Photoinduced chemical vapor deposition was used to grow organic coatings on NaCl nanoparticles. Aerosolized nanoparticles were mixed with a vapor-phase coating reactant and introduced into a room-temperature, atmospheric-pressure cell, where the mixture was exposed to 172-nm radiation from a Xe 2*excimer lamp. Several coating reactants were investigated; the most successful was methyl methacrylate (MMA). Tandem differential mobility analysis (TDMA) was used to determine coating thicknesses as a function of initial particle size. For NaCl particles ranging from 20 to 60 nm in mobility diameter, the thicknesses ranged from sub-nm to 20 nm depending on MMA flow rate and initial particle size.
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Acknowledgment This work was supported in part by the Defense-University Research Initiative in NanoTechnology (DURINT) of the US Army Research Laboratory and the US Army Research Office under agreement number DAAD-190110503, in part by the Minnesota Supercomputing Institute, and in part by the National Science Foundation under Grant No. CHE–0094911. The authors thank J. Holm and H. Ajo for their assistance in FTIR measurements, and Y.-C. He for her assistance in TEM measurements.
- Chemical vapor deposition
- Tandem differential mobility analysis