Preparation of sols from water-alcohol solutions of tetraethyl orthosilicate and SnCl4 and the effect of sol composition on the surface morphology of sol-gel films

We describe a process for the preparation of sols from water-alcohol solutions of tetraethyl orthosilicate and SnCl₄. The kinetics of this process have been studied by measuring the electrical conductivity of the sols, and the optical absorption spectra of the sols have been measured. The surface morphology of films prepared from the sols has been examined by scanning electron microscopy. The results are used to assess the influence of preparation conditions, sol composition, and processes underlying sol formation on the surface morphology of the gas-sensing films prepared from the sols.