Critical-point drying, high-resolution

Fig. 5.30 High resolution SEM images of a critical point dried and fractured FBI membrane reveal the fine structure quite clearly. The overview micrograph (A) shows the macrovoids (V) and the porous walls within the membrane. The robustness of the macrovoids suggests that the method is useful for observation of the in situ structure. The dense surface layer is composed of spherical particles (arrows) that are deformed into a dense monolayer while the support structure below is formed by a more open network of these spherical particles (B).

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