry is the capability of on-line real-time characterization of nanoparticles smaller than 50 nm. Electron microscopy is the gold standard for quality-assuring designed nanomaterial. However, imaging of a large number of particles needed for statistics, 10 000 per batch for example, is a daunting task and would take a prohibitively long time to complete, eliminating the possibility for using microscopy for practical process monitoring and control. A demonstration project was executed at Oak Ridge National Laboratory (ORNL) to evaluate the feasibility of using a commercial particle measurement system for on-line real-time characterization. Production of titanium nanoparticles in the vapor phase was chosen for the demonstration project. The results showed that the measurement system could be used as a continuous monitor for nanomanufacturing. However, it is noted that, after the completion of this project, a significant maintenance task was required to restore the commercial system to the operation-ready state, because of the corrosive nature of the sample stream. Thus, if the commercial measurement system is to be used on a continuous basis on an industrial process, the system will have to be reconstructed and possibly redesigned to be able to achieve long-term operation stability and reduce maintain cost.