Surfaces of films (20 g/m
) made of microfibrillated cellulose. (A) MFC obtained by mechanical homogenisation. The image corresponds to the film shown in Figure 3C. (B) MFC obtained with TEMPO-mediated oxidation as pre-treatment and mechanical homogenisation. The image corresponds to the film shown in Figure 3F. The insets in (A) and (B) represent the surface structure visualised at 50,000× magnification from areas without a metallic coating. Both MFC materials have been collected after passing five times through the homogeniser, at 1,000 bar. For details, see Chinga-Carrasco et al. .