Xinhua Liang, Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Campus Box 424, Boulder, CO 80309-0424, David M. King, Department of Chemical Engineering, University of Colorado, 1111 Engineering Dr., Campus Box 424, Boulder, CO 80309, Steven M. George, Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, and Alan W. Weimer, Department of Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Boulder, CO 80309-0424.
This work describes the conformal coating of ultra-thin aluminum alkoxide (alucone) polymer films on primary silica and titania nanoparticles using molecular layer deposition (MLD) in a fluidized bed reactor from 100 °C to 160 °C. In situ mass spectroscopy revealed that the growth of alucone MLD films was self-limiting as a function of the individual trimethylaluminum (TMA) and ethylene glycol (EG) exposures. The composition and highly conformal alucone films throughout the surface of both silica and titania nanoparticles were confirmed. The highest growth rate was observed at the lowest sample temperature. Primary nanoparticles were coated individually despite their strong tendency to aggregate during fluidization. This work presents herein the first attempt at placing ultra-thin conformal polymer films on nanoparticles at large scale. MLD has the advantage of low deposition temperature, precision thickness control, excellent conformality, and high film growth rate.