A METHOD OF PREPARING METAL OXIDE MICROTUBES

摘要

The present invention prescribes a new sol-gel method of preparing and formation of the metal oxide microtubes. According to the method firstly is prepared the precursor sol from metal oxides or mixtures of metal oxides and alkoxides, thereafter from the precursor sol are extruded the fibres, which are gelatinised afterwards until the inner sol which is less viscous of fibres is converted to thinner wall until alcohol from the precursor is left trough walls. The metal oxide microtubes are applicable as to conduct liquids or gasses, as ionic conductors, as catalyst carriers and as light emitters.

主权项

1. A method for preparing metal oxide microtubes from a precursor material, which is a mixture comprising metal alkoxides, metal-organic compounds or metal salts and a high boiling-point solvent, the method comprising the steps of
a) selecting the high boiling-point solvent material, concentration and amount of said material to achieve viscosity of the precursor material from 10-30000 P, b) directing the precursor material into jets in a humid environment, wherein the surface of the jets starts to solidify by a polycondensation process, which leads to the formation of a three-dimensional network of precursor particles forming a rigid solid shell on the surface of the jet, whereafter c) the thickening of the rigid solid shell continues by consuming solid content of the precursor material to form a thicker shell wall until a microtube is formed, which is filled by a liquid phase of released organic substances contained in the precursor material, thereafter d) aging the microtubes in a gaseous environment to remove the organic substances from the hollow core thereby densifying the wall material of the microtube.