Abstract: The porous TiO₂ anatase nanometer thin films were prepared from alkoxide solutions containing polyethylene glycol (PEG) by sol-gel method. The effects
of PEG addition to the precursor solution on the microstructure of the resultant thin films were studied. The larger amount and the larger molecular weight of PEG,
the larger size and more pores produce in the resultant films on the decomposition of PEG during heat-treatment. However, the transmittance of the films decreases
due to the light scattering by the larger size and more pores. The film thickness was measured by SEM and weight method, and the thickness of TiO₂ films prepared
by 1 cycle (from dipping to teat-treatment at 500℃1h ) was 0.08μm or so. The chemical composition and The adsorbed hydroxyl content of the films were analyzed
with X-ray photoelectron spectroscopy(XPS) and IR spectra. Experiment results show that in the film, besides Ti and O elements, there are a certain amount of residual carbon from
the starting organometallic components and a small amount of sodium and calcium ions diffused from the glass substrates. The adsorbed hydroxyl content of such
porous thin films increases due to the larger size and more pores in the films.

Key words: sol-gel method, porous titania nanometer thin films, preparation, microstructure