Synthesis and applications of functional materials via atomic layer deposition (ALD) or molecular layer deposition (MLD)
Fine particles have gained increased interest in a variety of fields for different applications. The performance of the particle applications could be improved when such particles are coated with ultra-thin inorganic or organic films, which can alter the surface characteristics without degrading the bulk properties of the substrate materials. These requirements exclude most thin film deposition techniques with the exception of atomic layer deposition (ALD). ALD methods are based on sequential, self-limiting surface reactions, and have been employed to grow films with precise atomic layer control. ALD has focused principally on the formation of dense thin film oxides, metals, or semiconductor alloys on solid substrates. Molecular layer deposition (MLD), which is similar to ALD, can be utilized to deposit polymer films. The MLD technique offers the same advantages for polymer film deposition as ALD does for ceramic films. In addition, MLD can deposit hybrid polymer films using suitable precursors, such as trimethylaluminum (TMA) and ethylene glycol (EG) for aluminum alkoxide (alucone) hybrid polymer. Examples of conformal ALD and MLD coatings are shown in Figures 1 and 2.
Figure 1 Cross-sectional TEM image of Al2O3 ALD coated porous polymer particles after 25 cycles (Published in Chemistry of Materials).
Figure 2. Scanning transmission electron microscopy (STEM) image of 50 cycles alucone MLD coated silica nanoparticles (Published in AIChE Journal).
First Author Publications:
- Xinhua Liang, David M. King, Peng Li, and Alan W. Weimer, Low-temperature atomic layer-deposited TiO
2 films with low photoactivity, Journal of the American Ceramic Society, in press, 2009
- Xinhua Liang, David M. King, Peng Li, Steven M. George, and Alan W. Weimer, Nanocoating hybrid polymer films on large quantities of cohesive nanoparticles by molecular layer deposition, AIChE Journal, in press (DOI: 10.1002/aic.11757), 2009
- Xinhua Liang, and Alan W. Weimer, Photoactivity passivation of TiO
2 nanoparticles using molecular layer deposited (MLD) polymer films, Journal of Nanoparticle Research, in press (DOI: 10.1007/s11051-009-9587-0), 2009
- Xinhua Liang, David M. King, Markus D. Groner, John H. Blackson, Joseph D. Harris, Steven M. George, and Alan W. Weimer, Barrier properties of polymer/alumina nanocomposite membranes fabricated by atomic layer deposition, Journal of Membrane Science, 322(1), 105-112, 2008
- Xinhua Liang, Guo-Dong Zhan, David M. King, Jarod A. McCormick, John Zhang, Steven M. George, and Alan W. Weimer, Alumina atomic layer deposition nanocoatings on primary diamond particles using a fluidized bed reactor, Diamond & Related Materials, 17(2), 185-189, 2008
- Xinhua Liang, Steven M. George, Alan W. Weimer, Nai-Hong Li, John H. Blackson, Joseph D. Harris, and Peng Li, Synthesis of a novel porous polymer/ceramic composite material by low-temperature atomic layer deposition, Chemistry of Materials, 19(22), 5388-5394, 2007
- Xinhua Liang, Luis F. Hakim, Guo-Dong Zhan, Jarod A. McCormick, Steven M. George, Alan W. Weimer, Joseph A. Spencer II, Karen J. Buechler, John Blackson, Charles J. Wood, and John R. Dorgan, Novel processing to produce polymer/ceramic nanocomposites by atomic layer deposition, Journal of the American Ceramic Society, 90(1), 57-63, 2007
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