Characterization of bamboo foam films by neutron and X-ray experiments

We report on small angle neutron and X-ray scattering experiments on single common black films in ordered bamboo foams stabilized by sodium dodecyl sulfate and dodecanol. We observed anisotropic scattering perpendicular to the film. The integrated signal exhibits clear Kiessig fringes over a wide range of diffusion vector q. We were able to fit our data by a single layer (neutron with contrast matching water/SDS) or a “three slabs” (X-ray) reflectivity. We also discuss about the wide range of reflected angle, despite the narrow distribution of incident angles. Though thermal surface fluctuations may induce off-specular reflectivity, we show here a simple geometrical explanation of the phenomenon. This angle distribution is indeed compatible with the curvature of the film.