Critical Micelle Concentration and the Transition Point for Micellar Size Distribution

Figure 3 shows a HREM image of a silica ge112 specimen. The corresponding optical transform (inset Figure 3) indicates that the Scherzer defocus condition is well-satisfied, with spacings in the range 2.4-6.3 A appearing in the image. In this case there is no evidence for departures from randomness, either in the image or its optical transform, and it might be argued that this is consistent with a random network model for silica (see, for example, ref 13). However, our considerations in ref 4 imply that no structural information is available from such an image, since the film thickness is unknown. If it could be established that the film is <20-A thick, then the most that could be deduced is that, since the image was recorded at the Scherzer defocus condition, and since dynamical scattering effects are small (cf. ref 4), the brighter areas