New Dimensions in the Sol–Gel Process

Particularly thin oxide layers of 4.3 nm—previously the layer thickness was at least 50 nm—were obtained with a new procedure of the solution sol–gel process (SSG). Here, the metal alkoxide is spread as a film on an aqueous phase and can thus be hydrolyzed on both sides of the film (shown on the right). These thin films can also be readily transferred onto other substrates. Furthermore, the SSG process has enabled the preparation of tubes with outer diameters of 0.05–1.00 μm for the first time.