The Optical Property And Assembly Of Titanic Acid And Titanate Sodium Nanotubes

Preparation and syntheses of one-dimensional nanostructured materials have been widely studied, because one-dimensional nanostructured materials are the base to get and develop nanodevice. Low dimensional nanostructured materials have special physical and chemical properties. In recent years, this aspect was highly strengthened. All kinds of one-dimensional nanotructured materials were gradually prepared and their physical and chemical properties were widely investigated.Nowadays, the study on nano-science and nano-technology is a hot-spot of studies of natural science in the world. The realization of nano-structural organ is the direction of study on nano-technique. For the realization of nano-structural organ, it is necessary to realize oriented assembly of nano-functional system on nano-scale. At present, there are some techniques by which could construct nano-patterns such as lithographical technique, self-assembly technique and Langmuir-Blodgett(LB) technique, etc. Using LB technique can realize controlled arrangement of molecules on nano-scale.Based on upper background, we had done some special work in this paper:1. We prepared titanic acid and titanate sodium nanotubes by the use of hydrogen-thermal method and studied the photoluminescence spectra. Under visible light excitation titanic acid and titanate sodium nanotubes showed a relatively intense emission, which red shifts with the increase of excitation wavelength. Under humid conditions this photoluminescence of titanic acid nanotubes was not stable. The intensity decreased, and the emission peak was at 480nm, which cannot shift with the change of excitation wavelength. This difference should be due to the adsorption of the water vapor at the surface of nanotube. Photoluminescence of titanate sodium nanotubes can be stable under humid conditions.2. Nanotube titanic acid was surface-modified by 1-hexadecanol, then its photoluminescence(PL) property was studied. The results showed that under visible light excitation, the surface-modified nanotube showed a relatively intense emission,which red shifts with the increase of excitation wavelength. Compared with PL of pure nanotube, the emission peak energy shift value was larger. This may result from the formation of oxygen vacancies in the nanotube during the process of surface-modification. The Ti-O-CH2(CH2)14CH3 at the surface of nanotube exhibited a good resistance to adsorption of water and the stable PL was obtained.We also studied the photoluminescence of titanic acid nanotubes under liquid nitrogen condition. Photoluminescence spectra showed titanic acid nanotubes had wide emission band under 360, 340, 320nm excitation at 77K. This band was different from emission band at room temperature. Photoluminescence character at 77K under visible light excitation was also different.3. The Titanate Sodium nanotubes Na2Ti2O4(OH)2 can be assembled through surface modification by n-Octadecyltrichlorosilane(OTS) because of the existence of Ti-OH on the surface of nanotubes. TEM image showed that nanorods form after the modification, which were 50~100nm in width and several microns in length. The rodlike nanostructures may be caused by the special packing of these OTS-coated nanotubes through hydrophobic interaction between the long fatty chains. Then the LB technique was attempted to assemble the nanorods.