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We have discovered that the long-term aging of the hexagonal columnar liquid-crystal phase of polydisperse gibbsite platelets leads to fractionated crystallization, that is, to the formation of coexisting columnar crystals with different periods. This process was revealed by microradian X-ray diffraction demonstrating the splitting of the Bragg intercolumnar reflections into sequences of sharper reflections. The fractionated crystallization was observed in a number of samples of sterically stabilized as well as charge-stabilized polydisperse gibbsite platelets. [ABSTRACT FROM AUTHOR]

In this paper we describe the use of columnar liquid crystals of silica coated colloidal gibbsite platelets as templates for the generation of ordered silica structures. The colloidal liquid crystal phases can be formed in a few hours by modest centrifugation forces (100–200g). Base catalysed hydrolysis of tetraethoxysilane (TEOS) is used to deposit silica in the space between the silica coated gibbsite particles. The size of the gibbsite platelets is varied between 200 and 500 nm and the thickness of the silica coating between 5 and 15 nm making the system a very versatile templating material. Acid leaching is used to selectively remove the gibbsite material. [ABSTRACT FROM AUTHOR]