The shape dependence of core-shell and hollow titania nanoparticles on coating thickness during layer-by-layer and sol-gel synthesis

Titania core - shell and hollow nanoparticles with different aspect ratios were synthesized using layer-by-layer assembly and sol - gel nanocoating methods with cellulose nanowhiskers as the template. During growth of the coating layer, the shape of the nanoparticles did not maintain the shape of the high aspect ratio template, as previously assumed. The shape of the coated particles is a function of the coating thickness. It is suggested that the overall particle shape and aspect ratio of the nanoparticles are tunable by choosing an appropriate template and coating thickness in layer-by-layer or sol - gel templating synthesis. The nanorods and hollow titania particles synthesized by these methods were characterized by transmission electron microscopy, scanning electron microscopy and x-ray diffraction.