Nanoscale porous coatings

Lee et al. s study also investigates the hydrophilicity of the heterocatalyst. They mention that the highly acidic surface of the material is more hydrophobic than the pure titanium oxide surface. They theorize that this is because the acidic surface results in fewer adsorbed OH ions and thus a weaker interaction with water. As expected, this increased hydrophobicity leads to an increase in the stability of dispersions of nanoscale powders of this material. Saltiel et al. showed that WOs-coated titanium oxide powders were much more stable than their uncoated counterparts. Even after agglomeration, the agglomerates of the coated powders were more porous than those of pure titanium oxide (the coated powders had a fractal dimension of 1.55 while the pure titanium oxide powders had a fractal dimension of 1.60). 

Ceramic coatings on fibers and powders have a variety of uses. For example, porous ceramic coatings on nanoscale metallic or ceramic particles can improve the catalytic properties of a powder. Also, the carbon fibers used as reinforcement in metallic matrices can be coated with a thin ceramic film (such as SiC or TiN) to reduce the rate of interdiffusion that may occur between the matrix materials and the fibers, and enhance the wetting of the fiber surface by metals. ... 

Bimbo LM, Sarparanta M, Santos HA, Airaksinen AJ, Makila E, Laaksonen T, Peltonen L, Lehto VP, Hirvonen J, Salonen J (2010) Biocompatibility of thermally hydrocarbontzed porous silicon nanoparticles and their Biodistribution in Rats. ACS Nano 4 3023 Bimbo LM, Makila E, Raula J, Laaksonen T, Laaksonen P, Strommer K, Kauppinen El, Salonen J, Linder MB, Hirvonen J, Santos HA (2011) Functional hydrophobin-coating of thermally hydrocarbonized porous silicon microparticles. Biomaterials 32 9089 Bimbo LM, Sarparanta M, Makila E, Laaksonen T, Laaksonen P, Salonen J, Linder MB, Hirvonen J, Airaksinen AJ, Santos HA (2012) Cellular interactions of surface modified nanoporous silicon particles. Nanoscale 4 3184... 

Gongalsky MB, Kharin AY, Osminkina LA, Timoshenko VY, Jeong J, Lee H, Chung BH (2012) Enhanced photoluminescence of porous silicon nanoparticles coated by bioresorbable polymers. Nanoscale Res Lett 7 446... 

Quite interestingly, the conductive conjugated polymers can be shaped at the nanoscale by anodic decttodeposition onto properly designed electrodes. For example, one side of porous membranes was coated by a metal (Au) to make them anodically polarizable. PPy nanotubules were then grown elec-trochemically into the pores and collected upon dissolution of the membrane (Figure 19). 

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